Effect of Activity at Time of Injury and Concomitant Ligament Injuries on Patient-Reported Outcome After Posterior Cruciate Ligament Reconstruction

BACKGROUND: The outcomes after posterior cruciate ligament reconstruction (PCLR) have been shown to be inferior to those of anterior cruciate ligament reconstruction. There is a lack of knowledge regarding prognostic factors of PCLR outcomes. PURPOSE: To explore the effect of injury mechanism and concomitant ligament injuries on patient-reported outcomes at 2-year follow-up after PCLR. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 373 patients who underwent primary PCLR and who were registered in the Norwegian Knee Ligament Registry were included. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used as the patient-reported outcome measure. At 2-year follow-up, 252 patients (68%) had completed the KOOS. Multiple regression analysis was used to evaluate the effects of injury activity and multiligament injuries on the KOOS outcomes. RESULTS: In the adjusted and unadjusted regression analyses, patients injured during sports reported significantly better outcome at 2-year follow-up after PCLR than patients injured during other activities (P < .001) according to all KOOS subscales. Adjusted analysis was as follows for the KOOS subscales: Symptoms (regression coefficient [β], 7.0; 95% CI, 1.9-12.2), Pain (β, 13.4; 95% CI, 8.0-18.9), Activities of Daily Living (β, 12.6; 95% CI, 7.1-18.1), Sport/Recreation (β, 15.3; 95% CI, 8.0-22.5), and Quality of Life (β, 13.5; 95% CI, 7.1-20.0). In the unadjusted analysis, patients with isolated PCL injuries reported higher scores in the Sport/Recreation subscale (β, –7.9; 95% CI, –15.5 to –0.3). The difference was not significant in the adjusted analysis. No other significant differences in KOOS outcomes were found between isolated and multiligament injuries. CONCLUSION: Patients injured in sports reported better outcomes at 2 years after PCLR as compared with patients injured in other activities. Multiligament injuries involving the PCL do not seem to predict a worse outcome than for isolated PCL injuries.