Increasing Incidence of Medial Meniscal Tears in Nonoperatively Treated Anterior Cruciate Ligament Insufficiency Patients Documented by Serial Magnetic Resonance Imaging Studies

Background: No consensus has been reached with regard to the ideal timing of anterior cruciate ligament reconstruction in terms of reducing secondary meniscal tears in anterior cruciate ligament-deficient knees. Hypothesis: Delay in anterior cruciate ligament reconstruction increases the incidence and severity of medial meniscal tears. Study Design: Case series; Level of evidence, 4. Methods: Thirty-one patients were evaluated with arthroscopic all-inside suturing of medial meniscal tears with concurrent anterior cruciate ligament reconstruction who had at least 2 preoperative magnetic resonance imaging studies. Patients were evaluated during the acute phase of injury, but anterior cruciate ligament reconstruction surgery was delayed at least 6 months. Mean interval between first and second imaging studies was 36.8 months. Subsequent medial meniscal tears were identified as longitudinal or bucket-handle types. Relationships between medial meniscal lesions and patient age, time interval between the date of initial injury and surgery, repetitive injury, and patient activity level were evaluated. Results: During the first preoperative magnetic resonance imaging studies, 14 knees had no medial meniscal tear, 15 a longitudinal tear, and 2 a bucket-handle-type tear; during the second preoperative imaging studies, 5 knees had no medial meniscal tear, 19 a longitudinal tear, and 7 a bucket-handle-type tear. The incidence of medial meniscal tears increased from 55% in first studies to 84% in second studies for chronic anterior cruciate ligament-insufficient knees (P = .0054). Eight knees without a tear during first studies had a longitudinal tear during second studies, 1 knee without a tear and 4 with a longitudinal tear in first studies had a bucket-handle-type tear in second studies. Thirteen knees (42%) had a worse meniscal status during the second studies. Conclusion: Delayed anterior cruciate ligament reconstruction increases the likelihood of a medial meniscal tear, suggesting that early anterior cruciate ligament reconstruction should reduce or prevent additional medial meniscal injury. The findings show that further medial meniscal damage is common if surgery is delayed by 6 months or more.