Volume index as a new measure of cartilage loss: a retrospective MRI-based study of chondral injury patterns in adult patients with knee pain

Background: Knee pain is one of the commonest symptoms in patients who attend the Orthopaedic outpatient clinics. Chondral defects result in a painful knee. Incidence of chondral defect is reported to be between 5 and 10% over the age of 40. It is well documented that chondral defects can lead to osteoarthritis. Early detection of these lesions and cartilage repair surgery can delay the onset of osteoarthritis. The purpose of this study is to highlight the incidence, associations and correlations between opposing cartilage defects in patients who present to the knee clinic with pain. Methods: A retrospective analysis was carried out on patients who had Magnetic Resonance Imaging scans for painful knees between June 2017 and May 2019. About 227 consecutive knees were studied for the incidence of chondral defects, number of lesions, grade and size of lesion, geographical location and associated pathology in the knee. Results: All the 227 patients had chondral lesions. Most patients had 2–3 lesions (66.1%) with patellar lesions (76.6%) being the commonest followed by medial femoral condyle (59.9%). Significant correlation was found in grade and size between opposing surface lesions in patella-trochlea, Medial Femoral Condyle-Medial Tibial Plateau and Lateral Femoral Condyle-Lateral Tibial Plateau. Females were more predisposed to patella lesions. Significance between age and lesions were established. Conclusion: Incidence of cartilage defects in the knee is very high. Kissing lesions must be considered when treating cartilage lesions. Volume index could be a promising method to quantify lesions.