The natural history of stage 5 osteochondral talar lesions
Creators: name: Shearer, Carl Thomas
Publisher: name: University of British Columbia
Year: 2009

description: Objective To describe the natural history of conservatively managed stage 5 osteochondral talar lesions. Background Osteochondral talar lesions (OUT) are a well recognized cause of chronic post traumatic ankle pain. In 1959 Berndt and Harty (1) described a 4 stage OLT classification scheme which has been universally adopted by the orthopedic and sports medicine communities. However, it has recently been recognized that the majority (77%) of chronic OLT exist as a radiolucent defect (subchondral cystic lesion) that does not fit into this classification scheme (2). This radiolucent defect has been classified as a stage 5 OLT(2) and is felt to represent avascular necrosis of lower stage lesions as a result of failed healing (2,3,4). The natural history of stage 5 OLT has not been described. Methodology Twenty-five subjects (26 ankles) with conservatively managed stage 5 OLT were reassessed at 2 or more years post diagnosis (mean 39 months). Five (6 ankles) of the 25 subjects opted for surgical management after a failed trial of conservative treatment. Their data was included only up to the point of the end of failed conservative management. Pain at rest, pain to walk, pain to run, and activity level were assessed at follow-up and retrospectively at the time of diagnosis using a 100 mm retrospective visual analogue scale (VAS) (end points no pain and the worst pain from this injury, or full activity and most limited activity level from this injury). Mean VAS pain scores at follow-up and diagnosis were compared via repeated measure Hotellings T squared. Mean VAS activity level scores at follow-up and diagnosis were compared via repeated measure t-test. The overall clinical result at follow-up was rated excellent, good, fair or poor based on a combination of symptom persistence, sport limitation, and pain frequency. CT scan and plain Xray were obtained at follow-up on 19/25 and 20/25 subjects respectively. The CT scans at diagnosis (where available, n=ll) and follow-up were compared via repeated measure t-test for changes in lesion size. Plain X-rays were examined for the presence or absence and degree of degenerative changes. Osteophytes, sclerosis and narrowing were each considered sufficient to diagnose degenerative change. The degree of degenerative change was determined according to a scale based on the size of the largest osteophyte, the presence or absence of sclerosis, and the presence or absence of focal or diffuse narrowing. Main results VAS results demonstrated a significant decrease in pain to run (29 mm = 29% of the worst pain to run from this injury, p=.005) and a significant decrease in pain to walk (23.5 mm = 23.5 % of the worst pain to walk from this injury, p=.009). Pain at rest decreased and activity level increased, however, neither was statistically significant. The overall clinical result was good or excellent in 50%, fair in 15% and poor in 35%. Lesions tended to increase in size, however this was not statistically significant. There was no correlation between changes in lesion size and clinical results. Mild degenerative changes were found in 13/20 ankles with OLT. All (10/10) subjects with asymmetric degenerative changes between their 2 ankles had the higher grade of degenerative change on the side with the OLT. This suggested a relationship between stage 5 OLT and the development of degenerative changes. However these degenerative changes were not found to be related to the clinical result. Lateral lesions tended to do better than medial lesions and adults tended to do better than juveniles (&lt;20 yr. age at diagnosis). Conclusion At a mean follow-up of 39 months conservatively managed stage 5 OLT were found to significantly improve clinically with respect to pain to run and pain to walk. The overall clinical result was good or excellent in 50 %, fair in 15 % and poor in 35%. Radiographically the lesions tended to increase in size (trend only), however changes in lesion size were not found to correlate with clinical result. Mild degenerative changes were common and appear to be related to the presence of stage 5 OLT. The presence or absence of theses degenerative changes does not appear to be related to the clinical result.