Sonoelastographic evaluation of the distal femoral cartilage in patients with anterior cruciate ligament reconstruction

Abstract

Objectives: This study aims to evaluate sonoelastographic properties of the distal femoral cartilage in patients with anterior cruciate ligament (ACL) reconstruction. Patients and methods: Demographic characteristics and operative data of 28 patients (27 males, 1 female; mean age 31.7±7.1 years; range 22 to 48 years) with unilateral ACL reconstruction were evaluated. Reconstruction was performed with patellar tendon graft in 22 patients (78.6%) and hamstring tendon graft in six patients (21.4%). Lysholm knee score was used for functional evaluation and chair stand test was used for lower extremity strength. Medial, intercondylar, and lateral distal femoral cartilage thicknesses of operated knees and healthy knees were measured with B-mode ultrasound, while strain ratios were measured with real time sonoelastography. Results: Postoperative mean follow-up duration was 20.4±9.8 months. Mean Lysholm knee and patient satisfaction scores were 88.0±8.5 and 8.2±1.8, respectively. Cartilage thicknesses were similar between operated and healthy knees (all p>0.05). Sonoelastographic strain ratio of medial distal femoral cartilage in operated knees was significantly higher (softer cartilage) (p=0.026). There was a negative correlation between strain ratio difference of medial cartilage of operated knees and lower extremity muscle strength (p=0.009, r= -0.487). Conclusion: While there was no difference for cartilage thickness between operated and healthy knees in B-mode ultrasound evaluation, detection of sonoelastographic strain ratio changes in medial distal femoral cartilage on the operated sides may indicate early structural changes following ACL reconstruction. Further studies are required to highlight the clinical effects of this relationship between the changes in cartilage structure and sonoelastography features.