Medial collateral ligament (MCL) reconstruction results in improved medial stability: results from the Danish knee ligament reconstruction registry (DKRR).

The aim of this study was to compare outcome data after isolated and combined (MCL) plus anterior cruciate ligament (ACL) reconstruction based on objective and subjective measures using data from the (DKRR). There are only a few small-sized case studies on outcomes after MCL reconstruction. MCL reconstruction was hypothesised to improve both objective and subjective outcomes.All patients who were registered in the DKRR between 2005 and 2016 (N = 25,281) and who underwent isolated ACL (n = 24,683), isolated MCL (n = 103) or combined MCL plus ACL (n = 495) reconstructions were retrospectively identified. Objective (valgus knee stability and sagittal knee laxity) and subjective (Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity scale score) outcomes in these three cohorts were evaluated at the 1-year follow-up by comparing pre- and post-operative values.Medial stability improved significantly pre- to post-operatively after both isolated MCL and combined MCL plus ACL reconstruction, with 26 (53%) and 195 (69%) of the patients, respectively, having normal valgus stability (0-2 mm laxity). Sagittal stability was similar after MCL plus ACL reconstruction and isolated ACL reconstruction (1.7 and 1.5 mm, respectively). At the 1-year follow-up, although the KOOS of the patients in the isolated MCL and combined MCL plus ACL reconstruction cohorts improved significantly, they were lower than those of the patients in the isolated ACL reconstruction cohort.Both isolated MCL reconstruction and combined MCL plus ACL reconstruction resulted in significant and clinically relevant improvements in the subjective outcomes from pre-operative conditions to the 1-year follow-up. Valgus stability also improved significantly, with two-thirds of patients obtaining normal valgus stability after MCL reconstruction. Subjective outcomes were similar between isolated MCL reconstruction and combined MCL plus ACL reconstructions, but were poorer than isolated ACL reconstructions.Level III.