Patients older than 50 years had similar results of knee strength and anteroposterior stability after ACL reconstruction compared to younger patients

Purpose: To evaluate knee strength, ligament stability, and functional outcomes in patients older than 50 years who underwent anterior cruciate ligament (ACL) reconstruction, and to compare these results with those obtained from a younger patient group (< 40 years). Methods: Forty patients older than 50 years and 50 patients younger than 40 years who underwent ACL reconstruction were retrospectively studied. Isokinetic extensor and flexor muscle strength were evaluated. The peak torque was determined at speeds of 60°/s and 180°/s. The highest peak torque at each velocity was compared with that on the uninjured side. Patients were also evaluated for knee anteroposterior (AP) laxity and functional outcomes, which were measured by the Lysholm and International Knee Documentation Committee (IKDC) scores. All tests were evaluated at baseline and 1 year postoperatively. Results: The groups were comparable at the baseline. Both groups had significant improvements in all parameters, including isokinetic muscle strength, AP laxity, and functional scores, at 1 year postoperatively (all p < 0.05). Compared with younger patients, older patients had similar results for extensor and flexor strength, AP laxity, and Lysholm score (n.s.). However, younger patients had better IKDC scores than did older patients [median 81.1; 95% confidence interval (CI) 95% CI 78.9–88.7 vs. median 75.6; 95% CI 70.1–79.3, p = 0.007]. Conclusions: Though with lower IKDC scores, older patients with ACL reconstruction had comparable results of knee strength and ligament laxity to younger patients. ACL reconstruction is recommended for treating patients older than 50 years with ACL insufficiency, especially for those with high functional demand. Level of evidence: Retrospective cohort study, III.