Sonography: a sensitive and specific method for detecting trochlear cartilage pathologies

MRI is now the modality of choice for evaluating articular cartilage. Nevertheless, it has some general drawbacks. Some patients cannot undergo MRI, and in others US scan could be the first examination and cartilage should be evaluated. Ultrasound could be a useful method for detecting trochlear cartilage low-grade lesions. In this study, our goal was to evaluate the efficacy of ultrasonography in detecting these lesions.

All patients referred to our hospital, from July 2018 to July 2019, who were arthroscopic candidates due to sport-related pathologies, underwent ultrasound scan 1 day prior to surgery. Ultrasound assessment was performed by an expert radiologist, with a 13-MHz probe, located transversely proximal to the patella in different degrees of knee flexion to assess trochlear lesion grade and thickness. Arthroscopic examination of all patients was performed by an experienced orthopedic knee surgeon (second author). Sensitivity and specificity of ultrasound were calculated.

A total of 48 patients were involved in the study with a mean age of 33.2 years (SD: 9.7), between 19 and 51 years of age. Patients were 81% male (39 patients). The sensitivity of ultrasound in grading of trochlear cartilage lesion was 100%, meanwhile its specificity was 88.2% (30 cases had normal cartilage while this figure was 34 in arthroscopy).

Sonography is a low-cost, accessible diagnostic tool with high sensitivity and specificity for early detection of trochlear cartilage pathologies. It can play an important role as an outpatient diagnostic workup in patients with anterior knee pain.