A clinical study of chondral-separated types of osteochondral lesions of the talus

Abstract

Background: The progress of diagnostic imaging technology, including CTs, MRIs, and ankle arthroscopy has encouraged more detailed descriptions of osteochondral lesions of the talus. These lesions can vary from chondral fragments separated from the subchondral bone with or without bone sclerosis or cysts in the subchondral layers. Isolated lesions of the cartilage, defined as chondral-separated types, as opposed to the osteochondral-separated types which were osteochondral fragments, were retrospectively evaluated in this study.

Materials and methods: Seventy-three osteochondral lesions of the talus in 69 patients were treated. There were 29 chondral-separated types in 29 patients confirmed by examining CT, MRI, and arthroscopic findings.

Results: The average age at onset of the chondral-separated type was 30.7 years. CT findings (29 ankles) showed sclerosis in seven ankles, micropores in nine, honeycombs in seven, and cysts in six. MRI T2-weighted image findings (28 ankles) showed micro to large pore high signals in the subchondral layers in 18 ankles, low to high mixed signals with poor margins in six, and high signals on the articular surfaces in four. Arthroscopic findings (29 ankles) showed softening of the articular cartilage in two ankles, fissures in 16, bulging and fissures in six, and detachment of the articular cartilage in five.

Conclusion: The onset of these lesions occurred in adults after bone maturity with involvement of the chondral and subchondral layers. Each layer seemed to have experienced different degenerative and reparative processes.