Summary
Comparable clinical and functional outcomes were achieved in middle-aged patients when compared to the control group.
Abstract
Background
The relative clinical and functional outcomes of single bundle ACL reconstruction in middle-aged patients compared to a control group are not well-known.
Purpose
To compare the clinical and functional outcomes of primary single bundle ACL reconstruction in patients aged 50 and older with those in patients under 50.
Method
A 1:1 propensity score matching was performed between patients aged 50 and older (Group A) who underwent single bundle primary ACL reconstruction from 2014 to 2022 and a control group of patients under 50 years old (Group B). The factors used for matching included sex, BMI, injury to ACLR interval, pre-injury Tegner activity scale, and graft type. Patients with revision ACLR, multiple ligament injuries, knee dislocation, combined procedures or previous surgeries, follow-up loss, open physes, or age under 20 were excluded from the study. Clinical outcomes were compared by assessing graft failure and patient-reported outcomes, including IKDC subjective score, Lysholm score, Tegner activity scale, and KOOS, as well as physical exams, including the Lachman test and pivot shift test. Functional outcomes were assessed by reviewing the isokinetic test results preoperatively, and at 6 months, 12 months, and 24 months postoperatively. The peak torque and limb symmetry index (injured/uninjured) for both extension at 60°/s and 180°/s, and flexion at 60°/s and 180°/s were compared between the two groups.
Results
As a result of the propensity score matching, 50 patients were included in each group for the study. The mean age was 53.4 ± 3.2 years in Group A and 29.0 ± 6.4 years in Group B (P < 0.001). The follow-up period was 37.7 ± 22.8 months for Group A and 32.9 ± 12.3 months for Group B, with no significant difference between the groups (P = 0.189). Graft failure occurred in 3 cases in Group A and 2 cases in Group B, with no significant difference between the groups (P = 0.646). There were no significant differences in the Lachman test and pivot shift test results between the two groups, both preoperatively and postoperatively. Preoperatively, there were no significant differences in patient-reported outcomes between the groups. However, postoperatively, significant differences were observed in the IKDC subjective score (Group A: 79.3 ± 13.3 vs. Group B: 84.7 ± 11.4, P = 0.035), Tegner activity scale (Group A: 4.8 ± 1.5 vs. Group B: 5.6 ± 1.4, P = 0.015), KOOS ADL (Group A: 93.7 ± 9.0 vs. Group B: 97.8 ± 4.6, P = 0.015), and KOOS Sports (Group A: 74.9 ± 17.1 vs. Group B: 81.9 ± 13.5, P = 0.044). In the isokinetic test, both groups showed significant improvement during follow-up. The peak torque on the injured side was lower in Group A compared to Group B at 6 months, 12 months, and 24 months. (P<0.05) The limb symmetry index did not show any significant differences between the two groups at any time point.
Conclusion
Comparable clinical and functional outcomes were achieved in middle-aged patients when compared to the control group.