COMPARISON OF SYMPTOMATIC VERSUS NONSYMPTOMATIC PATIENTS WITH CHRONICANTERIOR CRUCIATE LIGAMENT INSUFFICIENCY - RADIOGRAPHIC SAGITTAL DISPLACEMENT DURING WEIGHTBEARING

The sagittal anterior displacement of the tibia, induced by weightbear ing, in chronic anterior cruciate ligament-insufficient knees was meas ured radiographically in 2 groups of patients. All patients in both gr oups had an increased laxity when assessed with the Lachman and flexio n-rotation-drawer test. Sixteen patients were functionally improved an d were relatively asymptomatic after a neuromuscular rehabilitation pr ogram, while the second group consisted of another 16 patients with pe rsistent functional instability, despite the same rehabilitation progr am, 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 less-than-or-equal-to 2 mm. In the symptomatic group, the corresponding value was 8.1 mm (P < 0.05), and 3 patients had a displacement less-than-or-equal-to 2 mm. No correlations to meniscal injuries, age, or time from injury were fo und between the patients having a displacement >2 mm and those with le ss-than-or-equal-to 2 mm. The findings should be explained by differen ces in neuromuscular control of the increased laxity in the injured kn ee.