Thigh Muscle Volume Remains Decreased on 3-Dimensional Magnetic Resonance Imaging at Minimum of 5 Years After Patellar Tendon but not Allograft Anterior Cruciate Ligament Reconstruction.

Purpose: To evaluate thigh muscle volume differences in patients undergoing anterior cruciate ligament reconstruction (ACLR) with either allograft tissue or bone-patellar tendon-bone (BPTB) autografts, using 3-dimensional magnetic resonance imaging (MRI) modeling. Methods: This is a retrospective, single-center study of patients undergoing primary ACLR with either ipsilateral BPTB autograft or allograft tissue. Inclusion criteria were age 18-45 years, 5 to 8 years of follow-up, and body mass index <30. Patients were excluded if they had multiligamentous knee injuries, surgical treatment of meniscus tears (repair or reconstruction), and any subsequent knee procedures after the index ACLR. 3D MRI of the bilateral thighs was performed and images were rendered with 3D modeling software and the total thigh, anterior-, posterior-, and medial-thigh compartment musculature were individually segmented and the volumes were calculated. Data were evaluated using a Results: Ten allograft and 10 patients with BPTB were included. Patients with allograft were older at surgery (mean age 34.6 vs 23.4 years ( Conclusions: No significant side-to-side differences were found in individual thigh compartments or total volume after allograft ACLR. BPTB ACLR has a modest effect (∼3%) on long-term total thigh muscle volume. Level of Evidence: Level III, retrospective cohort study.