Functional and MRI outcomes after arthroscopic microfracture for treatment of osteochondral lesions of the distal tibial plafond

Background: Osteochondral lesions of the distal tibial plafond are uncommon compared with talar lesions. The objective of this study was to assess functional and magnetic resonance imaging (MRI) outcomes following microfracture for tibial osteochondral lesions. Methods: Thirty-one tibial osteochondral lesions in thirty-one ankles underwent arthroscopic microfracture. The Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) general health questionnaire were used to obtain patient-reported functional outcome scores preoperatively and postoperatively. MRI scans were assessed postoperatively with use of the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score for twenty-three ankles. Results: The average age was thirty-seven years (range, fifteen to sixty-eight years), and the average lesion area was 38mm² (range, 7.1 to 113 mm²). Twelve ankles had a kissing lesion on the opposing surface of the talus, and two ankles had a concomitant osteochondral lesion elsewhere on the talus. FAOS and SF-12 scores were significantly improved (p < 0.01) at the time of follow-up, at an average of forty-four months. The average postoperative MOCART score was 69.4 (range, 10 to 95), with a lower score in the ankles with kissing lesions (62.8) than in the ankles with an isolated lesion (73.6). Increasing age negatively impacted improvement in SF-12 (p < 0.01) and MOCART (p = 0.04) scores. Increasing lesion area was negatively correlated with MOCART scores (p = 0.04) but was not associated with FAOS or SF-12 scores. Lesion location and the presence of kissing lesions showed no association with functional or MRI outcomes. Conclusions: Arthroscopic microfracture provided functional improvements, but the optimal treatment strategy for tibial osteochondral lesions remains unclear. The repair tissue assessed on MRI was inferior to normal hyaline cartilage. The MRI outcomes appeared to deteriorate with increasing lesion area, and both functional and MRI outcomes appeared to deteriorate with increasing age. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.