Sagittal plane translation of the knee during stair walking - Comparison of healthy and anterior cruciate ligament deficient subjects

With an electrogoniometer system, we made bilateral measurements of the maximal sagittal plane anterior-posterior knee translations in 15 healthy subjects (controls) and 14 patients with arthroscopically confirmed unilateral anterior cruciate ligament deficiency during two types of ascents and descents (straight and side). In both groups, during the ascent cycle the tibia moved anteriorly in relation to the femur, whereas during the descent cycle it moved posteriorly, There was wide individual variation in maximal translation in both the control and anterior cruciate ligament-deficient groups (range, I to 12 mm; mean, 7 mm). The maximal translations were similar in both groups (P > 0.05), but they occurred at a significantly smaller flexion angle in the injured knees (38 degrees +/- 8 degrees) than in the control and noninjured knees (44 degrees +/- 8 degrees) (P < 0.05). The translation during step ascent and descent did not differ between the injured and control knees. These findings indicate that patients with anterior cruciate ligament injuries are able to control abnormal anterior translation during normal activity.