Paper 29: Untreated Type 4 Ramp Injuries at Index Anterior Cruciate Ligament Reconstruction Surgery Result in Higher Rates of Revision ACL-R within the First 2 Years

OBJECTIVES: Ramp lesions are commonly associated with ACL tears and recent studies have identified these lesions in 17-42% of patients undergoing treatment with ACL reconstruction. In addition to its association with ACL tears, there is increasing recognition that ramp lesions lead to significant biomechanical changes in the knee. Our study seeks to investigate whether patients with type 4 ramp lesions at the time of initial ACL reconstruction have higher rates of reoperation, specifically revision ACL-R, compared to those that undergo ACL-R without a ramp lesion. METHODS: Retrospective chart review was conducted on all patients surgically treated with ACL reconstruction at level I academic center from January 2015 to December 2019. Type 4 ramp lesions were diagnosed on preoperative MRIs by two MSK-trained radiologists blinded to clinical information. Demographic, associated injuries, intra-operative, clinical data, and re-operations were extracted from our ACL-R database. Statistical analysis using Students T-test and chi x(2) for comparing cohorts. Cox Regression with covariates for re-operation surgery was used. Risk factors evaluated for revision surgery included patient age, sex, BMI, treatment of ramp, timing to surgery. Inter-reliability coefficient correlation was used for MRI reliability. RESULTS: A total of 255 patients ACL-R were identified that met inclusion. There were 170 patients with ACL-R without a ramp present and 85 patients with ACL-R + type 4 ramp lesion. Revision ACL-R occurred in 10.5% in ramp group compared to 2.4% without ramp (P<0.005). Around 75% of the revision ACL-R for the ramp group occurred within the first 2 and half years after surgery. Risk factor associated with revision ACL-R included untreated ramp (HR 10.46 (CI: 2.13-109.70) p=0.01). CONCLUSIONS: Meniscal ramp lesions with ACL-R result in higher revision ACL-R when compared to no ramp ACL-R. Most significantly untreated type 4 ramp lesions with concomitant ACL-R were associated with increased risk of ACL-R revision surgery . Standard portals are not sufficient in diagnosing and assessing stability of ramp lesions intra-operatively.