A measurement of anterior tibial displacement in the closed and open kinetic chain.

Anterior displacement of the tibia during knee extension movement has been identified as a possible factor in anterior cruciate ligament (ACL) reconstruction failure due to the increased stress placed on the graft, leading to a creep response in the healing graft. Nineteen healthy subjects with a unilateral ACL deficiency were evaluated in an open and closed kinetic chain. A KT-1000 was used to measure anterior displacement of the tibia on the femur during isometric open and closed kinetic chain exercise at 30 and 60 degrees. An analysis of variance for repeated measures followed by Newman-Keuls multiple comparison tests were performed to determine the differences between the open and closed kinetic chain for the involved and uninvolved knee. Statistically significant differences were found when comparing the amount of anterior displacement between the open and closed kinetic chain for the involved and uninvolved knee at 30 and 60 degrees. Clinicians utilizing isometric exercise in rehabilitation of the anterior-cruciate-deficient and the anterior-cruciate-reconstructed patient should be aware of the increased amount of anterior tibial displacement when comparing open and closed kinetic chain exercise.