Rates of subtalar joint osteoarthritis after modified Chrisman-snook

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Biomechanics

Background:

• Ankle sprains frequently injure lateral ankle ligaments, causing instability and long-term dysfunction.
• Chronic ankle instability management often involves surgical ligament repair, with Brostrom and Chrisman-Snook procedures being common.
• Techniques crossing the subtalar joint raise concerns about potential osteoarthritis progression.

Purpose of the Study:

• To evaluate the incidence and severity of subtalar joint osteoarthritis progression after a modified Chrisman-Snook procedure.
• To assess the clinical significance of any observed changes in subtalar joint arthrosis.

Main Methods:

• Retrospective review of 56 consecutive cases undergoing a near-anatomic Chrisman-Snook procedure using semitendinosus allograft.
• Analysis of patient demographics, surgical details (including concomitant procedures and revisions), and follow-up duration (mean 16.5 months).
• Radiographic assessment of subtalar joint osteoarthritis using the Kellgren-Lawrence scale pre- and post-operatively.

Main Results:

• The overall complication rate was 10.7%, with one case requiring subtalar joint fusion.
• Mean Kellgren-Lawrence stage for subtalar joint osteoarthritis increased from 0.56 to 0.81 (p=0.0621), a statistically mild increase.
• This increase in osteoarthritis severity did not reach clinical significance in the observed follow-up period.

Conclusions:

• The modified Chrisman-Snook procedure demonstrated a mild, non-clinically significant increase in subtalar joint osteoarthritis.
• Long-term surveillance is recommended to determine if the observed arthritic changes are transient, permanent, or progressive.