Background: Prophylactic taping is commonly used to prevent ankle injuries during sports. However unnatural constraint of the ankle joint may increase the risk of injury to proximal joints such as the knee. Any association between the use of ankle tape and knee joint loading has not previously been investigated. Purpose: To determine changes in ankle and knee kinetics and kinematics associated with use of ankle taping during athletic activities. Thereby, both the prophylactic benefits and the potential of taping to be an isolated mechanism for a ligamentous injury of the knee will be examined.

Methods: A kinematic and inverse dynamics model was used to determine ankle and knee joint motion and loading in 22 healthy male participants undertaking running and sidestepping tasks. Both tasks were randomized to planned and unplanned conditions, and undertaken with and without the use of ankle tape.

Results: Taping reduced the range of motion at the ankle in all three planes (p< 0.05), as well as peak inversion (p=0.017) and average eversion moments (p=0.013). At the knee, internal rotation moments (p=0.049), internal rotation impulse (0.034), varus moment (p=0.015) and varus impulse (p=0.050) were reduced with the use of ankle tape. There was a trend toward increased valgus impulse for sidestepping trials undertaken with ankle tape (p=0.056).

Conclusion: By limiting motion at the ankle, taping increased the mechanical stability of this joint. Ankle taping also provided protective benefits to the knee via reduced internal rotation moments and varus impulses, although the effects were task-specific. Medial collateral and anterior cruciate ligament injuries may, however, occur through increased valgus impulse during sidestepping undertaken with ankle tape.

Achieving deep flexion after total knee replacement remains a challenge. In this study we compared the soft-tissue tension and tibiofemoral force in a mobile-bearing posterior cruciate ligament-sacrificing total knee replacement, using equal flexion and extension gaps, and with the gaps increased by 2 mm each. The tests were conducted during passive movement in five cadaver knees, and measurements of strain were made simultaneously in the collateral ligaments. The tibiofemoral force was measured using a customised mini-force plate in the tibial tray. Measurements of collateral ligament strain were not very sensitive to changes in the gap ratio, but tibiofemoral force measurements were. Tibiofemoral force was decreased by a mean of 40% (sd 10.7) after 90° of knee flexion when the flexion gap was increased by 2 mm. Increasing the extension gap by 2 mm affected the force only in full extension. Because increasing the range of flexion after total knee replacement beyond 110° is a widely-held goal, small increases in the flexion gap warrant further investigation.