The Overall Effect of Medial Meniscus Repair on Reducing Knee Pain at Ten Years after ACL Reconstruction is Negated by an Increase in Subsequent Surgery

Purpose (the aim of the study): Medial meniscus (MM) repair (MMR) performed at the time of primary anterior cruciate ligament (ACL) reconstruction (ACLR) has been shown to increase the likelihood of subsequent surgery. Surgery subsequent to ACLR is a known risk factor for increased knee pain and decreased patient satisfaction.Thus even though MMR may reduce knee pain, the overall effect when accounting for the increased likelihood subsequent surgery may negate the overall effect in reducing knee pain.Thus the relative contributions of an MMR and subsequent surgery to the clinical outcomes of ACLR cannot be determined using multivariable analysis.To determine the direct effect of MMR versus the indirect effect of subsequent surgery on knee pain 10 years after ACLR, a casual mediation analysis is required.Therefore the purpose of study was to compare the direct effects of MMR and MM excision (MME) performed with ACLR to the indirect effect through subsequent surgery on the development of knee pain 10 years after surgery.We hypothesized that MMR performed with ACLR decreases the likelihood of developing knee pain, while the occurrence of subsequent surgery other than revision ACLR would increase the likelihood of developing 10 years after surgery.