Magnetic resonance imaging combined with histological evaluation of repair process using the microfracture technique in an association of osteocartilaginous and meniscal surgically induced lesions of the knee. In vivo experiment on a rabbit model.

The present research study aimed to assess magnetic resonance imaging (MRI) changes and histological findings in the therapeutic effects of microfractures in the treatment of complex animal knee lesions resulting from osteochondral and meniscal defects resulting from non-total meniscectomies. The anterior cruciate ligament lesions are also proven to facilitate the development of osteoarthritis in the knee and worsen the prognosis. Surgery was performed on the right knee joint of 22 male rabbits in order to partially remove the anterior horn of the internal meniscus and to induce an osteochondral defect at the level of the internal femoral condyle. The induced lesion complex was aimed to simulate a clinical situation that occurs frequently in orthopedic practice when young adults undergo partial meniscectomy and at the time of surgery, an osteochondral defect is diagnosed. Rabbits were separated into two study groups: the control (C1) group and the microfractures (MF2) group. After the induced cartilage defect and partial meniscectomy, both groups were followed-up for six months using detailed MRI. Also, anatomical specimens were histologically analyzed to show modifications and signs of healing process, along with complications, in the study group. The results showed that the microfracture group had better results concerning articular surface defect healing in comparison to the control group. Our results suggest that microfractures do improve results concerning surface contact healing and serial MRI studies can be useful in observing the remodeling process in dynamics.

Current and Emerging Techniques in Articular Cartilage Repair.

Osteochondral lesions (OCL) of the knee are a common pathology that can be challenging to address. Due to the innate characteristics of articular cartilage, OCLs generally do not heal in adults and often progress to involve the subchondral bone, ultimately resulting in the development of osteoarthritis. The goal of articular cartilage repair is to provide a long-lasting repair that replicates the biological and mechanical properties of articular cartilage, but there is no widely adopted technique that results in true pre-injury state hyaline cartilage. Current treatment modalities have seen reasonable clinical success, but significant limitations remain. Microfracture provides short-term benefit with a fibrocartilage-based repair. While osteochondral autograft or allograft and autologous chondrocyte implantation can be effective, each have their strengths and shortcomings. Emerging concepts in cartilage repair, including scaffold engineering and one stage cell-based options, are continually advancing. These have the benefits of reduced surgical morbidity and potentially improved integration with surrounding articular cartilage but have not yet reached widespread clinical application. Tissue engineering strategies and gene therapy have the potential to advance the field, however, they remain in the early stages. The current article reviews the structure and physiology of articular cartilage, the strengths and limitations of present treatment modalities, and the newer ongoing innovations that may change the way we approach osteochondral lesions and osteoarthritis.

[Progress in surgical treatment of osteochondral lesion of talus].

Objective: To provide a comprehensive overview of the surgical treatments of osteochondral lesion of talus (OLT) and offer valuable insights for clinical practice. Methods: The advantages and limitations of surgical treatments for OLT were comprehensively summarized through an extensive review of domestic and abroad relevant literature in recent years. Results: Currently, there exist numerous surgical treatments for the OLT, all of which can yield favorable outcomes. However, each method possesses its own set of merits and demerits. The short-term effectiveness of bone marrow stimulation in treating primary OLT with a diameter less than 15 mm is evident, but its long-term effectiveness diminishes over time. Autologous osteochondral transplantation (AOT) and osteochondral allograft transplantation (OAT) are suitable for OLT with large defects and subchondral bone cysts. However, incomplete anatomical matching between the donor and recipient bones may results in the formation of new subchondral bone cysts, while AOT also presents potential complications at the donor site. In contrast to AOT and OAT, particulated juvenile cartilage allograft transplantation obviates the need for additional osteotomy. Furthermore, juvenile cartilage exhibits enhanced potential in delivering active chondrocytes to the site of cartilage defect, surpassing that of adult cartilage in tissue repair efficacy. Cell transplantation has demonstrated satisfactory effectiveness; however, it is associated with challenges such as the requirement for secondary surgery and high costs. Autologous matrix-induced chondrogenesis technology has shown promising effectiveness in the treatment of primary and non-primary OLT and OLT with large defect and subchondral bone cysts. However, there is a scarcity of relevant studies, most of which exhibit low quality. Adjuvant therapy utilizing biological agents represents a novel approach to treating OLT; nevertheless, due to insufficient support from high-quality studies, it has not exhibited significant advantages over traditional treatment methods. Furthermore, its long-term effectiveness remain unclear. Conclusion: The optimal choice of surgical treatment for OLT is contingent not only upon the characteristics such as nature, size, and shape but also takes into consideration factors like advancements in medical technology, patient acceptance, economic status, and other pertinent aspects to deliver personalized treatment.

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.

Implantation of hUCB-MSCs generates greater hyaline-type cartilage than microdrilling combined with high tibial osteotomy.

PURPOSE: To compare the outcomes of treating large cartilage defects in knee osteoarthritis using human allogeneic umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation or arthroscopic microdrilling as a supplementary cartilage regenerative procedure combined with high tibial osteotomy (HTO). METHODS: This 1-year prospective comparative study included 25 patients with large, near full-thickness cartilage defects (International Cartilage Repair Society grade ≥ IIIB) in the medial femoral condyles and varus malalignment. Defects were treated with hUCB-MSC implantation or arthroscopic microdrilling combined with HTO. The primary outcomes were pain visual analogue scale and International Knee Documentation Committee subjective scores at 12, 24 and 48 weeks. Secondary outcomes included arthroscopic, histological and magnetic resonance imaging assessments at 1 year. RESULTS: Fifteen and 10 patients were treated via hUCB-MSC implantation and microdrilling, respectively. Baseline demographics, limb alignment and clinical outcomes did not significantly differ between the groups. Cartilage defects and total restored areas were significantly larger in the hUCB-MSC group (7.2 ± 1.9 vs. 5.2 ± 2.1 cm2, p = 0.023; 4.5 ± 1.4 vs. 3.0 ± 1.6 cm2, p = 0.035). The proportion of moderate-to-strong positive type II collagen staining was significantly higher in the hUCB-MSC group compared to that in the microdrilled group (93.3% vs. 60%, respectively). Rigidity upon probing resembled that of normal cartilage tissue more in the hUCB-MSC group (86.7% vs. 50.0%, p = 0.075). Histological findings revealed a higher proportion of hyaline cartilage in the group with implanted hUCB-MSC (p = 0.041). CONCLUSION: hUCB-MSC implantation showed comparable clinical outcomes to those of microdrilling as supplementary cartilage procedures combined with HTO in the short term, despite the significantly larger cartilage defect in the hUCB-MSC group. The repaired cartilage after hUCB-MSC implantation showed greater hyaline-type cartilage with rigidity than that after microdrilling. LEVEL OF EVIDENCE: Level II, Prospective Comparative Cohort Study.

A Finite Element Model to Investigate the Stability of Osteochondral Grafts Within a Human Tibiofemoral Joint.

Osteochondral grafting has demonstrated positive outcomes for treating articular cartilage defects by replacing the damaged region with a cylindrical graft consisting of bone with a layer of cartilage. However, factors that cause graft subsidence are not well understood. The aim of this study was to develop finite element (FE) models of osteochondral grafts within a tibiofemoral joint, suitable for an investigation of parameters affecting graft stability. Cadaveric femurs were used to experimentally calibrate the bone properties and graft-bone frictional forces for use in corresponding image-based FE models, generated from µCT scan data. Effects of cartilage defects and osteochondral graft repair were measured by examining contact pressure changes using further in vitro tests. Here, six defects were created in the femoral condyles, which were subsequently treated with osteochondral autografts or metal pins. Matching image-based FE models were created, and the contact patches were compared. The bone material properties and graft-bone frictional forces were successfully calibrated from the initial tests with good resulting levels of agreement (CCC = 0.87). The tibiofemoral joint experiment provided a range of cases that were accurately described in the resultant pressure maps and were well represented in the FE models. Cartilage defects and repair quality were experimentally measurable with good agreement in the FE model pressure maps. Model confidence was built through extensive validation and sensitivity testing. It was found that specimen-specific properties were required to accurately represent graft behaviour. The final models produced are suitable for a range of parametric testing to investigate immediate graft stability.

Allogeneic umbilical cord blood-derived mesenchymal stem cell implantation versus microdrilling combined with high tibial osteotomy for cartilage regeneration.

This study compared cartilage regeneration outcomes in knee osteoarthritis (OA) using allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation and microdrilling with high tibial osteotomy (HTO). Fifty-four patients (60 knees) were included: 24 (27 knees) in the hUCB-MSC group and 30 (33 knees) in the microdrilling group. Both groups showed significant improvements in pain and functional scores at 6, 12, and 24 months compared to baseline. At 24 months, the hUCB-MSC group had significantly improved scores. Arthroscopic assessment at 12 months revealed better cartilage healing in the hUCB-MSC group. In subgroup analysis according to the defect site, hUCB-MSC implantation showed superior cartilage healing for anterior lesions. In conclusion, both treatments demonstrated effectiveness for medial OA. However, hUCB-MSC implantation had better patient-reported outcomes and cartilage regeneration than microdrilling. The study suggests promising approaches for cartilage restoration in large knee defects due to OA.

Correlation between articular cartilage status on outcomes and survivorship following meniscal allograft transplantation: A systematic review.

PURPOSE: To conduct a systematic review evaluating potential correlations between preoperative articular cartilage integrity on outcomes and survivorship in patients undergoing meniscal allograft transplantation (MAT). METHODS: A literature search was performed by querying SCOPUS, PubMed, Medline, and the Cochrane Central Register for Controlled Trials from database inception through May 2023 according to the 2020 PRISMA statement. Inclusion criteria were limited to studies reporting on outcomes and survivorship following MAT based on preoperative cartilage status. RESULTS: Sixteen studies, consisting of 1723 patients (n = 1758 total menisci), were identified in six level III and 10 level IV evidence studies. There was high heterogeneity in cartilage grading scales, reporting of concomitant cartilage procedures, and indications for MAT based on osteoarthritis. Patients with lower limb malalignment were either excluded or corrected with an osteotomy. MAT failure rate was reported in nine studies, with four studies reporting a greater rate of failure in knees with higher degrees of cartilage damage. Eight studies reported on clinical outcomes based on cartilage grade, with two studies reporting significant differences in clinical outcomes based on cartilage grade. Of the five studies reporting management of full-thickness chondral defects with cartilage surgery, three studies reported no significant difference in survivorship based on preoperative cartilage grade, while one study reported lower survivorship and one study reported unclear results. No studies found significant differences in survivorship and outcomes between medial and lateral MAT. CONCLUSIONS: Conflicting results and high variability in reporting of concomitant cartilage repair and indications for MAT exist in studies evaluating the efficacy of MAT based on articular cartilage status. The degree of preoperative chondral damage did not have a strong relationship with clinical outcomes following MAT. Higher degrees of cartilage damage were associated with higher MAT failure rates, with possible improvement in survivorship when treated with an appropriate cartilage procedure. LEVEL OF EVIDENCE: Level IV.

Viable cartilage allograft outperforms existing treatments for focal knee cartilage defects.

PURPOSE: Viable cartilage allograft (VCA) is a cartilage tissue matrix that contains cryopreserved viable allogeneic cartilage fibres. This study aimed to assess safety and benefits in treating focal knee cartilage defects with VCA. We hypothesized that VCA is a safe single-stage procedure in isolated chondral defects. METHOD: In vitro analysis, in vivo studies and a prospective case series were performed. VCA was evaluated in a goat cartilage repair model. Symptomatic International Cartilage Repair Society grade 3/4A lesions of the femoral condyle or patella were implanted with VCA. International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome (KOOS) subscales, Lysholm, Short Form-12, Visual Analog Scale and pain frequency levels were assessed. Radiographic and magnetic resonance imaging (MRI) was performed at regular intervals postoperatively. Data were analysed by statisticians to determine the power and significance of the results. RESULTS: The goat study confirmed that VCA is effective for cartilage repair. Twenty patients were implanted; the mean age was 28.1 (16-56), the mean body mass index (BMI) was 27.9 ± 5.6 and the mean follow-up was 24.1 months (range = 12.0-36.0 months). Lesions were in either the femoral condyle (7) or patella (13). Lesion sizes ranged from 1.5 to 6.0 cm2 (mean = 4.58 cm2 ). Outcome scores improved from preoperative baseline (POB): IKDC (78.2), Lysholm (89.0), KOOS: Pain (95.8), Symptoms (86.3), ADL (87.8), Sports (85.0) and QOL (75.0). MRI imaging demonstrated excellent osteochondral allograft assimilation. Second-look arthroscopy (two patients) demonstrated complete fill and incorporation (Brittberg scores 11/12). Functional scores were maintained at 24 (M): IKDC (86.24 ± 17.2), Lysholm (87.23 ± 15.0), KOOS: Pain (91.72 ± 17.3), Symptoms (84.92 ± 16.1), ADLs (93.80 ± 16.1), Sports (84.45 ± 27.7), QOL (81.30 ± 20.8). CONCLUSION: VCA is an off-the-shelf, single-stage, conformable allogeneic graft that treats chondral defects with no additional fixation. Preclinical and short-term prospective clinical studies show that VCA can safely treat chondral defects with potential advantages to existing options. LEVEL OF EVIDENCE: Level IV study.

Particulated juvenile cartilage allograft for the treatment of osteochondral lesions of the talus is associated with a high complication rate and a high failure rate at short-term follow-up: A systematic review.

PURPOSE: The purpose of this systematic review was to evaluate the clinical and radiological outcomes together with the complication rates and failure rates at short-term follow-up following particulated juvenile cartilage allograft (PJCA) for the management of osteochondral lesions of the talus (OLT). METHODS: During October 2023, the PubMed, Embase and Cochrane library databases were systematically reviewed to identify clinical studies examining outcomes following PJCA for the management of OLTs. Data regarding study characteristics, patient demographics, lesion characteristics, subjective clinical outcomes, radiological outcomes, complications and failures were extracted and analysed. RESULTS: Twelve studies were included. In total, 241 patients underwent PJCA for the treatment of OLT at a weighted mean follow-up of 29.0 ± 24.9 months. The weighted mean lesion size was 138.3 ± 59.6 mm2 . Prior surgical intervention was recorded in seven studies, the most common of which was microfracture (65.9%). The weighted mean American Orthopaedic Foot and Ankle Society score improved from a preoperative score of 58.5 ± 3.2 to a postoperative score of 83.9 ± 5.3. The weighted mean postoperative magnetic resonance observation of cartilage repair tissue (MOCART) score was 48.2 ± 3.3. The complication rate was 25.2%, the most common of which was allograft hypertrophy (13.2%). Thirty failures (12.4%) were observed at a weighted mean time of 9.8 ± 9.6 months following the index procedure. CONCLUSION: This systematic review demonstrated a moderate improvement in subjective clinical outcomes following PJCA for the treatment of OLT at short term follow-up. However, postoperative MOCART scores were reported as poor. In addition, a high complication rate (25.2%) and a high failure rate (12.4%) at short-term follow-up was observed, calling into question the efficacy of PJCA for the treatment of large OLTs. In light of the available evidence, PJCA for the treatment of large OLTs cannot be currently recommended. LEVEL OF EVIDENCE: Level IV.

Arthroscopic microfracture and associated techniques in the treatment of osteochondral lesions of the talus: A systematic review and metanalysis.

BACKGROUND: Osteochondral lesions of the talus are common in patients suffering even minor trauma; timely diagnosis and treatment can prevent the development of early osteoarthritis. The objectives of this systematic review and meta-analysis were to evaluate the effects of additional procedures on arthroscopic ankle microperforations for osteochondral lesions. METHODS: A systematic literature search was conducted using PubMed-Medline, Cochrane Central, and Google Scholar to select clinical studies analyzing the efficacy of platelet-rich plasma (PRP), hyaluronic acid (HA), and bone marrow concentrate (BMC) procedures. Ten articles following PRISMA guidelines with a total of 464 patients were included in this review. Quality assessment using MINORS was performed, and all studies demonstrated high quality. RESULTS: The results of the systematic review showed benefits in all patients undergoing infiltrative therapy with PRP, hyaluronic acid, and BMC. The best results in terms of AOFAS score and VAS scale were found in patients undergoing PRP injection. The meta-analysis showed improvements in pain relief and return to daily activities in patients undergoing arthroscopic microperforations and PRP, although not reporting statistically significant results (p = 0.42). CONCLUSION: All treatment strategies reported better scores compared to the control groups. Among the various treatments analyzed, the addition of PRP appears to be the most valuable probably for the larger population receiving this treatment, showing excellent outcomes in pain reduction, clinical outcomes, and return to daily activities. LEVEL OF EVIDENCE: II.

10-Year Prospective Clinical and Radiological Evaluation After Matrix-Induced Autologous Chondrocyte Implantation and Comparison of Tibiofemoral and Patellofemoral Graft Outcomes.

BACKGROUND: Long-term outcomes in larger cohorts after matrix-induced autologous chondrocyte implantation (MACI) are required. Furthermore, little is known about the longer-term clinical and radiological outcomes of MACI performed in the tibiofemoral versus patellofemoral knee joint. PURPOSE: To present the 10-year clinical and radiological outcomes in patients after MACI and compare outcomes in patients undergoing tibiofemoral versus patellofemoral MACI. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between September 2002 and December 2012, 204 patients who underwent MACI were prospectively registered into a research program and assessed preoperatively and at 2, 5, and 10 years postoperatively. Of these patients, 168 were available for clinical review at 10 years, with 151 (of a total of 182) grafts also assessed via magnetic resonance imaging (MRI). Patients were evaluated using the Knee injury and Osteoarthritis Outcome Score, a visual analog scale for pain frequency and severity, satisfaction, and peak isokinetic knee extensor and flexor strength. Limb symmetry indices (LSIs) were calculated for strength measures. Grafts were scored on MRI scans via the MOCART (magnetic resonance observation of cartilage repair tissue) system, with a focus on tissue infill and an overall MRI graft composite score. RESULTS: All patient-reported outcome measures improved (P < .0001) up to 2 years after surgery. Apart from the significant increase (P = .004) in the peak isokinetic knee extensor LSI, no other patient-reported outcome measure or clinical score had changed significantly from 2 to 10 years. At the final follow-up, 92% of patients were satisfied with MACI to provide knee pain relief, with 76% satisfied with their ability to participate in sports. From 2 to 10 years, no significant change was seen for any MRI-based MOCART variable nor the overall MRI composite score. Of the 151 grafts reviewed via MRI at 10 years, 14 (9.3%) had failed, defined by graft delamination or no graft tissue on MRI scan. Furthermore, of the 36 patients (of the prospectively recruited 204) who were not available for longer-term review, 7 had already proceeded to total knee arthroplasty, and 1 patient had undergone secondary MACI at the same medial femoral condylar site because of an earlier graft failure. Therefore, 22 patients (10.8%) essentially had graft failure over the period. At the final follow-up, patients who underwent MACI in the tibiofemoral (vs patellofemoral) joint reported significantly better Knee injury and Osteoarthritis Outcome Score subscale scores for Quality of Life (P = .010) and Sport and Recreation (P < .001), as well as a greater knee extensor strength LSI (P = .002). Even though the tibiofemoral group demonstrated better 10-year MOCART scores for tissue infill (P = .027), there were no other MRI-based differences (P > .05). CONCLUSION: This study reports the long-term review of a prospective series of patients undergoing MACI, demonstrating good clinical scores, high levels of patient satisfaction, and acceptable graft survivorship at 10 years. Patients undergoing tibiofemoral (vs patellofemoral) MACI reported better long-term clinical outcomes, despite largely similar MRI-based outcomes.

Quantitative Magnetic Resonance Imaging of Lateral Compartment Articular Cartilage After Lateral Extra-articular Tenodesis.

BACKGROUND: Concerns have arisen that anterior cruciate ligament reconstruction (ACLR) with lateral extra-articular tenodesis (LET) may accelerate the development of posttraumatic osteoarthritis in the lateral compartment of the knee. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate whether the augmentation of ACLR with LET affects the quality of lateral compartment articular cartilage on magnetic resonance imaging (MRI) at 2 years postoperatively. We hypothesized that there would be no difference in T1rho and T2 relaxation times when comparing ACLR alone with ACLR + LET. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A consecutive subgroup of patients at the Fowler Kennedy Sport Medicine Clinic participating in the STABILITY 1 Study underwent bilateral 3-T MRI at 2 years after surgery. The primary outcome was T1rho and T2 relaxation times. Articular cartilage in the lateral compartment was manually segmented into 3 regions of the tibia (lateral tibia [LT]-1 to LT-3) and 5 regions of the femur (lateral femoral condyle [LFC]-1 to LFC-5). Analysis of covariance was used to compare relaxation times between groups, adjusted for lateral meniscal tears and treatment, cartilage and bone marrow lesions, contralateral relaxation times, and time since surgery. Semiquantitative MRI scores according to the Anterior Cruciate Ligament OsteoArthritis Score were compared between groups. Correlations were used to determine the association between secondary outcomes (including results of the International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, Lower Extremity Functional Scale, 4-Item Pain Intensity Measure, hop tests, and isokinetic quadriceps and hamstring strength tests) and cartilage relaxation. RESULTS: A total of 95 participants (44 ACLR alone, 51 ACLR + LET) with a mean age of 18.8 years (61.1% female [58/95]) underwent 2-year MRI (range, 20-36 months). T1rho relaxation times were significantly elevated for the ACLR + LET group in LT-1 (37.3 ± 0.7 ms vs 34.1 ± 0.8 ms, respectively; P = .005) and LFC-2 (43.9 ± 0.9 ms vs 40.2 ± 1.0 ms, respectively; P = .008) compared with the ACLR alone group. T2 relaxation times were significantly elevated for the ACLR + LET group in LFC-1 (51.2 ± 0.7 ms vs 49.1 ± 0.7 ms, respectively; P = .03) and LFC-4 (45.9 ± 0.5 ms vs 44.2 ± 0.6 ms, respectively; P = .04) compared with the ACLR alone group. All effect sizes were small to medium. There was no difference in Anterior Cruciate Ligament OsteoArthritis Scores between groups (P = .99). Weak negative associations (rs = -0.27 to -0.22; P < .05) were found between relaxation times and quadriceps and hamstring strength in the anterolateral knee, while all other correlations were nonsignificant (P > .05). CONCLUSION: Increased relaxation times demonstrating small to medium effect sizes suggested early biochemical changes in articular cartilage of the anterolateral compartment in the ACLR + LET group compared with the ACLR alone group. Further evidence and long-term follow-up are needed to better understand the association between these results and the potential risk of the development of osteoarthritis in our patient cohort.

Bridging bench to body: ex vivo models to understand articular cartilage repair.

With little to no ability to self-regenerate, human cartilage defects of the knee remain a major clinical challenge. Tissue engineering strategies include delivering specific types of cells and biomaterials to the injured cartilage for restoration of architecture and function. Pre-clinical models to test the efficacy of the therapies come with high costs and ethical issues, and imperfect prediction of performance in humans. Ex vivo models represent an alternative avenue to trial cartilage tissue engineering. Defined as viable explanted cartilage samples, ex vivo models can be cultured with a cell-laden biomaterial or tissue-engineered construct to evaluate cartilage repair. Though human and animal ex vivo models are currently used in the field, there is a need for alternative methods to assess the strength of integration, to increase throughput and manage variability and to optimise and standardise culture conditions, enhancing the utility of these models overall.

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.

Treatment of cartilage defects in the patellofemoral joint with matrix-associated autologous chondrocyte implantation effectively improves pain, function, and radiological outcomes after 5-7 years.

INTRODUCTION: The aim of the present study was to evaluate midterm outcomes 5-7 years after matrix-associated autologous chondrocyte implantation (MACI) in the patellofemoral joint. MATERIALS AND METHODS: Twenty-six patients who had undergone MACI using the Novocart® 3D scaffold were prospectively evaluated. Clinical outcomes were determined by measuring the 36-Item Short-Form Health Survey (SF-36) and International Knee Documentation Committee (IKDC) scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) values preoperatively and 3, 6, and 12 months, and a mean of 6 years postoperatively. At the final follow-up, the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was evaluated. RESULTS: Twenty-two patients with 23 focal cartilage defects (19 patella and four trochlea) were available for the final follow-up. The mean defect size was 4.0 ± 1.9 cm2 (range 2.4-9.4 cm2). All clinical outcome scores improved significantly until 5-7 years after MACI (SF-36 score, 61.2 ± 19.6 to 83.2 ± 11.6; P = 0.001; IKDC score, 47.5 ± 20.6 to 74.7 ± 15.5; P < 0.001; and WOMAC, 29.8 ± 15.7 to 8.2 ± 10.3; P < 0.001). The mean MOCART score was 76.0 ± 11.0 at the final follow-up. Nineteen of the 22 patients (86.4%) were satisfied with the outcomes after 5-7 years and responded that they would undergo the procedure again. CONCLUSION: MACI in the patellofemoral joint demonstrated good midterm clinical results with a significant reduction in pain, improvement in function, and high patient satisfaction. These clinical findings are supported by radiological evidence from MOCART scores. LEVEL OF EVIDENCE: IV-case series.

High-Speed Centrifugation Efficiently Removes Immunogenic Elements in Osteochondral Allografts.

OBJECTIVES: The current clinical pulse lavage technique for flushing fresh osteochondral allografts (OCAs) to remove immunogenic elements from the subchondral bone is ineffective. This study aimed to identify the optimal method for removing immunogenic elements from OCAs. METHODS: We examined five methods for the physical removal of immunogenic elements from OCAs from the femoral condyle of porcine knees. We distributed the OCAs randomly into the following seven groups: (1) control, (2) saline, (3) ultrasound, (4) vortex vibration (VV), (5) low-pulse lavage (LPL), (6) high-pulse lavage (HPL), and (7) high-speed centrifugation (HSC). OCAs were evaluated using weight measurement, micro-computed tomography (micro-CT), macroscopic and histological evaluation, DNA quantification, and chondrocyte activity testing. Additionally, the subchondral bone was zoned to assess the bone marrow and nucleated cell contents. One-way ANOVA and paired two-tailed Student's t-test are used for statistical analysis. RESULTS: Histological evaluation and DNA quantification showed no significant reduction in marrow elements compared to the control group after the OCAs were treated with saline, ultrasound, or VV treatments; however, there was a significant reduction in marrow elements after LPL, HPL, and HSC treatments. Furthermore, HSC more effectively reduced the marrow elements of OCAs in the middle and deep zones compared with LPL (p < 0.0001) and HPL (p < 0.0001). Macroscopic evaluation revealed a significant reduction in blood, lipid, and marrow elements in the subchondral bone after HSC. Micro-CT, histological analyses, and chondrocyte viability results showed that HSC did not damage the subchondral bone and cartilage; however, LPL and HPL may damage the subchondral bone. CONCLUSION: HSC may play an important role in decreasing immunogenicity and therefore potentially increasing the success of OCA transplantation.

Autologous Costal Chondral/Osteochondral Transplantation and Costa-Derived Chondrocyte Implantation for Articular Cartilage Repair: Basic Science and Clinical Applications.

There has been increasing application of autologous costal chondral/osteochondral transplantation (ACCT/ACOT) and costa-derived chondrocyte implantation (ACCI) for articular cartilage repair over the past three decades. This review presents the major evidence on the properties of costal cartilage and bone and their qualifications as grafts for articular cartilage repair, the major clinical applications, and the risks and strategies for costal chondral/osteochondral graft(s) harvest. First, costal cartilage has many specific properties that help restore the articular surface. Costa, which can provide abundant cartilage and cylindrical corticocancellous bone, preserves permanent chondrocyte and is the largest source of hyaline cartilage. Second, in the past three decades, autologous costal cartilage-derived grafts, including cartilage, osteochondral graft(s), and chondrocyte, have expanded their indications in trauma and orthopaedic therapy from small to large joints, from the upper to lower limbs, and from non-weight-bearing to weight-bearing joints. Third, the rate of donor-site complications of ACCT or ACOT is low, acceptable, and controllable, and some skills and accumulated experience can help reduce the risks of ACCT and ACOT. Costal cartilage-derived autografting is a promising technique and could be an ideal option for articular chondral lesions with or without subchondral cysts. More high-quality clinical studies are urgently needed to help us further understand the clinical value of such technologies.

Biomaterials augmented with filtered bone marrow aspirate for the treatment of talar osteochondral lesions. A comparison of clinical and cellular parameters.

BACKGROUND: Biomaterials augmented with Bone Marrow Aspirate Concentrate (BMAC) are becoming increasingly utilized in the cartilage treatment. However, the potential role of cellular parameters in the intraoperatively applied BMAC have yet to be elucidated. PURPOSE: (A) To evaluate clinical outcomes and safety of a combined single-step approach with scaffolds (fibrin glues, collagen gels, collagen-hydroxyapatite membrane) and filtered Bone Marrow Aspirate (fBMA) for the treatment of osteochondral lesions of the talus (OLTs). (B) To identify significant factors for postoperative improvements, considering cellular parameters as potential predictors. METHODS: All the patients operated on due to OLTs by the combination above were selected from the hospital registry database (35 pts, years 16-55, and minimally 1 year follow-up). Treatment outcomes were followed clinically with Patient-reported outcome measures (PROMs), and by pursuing serious adverse events (SAE) and graft failures (GF). Cellular parameters of the injected fBMA were determined. Pre- and postoperative PROMs values were compared to evaluate postoperative improvements. Multivariable regression models were applied to identify potential factors (demographics, medical history, joint and lesion characteristics, scaffold type, surgical and cellular parameters) that predict the treatment outcomes. RESULTS: At the mean follow-up of 32.2 (12.5) months, all Foot and Ankle Outcome Score (FAOS) and European Quality of Life in Five Dimensions Three-Level (EQ-5D-3 L) values improved significantly. 4 (11%) SAE (3 arthrofibrosis, one hardware removal), and 3 (9%) GF occurred. Female gender and concomitant procedures were the main negative predictors for postoperative outcomes. The number of fibroblast colony forming units (CFU-F) or their proportion among total nucleated cells (CFU-F/TNC) were positively correlated with the improvements of some PROMs. CONCLUSIONS: Scaffolds augmented with fBMA proved as an adequate and safe approach for OLTs treatment. Cellular parameters seem to influence the treatment outcomes, thus further attention should be given to the intraoperatively applied products. LEVEL OF EVIDENCE: Level IV.

Impact of Wiberg Patellar Type on Outcomes and Survival Following Cell-Based Cartilage Repair for Patellar Chondral Lesions at Midterm Follow-up.

BACKGROUND: Cell-based cartilage repair procedures of the patellofemoral joint have less reliable outcomes than those of the tibiofemoral joint. No previous studies have evaluated the influence of patellar shape on cell-based cartilage repair outcomes. Patellar dysplasia may predispose patients to worse outcomes after cell-based cartilage repair. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate the relationship between Wiberg patellar type and outcomes after cell-based cartilage repair (autologous chondrocyte implantation or particulated juvenile allograft cartilage transplantation) for the treatment of patellar chondral lesions at a minimum 2-year follow-up. It was hypothesized that Wiberg classification of patellar shape would have no effect on patient-reported outcome measures (PROMs) or graft survival. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients undergoing autologous chondrocyte implantation or particulated juvenile allograft cartilage transplantation for full-thickness patellar chondral defects between 2016 and 2020 were retrospectively reviewed after institutional review board approval. The change in PROMs, including International Knee Documentation Committee (IKDC), Kujala, and Veterans RAND 12-item Health Survey Mental and Physical scores, from pre- to postoperatively and the percentage of patients who achieved the minimal clinically important difference (MCID) for IKDC and Kujala scores were compared for the Wiberg type A versus Wiberg type B versus Wiberg type C groups. The log-rank test was used to evaluate for differences in survival between subgroups. RESULTS: A total of 59 patients (63 knees) were included, with a mean age of 33.3 ± 8.6 years, median body mass index of 26.0 (IQR, 21.8-30.2), and median follow-up time of 3.5 years (IQR, 2.6-4.2 years). In total, 26 (41%) patellae were Wiberg type A, 29 (46%) were Wiberg type B, and 8 (13%) were Wiberg type C. There were no differences between Wiberg type A versus Wiberg type B versus Wiberg type C groups with respect to change in PROMs from pre- to postoperatively or the percentage of patients who achieved the MCID for IKDC or Kujala scores (P > .05 for all). There were no differences in survival between groups (P = .45). CONCLUSION: Wiberg patellar type has no effect on patient-reported outcomes or graft survival at midterm follow-up. Patellar dysplasia should not be seen as a contraindication for cell-based cartilage repair procedures.