Comparison of symptomatic versus nonsymptomatic patients with chronic anterior cruciate ligament insufficiency. Radiographic sagittal displacement during weightbearing.

Abstract

The sagittal anterior displacement of the tibia, induced by weightbearing, in chronic anterior cruciate ligament-insufficient knees was measured radiographically in 2 groups of patients. All patients in both groups had an increased laxity when assessed with the Lachman and flexion-rotation-drawer test. Sixteen patients were functionally improved and were relatively asymptomatic after a neuromuscular rehabilitation program, while the second group consisted of another 16 patients with persistent functional instability, despite the same rehabilitation program, who eventually had ligament reconstruction. The mean radiographic anterior displacement during weightbearing in the nonsymptomatic group was 4.3 mm, and 8 patients had a displacement < or = 2 mm. In the symptomatic group, the corresponding value was 8.1 mm (P < 0.05), and 3 patients had a displacement < or = 2 mm. No correlations to meniscal injuries, age, or time from injury were found between the patients having a displacement >2 mm and those with < or = 2 mm. The findings should be explained by differences in neuromuscular control of the increased laxity in the injured knee.