Autologous matrix-induced chondrogenesis provides better outcomes in comparison to autologous minced cartilage implantation in the repair of knee chondral defects.

PURPOSE: In symptomatic mid-sized focal chondral defects, autologous matrix-induced chondrogenesis (AMIC) and minced cartilage implantation (MCI) offer two versatile treatment options. This study aimed to conduct a matched-patient analysis of patient-reported outcome measures to compare these two surgical treatment methods for focal chondral defects. METHODS: At the first centre, patients underwent a single-stage procedure in which autologous cartilage was hand-minced, implanted into the defect and fixed with fibrin glue. At the second centre, patients underwent AMIC, which was fixed in place with fibrin glue. All patients were seen 2-4 years postoperatively. Postoperative outcomes were assessed using the visual analogue scale for pain (VAS), the Lysholm score and the five domains of the knee osteoarthritis outcome score (KOOS). Patients from each surgical centre were matched by age, sex, defect size and defect localisation. RESULTS: In total, 48 patients from two surgical centres (24 from each site) were matched for sex, age (MCI 30.3 ± 14.9 years vs. AMIC 30.8 ± 13.7 years) and defect size (MCI 2.49 ± 1.5 cm2 vs. AMIC 2.65 ± 1.1 cm2). Significantly better scores in the AMIC cohort were noted for VAS (p = 0.004), Lysholm (p = 0.043) and the KOOS subscales for pain (p = 0.016) and quality of life (p = 0.036). There was a significantly greater proportion of positive responders for Lysholm in the AMIC group (92%) compared with the MCI group (64%). CONCLUSIONS: The AMIC procedure delivers superior patient outcomes compared with hand-minced autologous cartilage implantation. These are mid-term outcomes, with follow-up between 2 and 4 years. LEVEL OF EVIDENCE: Level III.

Drop in survivorship 13 years after AMIC procedures in aligned knees: A long-term follow-up.

PURPOSE: Autologous matrix-induced chondrogenesis (AMIC) showed promising short-term results comparable to microfracture. This study aims to assess the 19-year outcomes of AMIC, addressing the lack of long-term data. METHODS: Retrospective cohort of 34 knees treated with AMIC underwent a 19-year follow-up. The primary outcome was AMIC survival, considering total knee arthroplasty as a failure event. Survival analysis for factors that were associated with longer survival of the AMIC was also performed. Clinical and radiological outcome scores were analysed for the AMIC group. RESULTS: Twenty-three knees were available for follow-up analysis. Of these, 14 (61%) underwent revision surgery for total knee arthroplasty (TKA). The mean time was 13.3 ± 2.5 years (range: 9-17 years). Secondary outcomes showed that increased age at surgery (hazard ratio [HR]: 1.05; p = 0.021) and larger defect size (HR: 1.95; p = 0.018) were risk factors for failure. Concomitant proximal tibial osteotomy (HR: 0.22; p = 0.019) was associated with longer survival. The remaining nine knees (39%) were analysed as a single group. The mean clinical score at follow-up of 18.6 ± 0.9 SD years was 79.5 ± 19.7 SD for the Lysholm score, 1.8 ± 1.5 SD for the visual analog scale score, 74.2 ± 22.4 SD for the KOOS score and a median of 3 (range: 3-4) for the Tegner activity scale. CONCLUSIONS: The mean survival time of 13.3 years indicates the durability of AMIC in properly aligned knees. Nonetheless, despite a 61% conversion to TKA, the knees that persisted until the 19-year follow-up remained stable, underscoring the procedure's longevity and consistent clinical outcomes. LEVEL OF EVIDENCE: Level IV.

The efficacy of autologous matrix-induced chondrogenesis (AMIC) for osteochondral lesions of the talus in the mid-long term: a systematic review and meta-analysis.

PURPOSE: The objective of this study was to provide a comprehensive review of the existing literature regarding the treatment of osteochondral lesions of the talus (OLT) using autologous matrix-induced chondrogenesis (AMIC), while also discussing the mid-long term functional outcomes, complications, and surgical failure rate. METHODS: We searched Embase, PubMed, and Web of Science for studies on OLT treated with AMIC with an average follow-up of at least 2 years. Publication information, patient data, functional scores, surgical failure rate, and complications were extracted. RESULTS: A total of 15 studies were screened and included, with 12 case series selected for meta-analysis and 3 non-randomized controlled studies chosen for descriptive analysis. The improvements in the Visual Analog Scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot, and Tegner scores at the last follow-up were (SMD = - 2.825, 95% CI - 3.343 to - 2.306, P < 0.001), (SMD = 2.73, 95% CI 1.60 to 3.86, P < 0.001), (SMD = 0.85, 95% CI 0.5 to 1.2, P < 0.001) respectively compared to preoperative values. The surgery failure rate was 11% (95% CI 8-15%), with a total of 12 patients experiencing complications. CONCLUSION: The use of AMIC demonstrates a positive impact on pain management, functional improvement, and mobility enhancement in patients with OLT. It is worth noting that the choice of stent for AMIC, patient age, and OLT size can influence the ultimate clinical outcomes. This study provides evidences supporting the safety and efficacy of AMIC as a viable treatment option in real-world medical practice.

Significant Clinical Improvement After Arthroscopic Autologous Matrix-Induced Chondrogenesis for Osteochondral Lesions of the Talus: A 5-Year Follow-Up.

PURPOSE: This study aims to evaluate the clinical outcomes of arthroscopic autologous matrix-induced chondrogenesis (A-AMIC) for osteochondral lesions of the talus (OLT) at 24 months and 60 months of follow-up. The secondary aim was to assess whether age, body mass index (BMI), and lesion surface affect outcomes. DESIGN: Sixty-three patients (32 males, 31 females) with a median age of 37 years [interquartile range (IQR): 25-48] were included. Preoperative and postoperative (24 months and 60 months) clinical outcomes were evaluated using a Visual Analog Score (VAS) for pain during walking, the American Orthopaedic Foot and Ankle Society (AOFAS), Short-Form Survey (SF-12), the Halasi, and the University of California, Los Angeles (UCLA) scores. Patients were categorized according to age, BMI, and lesion surface (1-1.5 cm2 and over 1.5 cm2). The effect of each category was evaluated. RESULTS: There were significant improvements in the VAS, AOFAS, SF-12, and UCLA, comparing the preoperative scores to the 60-month follow-up scores (P < 0.001). There were no significant differences in the above-mentioned outcomes between the follow-up periods. Patients older than 33 years had lower SF-12, Halasi, and UCLA scores (P = 0.005, 0.004, and <0.001, respectively). Overweight patients had lower VAS, SF-12, Halasi, and UCLA scores (P = 0.006, 0.002, 0.024, and 0.007, respectively). Lesion size was uninfluential. CONCLUSION: A-AMIC yielded clinical improvements at a minimum follow-up of 60 months in patients with symptomatic OLTs, with clinical improvement peaking in the first 2 years, followed by a plateau period. Increased age and BMI were significantly associated with inferior outcomes.

The development of a nucleus pulposus-derived cartilage analog scaffold for chondral repair and regeneration.

Focal chondral defects (FCDs) significantly impede quality of life for patients and impose severe economic costs on society. One of the most promising treatment options-autologous matrix-induced chondrogenesis (AMIC)-could benefit from a scaffold that contains both of the primary cartilage matrix components-sulfated glycosaminoglycans (sGAGs) and collagen type II. Here, 17 different protocols were evaluated to determine the most optimum strategy for decellularizing (decelling) the bovine nucleus pulposus (bNP) to yield a natural biomaterial with a cartilaginous constituency. The resulting scaffold was then characterized with respect to its biochemistry, biomechanics and cytocompatibility. Results indicated that the optimal decell protocol involved pre-crosslinking the tissue prior to undergoing decell with trypsin and Triton X-100. The residual DNA content of the scaffold was found to be 32.64 ± 9.26 ng/mg dry wt. of tissue with sGAG and hydroxyproline (HYP) contents of 72.53 ± 16.43. and 78.38 ± 8.46 µg/mg dry wt. respectively. The dynamic viscoelastic properties were found to be preserved (complex modulus: 17.92-16.62 kPa across a range of frequencies) while the equilibrium properties were found to have significantly decreased (aggregate modulus: 11.51 ± 9.19 kPa) compared to the non-decelled fresh bNP tissue. Furthermore, the construct was also found to be cytocompatible with bone marrow stem cells (BMSCs). While it was not permissive of cellular infiltration, the BMSCs were still found to have lined the laser drilled channels in the scaffold. Taken together, the biomaterial developed herein could be a valuable addition to the AMIC family of scaffolds or serve as an off-the-shelf standalone option for cartilage repair.

Arthroscopic and open approaches for autologous matrix-induced chondrogenesis repair of the knee have similar results: a meta-analysis.

BACKGROUND: Cartilage defects are debilitating injuries that can reduce quality of life in patients. However, the poor regenerative properties of cartilage mean that cartilage repair remains challenging, and many methods have arisen to address that. Autologous matrix-induced chondrogenesis (AMIC®) is a popular technique to manage cartilage defects. Recent advances have allowed AMIC® to be done arthroscopically, instead of a mini-open arthrotomy approach. This systematic review and meta-analysis aims to investigate whether the arthroscopic approach to AMIC® provides better clinical outcomes than does the mini-open approach, in hopes of delineating a gold standard in cartilage repair. METHODS: With reference to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic search of the following databases (PubMed, Embase, Scopus, and Cochrane Library) was performed on 26th October 2022 using a combination of the following search terms: "autologous matrix induced", "chondrogenesis", and "knee". A total of 390 studies were identified, of which, 24 studies were included in our final analysis. RESULTS: The arthroscopic approach achieves lower Visual Analogue Scale for pain scores. The International Knee documentation Committee) score and Knee Injury and Osteoarthritis Outcome Score were comparable between arthroscopic and open approaches. The open approach achieves a higher Magnetic Resonance Observation of Cartilage Repair Tissue score. Incidence of reported postoperative complications of revision surgery and knee stiffness was higher for the open approach than for the arthroscopic approach, whereas deep vein thrombosis was higher in the arthroscopic approach. CONCLUSION: The AMIC® repair outcomes indicate that the arthroscopic approach does not hold a distinct advantage over the open approach. The choice of approach should consider surgeon expertise, location of lesion, and patient-specific factors. LEVEL OF EVIDENCE: Systematic review and meta-analysis; Level III.

Positive outcomes following Autologous Matrix-Induced Chondrogenesis (AMIC) in the treatment of retropatellar chondral lesions: a retrospective analysis of a patient registry.

BACKGROUND: The patellofemoral joint is a challenging environment for treating chondral defects. Among the surgical options for the treatment of chondral defects, the single-stage Autologous Matrix-Induced Chondrogenesis (AMIC) procedure uses a porcine collagen I/III membrane to enhance bone-marrow stimulation. However, longer term outcomes data are rare for this specific indication. In order to provide real-world information, an ongoing registry has been established to record patient data and outcomes when AMIC is used to treat chondral and osteochondral lesions. METHODS: Patient data were retrieved from an ongoing, prospective, multisite registry of patients who had undergone AMIC treatment of chondral defects. We identified 64 patients who had undergone AMIC for patellofemoral chondral defects and for whom pre-operative and at least 1 post-operative score were available were included in this retrospective data analysis. Outcomes were assessed via the KOOS, VAS pain, and the Lysholm scores. Outcomes at the post-operative time-points were analysed using a factorial ANOVA with post-hoc testing while linear regression was used to assess associations between the change in the Lysholm score and lesion size. RESULTS: There was a significant improvement in Lysholm, VAS pain, and KOOS scores from pre-operative to the 1st year post-operative (p < 0.001), and this was maintained during the follow-up. CONCLUSIONS: The forces exerted on the patellofemoral joint make this a challenging scenario for chondral repair. Our data demonstrates that the AMIC procedure with a collagen I/III membrane is an effective treatment for retropatellar cartilage lesions, and provides reliable results, with decreased pain and improved function. Importantly, these improvements were maintained through the follow-up period.

Satisfactory patient-reported outcomes in patients treated with impaction bone grafting and autologous matrix-induced chondrogenesis for osteochondral knee defects.

PURPOSE: Osteochondral knee defects usually affect young, active patients and may alter knee biomechanics and progressively lead to joint degeneration. Various treatment options exist with autologous, impaction bone grafting in combination with autologous matrix-induced chondrogenesis (BG-AMIC) being a less-expensive, one-step, promising option. The purpose of this study is to evaluate the clinical and radiological mid-term outcomes of large osteochondral lesions treated with BG-AMIC, identify a possible correlation between the two and report postoperative complications and reoperation rate. METHODS: A retrospective analysis of 25 patients treated with the BG-AMIC technique for knee osteochondral lesions was performed. Patients were assessed using the following PROMs: the IKDC, the KOOS and the Lysholm score, the Tegner activity scale and a patient acceptable symptom state (PASS). The EQ-5D-5L score was used to assess health-related quality of life. Radiological assessment was performed using the MOCART 2.0 score on a 3 T MRI. RESULTS: At a mean of 3.8 (± 0.8)-year follow-up, all functional scores increased significantly (p < 0.005) when compared to the preoperative baseline. IKDC increased from 44.5 (± 15.9) to 81.4 (± 14.7), KOOS from 41.5 (± 16.1) to 91.6 (± 11.6) and Lysholm from 54.4 (± 23) to 95.2 (± 5.5) (p < 0.005). The EQ-5D-5L score also revealed a significant improvement [59.9 (± 25) to 93.4 (± 10.2), p < 0.005]. Mean Tegner score reached pre-injury levels. The PASS was positive in 100% of patients. The minimum clinically important difference was reached in all PROMs except for the KOOS Sports subscale. There were no re-operations. Morphological evaluation of the repair tissue using the MOCART 2.0 score revealed a mean total score of 52.8 (± 30.5). A statistically significant, positive correlation was found between the MOCART 2.0 score and the IKDC score, the KOOS ADL subscale and the EQ-5D-5L (p < 0.05). CONCLUSION: BG-AMIC is a safe and reliable option for treating deep, knee osteochondral lesions, providing a statistically significant and clinically important improvement in patient-reported outcomes. No complications were noticed, and no re-operations were performed after the procedure. A moderate positive correlation between the MOCART 2.0 score and the IKDC, KOOS ADL and EQ-5D-5L was noticed. However, this correlation is not necessarily clinically relevant, and excellent clinical results can be expected even in patients with low MOCART scores. LEVEL OF EVIDENCE: III.

Typical Complications After Cartilage Repair of the Ankle Using Autologous Matrix-Induced Chondrogenesis (AMIC).

Background: Autologous matrix-induced chondrogenesis (AMIC) for the treatment of osteochondral lesions of the talus (OLT) results in favorable clinical outcomes, yet high reoperation rates. The aim of this study was to report and analyze typical complications and their risk factors after AMIC for OLT. Methods: A total of 127 consecutive patients with 130 AMIC procedures for OLT were retrospectively assessed. All AMIC procedures were performed in an open fashion with 106 (81.5%) cases requiring a malleolar osteotomy (OT) to access the OLT. Seventy-one patients (54.6%) underwent subsequent surgery. These cases were evaluated at a mean follow-up of 3.1 years (±2.5) for complications reviewing postoperative imaging and intraoperative findings during revision surgery. Six patients (8.5%) were lost to follow-up. Regression model analysis was conducted to identify factors that were associated with AMIC-related complications. Results: Among the 65 (50%) patients who required revision surgery, 18 patients (28%) demonstrated AMIC-related complications with deep fissuring (83%) and thinning (17%) of the AMIC graft. Conversely, 47 patients (72%) underwent subsequent surgery due to AMIC-unrelated reasons including isolated removal of symptomatic hardware (n = 17) and surgery addressing concomitant pathologies with (n = 25) and without hardware removal (n = 5). Previous prior cartilage repair surgery was significantly associated with AMIC graft-associated complications in patients undergoing revision surgery (P = .0023). Among age, body mass index, defect size, smoking, and bone grafting, smoking was the only factor showing statistical significance with an odds ratio of 3.7 (95% CI 1.24, 10.9; P = .019) to undergo revision surgery due to graft-related complications, when adjusted for previous cartilage repair surgery. Conclusion: The majority of revision surgeries after AMIC for OLT are unrelated to the performed AMIC graft but frequently address symptomatic hardware and concomitant pathologies. Both smoking and previous cartilage repair surgery seem to significantly increase the risk of undergoing revision surgery due to AMIC-related complications. Level of evidence: Level IV, case series.

Satisfactory clinical outcomes with autologous matrix-induced chondrogenesis in the treatment of grade IV chondral injuries of the knee.

OBJECTIVE: The research aims to evaluate short- and medium-term outcomes of patients treated using autologous matrix-induced chondrogenesis (AMIC) with a hyaluronic acid scaffold (Hyalofast, Anika Therapeutics, MA, USA) in grade IV chondral lesions according to the Outerbridge classification in the knee. METHODS: This is a multicentre, non-randomized, retrospective study conducted between 2017 and 2022. To determine the clinical outcome of the patients, the follow-up was done with the subjective International Knee Documentation Committee (IKDC) score, pre-surgery, and with a follow-up at 12, 24, and 32 months. RESULTS: Fifty patients (28 female) with a mean age of 45.9 ± 12.7 years were recruited. The mean size of the lesion was 3.5 cm2, and the injuries located in the patella (30%) and trochlear groove (24%) were the most frequent. The total IKDC clinical score significantly increased from baseline to the 32 months of follow-up with a mean difference of 36.4 (95% CI, 29.1-43.7, p < 0.001). Besides, there was a statistically significant improvement in all categories of the IKDC (symptoms, sports activities, function, and activity of daily living) compared between pre-surgery and 24 and 32 months of follow-up. The patients younger than 45 years presented better clinical outcomes than older ones with a difference between medians of 10.40 (95% CI, 1.10-11.50, p = 0.0247), and a negative correlation was found between the 32-month IKDC score and the age. In addition, no statistically significant difference was found when comparing the last results of the IKDC between patients with and without associated surgical procedures or between patients with single and several lesions, neither nor between men and women. The level of satisfaction with the procedure of all the patients, on a score of 1-10, was on average 8 ± 1.5. CONCLUSION: Results of this study indicate that patients who underwent the AMIC procedure with hyaluronic acid scaffold for the treatment of grade IV chondral lesions in the knee presented satisfactory results throughout the follow-up. LEVEL OF EVIDENCE: Level IV.

Autologous matrix induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC) in chondral defects of the first metatarsophalangeal joint - 5-year follow-up.

BACKGROUND: The aim of the study was to assess the 5-year-follow-up (5FU) after Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral defects at the first metatarsophalangeal joint (MTP1). MATERIAL AND METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral lesion at MTP1 that were treated with AMIC+PBC from July 17, 2016 to May 31, 2017 were included. Size and location of the chondral lesions, the Visual-Analogue-Scale Foot and Ankle (VAS FA) and the EFAS Score before treatment and at 5FU were analysed and compared with previous 2-year-follow-up (2FU). Peripheral Blood Concentrate (PBC) was used to impregnate a collagen I/III matrix (Chondro-Gide, Wolhusen, Switzerland) that was fixed into the chondral lesion with fibrin glue. RESULTS: One hundred and ninety-eight patients with 238 chondral defects were included. In 21 % of patients no deformities in the forefoot were registered. The average degree of osteoarthritis was 2.2. The chondral defect size was 1.0 cm2 on average. The most common location was metatarsal dorsal (33 %), and in most patients one defect was registered (74 %). Corrective osteotomy of the first metatarsal was performed in 79 %. 176 (89 %)/164 (83 %) patients completed 2FU/5FU. VAS FA/EFAS Score were preoperatively 46.8/11.9 and improved to 74.1/17.1 at 2FU and 75.0/17.3 at 5FU on average. No parameter significantly differed between 2FU and 5FU. CONCLUSIONS: AMIC+PBC as treatment for chondral defects at MTP1 as part of joint preserving surgery led to improved and high validated outcome scores at 2FU and 5FU. The results between 2FU and 5FU did not differ.

Autologous matrix induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC) in chondral lesions at the ankle as part of a complex surgical approach - 5-year follow-up.

BACKGROUND: The aim of the study was to assess 5-year-follow-up (5FU) after Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral lesions at the ankle as part of a complex surgical approach. METHODS: In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral lesion at the ankle treated with AMIC+PBC from July 17, 2016 to May 31, 2017 were included. Size and location of the chondral lesions, the Visual-Analogue-Scale Foot and Ankle (VAS FA) and the EFAS Score before treatment and at 5FU were analysed and compared with previous 2-year-follow-up (2FU). Peripheral Blood Concentrate (PBC) was used to impregnate a collagen I/III matrix (Chondro-Gide, Wolhusen, Switzerland) that was fixed into the chondral lesion with fibrin glue. RESULTS: One hundred and twenty-nine patients with 136 chondral lesions were included in the study. The chondral lesions were located as follows (n (%)), medial talar shoulder only, 62 (46); lateral talar shoulder only, 42 (31); medial and lateral talar shoulder, 7 (10); tibia, 18 (13). The average for lesion size was 1.8 cm2, for VAS FA 45.7 and for EFAS Score 9.8. 2FU/5FU was completed in 105 (81 %)/104(81 %) patients with 112/111 previous chondral lesions. VAS FA improved to 79.8/84.2 and EFAS Score to 20.3/21.5 (2FU/5FU). No parameter significantly differed 2FU and 5FU. CONCLUSIONS: AMIC+PBC as part of a complex surgical approach led to improved and high validated outcome scores at 2FU/5FU. 2FU and 5FU did not differ.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]. / Chirurgische Therapie fokaler Knorpelschäden am Knie : Indikationen, Techniken, Modifikationen, Ergebnisse.

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

AMIC Procedure for Treatment of Osteochondral Lesions of Talus-A Systematic Review of the Current Literature.

Osteochondral lesions of talus are a common injury where surgery is indicated in case of failed non-operative treatment or displaced lesions. Many studies have been conducted on the effectiveness of the AMIC procedure. The goal of our study is to create an overview of the current literature. A systematic search adhering to the PRISMA guidelines was conducted in PubMed (MEDLINE) and EMBASE on May 27, 2020. All included studies were evaluated according to the modified Coleman Methodology Score and information on study type, patient numbers, age, follow-up period, grade, location and size of the lesion, study in- and exclusion criteria, associated surgery, surgical technique, scaffold- and fixation technique, postoperative restrictions, reoperation rates, study outcome score, rehabilitation program, and surgical complications was extracted. Ninety-six studies were identified with 18 studies being included in our analysis. The overall quality of the literature was fair with no studies being graded as excellent. Data on preoperative evaluation and surgical technique, complication and reoperation rates, postoperative management and study outcome was extracted in order to create an overview of the current literature. The literature supports the use of the AMIC procedure as an effective treatment for osteochondral lesions of talus. Great heterogeneity exists and comparative studies are missing. While the number of studies on the topic is increasing further are needed and especially with optimized design.

Injectable Scaffold with Microfracture using the Autologous Matrix-Induced Chondrogenesis (AMIC) Technique: A Prospective Cohort Study.

Introduction: Autologous matrix-induced chondrogenesis (AMIC) is a one-step surgical cartilage repair procedure involving the insertion of a scaffold into the chondral defect after microfracture. BST-CarGel [Smith and Nephew, Watford, England] is an injectable chitosan-based scaffold which can more easily fill defects with irregular shapes and be used to treat vertical or roof chondral lesions. The study aims to evaluate the clinical outcomes of knee cartilage repair with microfracture surgery and BST-CarGel using the AMIC technique for a minimum of two years. Materials and methods: A prospective study of patients undergoing cartilage repair with microfracture surgery and BST-CarGel at our institution from 2016 to 2019 was performed. Clinical outcomes were determined using the Lysholm Knee Scoring System and Knee Injury and Osteoarthritis Outcome Score (KOOS). These questionnaires were administered before the surgery and at a minimum of two years after surgery. Results: A total of 21 patients were identified and recruited into the study. 31 cartilage defects were seen and treated in 21 knees. These included horizontal lesions (e.g., trochlear, lateral tibial plateau), vertical lesions (e.g., medial femoral condyle, lateral femoral condyle) and inverted lesions (e.g., patella). No complications or reoperations were seen in our study population. For the average duration of follow-up of 42.5±8.55 months, there was an average improvement in Lysholm score of 25.8±18.6 and an average improvement in KOOS score of 22.5±15.0. Conclusion: BST-CarGel with microfracture surgery using the AMIC technique is a safe and effective treatment for cartilage defects in the short to medium term.

Autologous matrix-induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC) in chondral defects of the first metatarsophalangeal joint.

OBJECTIVE: Chondral restoration in chondral defects of the 1st metatarsophalangeal joint (MTP1) using autologous matrix-induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC). INDICATIONS: Chondral defects MTP1. CONTRAINDICATIONS: Acute infection. SURGICAL TECHNIQUE: Thigh tourniquet. Medial approach. Tenolysis of all tendons, arthrolysis, synovectomy. Bursectomy in case of bursitis. Resection osteophytes, optional cheilectomy. Debridement of chondral defects until surrounding cartilage stable. Microfracturing with 1.6 mm K­wire. 15 cc peripheral venous blood harvested with double lumina syringe. Centrifugation (10 min, 1500 RPM). Aspiration of supernatant including the entire fluid layer directly above the erythrocyte layer (peripheral blood concentrate [PBC]). Chondro-Gide matrix was cut to size and impregnated in PBC 3 min (impregnation). Fixation of the matrix into the chondral defect with fibrin glue (AMIC+PBC). Joint motion to ensure stable fixation. Insertion drainage and wound infiltration catheter. Layer wise closure. POSTOPERATIVE MANAGEMENT: Full weightbearing in a dressing shoe. Joint motion exercise starting at the day of surgery. RESULTS: The aim of the study was to compare matrix-associated stem cell transplantation (MAST) with AMIC+PBC. Patients who were treated with MAST from October 1, 2011 to July 15, 2016 (n = 623) or with AMIC+PBC from July 17, 2016 to March 19, 2018 (n = 230) were included. In all, 480 (89%)/176 (89%) patients (MAST/AMIC+PBC) completed 2­year follow-up. The average degree of osteoarthritis was 2.1/2.2. The chondral defect size was 0.9/1.0 cm2 on average. Visual Analogue Scale Foot and Ankle (VAS FA) and European Foot and Ankle Society score (EFAS score) improved to 72.4/74.1//16.8/17.1 (MAST//AMIC+PBC) at follow-up, respectively. No parameter significantly differed between the MAST and AMIC+PBC cohorts.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]. / Chirurgische Therapie fokaler Knorpelschäden am Knie : Indikationen, Techniken, Modifikationen, Ergebnisse.

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

Surgical management of focal chondral defects of the knee: a Bayesian network meta-analysis.

BACKGROUND: Focal chondral defects of the knee are common. Several surgical techniques have been proposed for the management of chondral defects: microfractures (MFX), osteochondral autograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC) and autologous chondrocyte implantation (ACI)-first generation (pACI), second generation (cACI) and third generation (mACI). A Bayesian network meta-analysis was conducted to compare these surgical strategies for chondral defects in knee at midterm follow-up. METHODS: This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Google Scholar, Embase and Scopus databases were accessed in July 2021. All the prospective comparative clinical trials investigating two or more surgical interventions for chondral defects of the knee were accessed. The network meta-analyses were performed through a Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measures were used for dichotomic variables, while the standardized mean difference (SMD) for the continuous variables. RESULTS: Data from 2220 procedures (36 articles) were retrieved. The median follow-up was 36 (24 to 60) months. The ANOVA test found good baseline comparability between symptoms duration, age, sex and body mass index. AMIC resulted in higher Lysholm score (SMD 3.97) and Tegner score (SMD 2.10). AMIC demonstrated the lowest rate of failures (LOR -0.22) and the lowest rate of revisions (LOR 0.89). As expected, MFX reported the lower rate of hypertrophy (LOR -0.17) followed by AMIC (LOR 0.21). No statistically significant inconsistency was found in the comparisons. CONCLUSION: AMIC procedure for focal chondral defects of the knee performed better overall at approximately 3 years' follow-up.

Autologous Matrix-Induced Chondrogenesis (AMIC) for Isolated Retropatellar Cartilage Lesions: Outcome after a Follow-Up of Minimum 2 Years.

PURPOSE: To evaluate autologous matrix-induced chondrogenesis (AMIC) for isolated focal retropatellar cartilage lesions and the influence of patellofemoral (PF) anatomy on clinical outcomes at a minimum of 2-year follow-up. METHODS: Twenty-nine consecutive patients (31 knees) who underwent retropatellar AMIC with a mean age of 27.9 ± 11.0 years were evaluated at a follow-up averaging 4.1 ± 1.9 years (range, 2-8 years). Patient factors, lesion morphology, and patient-reported outcome measures, including Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner, Kujula score, and visual analogue scale (VAS) score were collected. PF anatomy was assessed on pre- and postoperative imaging, and subsequently correlated to outcome scores and failure to determine risk factors for poor outcome. RESULTS: At final follow-up, the AMIC graft failed in 4 cases (12.9%) at a mean follow-up of 21 ± 14.1 months. Patients with failed grafts had a significantly smaller patellar and Laurins's PF angle than patients whose graft did not fail (P = 0.008 and P = 0.004, respectively). Concomitant corrective surgery for patellar instability was performed in 29 knees (93.5%). Grafts that did not fail presented with an average Kujala score of 71.3 ± 16.9, KOOS Pain of 76.2 ± 16.6 and Tegner scores of 4.2 ± 1.8. The patellar angle was significantly associated with the patient's satisfaction level (r = 0.615; P < 0.001). CONCLUSION: AMIC for retropatellar cartilage lesions in combination with concomitant corrective surgery for patellar instability results in low failure rate with satisfactory clinical outcome and patient satisfaction of almost 80% at mid-term follow-up. As most failures occurred in patients without concurrent tibial tubercle osteotomy and both a smaller patellar and Laurins's PF angle were associated with less favorable outcome, this study supports the growing evidence for the need of unloading retropatellar cartilage repair, when indicated. LEVEL OF EVIDENCE: Case series; level of evidence, 4.

Treatment of osteochondritis dissecans of the patella in adolescents with nanofractured autologous matrix-induced chondrogenesis (NAMIC): A report of five cases.

PURPOSE: Osteochondritis dissecans (OCD) of the patella is a very rare affliction. The aim of this case series is to evaluate the effectiveness of the Nanofractured Autologous Matrix-Induced Chondrogenesis (NAMIC) technique for the treatment of OCD in young adults. METHODS: Five consecutive patients with patellar osteochondral lesions treated with NAMIC were prospectively studied. There were 4 males and 1 female with a mean age of 15.2 years, ranging from 12 to 18 years. Clinically, they presented pain when going up and down stairs or squatting, effusion, swelling and functional limitation. The International Cartilage Repair Society (ICRS) grade was III in 4 patients and IV in 1 patient. Patients were functionally evaluated with the Lysholm knee score, the Tegner Activity Score (TAS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) and radiologically using the Magnetic resonance Observation of Cartilage Repair Tissue (MOCART) score. RESULTS: All the scores significantly improved two years after surgery with respect to pre-operative values (Lysholm score from 63.8 ± 3.9 before surgery to 91 ± 3.2 at 2 years; Tegner activity score from 3.6 ± 0.5 to 8.2 ± 0.8 and the KOOS score from 45.2 ± 2.6 to 91.2 ± 2.4). Both the X-rays and the Magnetic Resonance Imaging (MRI) showed good joint regularity with an average MOCART of 80 ± 7.1/100. CONCLUSIONS: Treatment of juvenile patellar osteochondritis dissecans with the NAMIC technique seems to be a reliable technique in the short term to restore the patella joint surface and obtain good functional results.