Comparison of Knee Function and Activity Level Between Bilateral and Unilateral ACL Reconstruction: A Matched-Group Analysis With Minimum 5-Year Follow-up.

Background: There is a lack of knowledge regarding knee function and activity level after bilateral anterior cruciate ligament reconstruction (ACLR) at midterm follow-up. Purpose: To compare activity level, patient-reported knee function, and quality of life in patients with bilateral ACLR and matched controls with unilateral ACLR at a minimum 5-year follow-up. Study Design: Cohort study; Level of evidence, 3. Methods: Patients with bilateral ACLR who were aged ≤40 years and had a second ACLR performed between 2010 and 2015 were identified in the authors' local database. Surgical data and preoperative Knee injury and Osteoarthritis Outcome Score (KOOS) were extracted. The patients were sent a letter with questionnaires including the KOOS, EuroQol 5-Dimensions (EQ-5D), and EuroQol visual analog scale (EQ-VAS) and were asked study-specific questions by telephone regarding activity level and knee function at a minimum 5-year follow-up. For every patient with bilateral ACLR, a control matched for age ±2 years, sex, year ACLR was performed, and preinjury activity level or sport at the time of injury were identified in the database. Results: A total of 98 patients (mean age ± SD, 33.3 ± 7.3 years) with bilateral ACLR and 98 patients with unilateral ACLR (mean age ± SD, 33.1 ± 7.7 years) were included. The mean postoperative follow-up was 7.6 ± 1.8 years (from the second ACLR) for patients with bilateral ACLR and 7.8 ± 1.7 years for patients with unilateral ACLR. Patients with bilateral ACLR reported lower scores on all KOOS subscales, the EQ-5D, and the EQ-VAS at follow-up ( Conclusion: Patient-reported knee function and health-related quality of life were inferior in patients with bilateral ACLR compared with patients with unilateral ACLR. Patients with bilateral ACLR cannot expect the same knee function and quality of life as patients with unilateral ACLR.