Remnant volume of anterior cruciate ligament correlates preoperative patients’ status and postoperative outcome

Abstract

A cohort study was conducted to evaluate the correlation of anterior cruciate ligament (ACL) remnant volume with preoperative status and postoperative outcome of the patients after a remnant-preserving double-bundle (DB) ACL reconstruction. Eighty-eight patients of 105 unilateral DB anatomic ACL reconstructions performed between 2006 and 2008 were followed up for 24 months or more. They were evaluated with regard to preoperative knee laxity data under anaesthesia. Postoperative outcome was evaluated based on knee extension and flexion strength, manual laxity tests, KT measurements, etc. Overall knee condition and sports performance were evaluated with Lysholm knee score and subjective rating scale. Overall correlation of the remnant volume with the preoperative and postoperative evaluation was assessed. Then, the patients were divided into three subgroups based on the remnant volume (remnant volume: ≤ 30, 35-55 and ≤ 60 %). The evaluation was performed and analysed statistically among the three subgroups. Generally, preoperative laxity tests showed a weak correlation with the ACL remnant volume. Postoperative knee stability also indicated a weak correlation with the ACL remnant volume. Statistical analyses revealed that there were significant differences among the three groups regarding age at surgery, preoperative period, number of giving-way and preoperative KT measurements. Postoperatively, there were significant differences in Lachman test, KT measurements, Lysholm knee scale, subjective and sports performance recovery scores. As the clinical relevance, the study suggests that the remnant volume will be important as a background of preoperative condition and a predictor of operative outcome for each patient and that a remnant preserving surgery may not be simply better than a non-preserving technique with regard to subjective evaluation and sports performance recovery. The preoperative condition of patients with ACL injury was different depending upon the remnant volume. The remnant volume was also weakly correlated with the postoperative outcome regarding objective stability and subjective recovery.