Osteochondral Allograft Transplantation Research Articles

Sport-specific Differences in Cartilage Treatment.

Articular cartilage defects in the knee are common in athletes who have a variety of loading demands across the knee. Athletes of different sports may have different baseline risk of injury. The most studied sports in terms of prevalence and treatment of cartilage injuries include soccer (football), American football, and basketball. At this time, the authors do not specifically treat patients by their sport; however, return to sports timing may be earlier in sports with fewer demands on the knee based on the rehabilitation protocol. If conservative management is unsuccessful, the authors typically perform a staging arthroscopy with chondroplasty, followed by osteochondral allograft transplantation with possible additional concomitant procedures, such as osteotomies or meniscal transplants. Athletes in a variety of sports and at high levels of competition can successfully return to sports with the appropriate considerations and treatment.

Outcomes After Single-Stage Anatomic Multiligament Knee Reconstruction With Early Range of Motion in Adolescents.

Multiligament knee injuries (MLKI), rare in adolescents, are challenging injuries that require complex surgical reconstruction. Historically, nonanatomic reconstructions have been associated with prolonged immobilization and failure to restore normal knee biomechanics, resulting in arthrofibrosis and high rates of graft failure. To describe the clinical and patient-reported outcomes (PROs) for adolescent patients treated with single-stage anatomic multiligament knee reconstruction. Case series; Level of evidence, 4. A single-center retrospective study was performed of patients ≤18 years old who underwent reconstruction of MLKIs by a single surgeon between 2014 and 2019 using a single-stage anatomic technique, with protected weightbearing and early range of motion. Complications were defined as infection, arthrofibrosis, deep vein thrombosis (DVT) or pulmonary embolus, and secondary surgery. PROs, including the pediatric version of the International Knee Documentation Committee (Pedi-IKDC) and the Tegner activity score, were obtained at a minimum of 2 years postoperatively. Included were 30 patients (21 male, 9 female; mean age, 15.4 years). The most common ligamentous reconstruction types were anterior cruciate ligament (ACL) + fibular collateral ligament (12 patients; 40%) and ACL + medial collateral ligament (9 patients; 30%). Three patients (10%) had secondary surgeries, including irrigation and debridement of a granuloma, a staged osteochondral allograft transplantation to a lateral femoral condyle impaction fracture, and repair of a medial meniscal tear and lateral femoral condyle fracture associated with new injuries 2 years after ACL + fibular collateral ligament reconstruction. Two patients (7%) developed arthrofibrosis and 1 patient (3%) developed DVT. PRO scores obtained at a mean of 37 months postoperatively included a mean Pedi-IKDC of 87 (range, 52-92) and a median highest Tegner score at any point postoperatively of 9 (range, 5-10). Of the patients who were athletes before their injury, 70% returned to the same or higher level of sport postoperatively. Reconstruction of MLKI in this series of adolescents with single-stage anatomic techniques and early range of motion resulted in low rates of secondary surgery, few complications, and good knee function as well as PRO scores at mean 3-year follow-up.

Cell-Mediated Immune Responses May Play Roles in Osteochondral Allograft Transplantation Osteointegration Failures.

Prolonged and incomplete osteochondral allograft (OCA) osteointegration is consistently cited as a major mechanism for OCA treatment failure. Subrejection immune responses may play roles in this mode of failure. Preimplantation OCA preparation techniques, including subchondral bone drilling, thorough irrigation, and autogenous bone marrow aspirate concentrate saturation, may dampen immune responses and improve OCA osteointegration. This study sought to further characterize potential immune system contributions to OCA transplantation treatment failures by analyzing donor-recipient ABO and Rh-factor mismatches and histological and immunohistochemical assessments of transplanted OCA tissues recovered from revision surgeries. Using a dedicated registry, OCA transplant recipients with documented treatment failures who met inclusion criteria (n = 33) as well as age-, body mass index-, and joint-matched patients with successful outcomes (n = 70) were analyzed to compare matched cohorts of patients with successful versus failed OCA transplantation outcomes. Tissues recovered from 18 failed OCA transplants and portions of 7 nonimplanted OCA controls were further analyzed to provide contributing evidence for potential immune response mechanisms. For patients analyzed, no statistically significant differences in proportions for treatment success versus failure based on mismatches for ABO type, Rh factor, or both were noted. Further, no statistically significant differences in proportions for histological immune response presence or absence based on mismatches for ABO type, Rh factor, or both were noted. Twelve (67%) of the failed OCA tissues contained lymphocyte aggregations in the subchondral bone, which were comprised of combinations of CD3 + , CD4 + , CD8 + , and CD20+ lymphocytes. The mechanisms of failure for these 12 OCA transplants involved insufficient OCA osteointegration. Results of this study suggest that T- and B-cell-mediated subrejection immune responses may play roles in OCA transplant treatment failures independent of donor-recipient blood type mismatch effects.

Strong Correlation Between Femoral Condyle Radius of Curvature and Anterior-Posterior Length

Background: The radius of curvature (ROC) of the femoral condyle is a factor in potential cartilage incongruities following osteochondral allograft (OCA) transplantation. Accurate restoration of the chondral surface may be achievable by using “best-fit” donor-recipient matching based on linear femorotibial dimensions, such as the femoral condyle anterior-posterior length (APL), femoral condyle width (lateral-medial length, LML), femoral hemicondyle width (HCW), and tibial plateau width (TPW), particularly if they correlate well with the ROC. This study aimed to investigate the correlative relationship between femorotibial dimensions and the ROC. Methods: Computed tomography (CT) scans from 49 patients (31 men 28 ± 10 years old and 18 women 27 ± 6 years old) were analyzed. Axial images were used for APL and LML measurements, while coronal images were used for HCW and TPW. True sagittal images of the medial femoral condyle (MFC) and lateral femoral condyle (LFC) were used to calculate their individual ROCs by determining the best-fit circles along the condylar surface. Linear regression models were used to determine the relationship between the femorotibial dimensions and ROC. Measurements were repeated for a randomly selected subset of the data, and intraclass correlation coefficients (ICCs) were calculated to investigate intra- and interobserver reliability. Results: All femorotibial dimensions showed significant correlations with the MFC and LFC ROCs (p < 0.01). The ROC correlations with femorotibial dimensions were found to be in the following descending order: APL (R2 ≥ 0.83), LML (R2 ≥ 0.52), TPW (R2 ≥ 0.36), and HCW (R2 ≥ 0.27). The intra- and interobserver reliabilities for the APL (ICC > 0.98) and ROC (ICC > 0.94) were excellent. Conclusions: The ROC was strongly correlated with the APL of the MFC and LFC. Donor-recipient APL matching in OCA transplantation may provide a level of matching similar to that achievable by direct ROC measurements. Clinical Relevance: Determining the most predictive femorotibial dimension for ROC restoration in the OCA matching process may improve clinical outcomes, particularly for patients with large osteochondral lesions.

Arthroscopic Measurements Predict Knee Chondral Lesion Size More Accurately Than Magnetic Resonance Imaging, and Mechanism of Injury Influences Ability of Either Technique to Predict Graft Size

PurposeTo compare osteochondral defect size measurements and characteristics across magnetic resonance imaging (MRI), arthroscopy, and at the time of implantation with osteochondral allograft (OCA) transplantation or autologous chondrocyte implantation (ACI). MethodsPatients who underwent ACI and OCA transplantation at a single institution between 2015 and 2019 were retrospectively identified. Patients were excluded if they had severe osteoarthritis, if MRIs were not available for review, if surgical records did not include defect sizing necessary for analysis, and if operative reports were not available. Osteochondral lesion characteristics including size were collected preoperatively from MRI and arthroscopy and at the time of definitive open surgical intervention. Subgroup analysis was performed comparing measurement techniques depending on the corrective surgical approach used as well as depending on the mechanism of chondral injury to determine if these had any effect on the ability of arthroscopy or MRI to predict graft size. ResultsOverall, 136 chondral lesions were addressed with restoration procedures in 117 patients (mean age 32.5 years). Average difference between final graft size and lesion area measured with index arthroscopy was 116 mm2, while average difference between final graft size and lesion size measured with preoperative MRI was 182 mm2 (P < .001). Depending on surgical technique, measurements with MRI were more similar to final graft size when a patient underwent OCA transplantation versus ACI (P = .007). Depending on mechanism of injury, MRI measurements of lesions were closer to graft area when lesions resulted from trauma (P = .047). ConclusionChondral lesion size determined by preoperative MRI imaging is less accurate than arthroscopic measurements. The mechanism injury leading to chondral damage and degree of damage may influence the ability of MRI and arthroscopy to accurately measure chondral lesions and predict the final graft size used in surgical correction. Level of EvidenceRetrospective Cohort Study (Level III)

Treatment of Medial Patellar Instability With Bipolar Patellofemoral Cartilage Lesions: Staged De-rotational Distal Femoral Osteotomy Followed by Bipolar Osteochondral Allograft Transplantation and Tibial-Tubercle Osteotomy

Background: Patellar instability with symptomatic cartilage lesions in young patients is a challenging problem to treat. The use of osteotomies to correct malalignment and fresh osteochondral allograft transplantation (OCA) to address cartilage lesions and patellofemoral dysplasia is a viable treatment option for carefully selected patients. Indications: The patient is a 22-year-old woman with medial patellar instability caused by iatrogenic distal femoral external rotation and uncontained grade IV patellofemoral lesions. The patient was indicated for OCA because the lesions were too large for an osteochondral autograft transfer system (OATS) and were uncontained and not amenable to autologous chondrocyte implantation. Bipolar OCA also addresses the patient’s patellofemoral dysplasia by restoring a more morphologically normal patellofemoral joint. The external rotation and mild varus deformity are corrected with a biplanar distal femoral osteotomy. Correction of malalignment is necessary prior to OCA transplantation to avoid abnormal graft loading and thereby decrease the risk of graft failure. Technique Description: (1) Diagnostic arthroscopy and fluoroscopic examination under anesthesia. (2) Lateral closing wedge de-rotational distal femoral osteotomy. (3) Bipolar OCA with tibial tubercle osteotomy and removal of hardware. Results: In this case, the patient had significant improvement in her symptoms and had full knee range of motion with a normal gait at 3 months after surgery. Depending on a patient’s preoperative function and the specific pathology, full recovery can take considerably longer. A successful outcome is considered return to activities of daily living without significant pain. Return to higher level athletic activities is significantly more unpredictable. Graft survival of bipolar patellofemoral OCA is variable, and the literature is limited by the small number of procedures performed, but published series range from 60% to 85% at 5 years. Discussion/Conclusion: A successful outcome in these unique, complex cases depends on good patient selection, preoperative planning, and surgical execution. Patellar instability can be reliably treated when the predisposing anatomical factors are appropriately corrected. Bipolar OCA can provide significant improvement in pain and function, but continues to have the highest rate of graft failure compared with other sites within the knee, and should be considered a salvage operation for patients with significant limitations in activities of daily living. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Osteochondral Allograft Transplantation: A Technical Note

Background: Chondral injuries in the knee are commonly discovered during knee arthroscopy procedures. Due to the poor restoration potential and avascular nature of cartilage, large defects are commonly treated with such surgical procedures. Treatment utilizing an osteochondral allograft (OCA) transplant for symptomatic focal cartilage defects in the patellofemoral joint has demonstrated strong, lasting clinical and radiographic outcomes. Indications: Active and otherwise healthy patients are indicated for surgery when presenting with significant joint-line pain and a large focal chondral defect verified on advanced imaging after an extensive course of nonoperative management. Technique Description: Beginning with diagnostic arthroscopy to confirm the large defect of the medial femoral condyle, we proceeded with OCA transplantation. A small medial peripatellar arthrotomy is performed. The fat pad is removed for visualization and retractors are placed both medially and laterally to appropriately visualize the defect. The defect is then sized according to the appropriate sizing guide. The guide is then placed perpendicular to the defect, and a central guide pin is drilled. A scoring reamer is used to carefully cut the size of the defect followed by a central reamer to prepare the defect. Any debris is removed, and the incision is thoroughly irrigated. The defect is then carefully measured in all four quadrants to match the donor. Any underlying bone is impacted for a stable base. A drill is then used for appropriate marrow venting underneath the defect. The corresponding donor site is selected and reamed with continuous irrigation to prevent thermal necrosis. The plug is removed and carefully measured to match the recipient site. The plug is thoroughly irrigated with pulse lavage to remove marrow elements. The graft is carefully inserted with gentle manual pressure until it is seated perfectly flush with the surrounding cartilage. Results: Clinical research has demonstrated good-to-excellent long-term survivorship of OCA transplantation. Long-term return to sport rates for recreational and competitive athletes are upward of 75%. Discussion/Conclusion: As surgical techniques continue to develop, surgeons should consider utilizing OCA transplants to treat large chondral defects in the patellofemoral joint. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

IPhone-Based Cartilage Topography Scanning Yields Similar Results to Computed Tomography Scanning

To investigate the feasibility and accuracy of 3-dimensional (3D) iPhone scans using commercially available applications compared with computed tomography (CT) for mapping chondral surface topography of the knee. Ten cadaveric dysplastic trochleae, 16 patellae, and 24 distal femoral condyles (DFCs) underwent CT scans and 3D scans using 3 separate optical scanning applications on an iPhone X. The 3D surface models were compared by measuring surface-to-surface least distance distribution of overlapped models using a validated 3D-3D registration volume merge method. The absolute least mean square distances for the iPhone-generated models from each scanning application were calculated in comparison to CT models using a point-to-surface distance algorithm allowing regional "inside/outside" measurement of the absolute distance between models. Only 1 of the 3 scanning applications created models usable for quantitative analysis. Overall, there was a median absolute least mean square distance between the usable model and CT-generated models of 0.18 mm. The trochlea group had a significantly lower median absolute least mean square distance compared with the DFC group (0.14 mm [interquartile range, 0.13-0.17] vs 0.19 mm [0.17-0.25], P= .002). iPhone models were smaller compared with CT models (negative signed distances) for all trochleae, 83% of DFCs, and 69% of patellae. In this study, we found minimal differences between a 3D iPhone scanning application and conventional CT scanning when analyzing surface topography. Emerging 3D iPhone scanning technology can create accurate, inexpensive, real-time 3D models of the intended target. Surface topography evaluation may be useful in graft selection during surgical procedures such as osteochondral allograft transplantation.

Osteochondral Allograft Transplantation for the Treatment of an Acetabular Defect: A Case Report.

A 20-year-old woman presented with a unipolar, 1.8 × 1.8-cm osteochondral defect of the left acetabulum. Osteochondral allograft transplantation was performed using a medial tibial plateau allograft resulting in excellent clinical outcomes across 4 different outcome scores and maintenance of the joint space at 4.3 years postoperatively. Although previous literature has demonstrated long-term clinical success of osteochondral allograft transplantation in knee, excellent clinical outcomes can also be obtained in the hip. Thus, osteochondral allograft transplantation may be a viable treatment option for adolescents and young adults with concomitant cartilage and subchondral bone hip defects.

Immune Hypersensitivity Is Associated With Higher Graft Failure Rate After Osteochondral Allograft Transplantation of the Knee

To analyze the effects of 1 or more patient-reported allergies on clinical outcomes, in particular graft failure rate, and patient-reported outcomes (PROs) following osteochondral allograft transplantation (OCA) of the knee. Retrospective review of patients who underwent knee OCA from August 2010 to May 2021 with a minimum of 2-year follow-up. Patients were initially divided into 2 cohorts: those with at least 1 allergy and those without any allergies. Clinical outcomes assessed included graft failure, reoperation rates, deep vein thrombosis/pulmonary embolism, and manipulation under anesthesia/lysis of adhesions (MUA/LOA). PROs assessed, including the visual analog scale (VAS) for pain and satisfaction, the Knee injury and Osteoarthritis Outcome Score (KOOS), and return to sport rates, were compared. In total, 285 patients were included with a mean clinical follow-up of 4.8 ± 2.0 years. The allergy cohort had a significantly higher rate of graft failure (P= .008). In a regression analysis controlling for confounding variables, graft failure remained significantly associated with the presence of medication allergies (odds ratio [OR], 3.631; 95% CI, 1.139-11.577; P= .029). Furthermore, an increasing number of allergies were associated with an increased rate of graft failure (OR, 1.644; 95% CI, 1.074-2.515; P= .022). There was no difference in rate of reoperation, complications, infection, and MUA/LOA. Of the 100 patients who completed PROs, there was no difference in VAS satisfaction, pain, and any of the KOOS outcome scores or return to sport. The presence of 1 or more patient-reported allergies was shown to be significantly associated with OCA graft failure. Furthermore, an increasing number of patient-reported allergies were associated with a higher rate of graft failure. However, there were no significant differences in VAS satisfaction or pain, KOOS symptom, quality of life, pain, or return to sport in patients with at least 1 patient-reported allergy and those without allergies. Level III, retrospective cohort study.

Participation in Sports or Recreational Activities After Osteochondral Allograft Transplantation of the Talus

Background: Fresh osteochondral allograft (OCA) transplantation is a viable treatment option for osteochondral defects of the talus. However, sufficient data are not available on patients’ participation in sports or recreational activities after the procedure. Purpose: To assess whether patients undergoing OCA transplantation of the talus participated in sports or recreational activities postoperatively. Study Design: Case series; level of evidence, 4. Methods: A total of 36 ankles in 34 patients underwent OCA transplantation of the talus. At a mean follow-up of 9.2 years, information on participation in sports or recreational activities pre- and postoperatively was obtained, as well as postoperative pain, function, and satisfaction. Results: The mean age at the time of surgery was 36.1 years (range, 20.5-57.7 years), and 50% of patients were men. The mean graft size was 3.6 cm2 (range, 1-7.2 cm2) or 41.1% of the talar dome. Before the injury, 63.9% of patients (23/36 ankles) reported being highly competitive athletes or well trained and frequently sporting; 36.1% of patients (13/36 ankles) reported sometimes sporting or were nonsporting. Also, 66.7% of patients (24/36 ankles) were able to participate in sports or recreational activities after OCA transplantation and 50% (18/36 ankles) were still participating in sports or recreational activities at the latest follow-up. In a subset of well-trained or highly competitive athletes, 73.9% (17/23 ankles) were able to return to sports or recreational activities at any point after OCA transplantation, and 65.2% (15/23 ankles) were still participating at the latest follow-up. Further surgery occurred in 16.7% of patients (6/36 ankles). Graft survivorship was 94.3% at 5 years and 85.3% at 10 years. There was a significant improvement in the mean Olerud-Molander Ankle Scores, and the mean Foot and Ankle Ability Measure scores were high postoperatively. Moreover, 79.4% of patients (27/34 ankles) were either satisfied or extremely satisfied with the allograft surgery. Conclusion: Fresh OCA transplantation is a reasonable surgical option for osteochondral defects of the talus for young, active patients who have failed previous operative management or have massive defects.

Influence of Concomitant Meniscal Allograft Transplantation on Midterm Outcomes After Osteochondral Allograft Transplantation: A Comparative Matched-Pair Analysis.

Osteochondral allograft transplantation (OCAT) is an accepted knee joint-preserving treatment strategy for focal osteochondral lesions that is often conducted in combination with meniscal allograft transplantation (MAT). Despite its frequent and simultaneous utilization, there remains a lack in the literature reporting on outcomes and failure rates after concomitant procedures. To determine (1) the midterm clinical success rate after OCAT+MAT in comparison with a matched-pair cohort undergoing isolated OCAT, (2) whether patient-specific and procedural variables influence the risk of failure, and (3) patient-reported outcome measures over time. Cohort study; Level of evidence, 3. A single-center matched-pair cohort study was conducted investigating outcomes in patients who underwent OCAT of the medial or lateral femoral condyle with and without MAT between 2004 and 2020. Patients were matched 1:1 by age (±5 years), sex (male or female), body mass index (±5), and grouped Kellgren and Lawrence grade (grades 0-1 or 2-4). The minimum follow-up time was 2 years. Radiographic variables (International Cartilage Regeneration & Joint Preservation Society [ICRS] grade and Kellgren and Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (Lysholm score, Knee injury and Osteoarthritis Outcome Score [KOOS] including subscores, International Knee Documentation Committee [IKDC] score, and visual analog scale score) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery for graft failure or conversion to total knee arthroplasty. Patient-reported, clinical, and radiographic outcomes were compared between groups. In total, 66 patients (33 treated with isolated OCAT, 33 treated with OCAT+MAT; 57.6% male) with a mean age of 26.3 years (range, 18-62 years) were followed for a mean of 5.6 years (minimum, 2 years; range, 24-218 months). The 2 cohorts showed no difference in Kellgren and Lawrence grade postoperatively (P = .59). There was a significantly higher ICRS grade detected at follow-up in the OCAT+MAT group (2.81 ± 1.10) compared with the OCAT group (2.04 ± 0.96) (P < .05). There were no statistically significant differences between the groups regarding reoperation rate (OCAT: n = 6; OCAT+MAT: n = 13; P = .116), time to reoperation (OCAT: 46.67 ± 47.27 months vs OCAT+MAT: 28.08 ± 30.16 months; P = .061), and failure rate (OCAT: n = 4 [12.1%] vs OCAT+MAT: n = 5 [15.2%]; P = .66). In the OCAT+MAT group, an increase of tibial slope by 1° conferred a 1.65-fold increase in the hazard for failure over decreased slope (hazard ratio, 1.65; 95% CI, 1.10-2.50; P < .05). The overall survival rate was 86% at a mean follow-up of 5.6 years. Patient-reported outcome scores were significantly improved at the final follow-up compared with preoperative status. No significant differences were seen between groups with respect to subjective IKDC, Lysholm, Tegner, and KOOS results, except for the KOOS Symptoms subscale score, which was significantly higher in the OCAT+MAT group than in the OCAT group (mean difference, 14.6; P < .05) and did exceed the minimal clinically important difference threshold of 10.7. Midterm results after isolated OCAT and OCAT+MAT show high rates of healing and sustainable subjective improvement of knee function and quality of life. However, it should be noted that the difference in reoperation rate and time to reoperation between the groups is arguably clinically important and that lack of statistical significance may be because of low power. These results imply that isolated OCAT is an efficient joint-preserving treatment that can be combined with MAT in well-selected patients with meniscal insufficiency without negative influence on global clinical outcomes.

New horizons in cartilage repair: update on treatment trends and outcomes

IntroductionArticular cartilage plays a crucial role in preserving the knee joint's structural integrity. Damage can manifest as focal chondral defects or progressive osteoarthritis. Treatment options for knee cartilage damage are multifaceted, encompassing surgical and nonsurgical interventions to repair defects, alleviate symptoms, restore function, and slow disease progression. ObjectivesGain insight and summarize the latest available evidence of knee joint preservation techniques. MethodsThe indications, outcomes, and biological characteristics of operative and nonoperative knee cartilage repair and joint preservation therapies were summarized. ResultsOsteochondral autologous transplantation and osteochondral allograft transplantation offer durable solutions with excellent long-term outcomes. Autologous chondrocyte implantation and matrix-induced autologous chondrocyte implantation are advanced, cell-based therapies effective for larger defects, especially in younger, active individuals. Non-operative therapies such as hyaluronic acid provide symptomatic relief for knee osteoarthritis. Bone marrow aspirate concentrate and platelet-rich plasma show efficacy in alleviating symptoms and improving joint function, presenting a minimally invasive approach with promising results for knee preservation and cartilage repair. ConclusionThe use of minimally invasive and nonsurgical interventions in addressing focal cartilage defects, osteoarthritis, and overall joint preservation has yielded varied results. Although recent literature has exhibited encouraging findings, the existing body of high-level evidence remains limited. The emerging evidence inspires optimism for the future, as medical practitioners shift focus to the next wave of knee cartilage repair and joint preservation methodologies. However, comprehensive research is essential to establish conclusive insights into outcomes, safety profiles, and comparative effectiveness among the diverse available treatments.

Ex vivo storage of human osteochondral allografts: Long-term analysis over 300 days using a Ringer-based solution.

Large osteochondral defects are a major challenge in orthopedics, for which osteochondral allograft (OCA) transplantation is nowadays considered as an option, especially in young patients. However, a major issue with OCA is the need for graft storage, which ensures adequate cartilage integrity over time. The aim of this study was to test how long a Ringer-based storage solution can provide good graft quality after explantation and thus meet the requirements for OCA. For this purpose, human osteochondral allografts of the knee and ankle were analyzed. Live/Dead analysis was performed and glycosaminoglycan, as well as hydroxyproline content, were measured as crucial chondrocyte integrity factors. Furthermore, biomechanical tests focusing on stress relaxation and elastic compression modulus were performed. The critical value of 70% living chondrocytes, which corresponds to a number of 300 cells/mm², was reached after an average of 16 weeks of storage. In addition, a constant cell shrinkage was observed over time. The amount of glycosaminoglycan and hydroxyroline showed a slight and constant decrease over time, but no significant differences when compared from Day 0 to the values at Weeks 40-43. Biomechanical testing also revealed no significant differences at the different time points. Therefore, the results show that the Ringer-based storage solution at 4°C is able to provide a chondrocyte survival of 70% until Week 16. This is comparable to previously published storage solutions. Therefore, the study contributes to the establishment of a Ringer-based osteochondral allograft transplantation system for countries where medium-based storage solution cannot be approved.

Comparison of Outcomes After Primary Versus Salvage Osteochondral Allograft Transplantation for Femoral Condyle Osteochondritis Dissecans Lesions.

Osteochondral allograft transplantation (OCAT) allows the restoration of femoral condyle osteochondritis dissecans (OCD) lesions using an osteochondral unit. When OCD lesions are irreparable, or treatments have failed, OCAT is an appropriate approach for revision or salvage surgery. Based on its relative availability, cost-effectiveness, lack of donor site morbidity, and advances in preservation methods, OCAT is also an attractive option for primary surgical treatment for femoral condyle OCD. OCAT for large femoral condyle OCD lesions would be highly successful (>90%) based on significant improvements in knee pain and function, with no significant differences between primary and salvage procedure outcomes. Cohort study; Level of evidence, 3. Patients were enrolled into a registry for assessing outcomes after OCAT. Those patients who underwent OCAT for femoral condyle OCD and had a minimum of 2-year follow-up were included. Reoperations, treatment failures, and patient-reported outcomes were compared between primary and salvage OCAT cohorts. A total of 22 consecutive patients were included for analysis, with none lost to the 2-year follow-up (mean, 40.3 months; range, 24-82 months). OCD lesions of the medial femoral condyle (n = 17), lateral femoral condyle (n = 4), or both condyles (n = 1) were analyzed. The mean patient age was 25.3 years (range, 12-50 years), and the mean body mass index was 25.2 kg/m2 (range, 17-42 kg/m2). No statistically significant differences were observed between the primary (n = 11) and salvage (n = 11) OCAT cohorts in patient and surgical characteristics. Also, 91% of patients had successful outcomes at a mean of >3 years after OCAT with 1 revision in the primary OCAT cohort and 1 conversion to total knee arthroplasty in the salvage OCAT cohort. For both primary and salvage OCATs, patient-reported measures of pain and function significantly improved at the 1-year and final follow-up, and >90% of patients reported that they were satisfied and would choose OCAT again for treatment. Based on the low treatment failure rates in conjunction with statistically significant and clinically meaningful improvements in patient-reported outcomes, OCAT can be considered an appropriate option for both primary and salvage surgical treatment in patients with irreparable OCD lesions of the femoral condyles.

Osteochondral Allograft Transplantation in the Knee

Osteochondral injuries of the knee can be a frequent source of debilitating pain and dysfunction. Significant chondral (>1.5-2 cm2) lesions of the femoral condyles can be especially difficult to manage with nonsurgical measures. Fresh osteochondral allograft (OCA) transplantation has been shown to be a reliable surgical procedure to manage a wide array of high-grade focal chondral lesions, with or without subchondral bone involvement. OCA transplantation affords the transfer of a size-matched allograft of mature hyaline cartilage with its associated subchondral bony scaffold. Indications include primary or secondary management of large, high-grade chondral or osteochondral defects secondary to trauma, developmental malformation, osteonecrosis, or other focal degenerative disease. Contraindications include end-stage osteoarthritis, uncorrected malalignment, ligament or meniscus deficiency, and inflammatory joint disease. Improvements in surgical technique, allograft storage, and tissue availability have created more reproducible clinical results and increased chondrocyte viability. Long-term (>10 year) graft survival rates have been shown to be between 70% and 91%, and the procedure has been shown to be cost-effective based on cost per quality-adjusted life year. Finally, OCA transplantation has been shown to provide excellent return to play rate for athletes with medium-to-large cartilage lesions. OCA transplantation is therefore an important option in the treatment algorithm of articular cartilage injuries.

Biomechanical properties of articular cartilage in different regions and sites of the knee joint: acquisition of osteochondral allografts

Osteochondral allograft (OCA) transplantation involves grafting of natural hyaline cartilage and supporting subchondral bone into the cartilage defect area to restore its biomechanical and tissue structure. However, differences in biomechanical properties and donor-host matching may impair the integration of articular cartilage (AC). This study analyzed the biomechanical properties of the AC in different regions of different sites of the knee joint and provided a novel approach to OCA transplantation. Intact stifle joints from skeletally mature pigs were collected from a local abattoir less than 8 h after slaughter. OCAs were collected from different regions of the joints. The patella and the tibial plateau were divided into medial and lateral regions, while the trochlea and femoral condyle were divided into six regions. The OCAs were analyzed and compared for Young’s modulus, the compressive modulus, and cartilage thickness. Young’s modulus, cartilage thickness, and compressive modulus of OCA were significantly different in different regions of the joints. A negative correlation was observed between Young's modulus and the proportion of the subchondral bone (r = − 0.4241, P < 0.0001). Cartilage thickness was positively correlated with Young’s modulus (r = 0.4473, P < 0.0001) and the compressive modulus (r = 0.3678, P < 0.0001). During OCA transplantation, OCAs should be transplanted in the same regions, or at the closest possible regions to maintain consistency of the biomechanical properties and cartilage thickness of the donor and recipient, to ensure smooth integration with the surrounding tissue. A 7 mm depth achieved a higher Young's modulus, and may represent the ideal length.

Outcomes and Return to Sport After Knee Osteochondral Allograft Transplant in Professional Athletes.

Limited data are available on the outcomes and return-to-sport rates after osteochondral allograft transplant in professional athletes. To evaluate the experience of a single senior surgeon in treating professional athletes with osteochondral allograft transplant, including analyzing clinical outcomes and return to sport. Case series; Level of evidence, 4. The authors performed a retrospective review of professional athletes treated with primary osteochondral allograft to the knee between January 1, 2001, and January 1, 2021, by a single surgeon. Athletes were required to play at the professional level in their sport and have a minimum of 2 years of follow-up. Return-to-sport rates and timing were evaluated. Patient-reported outcomes were assessed preoperatively and at final follow-up. Reoperations and failures were also tabulated. The study included 15 professional athletes who represented a variety of sports, with follow-up at a mean of 4.91 ± 2.2 years (range, 2.0-9.4 years). The majority (8 athletes; 53%) had undergone prior surgeries to the operative knee. Eleven (73%) returned to sport at a mean of 1.22 ± 0.4 years (range, 0.75-2 years), and of the 8 undergoing isolated osteochondral allograft, 7 (87.5%) returned at 1.28 ± 0.3 years. Ten athletes (66.7% of total; 90.9% of those who returned) returned to sport at the same level or higher compared with before surgery. Significant improvements were seen in each assessed patient-reported outcome score at final follow-up. Two of the 3 (66.7%) patients who underwent concomitant meniscal allograft transplant were able to return to sport at the same level or higher than presurgery. Three (20%) underwent second-look arthroscopy, 1 (6.7%) of whom underwent cartilage debridement of the osteochondral allograft. Osteochondral allograft transplant in professional athletes can result in a high rate of return to play at a similar or higher level as presurgery, even when performed with concomitant procedures such as meniscal allograft transplant. High-level athletes should expect significant postoperative improvement in clinical outcomes.

Increased kinesiophobia leads to lower return to sport rate and clinical outcomes following osteochondral allograft transplantation of the knee.

The purpose of this study is to describe the postoperative psychological state of patients following osteochondral allograft (OCA) transplantation in the knee and to determine whether patient-perceived kinesiophobia is associated with the rate of return to sport (RTS). A retrospective review of the electronic medical record at a single institution was conducted for all patients that underwent OCA transplantation from January 2010 to 2020. Patient-reported outcomes including the visual analog scale (VAS), knee injury and osteoarthritis outcome score (KOOS)and the Tampa scale of kinesiophobia-11 (TSK-11) were collected. Patients were surveyed regarding their postoperative RTS status. A total of 38 patients (52.6% female) were included in our analysis. Overall, 24 patients (63.2%) returned to sport with 12 (50%) of these patients returning at a lower level of play. When comparing patients that return to sport to those that did not, patients that return had significantly superior KOOS pain (p = 0.019) and KOOS QOL (p = 0.011). Measures of kinesiophobia (TSK-11) were significantly higher among patients that did not return to sport (p = 0.014), while satisfaction (n.s.) and pain intensity (n.s.) were comparable between groups. Logistic regression models controlling for demographic factors, VAS pain scoresand lesion size showed that for every one-point increase in TSK-11 kinesiophobia score, patients were 1.33 times more likely to return to sport at a lower level (p = 0.009). For every one-point increase in TSK-11 scores KOOS QOL decreased by 2.4 points (p < 0.001). Fear of reinjury decreases the likelihood that patients will return to their preoperative level of sport after OCA transplantation. Patients that do not return to sport report significantly greater fear of reinjury and inferior clinical outcomes, despite similar levels of satisfaction and pain compared to those that return. Level III.

Osteochondritis Dissecans Lesions of the Knee: Evidence-Based Treatment.

Osteochondritis dissecans (OCD) of the knee is a potentially disabling condition in adolescent and young adults, which is likely multifactorial in origin. In recent years, there have been notable improvements in identification and treatment. Clinical presentation varies based mostly on OCD lesion stability. Patients with stable lesions generally present with vague knee pain and altered gait while mechanical symptoms and effusion are more common with unstable lesions. Lesions most commonly occur on the lateral aspect of the medial femoral condyle in patients aged 10 to 20 years. Magnetic resonance imaging is vital to diagnose and predict clinical treatment, which is largely based on stability of the fragment. Conservative treatment of stable lesions in patients with open physis is recommended with protected weight-bearing and gradual progression of activities over the course of 3 to 6 months. Stable OCD lesions which failed a nonsurgical course can be treated with transarticular or retrograde drilling while unstable lesions usually require fixation, autologous chondrocyte implantation (ACI), osteochondral autograft transfer (OATS), or osteochondral allograft transplantation. This review highlights the most current understanding of knee OCD lesions and treatment options with the goal of optimizing outcomes in this difficult pathology.