• PURPOSE
    • To compare rates of revisions between patients with isolated anterior cruciate ligament (ACL) reconstruction and those who had concomitant medial collateral ligament (MCL) injuries managed either operatively or nonoperatively at the time of index anterior cruciate ligament reconstruction (ACLR).
  • METHODS
    • Using laterality-specific International Classification of Diseases, Tenth Revision (ICD-10) and Current Procedural Terminology (CPT) codes, we queried the PearlDiver-Mariner Database for all patients who underwent ACLR between 2016 and 2020. Patients were included if they were ages 15 or older and had a minimum of 2 years of follow-up after index ACLR. Patients were then divided into cohorts by presence or absence of concomitant MCL injury. The cohort of concomitant MCL injuries was further subdivided into those with MCL injuries managed nonoperatively, with MCL repair, or with MCL reconstruction at the time of index ACLR. Multivariate regression was performed between cohorts to evaluate for factors associated with revision ACLR.
  • RESULTS
    • We identified 47,306 patients with isolated ACL injuries and 10,846 with concomitant MCL and ACL injuries. In total, 93% of patients with concomitant MCL injuries had their MCL treated nonoperatively; however, the annual proportion of patients being surgically managed for their MCL injury increased by 70% from 2016 to 2020. Concomitant MCL injury patients had greater odds of undergoing revision ACLR compared with patients with isolated ACL injuries (odds ratio 1.50, 95% confidence interval 1.36-1.66, P < .001). Among patients with concomitant MCL injuries, surgically managed patients had a greater risk of revision ACLR compared with nonoperatively managed MCL injuries (odds ratio 1.39, 95% confidence interval 1.01-1.86, P = .034).
  • CONCLUSIONS
    • Despite an increase in operatively managed concomitant MCL injuries, most concomitant MCL injuries were still managed nonoperatively at the time of ACLR. Patients with concomitant MCL injuries, particularly those managed operatively, at the time of ACLR are at increased risk of requiring revision ACLR compared with those with isolated ACL injuries.
  • LEVEL OF EVIDENCE
    • Level III, retrospective comparative case series.