Lower Patient-Reported Outcomes After Isolated Anterior Cruciate Ligament Reconstruction Are Associated With Lower Muscle Strength Rather Than Graft Status During Second-Look Arthroscopic Evaluation

Purpose: To determine the relationship between patient-reported outcomes (PROs), objective graft status on second-look arthroscopy, and knee muscle strength during the early period after isolated primary anterior cruciate ligament reconstruction (ACLR). Methods: Patients who underwent second-look arthroscopy at least 1 year after primary ACLR between 2012 and 2020 were retrospectively reviewed. Those who completed follow-up muscle strength tests and PRO measures were included in this study. Subjective clinical outcomes were assessed on the basis of patient-reported outcome measures using the Lysholm score preoperatively and during second-look arthroscopy. Objective graft status was assessed during second-look arthroscopy using a numeric scale system consisting of the following 4 subscales: tension, vascularity, synovialization, and continuity of the graft. The graft score (0-8) was determined by adding the points from each subscale (0-2). Muscle strength was measured using isokinetic dynamometry to assess peak torque, limb symmetry index for both the quadriceps and hamstrings and the ratio of the hamstring and quadriceps before second-look arthroscopy. Second-look arthroscopy patients included in analysis were those without concomitant meniscal or cartilage procedures. Multivariate logistic regression was used to identify factors associated with inferior PROs (Lysholm score ≤83). Results: A total of 82 patients were enrolled in this study. At an average follow-up of 22.4 ± 4.8 months, 25 patients (30.5%) scored less than 83 on the Lysholm scale. No significant differences were found in total graft status scores between groups with superior or inferior outcomes (6.9 ± 1.8 vs 7.1 ± 1.2, P = .573). However, the group with inferior PROs showed significantly lower peak torque in both hamstring and quadriceps (P = .001 and P < .001, respectively). Multivariate analysis indicated that older age and lower limb symmetry index for extension and flexion (<70% and 90%, respectively) were significantly correlated with inferior PROs (odds ratios: 1.08, 5.11, and 5.66; P = .014, .013, and .006, respectively). Conclusions: Early inferior subjective outcomes after ACLR were associated with delayed recovery of quadriceps and hamstring muscle strength compared to graft appearance and tension. Level of Evidence: Level III, retrospective comparative case series.