MR diagnosis of retropatellar chondral lesions under compression. A comparison with histological findings.

PURPOSE: The aim of the study was to improve the chondromalacia patellae (CMP) diagnosis by MR imaging under defined compression of the retropatellar cartilage, using a specially designed knee compressor. The results were compared with histological findings to obtain an MR classification of CMP.

METHOD: MR imaging was performed in in vitro studies of 25 knees from cadavers to investigate the effects of compression on the retropatellar articular cartilage. The results were verified by subsequent histological evaluation.

RESULTS

There was a significant difference in cartilage thickness reduction and signal intensity behaviour under compression according to the stage of CMP.

CONCLUSION

Based on the decrease in cartilage thickness, signal intensity behaviour under compression, and cartilage morphology, the studies permitted an MR classification of CMP into stages I-IV in line with the histological findings. Healthy cartilage was clearly distinguished, a finding which may optimize CMP diagnosis.