Study of ulnar variance with high-resolution MRI: correlation with triangular fibrocartilage complex and cartilage of ulnar side of wrist.

PURPOSE: To investigate correlations with ulnar variance and the triangular fibrocartilage complex (TFCC) or cartilage of ulnar side of the wrist on high-resolution MRI with a microscopy coil.

MATERIALS AND METHODS: We reviewed ulnar variance, TFCC, and cartilage of the ulnar side of the wrist in 93 subjects (29 asymptomatic volunteers and 64 patients with suspected TFCC injury) with high-resolution MRI using a 47-mm microscopy surface coil. All MR images were obtained with a 1.5 T scanner. Coronal 2D gradient recalled echo T(2)*-weighted images were used for analysis. For qualitative analysis we measured ulnar variance, TFCC angle, thickness in the central portion of TFCC disc proper, and cartilage thickness of the lunate and the ulnar head on MRI and calculated the correlation coefficient between measured values. We also examined the relationship between ulnar variance and age or sex.

RESULTS: High-resolution MR images clearly demonstrated TFCC and cartilage of the wrist and ulnar variance. The mean ulnar variance on MRI was +0.26 mm (range, -4.59 to +3.71 mm). The mean TFCC angle and TFCC thickness were 23.9 degrees (range, -4.6 to +54.1 degrees ) and 1.11 mm (range, 0.4 to 3.22 mm), respectively. Ulnar variance and TFCC angle were positively correlated (r = 0.84), and ulnar variance and TFCC thickness were negatively correlated (r = -0.71). However, ulnar variance and lunate or ulnar head cartilage thickness were not significantly correlated.

CONCLUSION: High-resolution MRI with a microscopy coil is a useful tool for evaluating the relationship between ulnar variance and ulnar side structures.