Changes in contact area characteristics of the ankle after a cartilage biopsy at the postero-medial rim of the talar dome

Objective: Study the changes in local and generalized biomechanical characteristics of the ankle joint, associated with a well defined cartilage biopsy at the postero-medial rim of the talar dome, to evaluate its safety. Methods: Ten cadaver ankles were (sub-) physiologically loaded pre- and post-biopsy; in neutral position, 10 degrees of plantar-flexion (PF) and 10 degrees of dorsi-flexion (DF). Fuji film was used as transducer. Qualitatively, the coverage of the biopsy by the tibial plafond, and changes in the shape of the footprint were analyzed. Quantitatively, the pressure profile plot, normalized-tibio-talar contact area and the centroid position of pressure were examined. Results were reported as a mean for all specimens, and as individual values for every single specimen as well. Results: Mean results did not show significant changes, but those of some single specimens did. The majority of those changes were in PF. Some occurred in N, and besides two exceptions none occurred in DF. Two specimens did not show any change. One specimen showed an isolated quantitative change. Seven specimens showed both qualitative and quantitative changes. However, all changes were of low-magnitude and contact stresses did not show any rebound effect. Conclusions: Although biopsies at the postero-medial rim of the talar dome did not induce on average significant changes in quantitative contact characteristics, few specimens did show some alterations. Currently, the investigated biopsy site seems safe, but long term follow-up studies in patients are needed for confirmation. (C) 2009 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.