Ultrasonographic Assessment of Femoral Cartilage in Individuals With Anterior Cruciate Ligament Reconstruction: A Case-Control Study

Context: Developing osteoarthritis is common after anterior cruciate ligament reconstruction (ACLR). Monitoring changes in femoral cartilage size after ACLR may be a way to detect the earliest structural alterations before the radiographic onset of osteoarthritis. Diagnostic ultrasonography (US) offers a clinically accessible and valid method for evaluating anterior femoral cartilage size. Objective: To compare the US measurements of anterior femoral cross-sectional area and cartilage thickness between limbs in individuals with a unilateral ACLR and between the ACLR limbs of these individuals and the limbs of uninjured control participants. Design: Case-control study. Setting: Research laboratory. Patients or Other Participants: A total of 20 volunteers with an ACLR (37.0 +/- 26.6 months after surgery) and 28 uninjured volunteers. Main Outcome Measure(s): We used US to assess anterior femoral cartilage cross-sectional area and thickness (ie, medial, lateral, and intercondylar) in the ACLR and contralateral limbs of participants with ACLR and unilaterally in the reference limbs of uninjured participants. Results: The ACLR limb presented with greater anterior femoral cartilage cross-sectional area (96.68 +/- 22.68 mm(2)) than both the contralateral (85.69 +/- 17.57 mm(2), t(19) = 4.47; P < .001) and uninjured (84.62 +/- 15.89 mm(2), t(46) = 2.17; P = .04) limbs. The ACLR limb presented with greater medial condyle thickness (2.61 +/- 0.61 mm) than both the contralateral (2.36 +/- 0.47 mm, t(19) = 2.78; P = .01) and uninjured limbs (2.22 +/- 0.40 mm, t(46) = 2.69; P = .01) and greater lateral condyle thickness (2.46 +/- 0.65 mm) than the uninjured limb (2.12 +/- 0.41 mm, t(46) = 2.20; P = .03). Conclusions: Anterior femoral cartilage cross-sectional area and thickness assessed via US were greater in the ACLR limb than in the contralateral and uninjured limbs. Greater thickness and cross-sectional area may have been due to cartilage swelling or hypertrophy after ACLR, which may affect the long-term health of the joint.