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Updated: May 25, 2026

Treatment of Ankle Osteoarthritis with Total Ankle Replacement Through a Lateral Transfibular Approach
Published on: January 24, 2018
The postoperative COFAS end-stage ankle arthritis classification system: interobserver and intraobserver reliability
Fabian G Krause1, Matthew Di Silvestro, Murray J Penner
1Department of Orthopaedic Surgery, University of Berne, Berne, Switzerland.
Abstract:
End-stage ankle arthritis is operatively treated with numerous designs of total ankle replacement and different techniques for ankle fusion. For superior comparison of these procedures, outcome research requires a classification system to stratify patients appropriately. A postoperative 4-type classification system was designed by 6 fellowship-trained foot and ankle surgeons. Four surgeons reviewed blinded patient profiles and radiographs on 2 occasions to determine the interobserver and intraobserver reliability of the classification. Excellent interobserver reliability (κ = .89) and intraobserver reproducibility (κ = .87) were demonstrated for the postoperative classification system. In conclusion, the postoperative Canadian Orthopaedic Foot and Ankle Society (COFAS) end-stage ankle arthritis classification system appears to be a valid tool to evaluate the outcome of patients operated for end-stage ankle arthritis.
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