Arthroscopy has a higher discriminative capacity than MRI in detecting mild cartilage lesions

To determine whether current MRI could detect superficial cartilage lesions that are observed in patients with knee pain for whom arthroscopy was indicated for therapeutic reasons or when the cause of pain was unclear.

Adult patients with knee pain lasting more than 3 months, scheduled for a therapeutic/diagnostic arthroscopy, were recruited. Demographic and clinical data, pain assessment, MRI imaging and observations of cartilage damage in the medial femoral condyle during arthroscopic procedure were documented. Patients were categorized based on the presence of cartilage damage assessed via MRI and/or direct visualization. Concordance between these assessments and its variation with age and patient-reported pain were examined.

Out of the 95 patients recruited, 48 exhibited lesions in the medial femoral condyle (MFC) during arthroscopic examination, while only 24 of them showed lesions on the MRI scans. The thickness of the cartilage in the MFC was significantly lower in patients with cartilage damage detected by MRI compared with those without. Among patients with cartilage lesions identified during arthroscopy, those also showing lesions on the MRI had lower cartilage thickness and higher Outerbridge score than those without lesions on the MRI. Patients with detectable cartilage damage on the MRI were significantly older and reported higher levels of pain than those with damage detected only by arthroscopic examination.

Despite significant technological advancements in MRI, arthroscopy still proves superior in identifying mild structural cartilage lesions that are not identifiable by this technique.