| Summary: | 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 (<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. === Education, Faculty of === Kinesiology, School of === Graduate
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