Pre-Operative Femoral Cartilage Ultrasound Characteristics Are Altered in People Who Report Symptoms at 1 year After Anterior Cruciate Ligament Reconstruction

Abstract

We assessed whether pre-operative femoral cartilage thickness and echo intensity on ultrasound are different between individuals who are symptomatic (n = 6) and asymptomatic (n = 7) at 1 year after a primary unilateral anterior cruciate ligament (ACL) reconstruction (age, 23 ± 4 y; 31% women, 69% men; body mass index, 24.9 ± 3.7 kg/m2). A pre-operative, bilateral ultrasound assessment was used to quantify average thickness and echo intensity in the medial, middle and lateral femoral trochlear regions. An inter-limb ratio (ACL/contralateral limb) was calculated for average thickness and echo intensity. At 1 y after ACL reconstruction, we operationally defined the presence of symptoms as scoring ≤85% on at least two Knee Injury and Osteoarthritis Outcome Score subscales. Independent-sample t-tests and Cohen's d effect sizes were used to compare ultrasound pre-operative inter-limb ratios between participants with and without symptoms at 1 y after ACL reconstruction. For medial femoral cartilage, symptomatic participants had significantly greater average cartilage thickness inter-limb ratios (p = 0.01, d = −1.65) and significantly lower echo intensity inter-limb ratios (p = 0.01, d = 1.72) compared with asymptomatic participants. Middle and lateral femoral cartilage average thickness and echo intensity were not different between symptomatic and asymptomatic participants. These findings provide preliminary evidence that a clinically feasible ultrasound assessment of the femoral trochlear cartilage may be prognostic of self-reported symptoms at 1 y after ACL reconstruction.