Meniscal and Articular Cartilage Predictors of Clinical Outcome following Revision ACL Reconstruction

OBJECTIVES: Revision ACL reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions. The reasons why remain unknown. The purpose of this study was to determine if both the prevalence and/or degree of meniscal and chondral damage noted at the time of ACL revision reconstruction predicts activity level, sports function, and OA symptoms at two year follow-up. METHODS: Revision ACL reconstruction patients were identified and prospectively enrolled between 2006 and 2011. Data collected included baseline demographics, surgical technique and pathology, and a series of validated patient reported outcome instruments (IKDC, KOOS, WOMAC, and Marx activity rating score). Patients were followed up for 2 years, and asked to complete the identical set of outcome instruments. Regression analysis was used to control for age, gender, BMI, smoking status, activity level, baseline outcome scores, revision number, time since last ACLR, previous and current meniscal and articular cartilage pathology, in order to assess the meniscal and AC pathology risk factors for clinical outcomes 2 years after revision ACL reconstruction. 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. Surgeons noted previous pathology in the medial meniscus (39%), lateral meniscus (20%), and articular surfaces (12%) at the time of revision surgery. Surgeons reported current pathology in the medial meniscus (45%), lateral meniscus (37%), MFC (43%), LFC (29%), MTP (11%), LTP (17%), patella (30%), and trochlea (20%). At 2 years, follow-up was obtained on 82% (989/1205). Previous meniscal pathology (both medial and lateral), as well as current AC pathology (in the MFC, LFC, MTP, LTP, and trochlea) were found to be significant drivers of poorer outcomes at 2 years (Table 1). The most consistent cartilage-related factors driving outcome in revision patients were previous lateral meniscus pathology and current trochlea AC pathology. Having a previous excision on the lateral meniscus resulted in significantly poorer outcomes on the IKDC (odds ratio=1.69; 95% CI=1.16-2.44; p=0.005), all KOOS subscales (OR range=1.54-2.08; 95% CI=1.04-3.03; p<0.029), and all WOMAC subscales (OR=1.56; 95% CI=1.06-2.27; p=0.02). Having a current Grade 3-4 AC chondrosis of the trochlea resulted in significantly poorer outcomes in the IKDC (OR=1.89; 95% CI=1.25-2.94; p-0.003), 4 of 5 KOOS subscales (OR range = 1.64-2.70; 95% CI=1.09-4.17; p<0.02), and 2 of 3 WOMAC subscales (OR range = 1.61-2.70; 95% CI=1.04-4.17; p<0.03). Lower baseline outcome scores, lower baseline activity level, and shorter time since the patient’s last ACL reconstruction all significantly increased the odds of reporting poorer clinical outcomes at 2 years. Meniscal and AC pathology was not found to be a significant risk factor for 2 year activity levels. Interestingly, previous AC pathology and current meniscal pathology were not found to be significant risk factors for 2 year outcomes in this revision cohort. CONCLUSION: Having a previous meniscal excision, as well as grade 3-4 chondral damage noted at the time of ACL revision reconstruction results in decreased sports outcome scores and worse WOMAC scores at two years following revision surgery. However, incidence of meniscal and AC pathology was not found to be a predictor of a patient’s activity level at 2 years.