Effects of in vivo exercise on ankle cartilage deformation and recovery in healthy volunteers: an experimental study.

OBJECTIVE

To monitor ankle cartilage 3D volume changes after in vivo exercise and during recovery.

METHOD

Based on 3D MRI, 3D volumes of talar and tibial cartilage were calculated before and after 30 bilateral knee bends in 12 healthy volunteers. 3D volumes were calculated at five time points (one pre- and four post-scans) determining deformation and recovery for both cartilage plates of interest. Post-scans ran immediately after the exercise and were repeated according to a 15 min interval. 3D volumes were subjected to repeated measures GLM. Additionally, relative surface area use during deformation was compared between plates using a Wilcoxon Signed Ranks test and its correlation with deformation was investigated using Spearman's rho.

RESULTS

Mean 3D volume change percentages for talar cartilage after the exercise were: -10.41%, -8.18%, -5.61% and -3.90%. For tibial cartilage mean changes were: -5.97%, -5.75%, +0.89% and +1.51%. For talar cartilage changes were significant, except following 30 min post-exercise. For tibial cartilage no changes were significant. At all time points, no significant differences in relative volume changes between both cartilage plates existed. Although no significant differences in relative surface area use between plates were revealed, a moderate to strong correlation with deformation existed.

CONCLUSION

Ankle cartilage endures substantial deformation after in vivo loading that was restored within 30 min for the talus. Overall cartilage contact area involvement might be associated with cartilage quality maintenance in the upper ankle. Talar cartilage is suggested to play a critical role in intra-articular shock attenuation when compared to tibial cartilage.