Summary

The present study was done to investigate the gait mechanics pre- and post-ACL reconstruction in ACL-deficient patients with or without meniscal injury, and suggested that pivot shift avoidance was still notably observed especially in ACL with lateral meniscal injury group after the surgery.

Abstract

Introduction

According to previous studies, gait mechanics were reported to be more abnormal in anterior cruciate ligament (ACL)-deficient patients with severe meniscal injury than in isolated ACL-deficient patients without meniscal injury. However, little information has been available on whether this gait abnormality would improve after ACL reconstruction or not. It was hypothesized that gait asymmetry would be improved postoperatively. The purpose of the present study was to investigate the gait mechanics pre- and post-ACL reconstruction in ACL-deficient patients with or without meniscal injury.

Methods

A total of 16 ACL injured subjects (8 females and 8 males, mean age = 29.2 ± 8.3 yrs, mean body mass index = 22.6 ± 2.2 kg/m2) participated in the present study. All subjects underwent arthroscopically-assisted ACL reconstruction using semitendinosus tendon. Meniscal injury was observed in 9 patients (5 medial and 4 lateral meniscus). Partial meniscectomy was done for 6 patients without repair. All subjects underwent the same rehabilitation protocol with range-of-motion exercises on the early postoperative period. Partial weight-bearing exercises began 1 week after reconstruction and gradually increased to full weight bearing. Jogging was encouraged 3 months postoperatively, and return to sport was permitted 8 months postoperatively. The study protocol was approved by the University Ethics Committee and a written informed consent was obtained from each subject.
Gait analysis was performed at pre- and post-operative period (> 9 months after surgery). The three-dimensional motion analysis system consisted of eight cameras (120 fps; Oqus, Qualisys, Sweden), two force plates (frequency 600 Hz; AM6110, Bertec, Columbus, OH, USA), and 46 retroreflective markers. The biomechanical parameters were chosen during the stance phase. Marker tracking was performed using Qualisys Track Manager Software (version 2.7). Three-dimensional gait parameters were processed in Visual 3D (C-motion Company). Subjects were divided into three groups including isolated ACL injury group, ACL with medial meniscal injury group, and ACL with lateral meniscal injury group. For statistical analysis, biomechanical differences were compared between affected and unaffected sides using two-tailed paired t-test at pre- and post-operative period in all groups, separately. A significant difference was defined as a P value < 0.05.

Results

Stiffening strategy in the sagittal plane and pivot shift avoidance in the axial plane were observed preoperatively in all groups. Moreover, peak external rotation moment was smaller on the affected side than on the unaffected side only in ACL with medial meniscal injury group. After the surgery, although biomechanical parameters would improve in all groups to a certain extent, smaller peak internal rotation moment (pivot shift avoidance) was still notably observed on the affected side in ACL with lateral meniscal injury group, while peak external rotation moment would improve on the affected side in ACL with medial meniscal injury group.

DISCCUSION: Although preoperative gait abnormality improved in all groups after the surgery, gait asymmetry was still observed especially in ACL with lateral meniscal injury group. Condition of lateral meniscus is considered to be a key factor for gait symmetry, and it is extremely important to prevent anterolateral rotatory instability in the ACL-deficient patients.