Cartilage status in knees with recurrent patellar instability using magnetic resonance imaging T2 relaxation time value.

PURPOSE: The purpose of the study was to analyse the patellar status in patients with recurrent patellar instability and in healthy controls using magnetic resonance imaging (MRI).

METHODS

One hundred and thirteen patients with patellar instability (patellar instability group) and 50 healthy controls (control group) were studied. All patients underwent computed tomography (CT) to measure the patellofemoral joint anatomy. Meanwhile, MRI was used to investigate cartilage status and to determine the T2 relaxation time value of the patellar cartilage plate. The mean values of these parameters for the patellar instability group and the control group were compared.

RESULTS

The CT images of the patellar instability group revealed greatly abnormal anatomy of the patellofemoral joint compared with the control group. By MRI assessment, 32 patients were determined to have a cartilage defect, which was confirmed under arthroscopy. Among the other 81 patients, the T2 relaxation time value of the patellar instability group was significantly higher than that of the control group on the middle (p = 0.032) or medial sites (p = 0.041) of the patellar cartilage.

CONCLUSIONS

The patellar instability group exhibits a higher risk of cartilage lesions with abnormal patellofemoral joint anatomy. MRI may enable early detection of these cartilage defects within the patellofemoral joint, enabling clinicians to adopt strategies to delay or prevent cartilage degeneration.

LEVEL OF EVIDENCE: III.