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Brigham and Women's Hospital, Department of Orthopaedic Surgery, Harvard Medical School, 25 Patriot Place, Foxboro MA 02053, T: 617.732.4970, F: 617.264.5232
Brigham and Women's Hospital, Department of Orthopaedic Surgery, Harvard Medical School, 25 Patriot Place, Foxboro MA 02053, T: 617.732.4970, F: 617.264.5232
Hyaline articular cartilage is a unique, highly specialized tissue with a distinct architecture that lacks intrinsic means to heal effectively when injured in the adult. Symptomatic osteoarticular defects continue to be a formidable challenge for the clinical and the scientific communities alike. Of the various surgical treatment options that have been proposed to this end, only osteochondral grafting techniques reliably restore appropriate hyaline tissue in acquired articular cartilage lesions, especially when these involve the subchondral bone. Both autologous and allogeneic graft sources are available to the surgeon, who must consider the unique qualities and characteristics of either approach in the treatment algorithm. Autografts and allografts alike adhere to a common methodology, relying on osseous healing of mature osteochondral constructs to transplant the adherent viable articular cartilage. The required surgical technique is straightforward and reproducible but requires precision to restore articular surface congruity, achieve reliable bony ingrowth and, ultimately, clinical success. Scientific investigation to further validate empirical clinical practice and to improve implant quality and safety is ongoing and holds great promise for the future of osteochondral grafting in joint preservation.
The use of osteochondral grafts (OCG) of autologous (OAT) or allogeneic (OCA) origin is well supported on the basic science level and has a long successful clinical history as a means of biological resurfacing of (osteo-)chondral defects.
Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions].
While either application has unique advantages and challenges, both subscribe to a common paradigm of transplanting mature hyaline cartilage containing viable chondrocytes attached to the subchondral bone to restore the architecture and characteristics of native tissue in acquired osteoarticular defects. By transplanting structurally competent osteochondral units with an intact tidemark, the fixation issue is mostly relegated to that of osseous ingrowth.
One obvious disadvantage of autologous graft sources is that the maximum graft surface area is self-limited by donor volume, to small or at most medium sized lesions. This is especially true in the previously injured and or operated knee, where suitability regarding tissue quality and overall joint topography must be critically assessed. Also, donor site morbidity can significantly add to the disease burden during intra-articular transfer, or even introduce it if the transfer is inter-articular (eg knee to ankle)
Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions].
however, autologous grafting does hold advantages over other graft sources, such as fresh OCA. It is relatively cheap, immediately available, not antigenic, and osteogenic, leading to reliable osteointegration.
One advantage of osteochondral allografting is that even very large and multiple lesions can be addressed with a solid orthotopic graft that reproduces the anatomy of the native joint both macroscopically and microscopically, without the risk of inducing donor site morbidity. No other current cartilage repair procedure can match the versatility of osteochondral allograft when addressing complex lesions in topographically challenging environments, especially if they present with an osseous deficiency. Obvious drawbacks to the methodology are financial and logistical issues of graft procurement, and residual risk of infection, albeit small.
The surgical techniques for either graft source are straightforward but require precision to restore articular surface congruity while maximizing the potential for bone healing.
The mosaicplasty technique incorporates multiple, small autologous grafts, with fibrocartilage to fill in the space between osteochondral grafts, where is the osteochondral autologous transfer system utilizes bigger and fewer dowels.
Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions].
Osteochondral allografting employs orthotopic donor tissue to recreate topographically appropriate articular surface anatomy, using either dowels that are analogous to the OATS grafts, especially for containd small- to medium-sized condylar lesions that are accessible, while large, more complex lesions can be addressed with freehanded shell grafts.
The use of osteochondral grafts of either origin is well-established in the knee and is the subject of ongoing investigation with indications continuously expanding in other joints.
Graft Topography
Historically, the intercondylar notch and lateral trochlear were presumed to be non-load bearing and were the recommended donor sites for autologous osteochondral grafting. Recent reports have demonstrated that these areas do bear significant weight, which can theoretically contribute to increased donor site morbidity. In a cadaveric study utilizing stereophotogrammetry, Ahmad, et al
studied the contact pressures and surface curvature and osteochondral autografting. They reported that the lateral trochlea was the most involved in loading, followed by the intercondylar notch. The distal medial trochlea was the least involved in loading.
further analyzed the contact pressures in the patellofemoral joint. They concluded that the loading on the medial trochlea is less than on the lateral trochlea. They further suggested that because the lateral trochlea is wider than the medial side, the medial trochlea might best be suited for smaller donor plugs (<5mm). Larger plugs could be taken from the lateral trochlea, starting proximal to the sulcus terminalis (where the lowest contact pressures of the lateral trochlea were measured).
Utilizing customized software and fresh cadaveric femurs, Bartz, et al
also studied the topography of the femoral condyles. They found that grafts taken from the far medial and lateral margins of the femoral trochlea just proximal to the sulcus terminalis, provided the most accurate reconstruction of the surface anatomy of central lesions in the weightbearing portion of either femoral condyle. Smaller grafts (4 or 6mm) from the lateral intercondylar notch can also provide precise matches to similar lesions; however, significant inaccuracies are noted when the lateral intercondylar notch grafts are increased in size (8mm). In addition, they concluded that the concave central intercondylar notch donor best matched the topography of the central trochlea. Also, the curvatures of the medial and lateral trochlea better match the recipient sites at the femoral condyles.
on cadaveric pig knees looked at the effect of angled osteochondral grafting on contact pressures. They found that slightly countersunk grafts and angled grafts with the highest edge placed flush to neighboring cartilage demonstrated fairly normal contact pressures. On the other hand, elevated angled grafts increased contact pressures by as much as 40%, making them biomechanically disadvantageous. They concluded that it is more favorable to leave a graft slightly countersunk then elevated with respect to the neighboring cartilage.
While the ability to anatomically match OCA tissue to a respective recipient site in orthotopic fashion is considered a key advantage of the procedure, the statistical preponderance of cartilage disease of the medial femoral condyle (MFC)
means that, reciprocally, there is a relative surplus of lateral femoral condyle (LFC) allografts. To optimize utilization of OCA tissue, there has been a clinical move towards using OCA outside of their exact anatomic location among high volume OCA surgeons.
Several studies have investigated the feasibility of this practice in regards to obtaining a topographic match of non-orthotopic grafts despite known anatomic differences the shape, curvature, and size of MFC and LFC. Mologne et al reported that at a diameter of 20mm, contralateral LFC and MFC grafts produced equivalent surface matches in the weightbearing portion of the MFC.
Osteochondral Allograft Transplant to the Medial Femoral Condyle Using a Medial or Lateral Femoral Condyle Allograft: Is There a Difference in Graft Sources?.
Urita et al demonstrated that ipsilateral and contralateral LFC grafts provide similar articular cartilage surface, resulting in subchondral bone surface that matches that of MFC grafts, suggesting that LFCs could be a suitable OCA source for the treatment of MFC lesions.
Topographic Matching of Osteochondral Allograft Transplantation Using Lateral Femoral Condyle for the Treatment of Medial Femoral Condyle Lesions: A Computer-Simulated Model Study.
Based on these findings, and in an effort to make more OCA grafts available from limited donor condyles, tissue suppliers have moved to harvesting multiple smaller (<20mm diameter) “precut” fresh OCA plugs from a single donor condyle. Two diameter sizes (10 mm and 16 mm) of precut plugs are currently commercially available in the United States (Osteochondral Resurfacing System, JRF, Centennial, CO). Their smaller dimensions increase the number of grafts that may ultimately be harvested from a single donor condyle and make these available in a more “off the shelf” fashion, and likely decreasing the risk for orthotopic mismatching since their total cross-sectional surface area is small.
Chondrocytes are fragile cells, and mechanical or thermal insult during osteochondral graft harvest or implantation can lead to macroscopic injury and can induce chondrocyte necrosis and apoptosis. This particularly pertains to the cut graft margins during harvest, as well as the graft articular surface during implantation. This preferentially affects the superficial zone of articular cartilage, which is significant because chondrocytes in the zone of cartilage secrete the superficial zone protein lubricin, which contributes to the friction-lowering effect of synovial fluid.
On the other hand, superficial zone protein and synovial fluid is also likely to inhibit graft-to-host adhesion and ingrowth of opposing cartilage margins.
Marginal cell death, coupled with the inherent hypocellularity of articular cartilage, further helps to explain the lack of graft-host interface integration observed after implantation of osteochondral grafts over time.
This problem is obviously multiplied with a number of plugs used, as the portion of marginal cartilage and the overall surface increases. Given the fact that the interstitial bony bridges between mosaicplasty plugs heal over with fibrocartilage at best, this can have a significant impact on the overall quality of the repair tissue. Huntley et al
used confocal laser scanning microscopy to demonstrate a significant marginal zone of cell death and osteochondral dowels after harvest with use of the mosaicplasty technique and concluded that up to one third of a mosaicplasty surface is not compromised of viable hyaline cartilage. Evans, et al
demonstrated the advantages of using manual punches over power trephines during plug harvest, as the latter proved technically more difficult and resulted in more gross and light microscopic damage to the osteochondral grafts, with thermal necrosis being one possible cause.
The articular surface of osteochondral grafts is prone to impaction injury during implantation if excessive compressive force is used during seating of the dowels. Borazjani, et al
showed marked cell apoptosis was induced and the superficial layer of the transplanted osteochondral plugs and concluded that the amplitude, more than frequency, of peak forces during implantation was responsible for triggering apoptotic cascades that led to chondrocyte death, particularly in the superficial zone.
Preclinical studies have shown that fresh osteochondral allografts result in improved clinical outcomes over frozen or decellularized grafts, corroborating the importance of chondrocyte viability for successful outcomes. Tabbaa et al in their recent systematic review, included 55 peer-reviewed articles of ex-vivo (laboratory), animal and clinical studies. They found that although 60% of animal models suggest that storage time may influence outcomes and 80% indicate inferior outcomes with frozen OCA as compared with fresh OCA, 75% of clinical studies report no correlation between storage time and outcomes. Although those results might be challenged with longer follow up period, based on this review there remains limited evidence to support a threshold of viable chondrocytes and parameters of cartilage health needed for successful osteochondral repair.
Optimizing cartilage health and protecting chondrocyte viability are critical to long-term success of any cartilage restoration procedure. Care must be taken during harvest, storage, and implantation of osteochondral grafts to protect the integrity of the cartilage transplant and to maximize successful outcomes.
Osseous issues
The second integral component of any osteochondral graft is the osseous portion. Conceptually, this functions as the underlying support structure for the articular cartilage and serves as a vehicle for attachment and fixation of the graft to the host.
Osteochondral allograft tissue is generally considered immunologically privileged due the avascular intact chondral matrix functioning as a physiologic barrier to surveillance cells, thus not provoking clinically significant rejection in the host. In current practice, OCAs are thus not HLA or blood type matched between donor and recipient. Although patients immunologically tolerate allografts from a clinical perspective, they do elicit a variable cellular-mediated immune response.
Since allograft bone is known to be antigenic, it is likely that this phenomenon is conveyed by the bone and associated marrow elements, as with any type of allogenic bone graft,
Since it merely serves as an osteoconductive scaffold for healing to the host by creeping substitution, which is a rate limited process, this allogenic potential should be minimized along with the transplanted bone wherever possible, without compromising stability of the graft as warranted by the clinical situation.
Several authors have investigated the role of orthobiologics in improving OCA incorporation and avoiding clinical failure by mitigating these potentially deleterious effects at the graft/host interface. Chona et al subsequently performed a systematic review of the use of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) augmentation in the surgical treatment of cartilage defects.
They concluded that two of three studies on BMAC-augmented osteochondral allografts reported no difference in radiographic features postoperatively.
Oladeji et al reported that large femoral condylar OCAs treated with BMAC before implantation showed superior radiographic integration to bone and less sclerosis during the initial six-month postoperative period.
Effect of Autogenous Bone Marrow Aspirate Treatment on Magnetic Resonance Imaging Integration of Osteochondral Allografts in the Knee: A Matched Comparative Imaging Analysis.
Likewise, Wang et al did not find an association between OCA augmented with BMAC and improved osseous integration; decreased cystic changes; or other bone, cartilage, and ancillary feature changes at the graft-host junction compared with OCA alone in the early (∼6 months) and late (∼12 months) postoperative phases.
Bone Marrow Aspirate Concentrate Does Not Improve Osseous Integration of Osteochondral Allografts for the Treatment of Chondral Defects in the Knee at 6 and 12 Months: A Comparative Magnetic Resonance Imaging Analysis.
They concluded that multiple factors can influence the creeping substitution process, including patient age, smoking history, and BMAC harvest and preparation techniques.
Clearly, further research into the specific cells and growth factors within orthobiologic preparations and their potential impact on osseous integration of osteochondral allografts is warranted.
While sex mismatch between donor and recipient has been considered a potential contributor to adverse outcomes after solid organ transplantation, OCA tissue also had also not been routinely matched for sex between donor and recipient. Merkely et al recently evaluated the influence of donor-recipient sex on graft survival. After adjusting for adjusted for patient age, graft size, and body mass index, the concluded that mismatch between donor and recipient sex had a negative effect on OCA survival at five years after transplantation, particularly in those cases when male donor tissue was transplanted into a female recipient.
The osseous portion of autograft varies considerably from that of allografts, in that it is considered osteogenic and generally is incorporated rapidly and completely.
Postoperative hemarthrosis and, subsequently, arthrofibrosis due to bleeding from the donor site are concerns with autologous osteochondral grafting. Retrograde filling of the created defect using different artificial fillers has been investigated and proven helpful in preventing postoperative hemarthrosis and in creating a scaffold for the fibrocartilage repair process.
there is stability increasing with diameter. Since there are no immunological concerns, autologous plugs can be transplanted with more bone stock for press-fit stability if necessary.
whereas the osseous portion of an osteochondral allograft is usually limited to depth of a few millimeters and against press-fit stability through a wider base radius. However, depending on the clinical situation, the allograft may contain more copious amounts of bone, as required to restore injured or absent subchondral tissue.
The technique can be performed through standard arthrotomy, mini arthrotomy and/or arthroscopically. Nevertheless, the surgeon should always prepare for conversion to standard arthrotomy as certain locations, i.e., the posterior femoral condyle, may be difficult to access with less invasive approaches.
The lesion is accessed and measured after cartilage and subchondral bone have been debrided to healthy margins, at which point a determination on the osteochondral autografting technique to be implemented is made (OATS versus mosaicplasty). In current practice available plug sizes vary from 6 to 12 mm, depending on the technique utilized and the size of the chondral lesion, particularly in relative relationship to the size of the distal femur (Figure 1). The surgeon should consider the articular topography when deciding between OATS and mosaicplasty. In general, matching articular geometry becomes more difficult with larger donor plugs. In addition, the potential for donor site morbidity increases with larger dowels.
Figure 1Relative graft size. Relative appearance of equisized 15mm diameter cores on different size donor femoral hemicondyles.
Under direct visualization the appropriately sized tubular T-handled recipient harvester is tapped perpendicular to the defect to a minimal depth of 10 mm for standard cartilage lesions. The depth can be increased to as much as 25 mm for significant osteochondral conditions, ie, osteochondritis dissecans. The harvester chisel is then removed by rotating the driver 90 degrees clockwise, then 90 degrees counterclockwise.
Utilizing the same technique with a slightly larger T-handled harvester, the donor graft is taken from the far medial or lateral margin of the trochlea, just proximal to the sulcus terminalis. Alternatively, a smaller graft can be taken from the lateral intercondylar notch. After verifying the donor graft's depth measurement, it is then transplanted into the recipient site utilizing the donor tube harvester, which dilates the cartilage layer with its beveled edge creating a tight press-fit. The last 1 mm of impaction should be performed by lightly tapping an oversized bone tamp over the cartilaginous cap. If necessary, the osseous portion of the graft can be shortened to allow the cartilage to lie flush with the surrounding articular surface. If required, the process is repeated until the lesion is covered with healthy hyaline cartilage. A 1 to 2 mm bone bridge between the recipient sites is recommended to help achieve a tight press-fit. These bridges fill with fibrocartilage. In addition, the careful spacing of the plug is essential. To avoid premature amputation of the graft, the osseous portions should not intersect with one another. This can be most problematic with longer grafts (25mm) obtained in areas of the knee where there is high curvature, i.e., the posterior femoral condyle. Finally, to prevent recipient tunnel wall fracture, each plug transfer should be completed prior to proceeding with additional recipient sockets.
The surgeon may choose to retrofill the created defect to minimize donor site morbidity. Osteobiologic plugs that corresponds to the diameters of commercial coring devices are available for this purpose. Following the graft process, surface congruity is confirmed, and the joint is put through a range of motion to ensure graft stability and lack of impingement. The knee is closed in a standard fashion over a drain after irrigation of the joint and inspection for bony and soft tissue debris.
Osteochondral allografting technique–knee
The technique of fresh osteochondral allografting generally relies on an open procedure, including an arthrotomy of variable size (depending on the position and dimension of the lesion). Usually the patients have had previous surgery or are at least fully imaged; otherwise, a diagnostic arthroscopy can be performed prior to the allografting procedure to confirm adequacy of the available graft. It is the responsibility of the surgeon to inspect the graft and to confirm the adequacy of the size match and quality of the tissue prior to surgery.
The patient is positioned supine with a proximal thigh tourniquet, as above. A leg or foot holder can help to position and maintain the leg in between 70 and 100 degrees of flexion. For most femoral condyle lesions, eversion of the patella is not necessary.
A standard midline incision is made and elevated subcutaneously, depending on the location of the lesion (either medial or lateral), and the joint is entered by incising the fat pad without disrupting the anterior horn of the meniscus or damaging the articular surface. In some cases where the lesion is posterior or very large, the meniscus must be detached and reflected; generally, this can be done safely, leaving a small cuff of tissue adjacent to the anterior attachment of the meniscus. Once the joint capsule and synovium have been incised and retractors have been carefully placed, the knee is brought to a degree of flexion that presents the lesion into the arthrotomy site. The lesion then is inspected and palpated with a probe to determine the extent, margins, and maximum size.
The two commonly used techniques for the preparation and implantation of the osteochondral allografts include the press-fit plug technique and the shell graft technique. Each technique has advantages and disadvantages. The press-fit plug technique is similar, in principle, to autologous osteochondral transfer systems described above. This technique is optimal for contained condylar lesions between 15 and 35 mm in diameter. Fixation is generally not required, due to the stability achieved with a press-fit. Disadvantages include the fact that very posterior femoral and trochlear lesions are not conducive to the use of a circular coring system and may be more amicable to shell allografts. Additionally, the more ovoid a lesion in shape the more normal cartilage which needs to be sacrificed at the recipient site in order to accommodate the circular donor plug. Shell grafts are technically more difficult to perform and typically require fixation. However, depending on the technique employed last normal cartilage may need to be sacrificed.
Surgical techniques–dowel allograft
As with autologous dowels, there are several proprietary instrumentation systems that are currently available for the preparation and implantation of press-fit dowel allograft up to 35 mm in diameter, and surgical techniques are similar.
After a size determination is made, a guidewire is driven into the center of the lesion, perpendicular to the articular surface. The size of the graft is then determined utilizing sizing dowels, remembering that overlapping towels (in a "snowman" or "MasterCard" configuration can possibly deliver the best area fit (Figure 2). The remaining articular cartilage is scored to subchondral bone, and a core reamer is used to remove the articular cartilage remanence and at least 3 to 4 mm of subchondral bone. In deeper lesions fibrous and sclerotic bone is removed to a healthy, bleeding osseous base, not to exceed 10 mm in depth. Lesions below this depth should be curetted manually, and packed morselized autologous bone graft should be utilized to fill any deeper or more extensive osseous defects. Circumferential depth measurements of the prepared recipient site are made after the guide pin has been removed.
Figure 2Multi-dowel osteochondral allograft. Intraoperative appearance of an osteochondral allograft in “snowman” configuration. Note the additional bioabsorbable fixation devices in the larger dowel.
The graft is then placed into a graft holder or held manually with bone-holding forceps. The correspondent anatomic location is identified on the graft and, after a circular saw guide has been placed in position – again perpendicular to the articular surface – an appropriately sized tube saw is used to core out the graft. Prior to removing the graft from the condyle, identifying marks are made to ensure proper orientation (Figure 3). Once the dowel is removed, the recipient's depth measurements are transferred to the graft. This graft is then cut with an oscillating saw and trimmed with a rasp to the precise thickness in all four quadrants. The deep edges of the bone plug can be further chamfered with a rongeur and bone rasp to ease insertion (Figure 4).
Figure 3Osteochondral allograft core. Intraoperative appearance of an osteochondral allograft core prior to removal from the donor hemicondyle. Note the bone forceps and orientation ink mark.
Figure 4Osteochondral allograft plug prior to implantation. Fresh osteochondral allograft dowel plug. Note the minimal thickness of the transplanted subchondral bone to minimize bioburden and facilitate timely creeping substitution.
The graft is then irrigated copiously with a high-pressure lavage to remove all marrow elements possible (Figure 5), and the recipient site can be dilated using a slightly oversized tamp. This may ease the insertion of the graft to prevent excessive impact loading of the articular surface when the graft is inserted, while compacting the subchondral bone to prevent subsidence of the graft. At this time a knee remaining osseous defect are bone grafted to a level base. The allograft is then inserted by hand in the appropriate rotation and is gently tamped into place until it is flush, again minimizing mechanical insult to the articular surface of both the graft and surrounding native tissue.
Figure 5Pulse Lavaging of an osteochondral allograft dowel. Osteochondral allografts should be copiously irrigated to remove debris and marrow elements to reduce immunogenicity.
After the graft is seated, additional fixation with absorbable polydioxanone pins can be added if necessary, particularly if the graft is large or has an exposed edge within the notch (Figure 6). The knee is then brought through a complete range of motion to confirm that the graft is stable and there is no catching or soft tissue obstruction. The wound is then copiously irrigated, and routine closure is performed.
Figure 6Single fresh osteochondral allograft dowel in situ. Intraoperative appearance of a fresh osteochondral allograft dowel in typical location for treatment of an osteochondritis dissecans lesion. Note the additional bioabsorbable fixation devices in this uncontained dowel graft.
The defect is identified through the previously described arthrotomy and the dimensions of the lesions were marked with a surgical pen. Minimizing the sacrifice of normal cartilage, a geometric shape is created that is amenable to handcrafting a shell graft. A #15 scalpel blade is used to demarcate the lesion, and sharp and ring curettes are used to remove all tissue inside this mark. Using both motorized burrs and sharp curettes, the lesion is debrided down to a depth of 4 to 5 mm. The shape is transferred to the graft, which is molded in a freehand fashion, initially slightly oversizing the graft and carefully removing excess bone and cartilage from the template as necessary through multiple trial fittings. If there is a deeper bone loss in the defect, more bone can be left on the graft and the defect can be grafted with cancellous bone prior to graft insertion. The graft and host bed are then copiously irrigated and the graft placed flush with the articular surface. The need for fixation is based on the degree of inherent stability. Bioabsorbable pins, as previously described, are typically used when fixation is required, but countersunk compression screws may be used as an alternative, optimally avoiding the weightbearing portion. After cycling the knee through a full range of motion and irrigating the joint, standard closure is performed.
Postoperative protocol
A recent systematic review of 35 rehabilitation protocols at academic institutions demonstrated that there is considerable variability in the inclusion of specific rehabilitation modalities and the initiation of their timing after both autologous and allogeneic OCG procedures.
The most common modalities recommended in the reviewed protocols were the usage of CPM (96% for OAT and 94% for OCA), restricted postoperative knee flexion (100% for both OAT and OCA), and brace use (88% for OAT and 100% for OCA), particularly when grafting involves the patellofemoral joint, where flexion is limited to less than 30 degrees for the first 4 to 6 weeks, or in cases where bipolar tibial femoral grafts are used, unloader or range of motion brace is used to prevent excessive stress on the grafted surfaces. Generally, patients are kept on a touchdown weightbearing restriction for after OCG procedures depending on the source, size and position of the graft(s) and radiographic evidence of bony healing. Quadriceps strengthening and early range of motion are encouraged. The return to weightbearing and activity is gradual.
Clinical results
Clinical outcomes after osteochondral allografting have been amply reported in the literature.
Effect of Autogenous Bone Marrow Aspirate Treatment on Magnetic Resonance Imaging Integration of Osteochondral Allografts in the Knee: A Matched Comparative Imaging Analysis.
Bone Marrow Aspirate Concentrate Does Not Improve Osseous Integration of Osteochondral Allografts for the Treatment of Chondral Defects in the Knee at 6 and 12 Months: A Comparative Magnetic Resonance Imaging Analysis.
Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis.
reported on 164 knees in 163 patients (mean age 32.6 years) treated with OCA transplantation after prior subchondral marrow stimulation (SMS), osteochondral autograft transplantation (OAT), and autologous chondrocyte implantation (ACI). Mean allograft size was 8.5 ± 7.9 cm2. Survivorship of osteochondral allografting in this study was 82% at 10 years and 74.9% at 15 years, with 89% percent of patients reporting being “extremely satisfied” or “satisfied.” They showed that despite a high reoperation rate, OCA transplantation is a successful salvage surgical treatment after cartilage repair procedures, showing improved survivorship and functional outcomes of OCA transplantation after SMS, ACI, and OAT.
Chahal et al performed a systematic review of clinical outcomes of 19 eligible studies resulting in a total of 644 knees with a mean age was 37 years and mean follow-up of 58 months.
With regard to etiology, the most common indications for transplantation included post-traumatic (38%), osteochondritis dissecans (30%), osteonecrosis from all causes (12%), and idiopathic (11%). Forty-six percent of patients had concomitant procedures, and the mean defect size across studies was 6.3 cm
Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions].
. The overall satisfaction rate was 86%. Sixty-five percent of patients (72 of 110) showed little to no arthritis at final follow-up. The reported short-term complication rate was 2.4%, and the overall failure rate was 18%.
published a systematic review of clinical outcomes and failure rates after OCA in the knee. Amongst the 19 studies included, 1 was level II, 1 level III and 17 were level IV. The mean survival rate across studies was 86.7%, 78.7%, 72.8% and 67.5% at 5, 10, 15 and 20 years respectively. Revision cases, patellar lesions, and bipolar lesions were associated with worse survival rates. Overall, OCA yielded fair to good functional outcome scores, however this procedure is associated with considerable reoperation (30.2%) and failure (18.2%) rates over time.
systematically reviewed the literature to identify risk factors for failure after OCA of the knee. The definition of failure was largely consistent across the included studies and was defined as the need for revision OCA, conversion to arthroplasty, or gross appearance of graft failure at second-look arthroscopic surgery. A total of 16 studies (level IV) consisting of 1401 patients were included. Strong evidence was found supporting that bipolar chondral lesions, male sex, older age, and higher BMI at the time of OCA were significantly associated with an increased failure rate after OCA of the knee. There was no conclusive evidence to support that concomitant procedures, chondral defect size, or lesion location were associated with an increased risk of failure after OCA.
Return to play (RTP) criteria and rehabilitation protocol is still not standardized after OCA in the knee. Stark et al
performed a systematic review and identified 62 studies reporting rehabilitation protocols after OCA of the knee, of which 41 studies reported time-based rehabilitation criteria, and 13 studies included objective or subjective rehabilitation criteria. Allowance of full weightbearing was most seen at the 6 weeks mark but ranged from immediately postoperatively to 1 year. Early weightbearing can be beneficial for cartilage health but must be weighed against the potential risk of failure due to increased strain on the graft. Similarly, the use of a brace varied widely from a minimum of 2 weeks postoperatively up to 6 months, but more frequently being recommended for 4 weeks. Amongst the included studies, 71% allowed for initiation of ROM within the first postoperative week and 44.8% used CPM. Specific timelines for return to sport or activity were included in 41 studies (66.1%) with return to running occurring between 3 months and 1 year (mode 6 months). Thirteen studies (21.0%) included objective or subjective criteria for RTP. Objective criteria were all based off of the functional recovery of the patient. Factors most commonly cited included restoration of normal gait, quadriceps strength, coordination, and performance of sport-specific skills. The RTP rate was reported in 7 studies and ranged from 75.2% to 100% while the RTP at the same level was reported in only 4 studies and ranged from 50% to 80%. In summary, their study highlights the heterogeneity for postoperative rehabilitation guidelines and the RTP protocol after OCA of the knee in the literature. Better studies are needed to establish objective criteria for rehabilitation and RTP protocols after OCA of the knee.
A recent systematic review and meta-analysis reported that PROs improved by an average of 65.1% and 81.1% after OAT and OCA, respectively (P = .0001).
Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis.
They also reported no significant difference in postoperative PRO percentage change after OAT and OCA, with no significant differences between groups in postoperative clinical improvement after accounting for lesion size, mean age, sex, and number of plugs and grafts used. Additionally, there was no significant difference in postoperative failure after OAT and OCA. The mean survival at 5.4 years was 88.2% for the OAT cohort, and that of 5.2 years was 87.2% for the OCA cohort.
Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis.
reported 80% survival for the first 7 years and 60% survival for 15 years for OAT.
In a systematic review evaluating the long-term results of OAT Pareek et al reported a 72% long-term success rate with significant increase in clinical outcomes.
The success rate may be even higher for patients who are younger at the time of injury, have had less previous procedures and have more concomitant correctional procedures. The authors also report a 85% return to sport rate. There was no significant improvement in Tegner activity score in the long term. Additionally, OAT showed a 28% failure rate with a 19% reoperation rate. Patellofemoral lesions also predispose patients to worse outcomes compared with lesions on the femoral condyles.
Zamborsky and Danisovic conducted a systematic review and meta-analysis of RCT and found that there were significantly higher failure rates after MF compared to ACI at 10-year follow-up. Their study showed significantly more excellent or good results at the > 3-year follow-up when comparing OAT and MF, whereas MF had significantly more poor results versus ACI and MACI. Additionally, OAT had significantly more poor results over MACI at the 1-year follow-up period. Furthermore, OAT resulted in higher return to activity rates than MF at all time points (1-, 3- to 5- and 10-year).
Osteochondral grafting is a scientifically validated and intuitively reasonable approach to the treatment of osteoarticular defects, as it is the only restorative method that reintroduces structurally mature and appropriate hyaline and subchondral tissue into acquired articular surface defects. While both graft sources represent a common cartilage organ transplantation paradigm and are complementary, each of the graft sources has its unique, reciprocal challenges with regard to tissue availability and safety. The discerning surgeon is responsible for communicating these considerations to the patient, appropriately weighing them in the treatment algorithm and managing them accordingly.
Autograft is immediately, yet not abundantly, available and, thus, limited in its application, while allograft tissue must be allocated and processed, but allows solid, orthotopic reconstruction of even very large and topographically complex defects. Autologous tissue is theoretically safer to use and is not antigenic, but its use carries the tangible risk of donor site morbidity.
The surgical technique for either method is uncomplicated and reproducible, but requires precision to obtain predictable and reliable results. Clinical applications continue to evolve in regards to other joints and optimizing implant quality, both through adjustments in the methods of harvest and delivery, as well as modulation of the graft environment, especially during the storage interval. Technical advances and tissue engineering hold promise for allogeneic chondrocytes as a cell source and improving scaffold design to further optimize retro-– and, especially, anterograde defect coverage.
Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis.
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References
Czitrom A
Langer F
McKee N
Gross A.
Bone and cartilage allotransplantation. A review of 14 years of research and clinical studies.
Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions].
Osteochondral Allograft Transplant to the Medial Femoral Condyle Using a Medial or Lateral Femoral Condyle Allograft: Is There a Difference in Graft Sources?.
Topographic Matching of Osteochondral Allograft Transplantation Using Lateral Femoral Condyle for the Treatment of Medial Femoral Condyle Lesions: A Computer-Simulated Model Study.
Effect of Autogenous Bone Marrow Aspirate Treatment on Magnetic Resonance Imaging Integration of Osteochondral Allografts in the Knee: A Matched Comparative Imaging Analysis.
Bone Marrow Aspirate Concentrate Does Not Improve Osseous Integration of Osteochondral Allografts for the Treatment of Chondral Defects in the Knee at 6 and 12 Months: A Comparative Magnetic Resonance Imaging Analysis.
Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis.
Brigham and Women's Hospital, Department of Orthopaedic Surgery, Harvard Medical School, 25 Patriot Place, Foxboro MA 02053, T: 617.732.4970, F: 617.264.5232
Multi-dowel osteochondral allograft. Intraoperative appearance of an osteochondral allograft in “snowman” configuration. Note the additional bioabsorbable fixation devices in the larger dowel.
Osteochondral allograft core. Intraoperative appearance of an osteochondral allograft core prior to removal from the donor hemicondyle. Note the bone forceps and orientation ink mark.
Osteochondral allograft plug prior to implantation. Fresh osteochondral allograft dowel plug. Note the minimal thickness of the transplanted subchondral bone to minimize bioburden and facilitate timely creeping substitution.
Pulse Lavaging of an osteochondral allograft dowel. Osteochondral allografts should be copiously irrigated to remove debris and marrow elements to reduce immunogenicity.
Single fresh osteochondral allograft dowel in situ. Intraoperative appearance of a fresh osteochondral allograft dowel in typical location for treatment of an osteochondritis dissecans lesion. Note the additional bioabsorbable fixation devices in this uncontained dowel graft.
Hyaline articular cartilage is a unique, highly specialized tissue with a distinct architecture that lacks intrinsic means to heal effectively when injured in the adult. Symptomatic osteoarticular defects continue to be a formidable challenge for the clinical and the scientific communities alike. Of the various surgical treatment options that have been proposed to this end, only osteochondral grafting techniques reliably restore appropriate hyaline tissue in acquired articular cartilage lesions, especially when these involve the subchondral bone. Both autologous and allogeneic graft sources are available to the surgeon, who must consider the unique qualities and characteristics of either approach in the treatment algorithm. Autografts and allografts alike adhere to a common methodology, relying on osseous healing of mature osteochondral constructs to transplant the adherent viable articular cartilage. The required surgical technique is straightforward and reproducible but requires precision to restore articular surface congruity, achieve reliable bony ingrowth and, ultimately, clinical success. Scientific investigation to further validate empirical clinical practice and to improve implant quality and safety is ongoing and holds great promise for the future of osteochondral grafting in joint preservation.
The use of osteochondral grafts (OCG) of autologous (OAT) or allogeneic (OCA) origin is well supported on the basic science level and has a long successful clinical history as a means of biological resurfacing of (osteo-)chondral defects.1x1Czitrom, A, Langer, F, McKee, N, and Gross, A. Bone and cartilage allotransplantation. A review of 14 years of research and clinical studies. Clin Orthop Relat Res. 1986;
208: 141–145 Crossref | PubMed | Google ScholarSee all References,2x2Bobic, V. Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions]. Orthopade. 1999;
28: 19–25https://doi.org/10.1007/s001320050317 Crossref | PubMed | Google ScholarSee all References While either application has unique advantages and challenges, both subscribe to a common paradigm of transplanting mature hyaline cartilage containing viable chondrocytes attached to the subchondral bone to restore the architecture and characteristics of native tissue in acquired osteoarticular defects. By transplanting structurally competent osteochondral units with an intact tidemark, the fixation issue is mostly relegated to that of osseous ingrowth.3x3Kandel, RA, Gross, AE, Ganel, A, Mcdermott, AGP, Langer, F, and Pritzker, KPH. Histopathology of Failed Osteoarticular Shell Allografts. Clin Orthop Relat Res. 1985;
197: 103–110https://doi.org/10.1097/00003086-198507000-00012 Crossref | PubMed | Scopus (80) | Google ScholarSee all References
One obvious disadvantage of autologous graft sources is that the maximum graft surface area is self-limited by donor volume, to small or at most medium sized lesions. This is especially true in the previously injured and or operated knee, where suitability regarding tissue quality and overall joint topography must be critically assessed. Also, donor site morbidity can significantly add to the disease burden during intra-articular transfer, or even introduce it if the transfer is inter-articular (eg knee to ankle)2x2Bobic, V. Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions]. Orthopade. 1999;
28: 19–25https://doi.org/10.1007/s001320050317 Crossref | PubMed | Google ScholarSee all References however, autologous grafting does hold advantages over other graft sources, such as fresh OCA. It is relatively cheap, immediately available, not antigenic, and osteogenic, leading to reliable osteointegration.4x4Burchardt, H. The biology of bone graft repair. Clin Orthop Relat Res. 1983;
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One advantage of osteochondral allografting is that even very large and multiple lesions can be addressed with a solid orthotopic graft that reproduces the anatomy of the native joint both macroscopically and microscopically, without the risk of inducing donor site morbidity. No other current cartilage repair procedure can match the versatility of osteochondral allograft when addressing complex lesions in topographically challenging environments, especially if they present with an osseous deficiency. Obvious drawbacks to the methodology are financial and logistical issues of graft procurement, and residual risk of infection, albeit small.5x5Görtz, S and Bugbee, W. Fresh Osteochondral Allografts: Graft Processing and Clinical Applications. J Knee Surg. 2006;
19: 231–240https://doi.org/10.1055/s-0030-1248112 Crossref | PubMed | Scopus (56) | Google ScholarSee all References
The surgical techniques for either graft source are straightforward but require precision to restore articular surface congruity while maximizing the potential for bone healing.6x6Duchow, J, Hess, T, and Kohn, D. Primary Stability of Press-Fit-Implanted Osteochondral Grafts: Influence of Graft Size, Repeated Insertion, and Harvesting Technique. Am J Sports Med. 2000;
28: 24–27https://doi.org/10.1177/03635465000280011601 Crossref | PubMed | Scopus (105) | Google ScholarSee all References The mosaicplasty technique incorporates multiple, small autologous grafts, with fibrocartilage to fill in the space between osteochondral grafts, where is the osteochondral autologous transfer system utilizes bigger and fewer dowels.2x2Bobic, V. Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions]. Orthopade. 1999;
28: 19–25https://doi.org/10.1007/s001320050317 Crossref | PubMed | Google ScholarSee all References Osteochondral allografting employs orthotopic donor tissue to recreate topographically appropriate articular surface anatomy, using either dowels that are analogous to the OATS grafts, especially for containd small- to medium-sized condylar lesions that are accessible, while large, more complex lesions can be addressed with freehanded shell grafts.7x7Lane, JG, Massie, JB, Ball, ST et al. Follow-Up of Osteochondral Plug Transfers in a Goat Model: A 6-Month Study. Am J Sports Med. 2004;
32: 1440–1450https://doi.org/10.1177/0363546504263945 Crossref | PubMed | Scopus (114) | Google ScholarSee all References
The use of osteochondral grafts of either origin is well-established in the knee and is the subject of ongoing investigation with indications continuously expanding in other joints.
Graft Topography
Historically, the intercondylar notch and lateral trochlear were presumed to be non-load bearing and were the recommended donor sites for autologous osteochondral grafting. Recent reports have demonstrated that these areas do bear significant weight, which can theoretically contribute to increased donor site morbidity. In a cadaveric study utilizing stereophotogrammetry, Ahmad, et al8x8Ahmad, CS, Cohen, ZA, Levine, WN, Ateshian, GA, and Van, CM. Biomechanical and Topographic Considerations for Autologous Osteochondral Grafting in the Knee. Am J Sports Med. 2001;
29: 201–206https://doi.org/10.1177/03635465010290021401 Crossref | PubMed | Scopus (116) | Google ScholarSee all References studied the contact pressures and surface curvature and osteochondral autografting. They reported that the lateral trochlea was the most involved in loading, followed by the intercondylar notch. The distal medial trochlea was the least involved in loading.
Garretson, et al9x9Garretson, RB, Katolik, LI, Verma, N, Beck, PR, Bach, BR, and Cole, BJ. Contact Pressure at Osteochondral Donor Sites in the Patellofemoral Joint. Am J Sports Med. 2004;
32: 967–974https://doi.org/10.1177/0363546503261706 Crossref | PubMed | Scopus (106) | Google ScholarSee all References further analyzed the contact pressures in the patellofemoral joint. They concluded that the loading on the medial trochlea is less than on the lateral trochlea. They further suggested that because the lateral trochlea is wider than the medial side, the medial trochlea might best be suited for smaller donor plugs (<5mm). Larger plugs could be taken from the lateral trochlea, starting proximal to the sulcus terminalis (where the lowest contact pressures of the lateral trochlea were measured).
Utilizing customized software and fresh cadaveric femurs, Bartz, et al10x10Bartz, RL, Kamaric, E, Noble, PC, Lintner, D, and Bocell, J. Topographic Matching of Selected Donor and Recipient Sites for Osteochondral Autografting of the Articular Surface of the Femoral Condyles. Am J Sports Med. 2001;
29: 207–212https://doi.org/10.1177/03635465010290021501 Crossref | PubMed | Scopus (74) | Google ScholarSee all References also studied the topography of the femoral condyles. They found that grafts taken from the far medial and lateral margins of the femoral trochlea just proximal to the sulcus terminalis, provided the most accurate reconstruction of the surface anatomy of central lesions in the weightbearing portion of either femoral condyle. Smaller grafts (4 or 6mm) from the lateral intercondylar notch can also provide precise matches to similar lesions; however, significant inaccuracies are noted when the lateral intercondylar notch grafts are increased in size (8mm). In addition, they concluded that the concave central intercondylar notch donor best matched the topography of the central trochlea. Also, the curvatures of the medial and lateral trochlea better match the recipient sites at the femoral condyles.
A biomechanical study Koh, et al11x11Lee Koh, J, Kowalski, A, and Lautenschlager, E. The Effect of Angled Osteochondral Grafting on Contact Pressure: A Biomechanical Study. Am J Sports Med. 2006;
34: 116–119https://doi.org/10.1177/0363546505281236 Crossref | PubMed | Scopus (83) | Google ScholarSee all References on cadaveric pig knees looked at the effect of angled osteochondral grafting on contact pressures. They found that slightly countersunk grafts and angled grafts with the highest edge placed flush to neighboring cartilage demonstrated fairly normal contact pressures. On the other hand, elevated angled grafts increased contact pressures by as much as 40%, making them biomechanically disadvantageous. They concluded that it is more favorable to leave a graft slightly countersunk then elevated with respect to the neighboring cartilage.
While the ability to anatomically match OCA tissue to a respective recipient site in orthotopic fashion is considered a key advantage of the procedure, the statistical preponderance of cartilage disease of the medial femoral condyle (MFC)12x12Hjelle, K, Solheim, E, Strand, T, Muri, R, and Brittberg, M. Articular cartilage defects in 1,000 knee arthroscopies. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2002;
18: 730–734https://doi.org/10.1053/jars.2002.32839 Abstract | Full Text | Full Text PDF | PubMed | Scopus (679) | Google ScholarSee all References means that, reciprocally, there is a relative surplus of lateral femoral condyle (LFC) allografts. To optimize utilization of OCA tissue, there has been a clinical move towards using OCA outside of their exact anatomic location among high volume OCA surgeons.13x13Görtz, S, Tabbaa, SM, Jones, DG et al. Metrics of OsteoChondral Allografts (MOCA) Group Consensus Statements on the Use of Viable Osteochondral Allograft. Orthopaedic Journal of Sports Medicine. 2021;
9: 232596712098360https://doi.org/10.1177/2325967120983604 Crossref | PubMed | Scopus (3) | Google ScholarSee all References Several studies have investigated the feasibility of this practice in regards to obtaining a topographic match of non-orthotopic grafts despite known anatomic differences the shape, curvature, and size of MFC and LFC. Mologne et al reported that at a diameter of 20mm, contralateral LFC and MFC grafts produced equivalent surface matches in the weightbearing portion of the MFC.14x14Mologne, TS, Cory, E, Hansen, BC et al. Osteochondral Allograft Transplant to the Medial Femoral Condyle Using a Medial or Lateral Femoral Condyle Allograft: Is There a Difference in Graft Sources?. Am J Sports Med. 2014;
42: 2205–2213https://doi.org/10.1177/0363546514540446 Crossref | PubMed | Scopus (27) | Google ScholarSee all References
Urita et al demonstrated that ipsilateral and contralateral LFC grafts provide similar articular cartilage surface, resulting in subchondral bone surface that matches that of MFC grafts, suggesting that LFCs could be a suitable OCA source for the treatment of MFC lesions.15x15Urita, A, Cvetanovich, GL, Madden, BT et al. Topographic Matching of Osteochondral Allograft Transplantation Using Lateral Femoral Condyle for the Treatment of Medial Femoral Condyle Lesions: A Computer-Simulated Model Study. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2018;
34: 3033–3042https://doi.org/10.1016/j.arthro.2018.05.039 Abstract | Full Text | Full Text PDF | PubMed | Scopus (14) | Google ScholarSee all References
Based on these findings, and in an effort to make more OCA grafts available from limited donor condyles, tissue suppliers have moved to harvesting multiple smaller (<20mm diameter) “precut” fresh OCA plugs from a single donor condyle. Two diameter sizes (10 mm and 16 mm) of precut plugs are currently commercially available in the United States (Osteochondral Resurfacing System, JRF, Centennial, CO). Their smaller dimensions increase the number of grafts that may ultimately be harvested from a single donor condyle and make these available in a more “off the shelf” fashion, and likely decreasing the risk for orthotopic mismatching since their total cross-sectional surface area is small.16x16Jones, KJ, Mosich, GM, and Williams, RJ. Fresh Precut Osteochondral Allograft Core Transplantation for the Treatment of Femoral Cartilage Defects. Arthroscopy Techniques. 2018;
7: e791–e795https://doi.org/10.1016/j.eats.2018.03.016 Abstract | Full Text | Full Text PDF | PubMed | Scopus (13) | Google ScholarSee all References In short-term study, these unmatched precut allograft plugs performed equivalent to cores taken from size matched hemicondylar grafts.17x17Markus, DH, Blaeser, AM, Hurley, ET et al. No Difference in Outcomes Following Osteochondral Allograft with Fresh Precut Cores Compared to Hemi-Condylar Allografts. CARTILAGE. 2021;
13: 886S–893Shttps://doi.org/10.1177/19476035211021911 Crossref | PubMed | Scopus (1) | Google ScholarSee all References
Cartilage Health
Chondrocytes are fragile cells, and mechanical or thermal insult during osteochondral graft harvest or implantation can lead to macroscopic injury and can induce chondrocyte necrosis and apoptosis. This particularly pertains to the cut graft margins during harvest, as well as the graft articular surface during implantation. This preferentially affects the superficial zone of articular cartilage, which is significant because chondrocytes in the zone of cartilage secrete the superficial zone protein lubricin, which contributes to the friction-lowering effect of synovial fluid.18x18Borazjani, BH, Chen, AC, Bae, WC et al. Effect of Impact on Chondrocyte Viability During Insertion of Human Osteochondral Grafts. J Bone Joint Surg Am. 2006;
88: 1934–1943 Crossref | PubMed | Scopus (72) | Google ScholarSee all References On the other hand, superficial zone protein and synovial fluid is also likely to inhibit graft-to-host adhesion and ingrowth of opposing cartilage margins.19x19Englert, C, McGowan, KB, Klein, TJ, Giurea, A, Schumacher, BL, and Sah, RL. Inhibition of integrative cartilage repair by proteoglycan 4 in synovial fluid. Arthritis & Rheumatism. 2005;
52: 1091–1099https://doi.org/10.1002/art.20986 Crossref | PubMed | Scopus (72) | Google ScholarSee all References
Marginal cell death, coupled with the inherent hypocellularity of articular cartilage, further helps to explain the lack of graft-host interface integration observed after implantation of osteochondral grafts over time.20x20Mankin, HJ. The response of articular cartilage to mechanical injury. J Bone Joint Surg Am. 1982;
64: 460–466 Crossref | PubMed | Scopus (994) | Google ScholarSee all References This problem is obviously multiplied with a number of plugs used, as the portion of marginal cartilage and the overall surface increases. Given the fact that the interstitial bony bridges between mosaicplasty plugs heal over with fibrocartilage at best, this can have a significant impact on the overall quality of the repair tissue. Huntley et al21x21Huntley, JS, Bush, PG, Mcbirnie, JM, Simpson, AH, and Hall, AC. Chondrocyte Death Associated with Human Femoral Osteochondral Harvest as Performed for Mosaicplasty. J Bone Joint Surg Am. 2005;
87: 351–360 Crossref | PubMed | Scopus (104) | Google ScholarSee all References used confocal laser scanning microscopy to demonstrate a significant marginal zone of cell death and osteochondral dowels after harvest with use of the mosaicplasty technique and concluded that up to one third of a mosaicplasty surface is not compromised of viable hyaline cartilage. Evans, et al22x22Evans, PJ, Miniaci, A, and Hurtig, MB. Manual punch versus power harvesting of osteochondral grafts. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2004;
20: 306–310https://doi.org/10.1016/j.arthro.2004.01.012 Abstract | Full Text | Full Text PDF | PubMed | Scopus (65) | Google ScholarSee all References demonstrated the advantages of using manual punches over power trephines during plug harvest, as the latter proved technically more difficult and resulted in more gross and light microscopic damage to the osteochondral grafts, with thermal necrosis being one possible cause.
The articular surface of osteochondral grafts is prone to impaction injury during implantation if excessive compressive force is used during seating of the dowels. Borazjani, et al18x18Borazjani, BH, Chen, AC, Bae, WC et al. Effect of Impact on Chondrocyte Viability During Insertion of Human Osteochondral Grafts. J Bone Joint Surg Am. 2006;
88: 1934–1943 Crossref | PubMed | Scopus (72) | Google ScholarSee all References showed marked cell apoptosis was induced and the superficial layer of the transplanted osteochondral plugs and concluded that the amplitude, more than frequency, of peak forces during implantation was responsible for triggering apoptotic cascades that led to chondrocyte death, particularly in the superficial zone.
Preclinical studies have shown that fresh osteochondral allografts result in improved clinical outcomes over frozen or decellularized grafts, corroborating the importance of chondrocyte viability for successful outcomes. Tabbaa et al in their recent systematic review, included 55 peer-reviewed articles of ex-vivo (laboratory), animal and clinical studies. They found that although 60% of animal models suggest that storage time may influence outcomes and 80% indicate inferior outcomes with frozen OCA as compared with fresh OCA, 75% of clinical studies report no correlation between storage time and outcomes. Although those results might be challenged with longer follow up period, based on this review there remains limited evidence to support a threshold of viable chondrocytes and parameters of cartilage health needed for successful osteochondral repair.23x23Tabbaa, SM, Guilak, F, Sah, RL, and Bugbee, WD. Fresh Osteochondral and Chondral Allograft Preservation and Storage Media: A Systematic Review of the Literature. Am J Sports Med. 2022;
50: 1702–1716https://doi.org/10.1177/03635465211016832 Crossref | PubMed | Scopus (1) | Google ScholarSee all References
Optimizing cartilage health and protecting chondrocyte viability are critical to long-term success of any cartilage restoration procedure. Care must be taken during harvest, storage, and implantation of osteochondral grafts to protect the integrity of the cartilage transplant and to maximize successful outcomes.
Osseous issues
The second integral component of any osteochondral graft is the osseous portion. Conceptually, this functions as the underlying support structure for the articular cartilage and serves as a vehicle for attachment and fixation of the graft to the host.
Osteochondral allograft tissue is generally considered immunologically privileged due the avascular intact chondral matrix functioning as a physiologic barrier to surveillance cells, thus not provoking clinically significant rejection in the host. In current practice, OCAs are thus not HLA or blood type matched between donor and recipient. Although patients immunologically tolerate allografts from a clinical perspective, they do elicit a variable cellular-mediated immune response.24x24Phipatanakul, W, VandeVord, P, Teitge, R, and Wooley, P. Immune response in patients receiving fresh osteochondral allografts. Am J Orthop (Belle Mead NJ). 2004;
33: 345–348 PubMed | Google ScholarSee all References,25x25Langer, F and Gross, G. Immunogenicity of allograft articular cartilage. J Bone Joint Surg Am. 1974;
56: 297–304 Crossref | PubMed | Scopus (200) | Google ScholarSee all References,26x26Hunt, HE, Sadr, K, DeYoung, AJ, Gortz, S, and Bugbee, WD. The Role of Immunologic Response in Fresh Osteochondral Allografting of the Knee. Am J Sports Med. 2014;
42: 886–891https://doi.org/10.1177/0363546513518733 Crossref | PubMed | Scopus (49) | Google ScholarSee all References
Since allograft bone is known to be antigenic, it is likely that this phenomenon is conveyed by the bone and associated marrow elements, as with any type of allogenic bone graft,27x27Friedlaender, G and Horowitz, M. Immune responses to osteochondral allografts: nature and significance. Orthopedics. 1992;
15: 1171–1175 Crossref | PubMed | Google ScholarSee all References,28x28Strong, D, Friedlaender, G, Tomford, W et al. Immunologic responses in human recipients of osseous and osteochondral allografts. Clin Orthop Relat Res. 1996;
326: 107–114 Crossref | PubMed | Scopus (133) | Google ScholarSee all References demonstrating slower and less extensive bone formation and neovascularization and higher incidence of bone resorption and subchondral cyst formation.4x4Burchardt, H. The biology of bone graft repair. Clin Orthop Relat Res. 1983;
174: 28–42 Crossref | PubMed | Scopus (822) | Google ScholarSee all References Since it merely serves as an osteoconductive scaffold for healing to the host by creeping substitution, which is a rate limited process, this allogenic potential should be minimized along with the transplanted bone wherever possible, without compromising stability of the graft as warranted by the clinical situation.29x29Enneking, WF and Campanacci, DA. Retrieved Human Allografts: A Clinicopathological Study. The Journal of Bone and Joint Surgery-American Volume. 2001;
83: 971–986https://doi.org/10.2106/00004623-200107000-00001 Crossref | PubMed | Scopus (371) | Google ScholarSee all References
Several authors have investigated the role of orthobiologics in improving OCA incorporation and avoiding clinical failure by mitigating these potentially deleterious effects at the graft/host interface. Chona et al subsequently performed a systematic review of the use of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) augmentation in the surgical treatment of cartilage defects.30x30Chona, DV, Kha, ST, Minetos, PD et al. Biologic Augmentation for the Operative Treatment of Osteochondral Defects of the Knee: A Systematic Review. Orthopaedic Journal of Sports Medicine. 2021;
9: 232596712110497https://doi.org/10.1177/23259671211049756 Crossref | PubMed | Scopus (1) | Google ScholarSee all References They concluded that two of three studies on BMAC-augmented osteochondral allografts reported no difference in radiographic features postoperatively.
Oladeji et al reported that large femoral condylar OCAs treated with BMAC before implantation showed superior radiographic integration to bone and less sclerosis during the initial six-month postoperative period.31x31Oladeji, LO, Stannard, JP, Cook, CR et al. Effects of Autogenous Bone Marrow Aspirate Concentrate on Radiographic Integration of Femoral Condylar Osteochondral Allografts. Am J Sports Med. 2017;
45: 2797–2803https://doi.org/10.1177/0363546517715725 Crossref | PubMed | Scopus (51) | Google ScholarSee all References However, Ackermann et al reported that addition of BMAC did not result in superior imaging outcomes at six months post-operatively.32x32Ackermann, J, Mestriner, AB, Shah, N, and Gomoll, AH. Effect of Autogenous Bone Marrow Aspirate Treatment on Magnetic Resonance Imaging Integration of Osteochondral Allografts in the Knee: A Matched Comparative Imaging Analysis. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2019;
35: 2436–2444https://doi.org/10.1016/j.arthro.2019.03.033 Abstract | Full Text | Full Text PDF | PubMed | Scopus (10) | Google ScholarSee all References Likewise, Wang et al did not find an association between OCA augmented with BMAC and improved osseous integration; decreased cystic changes; or other bone, cartilage, and ancillary feature changes at the graft-host junction compared with OCA alone in the early (∼6 months) and late (∼12 months) postoperative phases.33x33Wang, D, Lin, KM, Burge, AJ, Balazs, GC, and Williams, RJ. Bone Marrow Aspirate Concentrate Does Not Improve Osseous Integration of Osteochondral Allografts for the Treatment of Chondral Defects in the Knee at 6 and 12 Months: A Comparative Magnetic Resonance Imaging Analysis. Am J Sports Med. 2019;
47: 339–346https://doi.org/10.1177/0363546518813915 Crossref | PubMed | Scopus (16) | Google ScholarSee all References They concluded that multiple factors can influence the creeping substitution process, including patient age, smoking history, and BMAC harvest and preparation techniques.
Clearly, further research into the specific cells and growth factors within orthobiologic preparations and their potential impact on osseous integration of osteochondral allografts is warranted.
While sex mismatch between donor and recipient has been considered a potential contributor to adverse outcomes after solid organ transplantation, OCA tissue also had also not been routinely matched for sex between donor and recipient. Merkely et al recently evaluated the influence of donor-recipient sex on graft survival. After adjusting for adjusted for patient age, graft size, and body mass index, the concluded that mismatch between donor and recipient sex had a negative effect on OCA survival at five years after transplantation, particularly in those cases when male donor tissue was transplanted into a female recipient.34x34Merkely, G, Ackermann, J, Farina, EM, VanArsdale, C, Lattermann, C, and Gomoll, AH. Shorter Storage Time Is Strongly Associated With Improved Graft Survivorship at 5 Years After Osteochondral Allograft Transplantation. Am J Sports Med. 2020;
48: 3170–3176https://doi.org/10.1177/0363546520956311 Crossref | PubMed | Scopus (7) | Google ScholarSee all References
The osseous portion of autograft varies considerably from that of allografts, in that it is considered osteogenic and generally is incorporated rapidly and completely.4x4Burchardt, H. The biology of bone graft repair. Clin Orthop Relat Res. 1983;
174: 28–42 Crossref | PubMed | Scopus (822) | Google ScholarSee all References Postoperative hemarthrosis and, subsequently, arthrofibrosis due to bleeding from the donor site are concerns with autologous osteochondral grafting. Retrograde filling of the created defect using different artificial fillers has been investigated and proven helpful in preventing postoperative hemarthrosis and in creating a scaffold for the fibrocartilage repair process.35x35Feczkó, P, Hangody, L, Varga, J et al. Experimental results of donor site filling for autologous osteochondral mosaicplasty. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2003;
19: 755–761https://doi.org/10.1016/S0749-8063(03)00402-X Abstract | Full Text | Full Text PDF | PubMed | Scopus (72) | Google ScholarSee all References While the optimal length is debatable, bottomed plug offers the most stable construct,36x36Kock, NB, Van Susante, JLC, Buma, P, Van Kampen, A, and Verdonschot, N. Press-fit stability of an osteochondral autograft: Influence of different plug length and perfect depth alignment. Acta Orthopaedica. 2006;
77: 422–428https://doi.org/10.1080/17453670610046352 Crossref | PubMed | Scopus (36) | Google ScholarSee all References,37x37Kordás, G, Szabó, JS, and Hangody, L. Primary Stability of Osteochondral Grafts Used in Mosaicplasty. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2006;
22: 414–421https://doi.org/10.1016/j.arthro.2005.12.011 Abstract | Full Text | Full Text PDF | PubMed | Scopus (33) | Google ScholarSee all References there is stability increasing with diameter. Since there are no immunological concerns, autologous plugs can be transplanted with more bone stock for press-fit stability if necessary.6x6Duchow, J, Hess, T, and Kohn, D. Primary Stability of Press-Fit-Implanted Osteochondral Grafts: Influence of Graft Size, Repeated Insertion, and Harvesting Technique. Am J Sports Med. 2000;
28: 24–27https://doi.org/10.1177/03635465000280011601 Crossref | PubMed | Scopus (105) | Google ScholarSee all References whereas the osseous portion of an osteochondral allograft is usually limited to depth of a few millimeters and against press-fit stability through a wider base radius. However, depending on the clinical situation, the allograft may contain more copious amounts of bone, as required to restore injured or absent subchondral tissue.38x38Görtz, S and Bugbee, WD. Allografts in Articular Cartilage Repair. The Journal of Bone & Joint Surgery. 2006;
88: 1374–1384https://doi.org/10.2106/00004623-200606000-00030 Crossref | PubMed | Scopus (98) | Google ScholarSee all References
Operative techniques
Osteochondral autografting technique–knee
The technique can be performed through standard arthrotomy, mini arthrotomy and/or arthroscopically. Nevertheless, the surgeon should always prepare for conversion to standard arthrotomy as certain locations, i.e., the posterior femoral condyle, may be difficult to access with less invasive approaches.
The lesion is accessed and measured after cartilage and subchondral bone have been debrided to healthy margins, at which point a determination on the osteochondral autografting technique to be implemented is made (OATS versus mosaicplasty). In current practice available plug sizes vary from 6 to 12 mm, depending on the technique utilized and the size of the chondral lesion, particularly in relative relationship to the size of the distal femur (Figure 1Figure 1). The surgeon should consider the articular topography when deciding between OATS and mosaicplasty. In general, matching articular geometry becomes more difficult with larger donor plugs. In addition, the potential for donor site morbidity increases with larger dowels.
Figure 1
Relative graft size. Relative appearance of equisized 15mm diameter cores on different size donor femoral hemicondyles.
Under direct visualization the appropriately sized tubular T-handled recipient harvester is tapped perpendicular to the defect to a minimal depth of 10 mm for standard cartilage lesions. The depth can be increased to as much as 25 mm for significant osteochondral conditions, ie, osteochondritis dissecans. The harvester chisel is then removed by rotating the driver 90 degrees clockwise, then 90 degrees counterclockwise.
Utilizing the same technique with a slightly larger T-handled harvester, the donor graft is taken from the far medial or lateral margin of the trochlea, just proximal to the sulcus terminalis. Alternatively, a smaller graft can be taken from the lateral intercondylar notch. After verifying the donor graft's depth measurement, it is then transplanted into the recipient site utilizing the donor tube harvester, which dilates the cartilage layer with its beveled edge creating a tight press-fit. The last 1 mm of impaction should be performed by lightly tapping an oversized bone tamp over the cartilaginous cap. If necessary, the osseous portion of the graft can be shortened to allow the cartilage to lie flush with the surrounding articular surface. If required, the process is repeated until the lesion is covered with healthy hyaline cartilage. A 1 to 2 mm bone bridge between the recipient sites is recommended to help achieve a tight press-fit. These bridges fill with fibrocartilage. In addition, the careful spacing of the plug is essential. To avoid premature amputation of the graft, the osseous portions should not intersect with one another. This can be most problematic with longer grafts (25mm) obtained in areas of the knee where there is high curvature, i.e., the posterior femoral condyle. Finally, to prevent recipient tunnel wall fracture, each plug transfer should be completed prior to proceeding with additional recipient sockets.
The surgeon may choose to retrofill the created defect to minimize donor site morbidity. Osteobiologic plugs that corresponds to the diameters of commercial coring devices are available for this purpose. Following the graft process, surface congruity is confirmed, and the joint is put through a range of motion to ensure graft stability and lack of impingement. The knee is closed in a standard fashion over a drain after irrigation of the joint and inspection for bony and soft tissue debris.
Osteochondral allografting technique–knee
The technique of fresh osteochondral allografting generally relies on an open procedure, including an arthrotomy of variable size (depending on the position and dimension of the lesion). Usually the patients have had previous surgery or are at least fully imaged; otherwise, a diagnostic arthroscopy can be performed prior to the allografting procedure to confirm adequacy of the available graft. It is the responsibility of the surgeon to inspect the graft and to confirm the adequacy of the size match and quality of the tissue prior to surgery.
The patient is positioned supine with a proximal thigh tourniquet, as above. A leg or foot holder can help to position and maintain the leg in between 70 and 100 degrees of flexion. For most femoral condyle lesions, eversion of the patella is not necessary.
A standard midline incision is made and elevated subcutaneously, depending on the location of the lesion (either medial or lateral), and the joint is entered by incising the fat pad without disrupting the anterior horn of the meniscus or damaging the articular surface. In some cases where the lesion is posterior or very large, the meniscus must be detached and reflected; generally, this can be done safely, leaving a small cuff of tissue adjacent to the anterior attachment of the meniscus. Once the joint capsule and synovium have been incised and retractors have been carefully placed, the knee is brought to a degree of flexion that presents the lesion into the arthrotomy site. The lesion then is inspected and palpated with a probe to determine the extent, margins, and maximum size.
The two commonly used techniques for the preparation and implantation of the osteochondral allografts include the press-fit plug technique and the shell graft technique. Each technique has advantages and disadvantages. The press-fit plug technique is similar, in principle, to autologous osteochondral transfer systems described above. This technique is optimal for contained condylar lesions between 15 and 35 mm in diameter. Fixation is generally not required, due to the stability achieved with a press-fit. Disadvantages include the fact that very posterior femoral and trochlear lesions are not conducive to the use of a circular coring system and may be more amicable to shell allografts. Additionally, the more ovoid a lesion in shape the more normal cartilage which needs to be sacrificed at the recipient site in order to accommodate the circular donor plug. Shell grafts are technically more difficult to perform and typically require fixation. However, depending on the technique employed last normal cartilage may need to be sacrificed.
Surgical techniques–dowel allograft
As with autologous dowels, there are several proprietary instrumentation systems that are currently available for the preparation and implantation of press-fit dowel allograft up to 35 mm in diameter, and surgical techniques are similar.
After a size determination is made, a guidewire is driven into the center of the lesion, perpendicular to the articular surface. The size of the graft is then determined utilizing sizing dowels, remembering that overlapping towels (in a "snowman" or "MasterCard" configuration can possibly deliver the best area fit (Figure 2Figure 2). The remaining articular cartilage is scored to subchondral bone, and a core reamer is used to remove the articular cartilage remanence and at least 3 to 4 mm of subchondral bone. In deeper lesions fibrous and sclerotic bone is removed to a healthy, bleeding osseous base, not to exceed 10 mm in depth. Lesions below this depth should be curetted manually, and packed morselized autologous bone graft should be utilized to fill any deeper or more extensive osseous defects. Circumferential depth measurements of the prepared recipient site are made after the guide pin has been removed.
Figure 2
Multi-dowel osteochondral allograft. Intraoperative appearance of an osteochondral allograft in “snowman” configuration. Note the additional bioabsorbable fixation devices in the larger dowel.
The graft is then placed into a graft holder or held manually with bone-holding forceps. The correspondent anatomic location is identified on the graft and, after a circular saw guide has been placed in position – again perpendicular to the articular surface – an appropriately sized tube saw is used to core out the graft. Prior to removing the graft from the condyle, identifying marks are made to ensure proper orientation (Figure 3Figure 3). Once the dowel is removed, the recipient's depth measurements are transferred to the graft. This graft is then cut with an oscillating saw and trimmed with a rasp to the precise thickness in all four quadrants. The deep edges of the bone plug can be further chamfered with a rongeur and bone rasp to ease insertion (Figure 4Figure 4).
Figure 3
Osteochondral allograft core. Intraoperative appearance of an osteochondral allograft core prior to removal from the donor hemicondyle. Note the bone forceps and orientation ink mark.
Osteochondral allograft plug prior to implantation. Fresh osteochondral allograft dowel plug. Note the minimal thickness of the transplanted subchondral bone to minimize bioburden and facilitate timely creeping substitution.
The graft is then irrigated copiously with a high-pressure lavage to remove all marrow elements possible (Figure 5Figure 5), and the recipient site can be dilated using a slightly oversized tamp. This may ease the insertion of the graft to prevent excessive impact loading of the articular surface when the graft is inserted, while compacting the subchondral bone to prevent subsidence of the graft. At this time a knee remaining osseous defect are bone grafted to a level base. The allograft is then inserted by hand in the appropriate rotation and is gently tamped into place until it is flush, again minimizing mechanical insult to the articular surface of both the graft and surrounding native tissue.
Figure 5
Pulse Lavaging of an osteochondral allograft dowel. Osteochondral allografts should be copiously irrigated to remove debris and marrow elements to reduce immunogenicity.
After the graft is seated, additional fixation with absorbable polydioxanone pins can be added if necessary, particularly if the graft is large or has an exposed edge within the notch (Figure 6Figure 6). The knee is then brought through a complete range of motion to confirm that the graft is stable and there is no catching or soft tissue obstruction. The wound is then copiously irrigated, and routine closure is performed.
Figure 6
Single fresh osteochondral allograft dowel in situ. Intraoperative appearance of a fresh osteochondral allograft dowel in typical location for treatment of an osteochondritis dissecans lesion. Note the additional bioabsorbable fixation devices in this uncontained dowel graft.
The defect is identified through the previously described arthrotomy and the dimensions of the lesions were marked with a surgical pen. Minimizing the sacrifice of normal cartilage, a geometric shape is created that is amenable to handcrafting a shell graft. A #15 scalpel blade is used to demarcate the lesion, and sharp and ring curettes are used to remove all tissue inside this mark. Using both motorized burrs and sharp curettes, the lesion is debrided down to a depth of 4 to 5 mm. The shape is transferred to the graft, which is molded in a freehand fashion, initially slightly oversizing the graft and carefully removing excess bone and cartilage from the template as necessary through multiple trial fittings. If there is a deeper bone loss in the defect, more bone can be left on the graft and the defect can be grafted with cancellous bone prior to graft insertion. The graft and host bed are then copiously irrigated and the graft placed flush with the articular surface. The need for fixation is based on the degree of inherent stability. Bioabsorbable pins, as previously described, are typically used when fixation is required, but countersunk compression screws may be used as an alternative, optimally avoiding the weightbearing portion. After cycling the knee through a full range of motion and irrigating the joint, standard closure is performed.
Postoperative protocol
A recent systematic review of 35 rehabilitation protocols at academic institutions demonstrated that there is considerable variability in the inclusion of specific rehabilitation modalities and the initiation of their timing after both autologous and allogeneic OCG procedures.39x39Crowley, SG, Pedersen, A, Fortney, TA et al. Rehabilitation Variability Following Osteochondral Autograft and Allograft Transplantation of the Knee. CARTILAGE. 2022;
13: 194760352210930https://doi.org/10.1177/19476035221093071 Crossref | PubMed | Scopus (0) | Google ScholarSee all References
The most common modalities recommended in the reviewed protocols were the usage of CPM (96% for OAT and 94% for OCA), restricted postoperative knee flexion (100% for both OAT and OCA), and brace use (88% for OAT and 100% for OCA), particularly when grafting involves the patellofemoral joint, where flexion is limited to less than 30 degrees for the first 4 to 6 weeks, or in cases where bipolar tibial femoral grafts are used, unloader or range of motion brace is used to prevent excessive stress on the grafted surfaces. Generally, patients are kept on a touchdown weightbearing restriction for after OCG procedures depending on the source, size and position of the graft(s) and radiographic evidence of bony healing. Quadriceps strengthening and early range of motion are encouraged. The return to weightbearing and activity is gradual.
Chahal et al performed a systematic review of clinical outcomes of 19 eligible studies resulting in a total of 644 knees with a mean age was 37 years and mean follow-up of 58 months.41x41Chahal, J, Gross, AE, Gross, C et al. Outcomes of Osteochondral Allograft Transplantation in the Knee. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2013;
29: 575–588https://doi.org/10.1016/j.arthro.2012.12.002 Abstract | Full Text | Full Text PDF | PubMed | Scopus (136) | Google ScholarSee all References With regard to etiology, the most common indications for transplantation included post-traumatic (38%), osteochondritis dissecans (30%), osteonecrosis from all causes (12%), and idiopathic (11%). Forty-six percent of patients had concomitant procedures, and the mean defect size across studies was 6.3 cm 2x2Bobic, V. Die Verwendung von autologen Knochen-Knorpel-Transplantaten in der Behandlung von Gelenkknorpelläsionen [Autologous osteo-chondral grafts in the management of articular cartilage lesions]. Orthopade. 1999;
28: 19–25https://doi.org/10.1007/s001320050317 Crossref | PubMed | Google ScholarSee all References. The overall satisfaction rate was 86%. Sixty-five percent of patients (72 of 110) showed little to no arthritis at final follow-up. The reported short-term complication rate was 2.4%, and the overall failure rate was 18%.
Familiari et al42x42Familiari, F, Cinque, ME, Chahla, J et al. Clinical Outcomes and Failure Rates of Osteochondral Allograft Transplantation in the Knee: A Systematic Review. Am J Sports Med. 2018;
46: 3541–3549https://doi.org/10.1177/0363546517732531 Crossref | PubMed | Scopus (102) | Google ScholarSee all References published a systematic review of clinical outcomes and failure rates after OCA in the knee. Amongst the 19 studies included, 1 was level II, 1 level III and 17 were level IV. The mean survival rate across studies was 86.7%, 78.7%, 72.8% and 67.5% at 5, 10, 15 and 20 years respectively. Revision cases, patellar lesions, and bipolar lesions were associated with worse survival rates. Overall, OCA yielded fair to good functional outcome scores, however this procedure is associated with considerable reoperation (30.2%) and failure (18.2%) rates over time.
Similarly, Kunze et al43x43Kunze, KN, Ramkumar, PN, Manzi, JE, Wright-Chisem, J, Nwachukwu, BU, and Williams, RJ. Risk Factors for Failure After Osteochondral Allograft Transplantation of the Knee: A Systematic Review and Exploratory Meta-analysis. Am J Sports Med. 2022;
: 036354652110639https://doi.org/10.1177/03635465211063901 (Published online January 20) Crossref | Scopus (4) | Google ScholarSee all References systematically reviewed the literature to identify risk factors for failure after OCA of the knee. The definition of failure was largely consistent across the included studies and was defined as the need for revision OCA, conversion to arthroplasty, or gross appearance of graft failure at second-look arthroscopic surgery. A total of 16 studies (level IV) consisting of 1401 patients were included. Strong evidence was found supporting that bipolar chondral lesions, male sex, older age, and higher BMI at the time of OCA were significantly associated with an increased failure rate after OCA of the knee. There was no conclusive evidence to support that concomitant procedures, chondral defect size, or lesion location were associated with an increased risk of failure after OCA.
Return to play (RTP) criteria and rehabilitation protocol is still not standardized after OCA in the knee. Stark et al44x44Stark, M, Rao, S, Gleason, B et al. Rehabilitation and Return-to-Play Criteria After Fresh Osteochondral Allograft Transplantation: A Systematic Review. Orthopaedic Journal of Sports Medicine. 2021;
9: 232596712110171https://doi.org/10.1177/23259671211017135 Crossref | PubMed | Scopus (3) | Google ScholarSee all References performed a systematic review and identified 62 studies reporting rehabilitation protocols after OCA of the knee, of which 41 studies reported time-based rehabilitation criteria, and 13 studies included objective or subjective rehabilitation criteria. Allowance of full weightbearing was most seen at the 6 weeks mark but ranged from immediately postoperatively to 1 year. Early weightbearing can be beneficial for cartilage health but must be weighed against the potential risk of failure due to increased strain on the graft. Similarly, the use of a brace varied widely from a minimum of 2 weeks postoperatively up to 6 months, but more frequently being recommended for 4 weeks. Amongst the included studies, 71% allowed for initiation of ROM within the first postoperative week and 44.8% used CPM. Specific timelines for return to sport or activity were included in 41 studies (66.1%) with return to running occurring between 3 months and 1 year (mode 6 months). Thirteen studies (21.0%) included objective or subjective criteria for RTP. Objective criteria were all based off of the functional recovery of the patient. Factors most commonly cited included restoration of normal gait, quadriceps strength, coordination, and performance of sport-specific skills. The RTP rate was reported in 7 studies and ranged from 75.2% to 100% while the RTP at the same level was reported in only 4 studies and ranged from 50% to 80%. In summary, their study highlights the heterogeneity for postoperative rehabilitation guidelines and the RTP protocol after OCA of the knee in the literature. Better studies are needed to establish objective criteria for rehabilitation and RTP protocols after OCA of the knee.
A recent systematic review and meta-analysis reported that PROs improved by an average of 65.1% and 81.1% after OAT and OCA, respectively (P = .0001).45x45Trofa, DP, Hong, IS, Lopez, CD et al. Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis. Am J Sports Med. 2022;
: 036354652110535https://doi.org/10.1177/03635465211053594 (Published online February 9) Crossref | Scopus (2) | Google ScholarSee all References They also reported no significant difference in postoperative PRO percentage change after OAT and OCA, with no significant differences between groups in postoperative clinical improvement after accounting for lesion size, mean age, sex, and number of plugs and grafts used. Additionally, there was no significant difference in postoperative failure after OAT and OCA. The mean survival at 5.4 years was 88.2% for the OAT cohort, and that of 5.2 years was 87.2% for the OCA cohort.45x45Trofa, DP, Hong, IS, Lopez, CD et al. Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis. Am J Sports Med. 2022;
: 036354652110535https://doi.org/10.1177/03635465211053594 (Published online February 9) Crossref | Scopus (2) | Google ScholarSee all References Similarly, Solheim et al46x46Solheim, E, Hegna, J, and Inderhaug, E. Long-Term Survival after Microfracture and Mosaicplasty for Knee Articular Cartilage Repair: A Comparative Study Between Two Treatments Cohorts. CARTILAGE. 2020;
11: 71–76https://doi.org/10.1177/1947603518783482 Crossref | PubMed | Scopus (36) | Google ScholarSee all References reported 80% survival for the first 7 years and 60% survival for 15 years for OAT.
In a systematic review evaluating the long-term results of OAT Pareek et al reported a 72% long-term success rate with significant increase in clinical outcomes.47x47Pareek, A, Reardon, PJ, Maak, TG, Levy, BA, Stuart, MJ, and Krych, AJ. Long-term Outcomes After Osteochondral Autograft Transfer: A Systematic Review at Mean Follow-up of 10.2 Years. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2016;
32: 1174–1184https://doi.org/10.1016/j.arthro.2015.11.037 Abstract | Full Text | Full Text PDF | PubMed | Scopus (59) | Google ScholarSee all References The success rate may be even higher for patients who are younger at the time of injury, have had less previous procedures and have more concomitant correctional procedures. The authors also report a 85% return to sport rate. There was no significant improvement in Tegner activity score in the long term. Additionally, OAT showed a 28% failure rate with a 19% reoperation rate. Patellofemoral lesions also predispose patients to worse outcomes compared with lesions on the femoral condyles.
Zamborsky and Danisovic conducted a systematic review and meta-analysis of RCT and found that there were significantly higher failure rates after MF compared to ACI at 10-year follow-up. Their study showed significantly more excellent or good results at the > 3-year follow-up when comparing OAT and MF, whereas MF had significantly more poor results versus ACI and MACI. Additionally, OAT had significantly more poor results over MACI at the 1-year follow-up period. Furthermore, OAT resulted in higher return to activity rates than MF at all time points (1-, 3- to 5- and 10-year).48x48Zamborsky, R and Danisovic, L. Surgical Techniques for Knee Cartilage Repair: An Updated Large-Scale Systematic Review and Network Meta-analysis of Randomized Controlled Trials. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2020;
36: 845–858https://doi.org/10.1016/j.arthro.2019.11.096 Abstract | Full Text | Full Text PDF | PubMed | Scopus (33) | Google ScholarSee all References
Conclusions
Osteochondral grafting is a scientifically validated and intuitively reasonable approach to the treatment of osteoarticular defects, as it is the only restorative method that reintroduces structurally mature and appropriate hyaline and subchondral tissue into acquired articular surface defects. While both graft sources represent a common cartilage organ transplantation paradigm and are complementary, each of the graft sources has its unique, reciprocal challenges with regard to tissue availability and safety. The discerning surgeon is responsible for communicating these considerations to the patient, appropriately weighing them in the treatment algorithm and managing them accordingly.
Autograft is immediately, yet not abundantly, available and, thus, limited in its application, while allograft tissue must be allocated and processed, but allows solid, orthotopic reconstruction of even very large and topographically complex defects. Autologous tissue is theoretically safer to use and is not antigenic, but its use carries the tangible risk of donor site morbidity.
The surgical technique for either method is uncomplicated and reproducible, but requires precision to obtain predictable and reliable results. Clinical applications continue to evolve in regards to other joints and optimizing implant quality, both through adjustments in the methods of harvest and delivery, as well as modulation of the graft environment, especially during the storage interval. Technical advances and tissue engineering hold promise for allogeneic chondrocytes as a cell source and improving scaffold design to further optimize retro-– and, especially, anterograde defect coverage.
The author(s) should confirm that written informed consent has been obtained from the involved patient(s) or if appropriate from the parent, guardian, power of attorney of the involved patient(s); and, they have given approval for this information to be published in this case report (series).
Please refer to Elsevier's policy regarding written patient consent requirements https://www.elsevier.com/about/policies/patient-consent#:∼:text=That%20individual%2C%20legal%20guardian%20or,writing%20of%20all%20such%20conditions
The authors declare that informed patient consent was not provided for the following reason:
Declaration of Competing Interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
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