Sagittal Knee Stability After Anterior Cruciate Ligament Reconstruction with a Patellar Tendon Strip

Abstract

Tibial anteroposterior displacement after anterior cru ciate ligament reconstruction with a patellartendon graft was followed prospectively for 2 years in 24 patients with an arthrometer. The femoral ligament insertion lo cation, in a lateral projection, and the change in intra articular fixation distance, measured with an isometer, were documented intraoperatively. Two years after sur gery, the overall mean injured-noninjured difference in anteroposterior displacement was 2.0 ± 2.3 mm. All grafts were fixed during surgery at 20° of knee flexion. Patients for whom this angle coincided with the angle of minimum intraarticular fixation distance (Group I), and patients who had a femoral ligament insertion location >2 mm anterior to the center of the normal anterior cru ciate ligament attachment (Group A) showed larger tibial displacement than the other patients. An injured- noninjured difference in tibial anteroposterior displace ment ≥3 mm was classified as failure. Groups I and A failure rates were higher than for the other patients. No correlation was found between anteroposterior dis placement and magnitude of the change in intraarticular fixation distance. We conclude that anterior femoral lo cations lead to larger sagittal play after 2 years than central or posterior locations and that the magnitude of the fixation distance is less important than the pattern.