Effect of variations in calcaneocuboid fusion technique on kinematics of the normal hindfoot.

Calcaneocuboid fusion with lengthening of the lateral column of the foot has been advocated as a method of treating flatfoot deformity. This study was designed to determine how the length of the lateral column chosen or the position of the foot selected when performing this fusion affect hindfoot kinematics in normal cadaver feet. An electromagnetic tracking system was used to monitor the positions of the talus, calcaneus, navicular, and cuboid while the intact cadaver feet were moved passively and then under reproducible loads. Calcaneocuboid fusion was then performed on these feet first with the feet in neutral position and the lateral column of normal length, then lengthened 10 mm or shortened 5 mm, and then with the lateral column lengthened 10 mm and the feet positioned in plantar flexion and eversion or dorsiflexion and inversion. Kinematic measurements were made at each stage using the same loads. Fusing the calcaneocuboid joint with lengthening or shortening the lateral column and the feet in neutral position did not affect hindfoot joint motion compared with intact. Changing the position of the foot for fusion, however, resulted in significant decreases in motion in the talocalcaneal and talonavicular joints. Tibiotalar joint motion was unaffected. This study, therefore, demonstrates that when fusing the calcaneocuboid joint, attention should be paid to maintaining a neutral position of the foot.