The Incidence of Subsequent Meniscal Surgery Is Higher in the Anterior Cruciate Ligament–Reconstructed Knee Than in the Contralateral Knee

Abstract

Background: A goal of anterior cruciate ligament (ACL) reconstruction is to provide a meniscal protective effect for the knee. Purpose: (1) To evaluate whether there was a different likelihood of subsequent meniscal surgery in the ACL-reconstructed knee or in the normal contralateral knee and (2) to compare the risk factors associated with subsequent meniscal surgery in the ACL-reconstructed knee and contralateral knee. Study Design: Cohort study; Level of evidence, 3. Methods: Using an integrated health care system’s ACL reconstruction registry, patients undergoing primary ACL reconstruction, with no meniscal injury at the time of index surgery and a normal contralateral knee, were evaluated. Subsequent meniscal tears associated with ACL graft revision were excluded. Subsequent meniscal surgery in either knee was the outcome of interest. Sex, age, and graft type were assessed as potential risk factors. Survival analysis was used to compare meniscal surgery–free survival rates and to assess risk factors of subsequent meniscal surgery. Results: Of 4087 patients, there were 32 (0.78%) patients who underwent subsequent meniscal surgery in the index knee and 9 (0.22%) in the contralateral knee. The meniscal surgery–free survival rate at 4 years was 99.08% (95% CI, 98.64%-99.37%) in the index knee and 99.65% (95% CI, 99.31%-99.82%) in the contralateral knee. There was a 3.73 (95% CI, 1.73-8.04; P < .001) higher risk of subsequent meniscal surgery in the index knee compared with the contralateral knee, or a 0.57% absolute risk difference. After adjustments, allografts (hazard ratio [HR], 5.06; 95% CI, 1.80-14.23; P = .002) and hamstring autografts (HR, 3.11; 95% CI, 1.06-9.10; P = .038) were risk factors for subsequent meniscal surgery in the index knee compared with bone–patellar tendon–bone (BPTB) autografts. Conclusion: After ACL reconstruction, the overall risk of subsequent meniscal surgery was low. However, the relative risk of subsequent meniscal surgery in the ACL-reconstructed knee was higher compared with the contralateral knee. Only graft type was found to be a risk factor for subsequent meniscal surgery in the ACL-reconstructed knee, with a higher risk for allografts and hamstring autografts compared with BPTB autografts.