Age as a predictor of residual muscle weakness after anterior cruciate ligament reconstruction

The objective of this study was to reveal the predicting factors for muscle recovery in the lower extremity after anterior cruciate ligament (ACL) reconstruction.

One hundred and thirty-five (135) patients who underwent ACL reconstruction using hamstring autograft were evaluated. Exclusion criteria were bilateral ACL injury, chondral treatment and multiple ligament injury. Nonanatomical single-bundle reconstruction (SB) was performed in 79 patients, and anatomical double-bundle reconstruction (DB) was performed in 56 patients. Strength of quadriceps and knee flexion muscles were assessed at 60°/s using a Cybex II dynamometer (Lumex, Ronkonkoma, NY) at 3, 6 and 9 months after ACL reconstruction. Anterior tibial translation and pivot shift test were also evaluated. The medical records were reviewed to extract the following information: age, gender, the amount of pre and postoperative KT 1000, technique of reconstruction (SB or DB) and postoperative knee rotation.

No significant difference of muscle recovery in the lower extremity was observed at any time point after ACL reconstruction between the SB and DB groups. The DB group showed significantly better postoperative antero-posterior and rotational knee laxity than the SB group. Logistic regression analysis showed significant correlation with only age and muscle recovery.

For clinical relevance, there is a risk of muscle recovery delay when ACL reconstruction is performed in elderly patients. Anatomical DB reconstruction resulted in significantly better knee stability, but had no positive effect on muscle recovery.

Retrospective study, Level II.