Association of patellofemoral malalignment with early trochlear and patellar chondromalacia: a prospective T2* mapping study.

Abstract

Purpose: To investigate the association between patellofemoral malalignment and early-stage trochlear and patellar chondromalacia using the T2* mapping method.

Methods: Seventy-five patients were included in the study and divided into two groups based on the presence (patient group) or absence (control group) of patellofemoral malalignment on magnetic resonance imaging. The T2* mapping measurements were evaluated by dividing patellar and trochlear cartilage into 12 quadrants on sagittal slices. The groups were first compared based on the mean T2* relaxation times of the cartilage. Subsequently, the 12 quadrants were compared individually between the two groups. Cut-off values were calculated for the quadrants, with significant differences observed.

Results: The patient group included 39 patients, and the control group included 36 patients. There was no significant difference between the groups in terms of mean T2* relaxation values for the trochlear and patellar cartilage. However, in the separate comparison of the 12 quadrants, T2* relaxation values in the upper-outer-outer (P1, T1) and upper-outer-inner (P2, T2) quadrants of both the trochlear and patellar cartilage were found to be statistically significantly higher in the patient group. Similarly, significant cut-off values were identified for the T1, P1, and P2 quadrants.

Conclusion: Early chondromalacia can be quantitatively detected using T2* mapping. In patients with elevated T2* relaxation values in the superior-lateral regions of the patellar and trochlear cartilage, patellofemoral malalignment should be considered in the etiology.

Clinical significance: Chondromalacia caused by patellofemoral malalignment may exhibit an asymmetric onset, with the superior-lateral quadrant as the initial site of cartilage damage in both trochlear and patellar cartilage.