Joint effusion, anteroposterior stability, muscle strength and degree of patellofemoral osteoarthritis significantly impact outcome following revision ACL reconstruction.

PURPOSE: Effusion, impaired muscle function and knee instability are considered as some of the most important factors effecting outcome following anterior cruciate ligament reconstruction (ACL-R) but the impact on revision ACL-R remains unclear. It was hypothesized that these factors will significantly worsen clinical outcome following revision ACL-R. METHODS: Seventy knees (13 female and 57 male) were followed retrospectively after revision ACL-R at a mean follow-up of 47.8 ± 20.7 months. Clinical examination was based on the International Knee Documentation Evaluation Form-2000 (IKDC), Tegner activity scale. Instrumented measurement of anterior tibial translation was performed using the Rolimeter® (DJO Global, Freiburg, Germany). Bilateral circumference of the thigh was measured 10 and 20 cm proximal to the medial joint space. Cartilage was assessed according to Outerbridge classification during both primary and revision ACL-R. RESULTS: Tegner activity scale decreased significantly from 7.8 ± 1.4 points at primary ACL-R to 7 ± 1.8 points at revision ACL-R, and 5.8 ± 1.7 points at the time of follow up (p < 0.001). Joint effusion (r = - 0.47, p < 0.01) and side to side differences in single leg hop test (r = - 0.48, p < 0.1) significantly correlated with inferior outcome. Cartilage lesions were found in 67% of the patients at the time of revision ACL-R compared to 38% at the time of primary ACL-R. According to the IKDC classification A was graded in three patients (4.3%), B in 35 (50%), C in 29 (41.4%) and D in three (4.3%). Joint effusion was measured in 35% of patients at the time of follow-up. Degeneration at the patellofemoral compartment of > grad 2 was responsible for IKDC grade C and D (p = 0.035). Instrumented anteroposterior site-to-site difference of ≥3 mm showed significant impact on clinical outcome (p < 0.019). CONCLUSION: The study has shown that chronic effusion, quadriceps dysfunction, cartilage lesions especially at the patellofemoral compartment and side to side difference in anteroposterior stability significantly influences patient outcome after revision ACL-R. These factors require special attention when predicting patient's outcome. LEVEL OF EVIDENCE: Level-IV, case-controlled study.