Comparison of MRI & direct MR arthrography with arthroscopy in diagnosing ligament injuries of wrist

Ligament injuries around the wrist leading to chronic wrist pain are often a diagnostic dilemma.Various imaging modalities like wrist radiographs, CT and MRI have been used to improve the diagnostic accuracy. The objective of this study was to assess the value of MRI & direct magnetic resonance arthrography (MRA) of the wrist for detecting & evaluating tears of the triangular fibrocartilage complex (TFCC) & scapholunate & luno triquetral interosseous ligament (LTIL & SLIL) injuries in comparison with arthroscopy of the wrist.

All patients presenting with chronic wrist pain of more than 3 months duration with suspected ligament injuries were included. MRI was performed with 8 channel wrist coil on 1.5 T machine. (PHILIPS, Netherlands). MRA was performed after obtaining consent. Retrospective MR findings were then correlated with results in those patients who underwent arthroscopy. Arthroscopic correlation was obtained in 22 (46.8%) cases out of the 45 patients who underwent both MRI & MRA.

The gold standard arthroscopic procedure diagnosed 15 peripheral & 6 central TFCC tears in 22 patients. 4 scapholunate ligament tears were also identified. MRI diagnosed 16 peripheral & 5 central TFCC tears in these 22 patients. MRA identified 9 central tears and 14 peripheral tears. The sensitivity in diagnosing an overall TFCC tears with MRI as well as MRA was 94.4 & 100%. The specificity of the MRI and MRA in diagnosing an overall TFCC tear was 100% & 75% respectively.

Direct MRA has better sensitivity in detecting TFCC central tears. In view of 'substantial' agreement between MRI & MRA with Kappa analysis, conventional MRI can be relied on, in diagnosing TFCC injury. With comparatively low specificity, caution and restraint is advised in interpreting MRA, which may influence decision on surgery.