Comparison of chondral versus osteochondral lesions of the talus after arthroscopic microfracture

Purpose To compare the outcomes of arthroscopic microfracture for chondral and osteochondral lesions of the talus, and to identify the characteristics. Method One hundred and four ankles were divided into two groups, namely chondral group (58 ankles) and osteochondral group (46 ankles). The chondral group consisted of 37 men and 21 women with a mean age of 41.5 years [95 % confidence interval (CI) 38.9–44.1] and a mean follow-up duration of 37.6 months (95 % CI 34.7–40.5). The osteochondral group consisted of 25 men and 21 women with a mean age of 22.5 years (95 % CI 19.5–22.5) and a mean follow-up duration of 38.3 months (95 % CI 35.4–41.2). Outcomes were measured using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale, and ankle activity score (AAS). Results Mean AOFAS score was 64.9 points (95 % CI 63.0–66.9) in the chondral group and 68.2 points (95 % CI 65.8–70.5) in the osteochondral group preoperatively, and it had improved to 88.8 points (95 % CI 86.8–90.8) and 93.5 points (95 % CI 91.4–95.6) at final follow-up. Mean AAS changed from 2.7 (95 % CI 2.5–2.9) preoperatively to 6.4 (95 % CI 6.0–6.8) in the chondral group, and from 2.5 (95 % CI 2.3–2.8) preoperatively to 6.6 (95 % CI 6.3–6.9) in the osteochondral group at final follow-up. No significant differences were found between the two groups in terms of AOFAS and AAS. The chondral group showed older age, less trauma history, longer symptom duration, smaller lesion size, and more frequent degenerative changes such as subchondral cyst and synovitis. Conclusion Both chondral and osteochondral lesions of the talus treated with arthroscopic microfracture showed similar good clinical outcomes. It is important to note that two groups had different characteristics in age distribution, frequency of trauma history, symptom duration, lesion size and location, and incidence of degenerative changes. This study demonstrated that microfracture could improve clinical outcomes significantly both chondral and osteochondral lesions of talus despite their different characteristics. Level of evidence Prospective comparative study, Level II.