Sagittal plane translation of the tibia in anterior cruciate ligament-deficient knees during commonly used rehabilitation exercises

It may be assumed that exercises that provoke high sagittal plane knee translations also induce high stresses on an anterior cruciate ligament substitute and, therefore, these exercises should be limited during the first months after reconstruction. In 18 patients with unilateral anterior cruciate ligament deficiency, sagittal plane knee translations were measured with a goniometer linkage system during common activities. The largest translations were found during low-speed isokinetic exercises. Further, isokinetic and isometric exercises on the Cybex-II dynamometer provoked in more than 40% of the patients larger translations on the injured than on the healthy knee. However, isometric exercises without distally applied load only provoked small translation. During bicycling, translations increased with increasing resistance similarly in both limbs. Except for walking downstairs, load-bearing exercises, such as sitting down and standing up from a chair and walking upstairs, only produced negligible amounts of tibial translation. In conclusion, during the early phase after anterior cruciate ligament reconstruction, activities such as bicycling and some weightbearing exercises seem to be more recommendable than low-speed isokinetic exercises, isometric contractions at a low knee flexion angle with distally applied load or walking downstairs.