FUNCTIONAL RECOVERY AFTER REVISION ACL RECONSTRUCTION WITH A SECOND AUTOGRAFT: A MATCHED COHORT ANALYSIS IN ADOLESCENT PATIENTS

BACKGROUND: Young patients are the highest risk demographic for ACL graft failure and revision surgery. Previous studies have shown higher rates of graft failure with the use of allograft tissue for ACL reconstruction (ACLR) in both primary and revision surgeries. However, questions remain regarding the functional consequence of taking a second autograft from the same knee for revision ACLR. PURPOSE: The purpose of this study was to evaluate 6-month functional testing in patients who underwent revision ACLR with a second autograft from the same knee compared to matched cohorts of primary ACL patients. METHODS: We retrospectively reviewed prospectively collected data from patients aged 19 or younger who had revision ACLR with a second autograft at our institution. We excluded patients with iliotibial band autografts, two autografts from a synergistic muscle groups, or grafts from the contralateral knee. Patients with previous significant injury or surgery to the contralateral leg, and those with multiligamentous knee injuries were excluded. Patients underwent functional testing 5-8 months after revision surgery including anthropometric measures, isometric strength, Y-Balance, and hop testing. Side-to-side deficits were then compared to age, sex, and BMI matched cohorts of primary ACLR patients, with hamstring or patellar tendon autografts. Multivariate analysis of variance (MANOVA) was used, and if significance was detected, pairwise comparison was performed by Bonferroni post-hoc correction. Statistical significance of p<0.05 was applied. RESULTS: Thirty-seven adolescents underwent functional testing at 6.25±0.56 months after revision ACLR with a second autograft. These patients were matched to 62 patients who underwent primary ACLR with hamstring autograft, and 47 who underwent ACLR with patellar tendon autograft (Table 1). Revision ACLR patients showed comparable knee extension strength deficits to the patellar tendon group (-9.45±12.09% vs -8.81±13.83%, p=0.999) which were significantly greater than hamstring group (-9.45±12.09% vs -0.99±12.00%, p<0.05). Greater strength deficits were seen in knee flexion strength in the hamstring group than the revision group (-38.90±16.21% vs -28.13±23.22%, p=0.009) which had significantly greater knee flexion strength deficits than the patellar tendon group (-28.13±23.22% vs -1.17±12.41%, p=0.001). The hamstring primary group also showed greater triple hop deficit (-21.08±25.99%) than the other two groups (-21.08±25.99% vs -10.75±12.85 vs -6.84±23.81, p=0.024), which were similar. CONCLUSIONS: After revision ACLR with a second autograft from the same knee, adolescents show similar knee extension strength deficits compared to primary ACL patients with patellar tendon grafts, but improved knee flexion strength deficits compared to primary ACL patients with hamstring grafts. TABLES/FIGURES: