Prior Bone Marrow Stimulation Surgery Influences Outcomes After Cell-Based Cartilage Restoration: A Systematic Review and Meta-analysis

Background: Cell-based cartilage restoration with autologous chondrocyte implantation (ACI) is a safe and effective treatment for symptomatic cartilage lesions. Many patients undergoing ACI have a history of prior surgery, including bone marrow stimulation (BMS). There is mounting evidence that a history of prior BMS may impede healing of the ACI graft. Purpose/Hypothesis: The purpose of this study was to compare the failure rates of primary ACI with ACI after prior BMS. We hypothesized that ACI after BMS would have a significantly higher failure rate (defined as reoperation, conversion to arthroplasty, and/or imaging-based failure) compared with primary ACI. Study Design: Systematic review; Level of evidence, 4. Methods: A literature search was performed by use of PubMed and Embase databases for relevant articles published through October 2, 2020, to identify studies evaluating outcomes and failures rates of ACI after prior BMS in the knee. Results: Included were 11 studies comprising 1479 ACI procedures. The mean age at surgery ranged from 18.3 to 39.1 years, and the mean follow-up ranged from 3 to 20.6 years. All studies reported failure rates. The overall failure rate was significantly higher in the patients who underwent ACI after BMS, at 26.4% compared with 14.8% in the ACI group ( P < .001). Meta-analysis demonstrated an increased risk of failure in patients with a history of prior BMS (log odds ratio = –0.90 [95% confidence interval, –1.38 to –0.42]). Conclusion: This systematic review demonstrated that failure rates were significantly higher for patients treated with ACI after BMS relative to patients undergoing ACI without prior BMS. This finding has important implications when considering the use of BMS for defects that are amenable to cell-based restoration and when determining treatment options after failed BMS. Registration: PROSPERO (CRD42020180387).

PATELLOFEMORAL JOINT CARTILAGE RESTORATION WITH PARTICULATED JUVENILE ALLOGRAFT IN PATIENTS UNDER 21 YEARS OLD: POSTOPERATIVE MRI ANALYSIS AND RETURN TO SPORT RATES

Background: Patellofemoral joint cartilage defects are difficult to treat due to their unique thickness and topography. Numerous cartilage restoration techniques are available to surgeons treating articular cartilage defects. However, patellofemoral joint restoration historically produces worse outcomes than tibiofemoral joint restoration. One cell-based option is particulated juvenile allograft cartilage (PJAC), though literature regarding the efficacy of this treatment is sparse, especially in patients under the age of 21 years. Hypothesis/ Purpose: The aim of this study is to investigate postoperative outcomes of PJAC for patellofemoral chondral defects using MRI and return to sport rates in this active, high-demand patient population. Methods: Patients at an urban tertiary care musculoskeletal institution who underwent PJAC for patellofemoral joint cartilage restoration were identified through records review. Patients 21 years old or younger with minimum clinical follow-up of 1 year and postoperative MRI at a minimum of 6 months after surgery were included. Cartilage restoration was assessed by MRI using the International Cartilage Repair Society’s standardized system. Sport activity was collected from medical records. Results: Thirty-six knees in 34 patients with a mean age of 16.1 ± 3.1 years old (range 10—21 years old) were analyzed. Mean follow-up was 32.1 months. Defects were located on the patella in 25 knees, and trochlea in 11 knees (Figure 1). There were no bipolar lesions in the cohort. Mean defect size was 2.47 cm2. Twenty-four knees (66.7%) were graded either ‘normal’ or ‘nearly normal’, and 28 knees (77.8%) had greater than 50% of the defect filled on follow-up imaging. Return to sport rates among patients who participated in a sport preoperatively was 100%. Conclusion: Restoration of patellofemoral chondral defects in young patients with particulated juvenile allograft can be performed with satisfactory short-term efficacy, excellent postoperative MRI appearance, and very high rates of return to sport. Tables/Figures: [Figure: see text]

Clinical Outcomes of ProChondrix® Osteochondral Allograft in the Knee: A Case Series

PurposeFocal articular cartilage injuries are common and may lead to progression of osteoarthritis. The complications associated with traditional treatment strategies have influenced the development of new biotechnologies, such as the ProChondrix® osteochondral allograft. Clinical evidence on the outcomes associated with ProChondrix® osteochondral allografts are limited. Thus, the primary purpose of this study was to evaluate the clinical outcomes following treatment of an isolated cartilage defect with a ProChondrix® osteochondral allograft implant.MethodsRetrospective analysis of patients who underwent a cartilage restoration procedure using ProChondrix® osteochondral allograft has been performed. Patients completed patient-reported outcome surveys which included the Knee injury and Osteoarthritis Outcome Score (KOOS), consisting of the 5 subscales of Pain, Symptoms, Activities of Daily Living, Sports and Recreation, and Quality of Life, the Marx Activity Scale, and the visual analog pain scale.ResultsSix patients underwent a cartilage restoration procedure using ProChondrix® between January 2016 and December 2019. Three males and three females were included with a median age of 33.5 years (range 18–48 years). The median follow-up duration was 15 months (range 9–24 months). There were 4 patellar grafts, 1 medial femoral condyle graft, and 1 lateral femoral condyle graft, with a median defect size of 18.5mm (range 13-20mm). At the most recent clinical follow-up, all six patients were pain free and all patients had returned to pre-op activity level.ConclusionTo our knowledge, this is the first study to report the clinical outcome, activity level, and patient orientated outcomes in a case series of patients following treatment of an isolated cartilage defect with a ProChondrix® osteochondral allograft implant. Our study demonstrates promising short-term results in patient reported clinical outcome scores.

Decellularized Porcine Cartilage Scaffold; Validation of Decellularization and Evaluation of Biomarkers of Chondrogenesis

Osteoarthritis is a major concern in the United States and worldwide. Current non-surgical and surgical approaches alleviate pain but show little evidence of cartilage restoration. Cell-based treatments may hold promise for the regeneration of hyaline cartilage-like tissue at the site of injury or wear. Cell–cell and cell–matrix interactions have been shown to drive cell differentiation pathways. Biomaterials for clinically relevant applications can be generated from decellularized porcine auricular cartilage. This material may represent a suitable scaffold on which to seed and grow chondrocytes to create new cartilage. In this study, we used decellularization techniques to create an extracellular matrix scaffold that supports chondrocyte cell attachment and growth in tissue culture conditions. Results presented here evaluate the decellularization process histologically and molecularly. We identified new and novel biomarker profiles that may aid future cartilage decellularization efforts. Additionally, the resulting scaffold was characterized using scanning electron microscopy, fluorescence microscopy, and proteomics. Cellular response to the decellularized scaffold was evaluated by quantitative real-time PCR for gene expression analysis.