Predictors of Patient Reported Outcomes at Two Years Following Revision ACL Reconstruction

BACKGROUND: Patient reported outcomes (PROs) are a valid measure of results following revision anterior cruciate ligament (ACL) reconstruction. Revision ACL reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions. Understanding positive and negative predictors of PROs will allow surgeons to modify and potentially improve outcome for these patients. HYPOTHESIS/PURPOSE: The purpose of this study was to describe PROs following revision ACL reconstruction and test the hypothesis that patient and technique specific variables are associated with these outcomes. STUDY DESIGN: Cohort study METHODS: Revision ACL reconstruction patients were identified and prospectively enrolled by 83 surgeons over 52 sites. Data collected included baseline demographics, surgical technique and pathology, and a series of validated PRO instruments (IKDC, KOOS, WOMAC and Marx activity rating score). Patients were followed up at 2 years, and asked to complete the identical set of outcome instruments. Multivariate regression models were used to control for a variety of demographic and surgical factors, in order to determine both the positive and negative predictors of PRO scores at 2 years following revision surgery. RESULTS: 1205 patients met the inclusion criteria and were successfully enrolled. 697 (58%) were males, with a median cohort age of 26 years. The median time since their last ACL reconstruction was 3.4 years. Two-year questionnaire follow-up was obtained on 989 subjects (82%). The most significant positive predictors of 2-year IKDC scores were a high baseline IKDC score, high baseline Marx activity level, male gender, and having a longer time between a patient’s last ACL reconstruction, while negative predictors included having a previous lateral meniscectomy prior to the revision ACL reconstruction or having Grades 3/4 chondrosis in either the trochlear groove or medial tibial plateau at the time of the revision surgery. For KOOS, having a high baseline score and having a longer time between their last ACL reconstruction and revision surgery were significant positive predictors for having better (i.e. higher) 2-year KOOS scores, while having a previous lateral meniscectomy prior to the revision ACL reconstruction was a consistent predictor for having significantly worse (i.e. lower) 2-year KOOS scores. Statistically significant positive predictors for 2-year Marx activity levels included higher baseline Marx activity levels, younger age, male gender, and being a non-smoker. Negative 2-year activity level predictors included having an allograft or a biologic enhancement at the time of revision surgery. CONCLUSIONS: PROs following revision ACL reconstruction are associated with a variety of patient and surgeon related variables. Understanding positive and negative predictors of PROs will allow surgeons to guide patient expectation as well as potentially improve outcome for these patients.