TENODESES DESTROY THE KINEMATIC COUPLING OF THE ANKLE JOINT COMPLEX -A 3-DIMENSIONNAL IN-VITRO ANALYSIS OF JOINT MOVEMENT

To study the effect of ligament injuries and surgical repair we invest igated the three-dimensional kinematics of the ankle joint complex and the talocrural and the subtalar joints in seven fresh-frozen lower le gs before and after sectioning and reconstruction of the ligaments. A foot movement simulator produced controlled torque in one plane of mov ement while allowing unconstrained movement in the remainder. After te sting the intact joint the measurements were repeated after simulation of ligament injuries by cutting the anterior talofibular and calcaneo fibular ligaments. The tests were repeated after the Evans, Watson-Jon es and Chrisman-Snook tenodeses. The range of movement (ROM) was measu red using two goniometer systems which determined the relative movemen t between the tibia and talus (talocrural ROM) and between the talus a nd calcaneus (subtalar ROM). Ligament lesions led to increased inversi on and internal rotation, predominantly in the talocrural joint. The r econstruction procedures reduced the movement in the ankle joint compl ex by reducing subtalar movement to a non-physiological level but did not correct the instability of the talocrural joint.