Osteochondral Allograft Transplantation in Patients With Osteochondritis Dissecans of the Knee

Single-plug osteochondral autograft transplantation for knee osteochondritis dissecans: Clinical improvement and long-term survivorship at a minimum ten year follow-up

PURPOSE

Osteochondritis dissecans (OCD) can lead to detrimental effects in the affected joints. Osteochondral autologous transplantation (OAT) allows to restore the articular surface with an autologous osteochondral unit. While short-term results are documented, there is a lack of long-term data. Aim of this study was to analyze the long-term clinical results of single-plug OAT for the treatment of knee OCD.

METHODS

Twenty patients (14 men, 6 women) were treated with single plug-OAT. Mean age was 23.6 ± 9.9 years and BMI was 23.3 ± 3.6 kg/m2. Lesion size was 2.3 ± 1.6 cm2 and defects included 14 medial femoral condyles (MFC) and 6 lateral femoral condyles (LFC). Patients were followed up prospectively at baseline, 24 months, 60 months, and at minimum ten years (12.6 ± 2.0 years) using the IKDC subjective score and through an overall judgment on treatment satisfaction. The activity level was evaluated with the Tegner score and adverse events and failures were also recorded. Factors influencing the clinical outcomes, including age, sex, BMI, lesions size, and lesion location were also investigated.

RESULTS

No severe adverse events and no surgical failures were reported and 85.0% of patients were satisfied at a minimum ten year follow-up. Subjective IKDC showed a significant and stable improvement at all follow-ups, passing from 45.3 ± 16.5 at baseline to 73.7 ± 16.6 at 24 months (p < 0.0005), to 72.9 ± 16.6 at 60 months (p < 0.0005), and to 74.1 ± 20.8 at long-term follow-up (p < 0.0005). Patients with OCD lesions localized on the LFC obtained lower results compared to those with MFC lesions at two years and five years (p = 0.034 and p = 0.023). The highest long-term scores were obtained in patients with lesion size lower than 2 cm2 (89.1 ± 8.8) compared to patients with lesion size between 2 and 4 cm2 (69.2 ± 15.7), and patients with lesion size larger than 4 cm2 (63.8 ± 34.6).

CONCLUSIONS

OAT is a suitable technique to treat knee OCD in young patients and offers a high patient satisfaction and a significant improvement in terms of clinical subjective scores, with results remaining stable over time, although without reaching the pre-injury activity level. No severe adverse events and no surgical failures have been documented confirming OAT as a valid treatment option, although the best long-term results for lesions smaller than 2 cm2 and for MFC lesions should be considered when choosing this procedure to address knee OCD lesions.

Do reconstructive techniques for osteochondritis dissecans of the skeletally mature knee work? A systematic review and meta-analysis

PURPOSE

Osteochondritis dissecans (OCD) is a common cause of knee pain. Management for adult-onset OCD (AOCD) usually involves surgery. Surgical treatments include palliative, reparative and reconstructive techniques. The aim of this systematic review and meta-analysis is to evaluate the efficacy of reconstructive techniques for the treatment of OCD in skeletally mature knees.

METHODS

A systematic search was carried out on four databases up to November 2023 (Medline, Embase, Cochrane Library, Web of Science). The study was registered on international prospective register of systematic reviews and performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Clinical studies on skeletally mature patients were included, which utilised reconstructive techniques such as autologous chondrocyte implantation (ACI), matrix-induced autologous chondrocyte implantation, osteochondral allograft transplantation surgery or bone marrow-derived cellular transplantation. Demographical data, patient-reported outcome measures and postoperative complications were recorded. Quantitative outcome measures that were comparable across studies were pooled for meta-analysis. A random effects model was used. Heterogeneity was assessed using the I2 statistic and Cochran's Q test. Statistical significance was set at p < 0.05. Risk of bias was assessed using the risk of bias in non-randomised studies - of interventions tool for nonrandomised studies.

RESULTS

Sixteen studies were included with 458 OCD lesions in 432 patients. The average age was 24.9, and 62.6% were male. The mean follow-up time was 61.5 months. At 36 months follow-up, International Knee Documentation Committee (IKDC) subjective, Tegner and EuroQol-visual analogue scale (EQ-VAS) scores improved from 42.4 to 78.6 (standard mean difference [SMD]: 2.47; p < 0.001), 2.27-4.99 (SMD: 2.363; p = 0.002) and 30.4-57.5 (SMD: 2.390; p < 0.001), respectively. Overall complication rate was 8.9%. Smaller OCD lesion sizes resulted in a greater improvement in IKDC subjective (SMD: 2.64 vs. 2.01; p = 0.038), EQ-VAS (SMD: 3.16 vs. 0.95; p = 0.046) and Tegner scores (SMD: 3.13 vs. 1.05; p = 0.007) and had a lower complication rate (p = 0.008). Males showed a larger improvement in IKDC subjective scores than females (SMD: 2.56 vs. 1.56; p = 0.029), while younger patients had a larger improvement in IKDC subjective scores (SMD: 2.71 vs. 2.12; p = 0.045) and fewer complications than older patients (p = 0.003). There were no significant differences between cohorts treated with ACI and those treated with non-ACI reconstructive techniques. Publication bias was not detected (n.s.).

CONCLUSION

Reconstructive techniques used to treat OCD in the skeletally mature knee resulted in significant improvements in clinical and functional outcomes, with a low overall complication rate. Since a younger age leads to a greater improvement in IKDC subjective score and a lower complication rate, surgical intervention should not be delayed, especially in AOCD lesions which are more likely to follow a progressive and unremitting clinical course.

LEVEL OF EVIDENCE

Level III.

Fresh osteochondral allograft transplantation for knee full-thickness articular cartilage lesions using femoral head of living donors: short-term results

BACKGROUND

Fresh osteochondral allograft transplantation is a good treatment option of cartilage defects. However, this treatment option is not available in all countries due to limited graft availability and tissue banks limitations. The purpose of this study is to assess the short term functional and imaging outcomes of fresh osteochondral allograft transplantation in the knee using the femoral head of living donors.

HYPOTHESIS

Fresh osteochondral allografts from the femoral heads of living donors is a valid graft source for management of distal Femur cartilage defects. This technique can improve functional knee scores with good radiological outcomes.

STUDY DESIGN

Prospective case series.

METHODS

Fifteen patients with full thickness cartilage defects of the distal femur underwent osteochondral allograft transplantation from the femoral heads of living donors. Grafts were transplanted by both shell and multiple dowels techniques. The average follow up duration was 18.3 months (range, 12-25 months). Patients were evaluated by Lysholm and International Knee Documentation Committee (IKDC) scores, radiography and MR imaging using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

There was a statistically significant improvement (P < 0.001) in both Lysholm and IKDC average scores at 6 months and 12 months postoperative. Postoperative MRI was done at an average 6.8 months (range, 5-11 months) postoperative. The mean total OCAMRISS score was 3.4 (range, 1-7). A second look arthroscopy was done in four patients and showed intact articular cartilage in all three patients.

CONCLUSION

Femoral head of living donors is a valid new source for fresh osteochondral allograft transplantation of knee osteochondral lesions. Short term results showed improvement in clinical assessment scores. Follow up imaging showed graft incorporation and good MRI scores.

A Unique Approach to Irreparable Radial Head Fracture Using an Osteochondral Plug: A Case Report

CASE

An 18-year-old male patient sustained a traumatic injury that resulted in the loss of approximately 50% of the radial head. Subsequently, reconstruction was performed by transplanting an osteochondral plug harvested from the lateral femoral condyle. At the 1-year postoperative follow-up, the patient was pain-free and had a good range of motion.

CONCLUSION

Using a novel technique, an irreparable radial head fracture was reconstructed using an osteochondral plug from the lateral femoral condyle. Reconstruction with osteochondral plugs may be a treatment option for partial loss of the radial head.

The role of autologous bone grafting in matrix-associated autologous chondrocyte implantation at the knee: Results from the German Cartilage Registry (KnorpelRegister DGOU)

PURPOSE

To investigate whether concomitant autologous bone grafting adversely affects clinical outcome and graft survival after matrix-associated autologous chondrocyte implantation (M-ACI).

METHODS

The present study examines registry data of patients who underwent M-ACI with or without autologous bone grafting for large-sized chondral or osteochondral defects. Propensity score matching was performed to exclude potential confounders. A total of 215 patients with similar baseline characteristics were identified. Clinical outcome was assessed at the time of surgery and at 6, 12, 24, 36 and 60 months using the Knee Injury and Osteoarthritis Outcome Score (KOOS). KOOS change, clinical response rate, KOOS subcomponents and failure rate were determined.

RESULTS

Patients treated with M-ACI and autologous bone grafting achieved comparable clinical outcomes compared with M-ACI alone. At 24 months postoperatively, the patient-reported outcome (PRO) of patients treated with M-ACI and autologous bone grafting was even significantly better as measured by KOOS (74.9 ± 18.8 vs. 79.2 ± 15.4; p = 0.043). However, the difference did not exceed the minimal clinically important difference (MCID). In patients with M-ACI and autologous bone grafting, a greater change in KOOS relative to baseline was observed at 6 (9.3 ± 14.7 vs. 15.0 ± 14.7; p = 0.004) and 12 months (12.6 ± 17.2 vs. 17.7 ± 14.6; p = 0.035). Overall, a high clinical response rate was observed in both groups at 24 months (75.8% vs. 82.0%; p = n.s.). The estimated survival at the endpoint of reoperation for any reason was 82.1% (SD 2.8) at 8.4 years for isolated M-ACI and 88.7% (SD 2.4) at 8.2 years for M-ACI with autologous bone grafting (p = 0.039).

CONCLUSIONS

Even in the challenging cohort of large osteochondral defects, the additional treatment with autologous bone grafting leads to remarkably good clinical outcomes in patients treated with M-ACI. In fact, they tend to benefit more from surgery, have lower revision rates and achieve clinical response rates earlier. Subchondral bone management is critical to the success of M-ACI and should be addressed in the treatment of borderline defects.

LEVEL OF EVIDENCE

Level III.

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

Background

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.

Hypothesis

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.

Study Design

Cohort study; Level of evidence, 3.

Methods

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.

Results

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.

Conclusion

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.

Young Age and Concomitant or Prior Bony Realignment Procedures are Associated with Decreased Risk of Failure of Osteochondral Allograft Transplantation in the Knee: A Nationwide Database Study

OBJECTIVE

Osteochondral allograft (OCA) transplantation is a restorative surgical option for large, full-thickness chondral or osteochondral defects in the knee. Variability in outcomes reporting has led to a broad range of graft survival rates. Using rate of salvage surgery following OCA as a failure metric, the purpose of this study was to analyze the incidence and risk factors for failure in a nationwide cohort.

DESIGN

The M151Ortho PearlDiver database was queried for patients aged 20 to 59 who underwent primary OCA between 2010 and 2020. Patients with prior cartilage procedures or arthroplasty were excluded. Kaplan-Meier survival analysis was performed to characterize cumulative rate of salvage surgery, defined as any patient subsequently undergoing revision OCA, autologous chondrocyte implantation (ACI), osteochondral autograft transfer system (OATS), unicompartmental knee arthroplasty (UKA), or total knee arthroplasty (TKA). Multivariable logistic regression was used to determine the effect of several variables on odds of salvage surgery.

RESULTS

Around 6,391 patients met inclusion criteria. Cumulative 5-year salvage rate was 1.71%, with 68.8% in the first 2 years. Age 20 to 29 and concomitant or prior bony realignment procedures were associated with significantly decreased rate of salvage surgery (age-adjusted odds ratio [aOR] = 0.49, 95% confidence interval [CI], 0.24-0.99, P = 0.046; realignment-aOR = 0.24, 95% CI, 0.04-0.75, P = 0.046).

CONCLUSIONS

In the largest OCA cohort studied to date, less than 2% of patients required salvage surgery. Young age and bony realignment were protective. These findings suggest that OCA in the knee is a durable cartilage-restoration procedure, especially in young patients with corrected alignment.

A systematic review of cartilage procedures for unstable osteochondritis dissecans

OBJECTIVES

Osteochondritis dissecans can result in significant limitations in activity, pain, and early osteoarthritis. There are various treatment modalities to address these defects. The purpose of this study was to provide a qualitative summary of the various treatment options for unstable osteochondritis dissecans in the knee.

METHODS

A literature search was performed on osteochondritis dissecans in the knee using PubMed (MEDLINE), Embase, and Cochrane electronic databases. The search was completed using a combination of the following terms: 'osteochondritis dissecans,' 'OCD,' 'osteochondral,' 'articular cartilage,' 'repair,' 'surgery,' 'treatment,' 'osteochondral allograft,' 'autologous chondrocyte implantation,' 'unstable,' 'knee,' 'clinical studies.'

RESULTS

A total of 682 studies were found, of which 24 were included in the qualitative analysis. The quality score ranged from 46 to 80, and the mean follow-up ranged from 2 to 17 years. The most common surgical procedures were internal fixation (n = 7 studies), ACI (n = 6), fragment excision (n = 3), MACI (n = 2), bone graft + ACI (n = 2), OCA (n = 2), mosaicplasty/OAT (n = 2), and scaffold (n = 2). Overall, the reported outcome measures were heterogeneous in nature. Post-operative International Knee Documentations Committee (IKDC) scores ranged from 75 to 85 and Lysholm scores ranged from 70 to 93.5. Tegner scores ranged from 4 to 5. Rates of failure, complication, and revision were highly variable across studies and surgical techniques.

CONCLUSION

There are a variety of surgical options for the treatment of unstable osteochondritis dissecans. In skeletally immature patients, internal fixation demonstrated acceptable rates of radiographic union and patient reported outcome measures. In skeletally mature patients with large lesions, MACI and OCA transplantation provided similar patient reported outcomes.

Cartilage thickness mismatches in patellar osteochondral allograft transplants affect local cartilage stresses

Osteochondral allograft implantation is a form of cartilage transplant in which a cylindrical graft of cartilage and subchondral bone from a donor is implanted into a patient's prepared articular defect site. No standard exists for matching the cartilage thickness of the donor and recipient. The goal of this study was to use finite element (FE) analysis to identify the effect of cartilage thickness mismatches between donor and recipient cartilage on cartilage stresses in patellar transplants. Two types of FE models were used: patient-specific 3D models and simplified 2D models. 3D models highlighted which geometric features produced high-stress regions in the patellar cartilage and provided ranges for the parameter sweeps that were conducted with 2D models. 2D models revealed that larger thickness mismatches, thicker recipient cartilage, and a donor-to-recipient cartilage thickness ratio (DRCR) < 1 led to higher stresses at the interface between the donor and recipient cartilage. A surface angle between the donor-recipient cartilage interface and cartilage surface normal near the graft boundary increased stresses when DRCR > 1, with the largest increase observed for an angle of 15°. A surface angle decreased stresses when DRCR < 1. Clinical Significance: This study highlights a potential mechanism to explain the high rates of failure of patellar OCAs. Additionally, the relationship between geometric features and stresses explored in this study led to a hypothetical scoring system that indicates which transplanted patellar grafts may have a higher risk of failure.

Hyperplastic Human Macromass Cartilage for Joint Regeneration

Cartilage damage affects millions of people worldwide. Tissue engineering strategies hold the promise to provide off-the-shelf cartilage analogs for tissue transplantation in cartilage repair. However, current strategies hardly generate sufficient grafts, as tissues cannot maintain size growth and cartilaginous phenotypes simultaneously. Herein, a step-wise strategy is developed for fabricating expandable human macromass cartilage (macro-cartilage) in a 3D condition by employing human polydactyly chondrocytes and a screen-defined serum-free customized culture (CC). CC-induced chondrocytes demonstrate improved cell plasticity, expressing chondrogenic biomarkers after a 14.59-times expansion. Crucially, CC-chondrocytes form large-size cartilage tissues with average diameters of 3.25 ± 0.05 mm, exhibiting abundant homogenous matrix and intact structure without a necrotic core. Compared with typical culture, the cell yield in CC increases 2.57 times, and the expression of cartilage marker collagen type II increases 4.70 times. Transcriptomics reveal that this step-wise culture drives a proliferation-to-differentiation process through an intermediate plastic stage, and CC-chondrocytes undergo a chondral lineage-specific differentiation with an activated metabolism. Animal studies show that CC macro-cartilage maintains a hyaline-like cartilage phenotype in vivo and significantly promotes the healing of large cartilage defects. Overall, an efficient expansion of human macro-cartilage with superior regenerative plasticity is achieved, providing a promising strategy for joint regeneration.

Characteristics and Clinical Outcomes After Osteochondral Allograft Transplantation for Treating Articular Cartilage Defects: Systematic Review and Single-Arm Meta-analysis of Studies From 2001 to 2020

Background

Osteochondral allograft transplantation (OCA) treats symptomatic focal cartilage defects with satisfactory clinical results.

Purpose

To comprehensively analyze the characteristics and clinical outcomes of OCA for treating articular cartilage defects.

Study Design

Systematic review; Level of evidence, 4.

Methods

We searched Embase, PubMed, Cochrane Database, and Web of Science for studies published between January 1, 2001, and December 31, 2020, on OCA for treating articular cartilage defects. Publication information, patient data, osteochondral allograft storage details, and clinical outcomes were extracted to conduct a comprehensive summative analysis.

Results

In total, 105 studies involving 5952 patients were included. The annual reported number of patients treated with OCA increased from 69 in 2001 to 1065 in 2020, peaking at 1504 cases in 2018. Most studies (90.1%) were performed in the United States. The mean age at surgery was 34.2 years, and 60.8% of patients were male and had a mean body mass index of 26.7 kg/m2. The mean lesion area was 5.05 cm2, the mean follow-up duration was 54.39 months, the mean graft size was 6.85 cm2, and the number of grafts per patient was 54.7. The failure rate after OCA was 18.8%, and 83.1% of patients reported satisfactory results. Allograft survival rates at 2, 5, 10, 15, 20, and 25 years were 94%, 87.9%, 80%, 73%, 55%, and 59.4%, respectively. OCA was mainly performed on the knee (88.9%). The most common diagnosis in the knee was osteochondritis dissecans (37.9%), and the most common defect location was the medial femoral condyle (52%). The most common concomitant procedures were high tibial osteotomy (28.4%) and meniscal allograft transplantation (24.7%). After OCA failure, 54.7% of patients underwent revision with primary total knee arthroplasty.

Conclusion

The annual reported number of patients who underwent OCA showed a significant upward trend, especially from 2016 to 2020. Patients receiving OCA were predominantly young male adults with a high body mass index. OCA was more established for knee cartilage than an injury at other sites, and its best indication was osteochondritis dissecans. This analysis demonstrated satisfactory long-term postoperative outcomes.

Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Focal cartilage lesions of the knee remain a difficult entity to treat. Current treatment options include arthroscopic debridement, microfracture, autograft or allograft osteochondral transplantation, and cell-based therapies such as autologous chondrocyte transplantation. Osteochondral transplantation techniques restore the normal topography of the condyles and provide mature hyaline cartilage in a single-stage procedure. However, clinical outcomes comparing autograft versus allograft techniques are scarce.

PURPOSE

To perform a comprehensive systematic review and meta-analysis of high-quality studies to evaluate the results of osteochondral autograft and allograft transplantation for the treatment of symptomatic cartilage defects of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 2.

METHODS

A comprehensive search of the literature was conducted using various databases. Inclusion criteria were level 1 or 2 original studies, studies with patients reporting knee cartilage injuries and chondral defects, mean follow-up ≥2 years, and studies focusing on osteochondral transplant techniques. Exclusion criteria were studies with nonknee chondral defects, studies reporting clinical outcomes of osteochondral autograft or allograft combined with other procedures, animal studies, cadaveric studies, non-English language studies, case reports, and reviews or editorials. Primary outcomes included patient-reported outcomes and failure rates associated with both techniques, and factors such as lesion size, age, sex, and the number of plugs transplanted were assessed. Metaregression using a mixed-effects model was utilized for meta-analyses.

RESULTS

The search resulted in 20 included studies with 364 cases of osteochondral autograft and 272 cases of osteochondral allograft. Mean postoperative survival was 88.2% in the osteochondral autograft cohort as compared with 87.2% in the osteochondral allograft cohort at 5.4 and 5.2 years, respectively (P = .6605). Patient-reported outcomes improved by an average of 65.1% and 81.1% after osteochondral autograft and allograft, respectively (P = .0001). However, meta-analysis revealed no significant difference in patient-reported outcome percentage change between osteochondral autograft and allograft (P = .97) and a coefficient of 0.033 (95% CI, -1.91 to 1.98). Meta-analysis of the relative risk of graft failure after osteochondral autograft versus allograft showed no significant differences (P = .66) and a coefficient of 0.114 (95% CI, -0.46 to 0.69). Furthermore, the regression did not find other predictors (mean age, percentage of female patients, lesion size, number of plugs/grafts used, and treatment location) that may have significantly affected patient-reported outcome percentage change or postoperative failure between osteochondral autograft versus allograft.

CONCLUSION

Osteochondral autograft and allograft result in favorable patient-reported outcomes and graft survival rates at medium-term follow-up. While predictors for outcomes such as mean age, percentage of female patients, lesion size, number of plugs/grafts used, and treatment location did not affect the comparison of the 2 cohorts, proper patient selection for either procedure remains paramount to the success and potentially long-term viability of the graft.

Osteochondral Allografts for Large Oval Defects of the Medial Femoral Condyle: A Comparison of Single Lateral Versus Medial Femoral Condyle Oval Grafts Versus 2 Overlapping Circular Grafts

BACKGROUND

Studies have demonstrated the acceptability of using a contralateral nonorthotopic lateral femoral condyle (LFC) graft for a circular medial femoral condyle (MFC) osteochondral defect up to 20 to 25 mm in diameter. Larger oblong defects can now be managed using either overlapping circle grafts or a single oblong-shaped osteochondral allograft (OCA).

PURPOSE

To determine if an oblong contralateral nonorthotopic LFC OCA can attain an acceptable surface contour match compared with an oblong ipsilateral MFC OCA or an overlapping circle technique for large oblong defects of the MFC.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 120 fresh-frozen human femoral condyles were matched by tibial width into 30 groups of 4 condyles (1 recipient MFC, 3 donor condyles). The recipient MFC was initially imaged using nano-computed tomography (nano-CT). A 17 × 36-mm oblong defect was created in the recipient MFC. Overall, 3 donor groups were formed: MFC oblong, LFC nonorthotopic oblong, LFC or MFC overlapping circles. After each transplant, the recipient condyle underwent nano-CT and was digitally reconstructed, which was superimposed on the initial nano-CT scan of the native recipient condyle. Dragonfly 3D software was used to determine the root mean square (RMS) of both the surface height deviation and the circumferential step-off height deviation between the native and donor cartilage surfaces for each graft.

RESULTS

RMS surface height deviations were as follows: 0.59 mm for MFC oblong grafts, 0.58 mm for LFC oblong grafts, and 0.78 mm for overlapping circle grafts. The MFC and LFC oblong grafts had significantly less surface height deviation than the overlapping circle grafts (P = .004 and P = .002, respectively). RMS step-off height deviations were as follows: 0.68 mm for MFC oblong grafts, 0.70 mm for LFC oblong grafts, and 0.85 mm for overlapping circle grafts. The MFC and LFC oblong grafts had significantly less step-off height deviation than the overlapping circle grafts (P < .001 and P = .002, respectively). The majority of this difference was on the medial segment of the overlapping circle grafts.

CONCLUSION

Oblong ipsilateral MFC OCAs and oblong contralateral nonorthotopic LFC OCAs produced a significantly better surface contour match to the native MFC than overlapping circle grafts for oblong defects 17 × 36 mm in size.

CLINICAL RELEVANCE

Size-matched contralateral nonorthotopic LFC grafts are acceptable for MFC defects, which may allow for a quicker match, earlier patient care, and less wastage of valuable donor tissue.

Reoperation After Osteochondral Autograft and Allograft Transfer in the Pediatric Knee

Osteochondral autograft (OAU) transfer and osteochondral allograft (OAL) transfer are options for treating sizable articular cartilage lesions in the knee, but there is little evidence to support one technique over another. The goal of this study is to compare the rate of reoperation among children and adolescents undergoing OAU or OAL of the knee. In this retrospective cohort study, the Pediatric Health Information System, a national database consisting of 49 children's hospitals, was queried for all patients undergoing OAU and OAL between 2012 and 2018. A total of 732 subjects with a mean age of 15.4±2.4 years were included. Of these, 393 (53.7%) initially underwent OAL and 339 (46.3%) underwent OAU. The overall reoperation rate was 144 of 732 (19.7%) at a median of 6.6 months (range, 0.6-53.5 months) after the index operation. This rate was similar for OAL and OAU. For 18 subjects (2.5%), OAU, OAL, or autologous chondrocyte implantation (ACI) was performed at the time of revision surgery. When analyzing only open procedures, we found that the reoperation rate was 25.5% for open OAU compared with 16.5% for open OAL (P=.03). When adjusting for covariates in multivariate regression, we found that those who underwent open OAU had 1.7 times higher odds of requiring a future reoperation than those who underwent open OAL (95% CI, 1.1-2.8; P=.04). Although the rate of reoperation after OAU or OAL among children and adolescents is relatively high, few require revision OAU, OAL, or ACI. Patients undergoing open OAU have higher odds of ultimately requiring reoperation than those undergoing open OAL. [Orthopedics. 2022;45(6):378-383.].

Osteochondral Allografts in Knee Surgery: Narrative Review of Evidence to Date

Knee articular cartilage defects can result in significant pain and loss of function in active patients. Osteochondral allograft (OCA) transplantation offers a single-stage solution to address large chondral and osteochondral defects by resurfacing focal cartilage defects with mature hyaline cartilage. To date, OCA transplantation of the knee has demonstrated excellent clinical outcomes and long-term survivorship. However, significant variability still exists among clinicians with regard to parameters for graft acceptance, surgical technique, and rehabilitation. Technologies to optimize graft viability during storage, improve osseous integration of the allograft, and shorten recovery timelines after surgery continue to evolve. The purpose of this review is to examine the latest evidence on treatment indications, graft storage and surgical technique, patient outcomes and survivorship, and rehabilitation after surgery.

Patellofemoral joint cartilage restoration with particulated juvenile allograft in patients under 21 years old

BACKGROUND

Patellofemoral joint cartilage defects are difficult to treat due to their unique thickness and topography.

PURPOSE

To report the postoperative outcomes of patients age 21 and younger treated with particulated juvenile allograft cartilage (PJAC) for full-thickness cartilaginous defects of the patellofemoral joint. The primary aim was to report surgical outcomes and complication rates, as well as return to sport activity. A secondary aim was to provide objective scores of defect restoration by magnetic resonance imaging (MRI) assessment.

METHODS

A retrospective review of all PJAC cases conducted between 2012 and 2019 at a single tertiary care urban musculoskeletal institution was conducted. Patients 21 years old or younger with minimum clinical follow up of 1 year and postoperative MRI at a minimum of 6 months were included. Cartilage restoration by MRI was independently assessed using the International Cartilage Repair Society's (ICRS) standardized system.

RESULTS

Thirty four patients, 36 knees, were included, with mean age 16.1 ± 3.1 years old. Return to sport rate among patients who participated in a sport preoperatively was 100%. On independent MRI assessment, two thirds of defects achieved an overall grade of normal or nearly normal, while 28 patients (78%) had majority defect fill. Primary graft failure occurred in two cases and one patient experienced a surgical complication.

CONCLUSION

Restoration of patellofemoral chondral defects in young patients with particulated juvenile allograft results in satisfactory short-term outcomes and postoperative MRI appearance, along with high rates of return to sport and low rate of complications and graft failure. What is known about the subject: Patellofemoral joint cartilage defects are difficult to treat due to their unique thickness and topography. Several cartilage restoration techniques are available, but these rarely achieve the same mechanical properties as native hyaline cartilage. PJAC is a cell-based technique that has demonstrated promise since its introduction in 2007.

WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE

This series of patients adds the largest single cohort of pediatric and adolescent patients who receive PJAC for defects of the patellofemoral joint. Surgeons treating patients in this age group should be aware of every technique, and their respective outcomes.

Osteochondral Allograft for Unsalvageable Osteochondritis Dissecans in the Skeletally Immature Knee

Background:

While an excellent option for osteochondral defects in the adult knee, fresh osteochondral allograft (FOCA) in the skeletally immature adolescent knee has been infrequently studied.

Purpose:

To compare radiographic and patient-reported outcomes (PROs) in skeletally mature and immature adolescents after FOCA in the knee for treatment of unsalvageable osteochondritis dissecans (OCD).

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were 34 patients (37 knees) who underwent size-matched FOCA of the knee for unsalvageable OCD lesions. All patients were aged ≤19 years and had a minimum of 12 months of follow-up. Patient characteristics, lesion characteristics, reoperations, and PROs were evaluated and compared between patients with open physes (skeletally immature; n = 20) and those with closed physes (skeletally mature; n = 17). Graft failure was defined as the need for revision osteochondral grafting. Postoperative radiographs were analyzed at 1 year and the final follow-up for graft incorporation and classified as A (complete), B (≥50% healed), or C (<50% healed).

Results:

The mean patient age was 15.4 years (range, 9.6-17.6 years), and the mean follow-up was 2.1 years (range, 1-5.3 years). The mean graft size was 5.0 cm² and did not differ significantly between the study groups. Patients with open physes were younger (14.7 vs 16.2 years; P = .002) and more commonly male (80% vs 35%; P = .008). At the 1-year follow-up, 85% of immature patients and 82% of mature patients had radiographic healing grades of A or B. Patients with open physes were more likely to achieve complete radiographic union at 1 year (65% vs 15%; P = .007) and demonstrated better Knee injury and Osteoarthritis Outcome Score (KOOS) Daily Living (96.8 vs 88.5; P = .04) and KOOS Quality of Life (87.0 vs 56.8; P = .01) at the final follow-up. Complications were no different in either group, and graft failure occurred in only 1 skeletally mature patient with a trochlear lesion.

Conclusion:

FOCA treatment for unsalvageable OCD in the young knee may be expected to yield excellent early results. Despite the presence of open physes and immature epiphyseal osteochondral anatomy, equivalent or improved healing and PRO scores compared with those of skeletally mature patients may be expected.

Repair of Osteochondritis Dissecans of the Lateral Femoral Condyle by a Trochlea Osteochondral Autograft: A Case Report

CASE

A 17-year-old adolescent boy with large deep osteochondritis dissecans (OCD) of the right lateral femoral condyle was treated with ipsilateral trochlea osteochondral autograft transplantation combined with iliac cancellous bone grafting to the donor site of the lateral trochlea. Both autografts were fused 3 months after surgery. It was radiographically confirmed that the OCD lesion was successfully reconstructed.

CONCLUSION

This procedure is an alternative surgical option for large and deep OCDs. It offers sufficient loading strength to the joint and adequate reconstruction of the congruent joint surface and can be performed at any regular facility.

Fresh Osteochondral Allograft Transplantation in Osteochondritis Dissecans in the Knee Joint

Osteochondritis dissecans (OCD) is a chronic and painful joint condition that can occur from childhood through to adult life. Microtrauma, vascular insufficiency, or abnormal endochondral ossification are the most common causes of OCD. Reconstructive techniques for OCD of the knee are typically necessary when either non-operative or reparative/regenerative operative treatments fail, or when the OCD is irreversible. To analyze the clinical outcomes and failure rates of fresh osteochondral allograft transplantation (FOCA) used as a reconstructive strategy in OCD patients, an in-depth search was carried out on the PubMed, Scopus, and Web of Science databases concerning the existing evidence related to the use of FOCA for OCD patients in the knee joint. A total of 646 studies were found through the search and 2 studies were added after a cross-referenced examination of the articles within the bibliography. Six studies with a total of 303 OCD lesions treated with FOCA, with a mean follow-up of 6.3 years, were included. Although a limited number of low-level evidence studies on this topic are available in previous research, satisfactory clinical results and survival rates of the reconstruction are reported. However, to better define the real advantages of FOCA in the healing process of OCD lesions, comparative studies with different techniques are needed.

rAAV-Mediated sox9 Overexpression Improves the Repair of Osteochondral Defects in a Clinically Relevant Large Animal Model Over Time In Vivo and Reduces Perifocal Osteoarthritic Changes

BACKGROUND

Gene transfer of the transcription factor SOX9 with clinically adapted recombinant adeno-associated virus (rAAV) vectors offers a powerful tool to durably enhance the repair process at sites of osteochondral injuries and counteract the development of perifocal osteoarthritis (OA) in the adjacent articular cartilage.

PURPOSE

To examine the ability of an rAAV sox9 construct to improve the repair of focal osteochondral defects and oppose perifocal OA development over time in a large translational model relative to control gene transfer.

STUDY DESIGN

Controlled laboratory study.

METHODS

Standardized osteochondral defects created in the knee joints of adult sheep were treated with rAAV-FLAG-hsox9 relative to control (reporter) rAAV-lacZ gene transfer. Osteochondral repair and degenerative changes in the adjacent cartilage were monitored using macroscopic, histological, immunohistological, and biochemical evaluations after 6 months. The microarchitecture of the subchondral bone was assessed by micro-computed tomography.

RESULTS

Effective, prolonged sox9 overexpression via rAAV was significantly achieved in the defects after 6 months versus rAAV-lacZ treatment. The application of rAAV-FLAG-hsox9 improved the individual parameters of defect filling, matrix staining, cellular morphology, defect architecture, surface architecture, subchondral bone, and tidemark as well as the overall score of cartilage repair in the defects compared with rAAV-lacZ. The overexpression of sox9 led to higher levels of proteoglycan production, stronger type II collagen deposition, and reduced type I collagen immunoreactivity in the sox9- versus lacZ-treated defects, together with decreased cell densities and DNA content. rAAV-FLAG-hsox9 enhanced semiquantitative histological subchondral bone repair, while the microstructure of the incompletely restored subchondral bone in the sox9 defects was not different from that in the lacZ defects. The articular cartilage adjacent to the sox9-treated defects showed reduced histological signs of perifocal OA changes versus rAAV-lacZ.

CONCLUSION

rAAV-mediated sox9 gene transfer enhanced osteochondral repair in sheep after 6 months and reduced perifocal OA changes. These results underline the potential of rAAV-FLAG-hsox9 as a therapeutic tool to treat cartilage defects and afford protection against OA.

CLINICAL RELEVANCE

The delivery of therapeutic rAAV sox9 to sites of focal injuries may offer a novel, convenient tool to enhance the repair of osteochondral defects involving both the articular cartilage and the underlying subchondral bone and provide a protective role by reducing the extent of perifocal OA.

Rehabilitation and Return-to-Play Criteria After Fresh Osteochondral Allograft Transplantation: A Systematic Review

Background:

Fresh osteochondral allograft (OCA) is a treatment option that allows for the transfer of size-matched allograft cartilage and subchondral bone into articular defects of the knee. Although long-term studies show good functional improvement with OCA, there continues to be wide variability and a lack of consensus in terms of postoperative rehabilitation protocols and return to sport.

Purpose:

To systematically review the literature and evaluate the reported rehabilitation protocols after OCA of the knee, including weightbearing and range of motion (ROM) restrictions as well as return-to-play criteria.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

PubMed, EMBASE, Cumulative Index of Nursing Allied Health Literature, SPORTDiscus, and Cochrane databases were searched according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies on knee OCA. Studies were included if they reported return-to-play data or postsurgical rehabilitation protocols.

Results:

A total of 62 studies met the inclusion criteria, with a total of 3451 knees in 3355 patients. Concomitant procedures were included in 30 of these studies (48.4%). The most commonly cited rehabilitation protocols included weightbearing restrictions and ROM guidelines in 100% and 90% of studies, respectively. ROM was most commonly initiated within the first postoperative week, with approximately half of studies utilizing continuous passive motion. Progression to weightbearing as tolerated was reported in 60 studies, most commonly at 6 weeks (range, immediately postoperatively to up to 1 year). Of the 62 studies, 37 (59.7%) included an expected timeline for either return to play or return to full activity, most commonly at 6 months (range, 4 months to 1 year). Overall, 13 studies (21.0%) included either objective or subjective criteria to determine return to activity within their rehabilitation protocol.

Conclusion:

There is significant heterogeneity for postoperative rehabilitation guidelines and the return-to-play protocol after OCA of the knee in the literature, as nearly half of the included studies reported use of concomitant procedures. However, current protocols appear to be predominantly time-based without objective criteria or functional assessment. Therefore, the authors recommend the development of objective criteria for patient rehabilitation and return-to-play protocols after OCA of the knee.

Osteochondritis Dissecans: Current Understanding of Epidemiology, Etiology, Management, and Outcomes

➤

Osteochondritis dissecans occurs most frequently in the active pediatric and young adult populations, commonly affecting the knee, elbow, or ankle, and may lead to premature osteoarthritis.

➤

While generally considered an idiopathic phenomenon, various etiopathogenetic theories are being investigated, including local ischemia, aberrant endochondral ossification of the secondary subarticular physis, repetitive microtrauma, and genetic predisposition.

➤

Diagnosis is based on the history, physical examination, radiography, and advanced imaging, with elbow ultrasonography and novel magnetic resonance imaging protocols potentially enabling early detection and in-depth staging.

➤

Treatment largely depends on skeletal maturity and lesion stability, defined by the presence or absence of articular cartilage fracture and subchondral bone separation, as determined by imaging and arthroscopy, and is typically nonoperative for stable lesions in skeletally immature patients and operative for those who have had failure of conservative management or have unstable lesions.

➤

Clinical practice guidelines have been limited by a paucity of high-level evidence, but a multicenter effort is ongoing to develop accurate and reliable classification systems and multimodal decision-making algorithms with prognostic value.

Unestable knee osteochondritis dissecans: arthroscopic fixation with bio-absorbable device

INTRODUCTION

Knee ostheochondritis dissecans is an osteochondral disease, whose treatment is still debated. The purpose this study was to analyze the patients attached with bioabsorbable nail, assisted by arthroscopy.

MATERIAL AND METHOD

Analysis was performed using median and interquartile range (P25-P75), with a follow-up of 9 patients (10 knees) operated for stage III osteochondral lesions. After a minimum of 12 months, the KOOS, IKDC, satisfaction questionnaires were evaluated and a MR control was perfomed.

RESULTS

Bone healing was observed in 80% of patients in the first year, with a delay in union in 20%. The median for age was 15 years. The average follow-up was 5.93 years. All cases were located in the internal condyle. The OCD lesions did not show comminution or necrosis. The 40% of stable lesions, according to preoperative MR, were unestable in arthroscopy and it were attached with internal nail. Two groups of osteochondral lesions were differentiated: juvenile OCD (60%) and adult OCD (40%); all of them were stage III lesions. IKDC questionnaire results were an improvement of 29.5 (22.25, 37.52). In the KOOS questionnaire, an improvement was obtained in symptoms of 18.07, in pain of 29.12, in daily living 25.53, in function (sports, recreational activities) of 35 and in quality of life of 34.42.

CONCLUSIONS

The bioabsorbable nail is a valid, reproducible option for unestable lesions with lesion integrity, with great improvement in function, quality of life and with few complications.

Metrics of OsteoChondral Allografts (MOCA) Group Consensus Statements on the Use of Viable Osteochondral Allograft

Background:

Osteochondral allograft (OCA) transplantation has evolved into a first-line treatment for large chondral and osteochondral defects, aided by advancements in storage protocols and a growing body of clinical evidence supporting successful clinical outcomes and long-term survivorship. Despite the body of literature supporting OCAs, there still remains controversy and debate in the surgical application of OCA, especially where high-level evidence is lacking.

Purpose:

To develop consensus among an expert group with extensive clinical and scientific experience in OCA, addressing controversies in the treatment of chondral and osteochondral defects with OCA transplantation.

Study Design:

Consensus statement.

Methods:

A focus group of clinical experts on OCA cartilage restoration participated in a 3-round modified Delphi process to generate a list of statements and establish consensus. Questions and statements were initially developed on specific topics that lack scientific evidence and lead to debate and controversy in the clinical community. In-person discussion occurred where statements were not agreed on after 2 rounds of voting. After final voting, the percentage of agreement and level of consensus were characterized. A systematic literature review was performed, and the level of evidence and grade were established for each statement.

Results:

Seventeen statements spanning surgical technique, graft matching, indications, and rehabilitation reached consensus after the final round of voting. Of the 17 statements that reached consensus, 11 received unanimous (100%) agreement, and 6 received strong (80%-99%) agreement.

Conclusion:

The outcomes of this study led to the establishment of consensus statements that provide guidance on surgical and perioperative management of OCAs. The findings also provided insights on topics requiring more research or high-quality studies to further establish consensus and provide stronger evidence.

Bipolar Osteochondral Allograft Transplantation of the Patella and Trochlea

OBJECTIVE

To evaluate clinical, functional, and radiographic outcomes of patients who underwent bipolar osteochondral allograft transplantation (OCAT) of the patellofemoral joint (PFJ).

DESIGN

Prospectively collected data on 18 knees who underwent fresh osteochondral allograft transplantation of the patella and trochlea by a single surgeon were reviewed. Inclusion criteria were: high-grade chondral lesions of PFJ (5 knees), or recurrent patella dislocations with trochlear dysplasia and chondral injury to the patella and/or trochlea (13 knees). Functional scores were obtained preoperatively and at follow-up appointments included Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), Oxford, Cincinnati, Tenger-Lysholm, visual analogue scale (VAS)-pain, and Single Assessment Numeric Evaluation (SANE). Grafts were also evaluated using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

Three patients were lost to follow-up, leaving 4 knees in group 1, and 11 knees in group 2. Average age was 28.9 years (range 16-52 years). The average follow-up was 33.2 months (range 12-64 months). There was significant improvement of KOOS (from 38.7 to 83.1), IKDC (from 28.2 to 76.6), Tegner-Lysholm (from 38.3 to 88.3), Oxford (from 22.7 to 42.9), Cincinnati (from 35.1 to 83.6), VAS (from 71 to 17.9.), and SANE (from 43.3 to 83) (P < 0.0001). The OCAMRISS score for patella was 2.23 and for trochlea 4.69. There were no revisions or conversions to arthroplasty.

CONCLUSION

Bipolar OCAT of the patella and trochlea provide significant improvement in functional outcomes, relief from pain, activity level, and prevent recurrent instability.

Osteochondral autograft transplantation versus autologous bone-cartilage paste grafting for the treatment of knee osteochondritis dissecans

PURPOSE

To compare the results of two groups of patients affected by osteochondritis dissecans (OCD) of the knee and treated with either osteochondral autologous transplantation (OAT) or bone-cartilage paste grafting (PG).

METHODS

A total of 27 patients affected by OCD lesions of the femoral condyles were included: 15 treated with OAT, 12 with PG, with comparable baseline characteristics (mean age 22.4 ± 7.2 vs. 24.2 ± 8.5 p = n.s., mean defect size 2.2 ± 1 cm² vs 2.6 ± 1 cm² p = n.s.). Patients were evaluated pre-operatively and at 24 and 84 months post-operatively with the International Knee Documentation Committee (IKDC) subjective and objective scores. Sport activity level was evaluated with the Tegner activity score. Adverse events and failures were also recorded.

RESULTS

The IKDC subjective score improved significantly in both groups. At 24 months, a significant improvement from 53.4 ± 9.1 to 80.8 ± 12.9 (p = 0.005) was obtained in the OAT group and from 44.6 ± 11.0 to 71.4 ± 25.3 in the PG group (p = 0.008). A further statistically significant increase was observed at 84 months in both groups. No significant differences were found between OAT and PG at both follow-ups. One OAT patient required post-operative knee mobilization under narcosis and two complained of donor site symptoms. More failures were documented in the PG vs OAT group (25% vs 0%; p = 0.043).

CONCLUSION

Both PG and OAT provided overall satisfactory results up to 84 months follow-up. However, while PG presents the advantages of a less invasive approach with lower adverse events, the higher failure rate of PG should be considered when choosing between these two surgical treatment options for restoration of the articular surface in patients affected by knee OCD.

Adjunct use of radiofrequency coblation for osteochondritis dissecans in children: A case report

RATIONALE

Osteochondritis dissecans (OCD) lesions involve disruption of the osteochondral unit along articular surfaces, with significant potential for joint deterioration if not managed appropriately.

PATIENT CONCERNS

A 15-year-old male presented with persistent and insidious right knee pain, which had worsened following a collision with another player during a basketball game, resulting in episodes of locking.

DIAGNOSES

Magnetic resonance imaging revealed a lateral trochlear OCD extending into the anterior lateral femoral condyle.

INTERVENTIONS

Chondral fraying was observed along the margins of the OCD. Retrograde drilling ensued with use of a 0.045-inch Kirschner wire throughout the lesion to a depth that would allow for penetration of healthy underlying subchondral bone to create an influx of healing factors. Three resorbable pegs were arthroscopically placed through an accessory portal overlying the lesion to stabilize the fracture and compress the gapped cartilage mantle to reduce flow of synovial fluid behind the lesion. Bipolar radiofrequency coblation was used to stabilize the chondral fraying and seal the gap along the periphery of the lesion.

OUTCOMES

The patient was put on a nonweight bearing protocol for 6 weeks, after which crutches and brace were discontinued, but therapy persisted. Repeat imaging at 3 months demonstrated excellent interval healing. The patient was released to slowly engage impact activities. Although he returned at approximately 8 months postoperatively with a contralateral anterior cruciate ligament tear, he reported the operative knee with the OCD was doing extremely well.

LESSONS

Radiofrequency coblation appears to be a viable strategy as an adjunct to management for OCD in children.

Osteochondritis Dissecans of the Knee: Short-Term Outcomes of a Hybrid Technique to Restore a Partially Salvageable Progeny Fragment

OBJECTIVE

This retrospective case series describes a hybrid fixation technique and determines the clinical outcomes, knee function, and activity level of patients at short-term follow-up.

DESIGN

Seventeen patients (18 knees) with unstable osteochondritis dissecans (OCD) lesions involving the knee were treated with a hybrid fixation technique in which the salvageable fragment was fixed and osteochondral autograft transplantation system (OATS) was used for the unsalvageable fragment. Thirteen lesions involved the medial femoral condyle, 4 involved the lateral femoral condyle, and 1 involved the patella. Mean patient age was 17 years (range 12-28 years). All lesions were International Cartilage Repair Society (ICRS) grade III or IV. The patients were prospectively followed postoperatively. Outcome measures included the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and the Tegner activity scale.

RESULTS

At mean follow-up of 36 months (range 24-67.2 months), the mean postoperative KOOS scores, given as mean (SD), were as follows: Quality of Life (QoL) 91.1 (17.0), Activities of Daily Living (ADL) 99.5 (1.5), Sport 94.5 (11.2), Pain 97.4 (5.8), and Symptoms 95.9 (6.5). Mean IKDC score was 96.2 (7.0). There was no significant difference between mean preinjury (7.95, SD = 1.1) and mean postoperative (7.45, SD = 1.5) Tegner scores (P = 0.363). The mean Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was 87.5 at a mean 7.8 months (range 3-18 months) postoperation. There were no reported complications.

CONCLUSION

The results of this case series suggest that patients with partially salvageable OCD lesions involving the knee can have positive short-term outcomes and can expect a low complication rate when treated with a hybrid technique of fixation with osteochondral autograft transfer.

Management of the Failed OCD

PURPOSE OF THE REVIEW

Osteochondritis dissecans (OCD) is a pathologic condition of subchondral bone most frequently occurring in the medial femoral condyle of the knee in children and adolescents. Salvage techniques are necessary when either nonoperative or typical operative treatments fail, or the OCD presents in an unsalvageable state. The purpose of this review is to describe the evaluation and management of failed OCDs.

RECENT FINDINGS

Thorough preoperative planning is essential to the treatment of failed OCDs. Radiographs and advanced imaging such as MRI and CT allow for a detailed assessment of subchondral bone and cartilage. Long-leg alignment radiographs are critical to assess for malalignment which may increase the contact forces on the affected condyle. Malalignment can be corrected with hemiepiphysiodesis or an osteotomy depending on the skeletal maturity of the patient. Osteochondral allografts and autologous chondrocyte implantation treat the defect in both bone and cartilage or solely cartilage and have good short to moderate term outcomes, particularly as compared to the inferior outcomes of microfracture of larger OCDs. Osteochondritis dissecans of the knee that fails to heal with initial operative measures can result in a large defect of bone and cartilage in the knee of adolescents. Treatment of the bone and cartilage defect can be accomplished with either osteochondral allograft transplantation or matrix-assisted autologous chondrocyte implantation can be performed with good outcomes. Assessment and correction of lower extremity malalignment is a critical component of treatment. Durable long-term solutions are necessary for the treatment of these difficult lesions.

The Influence of Physeal Status on Rate of Reoperation After Arthroscopic Screw Fixation for Symptomatic Osteochondritis Dissecans of the Knee

PURPOSE

To determine if physeal status or other preoperative or intraoperative variables influence the failure rate after arthroscopic reduction and internal fixation of osteochondritis dissecans (OCD) lesions in the knee.

METHODS

Consecutive patients undergoing screw fixation of osteochondral fragments from OCD by a single surgeon from 2005 to 2015 with a minimum 2-year follow-up were included. Demographic, preoperative imaging, and intraoperative data were analyzed to determine risk factors associated with failure, which was defined as the need for a revision reoperation or arthroplasty after initial OCD fixation.

RESULTS

A total of 45 knees met the inclusion criteria, including 26 skeletally mature patients and 19 patients with incompletely closed physes on preoperative imaging. The mean ages of the skeletally mature and immature groups were 18.3 ± 2.5 years and 14.9 ± 2.2 years, respectively (P < .001), and the mean body mass index values were 24.3 ± 3.6 and 23.2 ± 4.0, respectively (P = .432). We excluded 10 patients from the survivorship analysis because they had less than 2 years' follow-up. No statistically significant difference in failure rates was found between skeletally mature and immature individuals (30% and 40%, respectively; P = .721). The only factor significantly associated with fixation failure was undergoing a prior surgical procedure to address the OCD lesion (P = .038). Kaplan-Meier analysis showed rates of overall survivorship from revision reoperations of 88.6% at 1 year and 68.8% at 5 years.

CONCLUSIONS

Outcomes after internal fixation of OCD fragments are guarded, with a fragment survival rate of 65.7% at a mean of 4.1 years' follow-up. No difference in fragment survival was noted in skeletally mature versus immature patients. The only independent risk factor identified for fixation failure was the number of previous operations. LEVEL OF EVIDENCE: Level IV, case series with subgroup analysis.

Contralateral Lateral Femoral Condyle Allografts Provide an Acceptable Surface Match for Simulated Classic Osteochondritis Dissecans Lesions of the Medial Femoral Condyle

Background:

Osteochondral allograft transplantation is an effective technique for repairing large lesions of the medial femoral condyle (MFC), but its use is limited by graft availability.

Purpose/Hypothesis:

The present study aimed to determine whether contralateral lateral femoral condyle (LFC) allografts can provide an acceptable surface match for posterolateral MFC lesions characteristic of classic osteochondritis dissecans (OCD). The hypothesis was that LFC and MFC allografts will provide similar surface contour matches in all 4 quadrants of the graft for posterolateral MFC lesions characteristic of OCD.

Study Design:

Controlled laboratory study.

Methods:

Ten fresh-frozen recipient human MFCs were each size-matched to 1 ipsilateral medial and 1 contralateral LFC donor (N = 30 condyles). After a nano–computed tomography (nano-CT) scan of the native recipient condyle, a 20-mm circular osteochondral “defect” was created 1 cm posterior and 1 cm medial to the roof of the intercondylar notch (n = 10). A size-matched, random-order donor MFC or LFC plug was then harvested, transplanted, and scanned with nano-CT. Nano-CT scans were then reconstructed, registered to the initial scan of the recipient MFC, and processed in MATLAB to determine the height deviation (d_RMS) between the native and donor surfaces and percentage area unacceptably (>1 mm) proud (%A_proud) and sunken (%A_sunk). Circumferential step-off height (h_RMS) and percentage circumference unacceptably (>1 mm) proud (%C_proud) and sunken (%C_sunk) were measured using DragonFly software. The process was then repeated for the other allograft plug.

Results:

Both MFC and LFC plugs showed acceptable step-off heights in all 4 quadrants (range, 0.53-0.94 mm). Neither allograft type nor location within the defect had a significant effect on step-off height (h_RMS), surface deviation (d_RMS), %A_proud, or %A_sunk. In general, plugs were more unacceptably sunken than proud (MFC, 13.4% vs 2.4%; LFC, 13.2% vs 8.1%), although no significant differences in %C_sunk were seen between allograft types or locations within the defect. In LFC plugs, %C_proud in the lateral quadrant (28.0% ± 26.1%) was significantly greater compared with all other quadrants (P = .0002).

Conclusion:

The present study demonstrates that 20-mm contralateral LFC allografts provide an acceptable surface match for posterolateral MFC lesions characteristic of OCD.

Clinical Relevance:

With comparable surface matching, MFC and LFC allografts can be expected to present similar stresses on the knee joint and achieve predictably positive clinical outcomes, thus improving donor availability and reducing surgical wait times for matches.

Therapeutic "Tool" in Reconstruction and Regeneration of Tissue Engineering for Osteochondral Repair

Repairing osteochondral defects to restore joint function is a major challenge in regenerative medicine. However, with recent advances in tissue engineering, the development of potential treatments is promising. In recent years, in addition to single-layer scaffolds, double-layer or multilayer scaffolds have been prepared to mimic the structure of articular cartilage and subchondral bone for osteochondral repair. Although there are a range of different cells such as umbilical cord stem cells, bone marrow mesenchyml stem cell, and others that can be used, the availability, ease of preparation, and the osteogenic and chondrogenic capacity of these cells are important factors that will influence its selection for tissue engineering. Furthermore, appropriate cell proliferation and differentiation of these cells is also key for the optimal repair of osteochondral defects. The development of bioreactors has enhanced methods to stimulate the proliferation and differentiation of cells. In this review, we summarize the recent advances in tissue engineering, including the development of layered scaffolds, cells, and bioreactors that have changed the approach towards the development of novel treatments for osteochondral repair.

Comparative Effectiveness of Cartilage Repair With Respect to the Minimal Clinically Important Difference

BACKGROUND

Recent studies demonstrated a 5% increase in cartilage repair procedures annually in the United States. There is currently no consensus regarding a superior technique, nor has there been a comprehensive evaluation of postoperative clinical outcomes with respect to a minimal clinically important difference (MCID).

PURPOSE

To determine the proportion of available cartilage repair studies that meet or exceed MCID values for clinical outcomes improvement over short-, mid-, and long-term follow-up.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review was performed via the Medline, Scopus, and Cochrane Library databases. Available studies were included that investigated clinical outcomes for microfracture (MFX), osteoarticular transfer system (OATS), osteochondral allograft transplantation, and autologous chondrocyte implantation/matrix-induced autologous chondrocyte implantation (ACI/MACI) for the treatment of symptomatic knee chondral defects. Cohorts were combined on the basis of surgical intervention by performing a meta-analysis that utilized inverse-variance weighting in a DerSimonian-Laird random effects model. Weighted mean improvements in International Knee Documentation Committee (IKDC), Lysholm, and visual analog scale for pain (VAS pain) scores were calculated from preoperative to short- (1-4 years), mid- (5-9 years), and long-term (≥10 years) postoperative follow-up. Mean values were compared with established MCID values per 2-tailed 1-sample Student t tests.

RESULTS

A total of 89 studies with 3894 unique patients were analyzed after full-text review. MFX met MCID values for all outcome scores at short- and midterm follow-up with the exception of VAS pain in the midterm. OATS met MCID values for all outcome scores at all available time points; however, long-term data were not available for VAS pain. Osteochondral allograft transplantation met MCID values for IKDC at short- and midterm follow-up and for Lysholm at short-term follow-up, although data were not available for other time points or for VAS pain. ACI/MACI met MCID values for all outcome scores (IKDC, Lysholm, and VAS pain) at all time points.

CONCLUSION

In the age of informed consent, it is important to critically evaluate the clinical outcomes and durability of cartilage surgery with respect to well-established standards of clinical improvement. MFX failed to maintain VAS pain improvements above MCID thresholds with follow-up from 5 to 9 years. All cartilage repair procedures met MCID values at short- and midterm follow-up for IKDC and Lysholm scores; ACI/MACI and OATS additionally met MCID values in the long term, demonstrating extended maintenance of clinical benefits for patients undergoing these surgical interventions as compared with MFX.

Fluid imbibition at the bone-cartilage interface is associated with need for early chondroplasty following osteochondral allografting of the knee

PURPOSE

To determine the clinical significance of fluid imbibition at the bone-cartilage interface seen on postoperative MRI scans after osteochondral grafting of chondral lesions of the knee.

METHODS

Retrospective review of patients enrolled in a prospective cartilage repair registry. Included patients underwent osteochondral autografting or allografting of the knee, had minimum one year of clinical follow-up, and underwent at least two postoperative MRI scans. The primary outcome was reoperation for arthroscopic debridement and chondroplasty or graft revision. Secondary outcomes included the radiographic fate of fluid imbibition.

RESULTS

A total of 48 knees in 46 patients were analyzed, with mean 39 months clinical follow-up. Nine patients (19%) had fluid imbibition on at least one postoperative MRI scan, all of whom received allograft. Of these, two (22%) required eventual graft revision, four (45%) underwent arthroscopic chondroplasty but did not require revision, and three (33%) did not require any additional surgery by final follow-up. No demographic or surgical variable was associated with the presence of fluid imbibition. Fluid imbibition was significantly associated with need for chondroplasty (p = 0.05), but not graft revision.

CONCLUSIONS

Fluid imbibition on postoperative MRI following osteochondral allografting of the knee is associated with the need for arthroscopic chondroplasty, but should not be interpreted as a sign of a failing graft.

LEVEL OF EVIDENCE

Level IV, Case Series.

Fresh osteochondral grafting in the United States: the current status of tissue banking processing

The use of musculoskeletal allografts has become increasingly popular among surgeons. The purpose of this review is to highlight the procurment and delievery process of fresh osteochondral allografts in the United States. The four distributors of fresh osteochondral allografts in the United States were contacted. Surveys containing quantitative and qualitative sections concerning the procurement and processing of osteochondral allograft tissue were obtained. Our results showed an average of 13 ± 4.24 years of experience with osteochondral allografts. The average donor age ranged from 13.5 ± 3 to 37.5 ± 5 years, with an average age of 27 ± 2.83 years. All donors were between ages 12 and 45 years old. The percentage of screened donors that were accepted for allograft transplant was consistent at 70-75% for 3 out of the 4 tissue banks. The percentage of grafts that expire without implantation ranged from 20% to 29%. Maximum shipping time varied between 24 and 96 hours. Each tissue bank used its own proprietary storage medium. The time from donor death to the harvest of allograft tissue was < 24 hours. The most commonly requested osteochondral allograft tissue for all banks was the medial femoral condyle. The market share of fresh allografts is as follows: Joint Restoration Foundation (JRF) 59.9%, Muskuloskeletal Transplant Foundation (MTF) 15.3%, LifeNet Health (LN) 14.5%, and Regeneration Technology Incorporated (RTI) 10.2%, with approximately 4700 fresh allografts distributed in 2018. This compiled data from the four tissue banks that supply fresh osteochondral allograft in the United States  provides important background information for patients and orthopaedic surgeons.

Outcomes Associated with Return to Sports Following Osteochondral Allograft Transplant in the Knee: a Scoping Review

PURPOSE OF REVIEW

The purposes of this review were to report the currently validated outcomes for OCA transplant patients, discuss the benefits and challenges associated with "return to sports" as an outcome measure, and summarize the currently available data on patients' ability to return to sports after OCA transplant.

RECENT FINDINGS

College athletes may take less time than professionals to return to basketball, but there are many factors that can influence this timeframe. Player productivity is decreased ~ 40% and future career length is only 1 to 2 years following return to play. When evaluating all OCA transplant patients, 75-88% of patients return to sport and 38-80% return to their previous level of play at approximately 8-10 months following surgery. Overall graft failure rates are low (0-9.4%) but are based on limited short- to medium-term data. Data on the return to professional and college sports after OCA transplant is limited. Surgeons should consider collecting patient outcomes across multiple domains and contributing data to aggregate databases to allow for better quality outcome data to be reported.

Treatment of unstable knee osteochondritis dissecans in the young adult: results and limitations of surgical strategies-The advantages of allografts to address an osteochondral challenge

Joint surface incongruence resulting from osteochondritis dissecans (OCD) alters the articular physiologic congruence, increasing the contact stress on adjacent joint surfaces and accelerating wear and the cascade of joint degeneration. Accordingly, the restoration of articular surface integrity is of major importance, especially in young adults where, in lesions left untreated or following simple fragment excision, early osteoarthritis can be anticipated. Therefore, the treatment algorithm in unstable knee OCD of the young adult foresees surgical options to restore the articular surface. Several procedures have been proposed, including refixation of the detached fragment bone marrow stimulation, osteochondral autograft implantation, fresh osteochondral allograft transplantation, and cell-based or cell-free regenerative techniques. The aim of this review was to summarize the evidence for these surgical strategies, reporting their results and limitations. The overall evidence documents positive results for each of the assorted surgical procedures applied to treat unstable OCD, thus indicating support for their selected use to treat osteochondral defects paying particular attention to their specific indications for the lesion characteristics. The fixation of a good quality fragment should be pursued as a first option, while unfixable small lesions may benefit from autografts. For large lesions, available cell-based or cell-free osteochondral scaffold are a feasible solution but with limitation in terms of regenerated tissue quality. In this light, fresh allografts may offer articular surface restoration with viable physiologic osteochondral tissue providing a predictably successful outcome, and therefore they may currently represent the most suitable option to treat unstable irreparable OCD lesion in young adults. LEVEL OF EVIDENCE: V.

Osteochondral Allograft Transplantation of the Femoral Condyle Utilizing a Thin Plug Graft Technique

BACKGROUND

Previous studies showed clinical benefit and durable results of osteochondral allograft (OCA) transplantation for the treatment of femoral condyle lesions. However, the majority of these studies are difficult to interpret owing to the mixed results of different techniques and anatomic locations.

PURPOSE

To evaluate the outcome of OCA transplantation with thin plug grafts for treatment of isolated femoral condyle osteochondral lesions.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This study included 187 patients (200 knees) who underwent OCA transplantation for isolated osteochondral lesions on the femoral condyle between 1999 and 2014. For all cases, a thin plug technique was used with commercially available surgical instruments and the minimum amount of bone necessary for fixation. Evaluation included International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, and patient satisfaction. Frequency and type of further surgery were assessed. Failure of the allograft was defined as further surgery involving removal of the allograft.

RESULTS

Mean follow-up was 6.7 years (range, 1.9-16.5 years). The mean age of patients at the time of surgery was 31 years, and 63% were male. The medial femoral condyle was affected in 69% of knees. A single thin plug graft was used in 145 knees (72.5%), and 2 grafts were used in 55 knees (27.5%). Mean allograft area was 6.3 cm², and graft thickness was 6.5 mm (cartilage and bone combined). Further surgery was required for 52 knees (26%), of which 16 (8% of entire cohort) were defined as allograft failures (4 OCA revisions, 1 arthrosurface, 6 unicompartmental knee arthroplasties, and 5 total knee arthroplasties). Median time to failure was 4.9 years. Survivorship of the allograft was 95.6% at 5 years and 91.2% at 10 years. Among patients with grafts remaining in situ at latest follow-up, clinically meaningful improvement in pain, function, and quality of life was reported. Satisfaction was reported by 89% of patients.

CONCLUSION

OCA transplantation with a thin plug graft technique is a valuable procedure for the treatment of femoral condyle osteochondral lesions, resulting in significant improvement in clinical scores, high patient satisfaction, and low reoperation and clinical failure rates.

Outcomes After Fresh Osteochondral Allograft Transplantation for Medium to Large Chondral Defects of the Knee

Background:

Articular cartilage defects of the knee can significantly impair function among young, high-demand patients. There are several techniques for chondral restoration, including osteochondral allograft transplantation (OCA), that may alleviate pain and re-create the native anatomy. However, clinical outcomes among athletic cohorts are limited.

Purpose:

To evaluate the efficacy and functional outcomes of OCA for medium to large osteochondral defects of the knee in physically active United States military servicemembers.

Study Design:

Case series; Level of evidence, 4.

Methods:

A military health care database was queried to identify all OCA procedures performed between January 2009 and March 2013. Inclusion criteria were army personnel with a minimum of 2 years’ follow-up. Exclusion criteria included incomplete follow-up, inaccurate coding, and nonmilitary status. Variables of interest included sex, age, lesion location, grade and size of the lesion, body mass index, tobacco use, preoperative and postoperative visual analog scale (VAS) scores for pain, and presence of perioperative complications. Overall failure was defined as the inability to return to preoperative functional activities because of persistent knee complaints (clinical failure) or a revision cartilage procedure or arthroplasty (surgical failure).

Results:

A total of 61 patients (52 male; mean age, 31.7 years) were identified, with a mean 46.2-month follow-up. The mean VAS pain score improved from 4.10 ± 2.17 preoperatively to 2.68 ± 2.73 postoperatively (P < .0009), and only 6 (9.8%) required a subsequent revision chondral procedure. Overall, 39 patients (63.9%) were able to return to a level of activity that allowed for the completion of military duties. Risk factors for clinical failure were preoperative body mass index, preoperative pain as measured on the VAS, and moderate to severe postoperative pain on the VAS. The risk factor for surgical failure was the presence of a complication. Risk factors for overall failure were the presence of a complication and moderate to severe postoperative pain on the VAS.

Conclusion:

OCA provided moderate success in retaining active-duty army servicemembers. Approximately two-thirds of patients undergoing OCA were able to return to their preinjury occupational activity, while approximately 57% of patients returned to prior levels without a subsequent revision chondral procedure or arthroplasty.

Fresh Osteochondral Allograft Transplantation for Uncontained, Elongated Osteochondritis Dissecans Lesions of the Medial Femoral Condyle

Osteochondritis dissecans (OCD) lesions of the knee are a significant source of pain and disability. Although the pathologic process for this condition remains poorly understood, histologic studies suggest vascular insufficiency of the subchondral bone may be the underlying cause for focal necrosis and subsequent compromise of the overlying articular cartilage. These lesions most commonly affect the medial femoral condyle and can be found along the margins of the intercondylar notch. Because of significant bone involvement, osteochondral allograft (OCA) transplantation has emerged as a dominant treatment option for OCD lesions because it can accurately restore the entire osteochondral unit. Given the characteristic location and large, irregular shapes of these lesions, surgical management can be challenging. These lesions are often uncontained along the periphery of the condyle, which can compromise OCA graft fixation and healing. We describe our preferred technique for the treatment of large, uncontained OCD lesions of the medial femoral condyle using a unicompartmental OCA augmented with screw fixation.

The cost-effectiveness of osteochondral allograft transplantation in the knee

PURPOSE

Osteochondral allografts (OCA) consist of a layer of hyaline cartilage and a layer of underlying bone. They are used to repair combined defects of articular cartilage and bone. Such defects often occur in people far too young to have knee arthroplasty, for whom the main alternative to OCA is conservative symptomatic care, which will not prevent development of osteoarthritis. The aim of this report was to assess the cost-effectiveness of osteochondral allograft transplantation in the knee.

METHODS

Systematic review of evidence on clinical effectiveness and economic modelling.

RESULTS

The evidence on osteochondral allograft transplantation comes from observational studies, but often based on good quality prospective registries of all patients having such surgery. Without controlled trials, it was necessary to use historical cohorts to assess the effect of osteochondral grafts. There is good evidence that OCA are clinically effective with a high graft survival rate over 20 years. If an OCA graft fails, there is some evidence that revision with a second OCA is also effective, though less so than primary OCA. Economic modelling showed that osteochondral allograft transplantation was highly cost-effective, with costs per quality adjusted life year much lower than many other treatments considered cost effective.

CONCLUSIONS

Osteochondral allograft transplantation appears highly cost-effective though the cost per quality adjusted life year varies according to the widely varying costs of allografts. Based on one small study, revision OCA also appears very cost-effective, but more evidence is needed.

LEVEL OF EVIDENCE

II.

Clinical Outcomes and Failure Rates of Osteochondral Allograft Transplantation in the Knee: A Systematic Review

BACKGROUND

Cartilage lesions are a significant cause of morbidity and impaired knee function; however, cartilage repair procedures have failed to reproduce native cartilage to date. Thus, osteochondral allograft (OCA) transplantation represents a 1-step procedure to repair large chondral defects without the donor site morbidity of osteochondral autograft transplantation.

PURPOSE

To perform a systematic review of clinical outcomes and failure rates after OCA transplantation in the knee at a minimum mean 2 years' follow-up.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature regarding the existing evidence for clinical outcomes and failure rates of OCA transplantation in the knee joint was performed using the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, and MEDLINE from studies published between 1980 and 2017. Inclusion criteria were as follows: clinical outcomes and failure rates of OCAs for the treatment of chondral defects in the knee joint, English language, mean follow-up of 2 years and minimum follow-up of 18 months, minimum study size of 20 patients, and human studies. The methodological quality of each study was assessed using a modified version of the Coleman methodology score.

RESULTS

The systematic search identified 19 studies with a total of 1036 patients. The mean 5-year survival rate across the studies included in this review was 86.7% (range, 64.1%-100.0%), while the mean 10-year survival rate was 78.7% (range, 39.0%-93.0%). The mean survival rate was 72.8% at 15 years (range, 55.8%-84.0%) and 67.5% at 20 years (range, 66.0%-69.0%). The weighted mean patient age was 31.5 years (range, 10-82 years), and the weighted mean follow-up was 8.7 years (range, 2-32 years). The following outcome measures showed significant improvement from preoperatively to postoperatively: d'Aubigné-Postel, International Knee Documentation Committee, Knee Society function, and Lysholm scores. The weighted mean reoperation rate was 30.2% (range, 0%-63%). The weighted mean failure rate was 18.2% (range, 0%-31%). Of note, revision cases, patellar lesions, and bipolar lesions demonstrated worse survival rates.

CONCLUSION

Improved patient-reported outcomes can be expected after OCA transplantation, with a survival rate of 78.7% at 10 years. Revision cases, patellar lesions, and bipolar lesions were associated with worse survival rates; therefore, utilization of the most appropriate index cartilage restoration procedure and proper patient selection are key to improving results.

Mechanism research on a bioactive resveratrol- PLA-gelatin porous nano-scaffold in promoting the repair of cartilage defect

BACKGROUND

Articular cartilage defects are difficult to treat, but drug-loaded tissue engineering scaffolds provide a possible treatment option for these types of injuries.

PURPOSE

In this study, we designed a bioactive resveratrol-PLA-gelatin porous nano-scaffold using electrospinning, freeze drying, and uniform dispersion techniques to repair articular cartilage defects, and then investigated the possible mechanism behind the successful repair.

METHODS

We established an articular cartilage defect rat model with a 2 mm diameter wound in the middle of the knee joint femoral condyle non-weight-bearing area, with a depth reaching the full thickness of the subchondral bone. Postmodel specimens and micro computed tomography (CT) were used to observe any macroscopic morphological changes in the articular cartilage and subchondral bone, whereas multiple staining methods were used to observe all microcosmic morphological changes. Gross scores and Mankin scores were used to evaluate the repair condition. Immunohistochemical staining was employed to detect protein expression.

RESULTS

When the repair included the resveratrol-PLA-gelatin porous nano-scaffold, the repaired cartilage and subchondral bone were in better condition. The expression levels of SIRT1, type II collagen, and PI3K/AKT signaling pathway-related proteins (AKT, VEGF, PTEN, Caspase 9, and MMP13) changed significantly. The expression levels of SIRT1,AKT and type II collagen proteins increased significantly, while the expression levels of VEGF, PTEN, Caspase9 and MMP13 proteins decreased significantly compared with the repair included blank porous PLA-gelatin nano-scaffold and without scaffold.

CONCLUSION

We designed a bioactive resveratrol-PLA-gelatin porous nano-scaffold with better performance, which promoted the repair of cartilage injury as a whole, and explained its possible mechanism in accelerating cartilage repair via the PI3K/AKT signaling pathway.

Treatment of osteochondral defects with a combination of bone grafting and AMIC technique

INTRODUCTION

Osteochondral defects of the knee may cause functional impairment of young and sportively active patients. Different surgical treatment options have been proposed using either one or two step procedures. The aim of the current study was to evaluate mid-term outcomes of combined bone grafting with autologous matrix-associated chondrogenesis (AMIC) for the treatment of large osteochondral defects.

MATERIALS AND METHODS

15 Patients with osteochondrosis dissecans of the medial femoral condyle grade III or IV according to ICRS classification were treated with a single step surgical procedure combining bone grafting and the AMIC procedure. Mean defect size was 4.98 cm² (± 3.02) and patients were examined at 6, 12 weeks, 6 and 12 month and at mean final follow-up of 49 months (36-61). Patients were evaluated using VAS, IKDC, KOOS, Lysholm, Tegner activity scores and psychological and physical health assessed using the SF 12. MRI evaluation was performed at final follow-up using the MOCART score.

RESULTS

Pain had significantly decreased at final follow-up (7.2 ± 1.4 vs. 2.4 ± 2.6) compared to preoperative baseline. All functional scores had improved significantly throughout the follow-up period (IKDC from 36.6 ± 20.6 vs. 72.2 ± 18.7; KOOS 50.0 ± 18.9 vs. 81.7 ± 13.9; LYSHOLM 39.3 ± 19.5 vs. 79.8 ± 15.1). SF12 evaluation showed a significant increase in physical component summary (PCS) (31.2 ± 11.1 preoperative vs. 46.3 ± 9.9 at final follow-up), while mental component summary (MCS) remained stable (51.8 ± 8.9 vs. 57.3 ± 3.3). MOCART score revealed a mean overall score of 77 ± 15 at final follow-up. Integration to the adjacent cartilage was complete in 79%, incomplete in 21%. Defect filling was complete in 64%, incomplete in 36%.

CONCLUSION

Significant improvement of knee function and restoration of homogenous cartilage morphology could be achieved with simultaneous AMIC procedure and bone grafting in 2/3 of all patients with large osteochondral lesions at 4 years postoperatively.