Outcomes Following Treatment of Talar Osteochondral Lesions with a Mixture of Particulate Allogenic Cartilage Extracellular Matrix and Bone Marrow Aspirate Concentrate: A Case Control Series

Abstract

Objectives: There continues to be a general lack of consensus regarding the optimal treatment for osteochondral lesions of the talus (OLTs). Microfracture, once considered the gold-standard, has been associated with poor long-term results due to the formation of biomechanically inferior reparative fibrocartilage as opposed to hyaline cartilage. Particulate allogenic cartilage extracellular matrix offers a promising solution as an adjuvant therapy; however, there is currently minimal objective evidence to indicate its effect on post-operative outcomes. This study compares post-operative radiographic and clinical outcomes following treatment of OLTs with an adjuvant mixture of particulate cartilage extracellular matrix and bone marrow aspirate concentrate (BMAC) against outcomes following microfracture with or without BMAC. Methods: Patients diagnosed with an OLT and treated by a fellowship-trained orthopedic surgeon were screened for inclusion. Those whose surgical intervention included microfracture, microfracture augmented with BMAC alone, or microfracture augmented with a mixture of BMAC and particulate allogenic cartilage extracellular matrix were eligible for this case-control study. Lesion size, location, and concurrent injuries were recorded following retrospective chart review. Foot and Ankle Outcome Scores (FAOS) were collected pre-operatively and at a minimum of 1 year post-operatively through the prospective Registry database at the authors’ institution. Modified magnetic resonance observation of cartilage repair tissue (MOCART) scoring evaluated the structural quality of repaired lesions on MRIs collected greater than six months post-operatively. Differences in post-operative MOCART and FAOS scores were evaluated using ANOVA tests. Results: Forty-seven patients treated with microfracture alone, forty-seven treated with microfracture augmented by BMAC, and fifty-two treated with an adjuvant mixture of particulate allogenic cartilage extracellular matrix and BMAC were identified at a minimum of 2 years post-operatively. Average MOCART scores were significantly different between treatment groups (p=0.03). At an average follow-up of 10.86 months, patients who received adjunctive therapy had an average MOCART score of 73.5 ± 11.13. At an average follow-up of 23.06 months and 43.6 months respectively, patients treated with microfracture and BMAC and microfracture alone scored 63.33 ± 22.23 and 55 ± 23.92. There was no detectable statistically significant difference in post-operative FAOS scores between treatment groups. With respect to revision surgery, two patients (3.84%) originally treated with adjuvant particulate cartilage extracellular matrix and BMAC have required a secondary surgery as opposed to nine patients (9.57%) treated with microfracture and BMAC or microfracture alone. Conclusion: Increases in post-operative FAOS scores compared to pre-operative FAOS scores for all treatment groups indicate patients’ function and symptoms improved regardless of intervention received. However, significantly higher MOCART scores for the particulate cartilage extracellular matrix and BMAC treatment group suggest adjuvant treatment may help achieve better post-operative fill and structural integrity. Thus, long-term outcomes and the quality of reparative tissues may be improved through use of adjuvant treatments such as particulate allogenic cartilage extracellular matrix and BMAC.