Purpose: To investigate whether a delay in the timing of surgery of > 6 months compared with performing the surgery ≤ 6 months after the anterior cruciate ligament (ACL) injury leads to an increased risk of injuries or degenerative changes in the ACL-deficient knee.
Methods: Patients who underwent primary ACL reconstruction at an academic tertiary care center, and had preoperative magnetic resonance imaging (MRI) performed within 2 months of the time of the ACL injury were included. The prevalence of degenerative changes at the time of surgery was assessed and related to the timing of ACL surgery, with "early reconstruction" defined as a surgery performed ≤ 6 months and "delayed reconstruction" defined as surgery performed > 6 months after ACL injury. "New" meniscal tears were defined as lesions detected at the time of surgery that were not detected by MRI.
Results: Of 195 patients who were selected based on inclusion criteria, 171 patients underwent surgery ≤ 6 months after their ACL injury, and 24 patients underwent surgery > 6 months after their ACL injury. The prevalence of new medial meniscal tears in the early reconstruction group was 4.1%, while in the delayed reconstruction group, the prevalence was 16.7% (P = 0.012).
Conclusion: A delay in the timing of ACL reconstruction from ≤ 6 months to > 6 months following injury is associated with a significant increase in the prevalence of medial meniscal tears (P = 0.012), with a relative risk of 4.07 (CI, 1.29-12.88).