Traumatic injury of the triangular fibrocartilage complex (TFCC)-a refinement to the Palmer classification by using high-resolution 3-T MRI.

OBJECTIVE: The aim of this study was to investigate the MR features of the traumatic injury of the triangular fibrocartilage complex (TFCC) by using high-resolution 3-T magnetic resonance imaging (MRI) and to refine the Palmer classification system.

MATERIALS AND METHODS: From November 2015 to May 2019, sixty-seven patients met the including and excluding criteria and were enrolled into this retrospective study. All subjects had high-resolution 3-T MRI scan of the wrist and eleven had indirect MR arthrography of the wrist. All the MRI were read by two experienced musculoskeletal radiologists. Diagnostic sensitivity, specificity, and accuracy of MRI were calculated by using the arthroscopy and surgery as the standard of reference. A P value less than 0.05 was considered statistically significant. The interobserver agreement was assessed by kappa analysis.

RESULTS: There were 49 cases of TFCC injuries proven by the arthroscopy or surgery. The TFCC injuries in the other 18 patients were proved by the combination of clinical follow-up examination and follow-up MRI. Among the arthroscopy- or surgery-confirmed cases, there were 32 patients with original Palmer injuries (IA = 10, IB = 19, ID = 3), 5 with capsular detachment, 4 with bucket-handle tear of the TFCC that have rarely been reported, and 8 with complex injuries that involved the listed classifications above. The sensitivities and specificities of MRI for diagnosing IA, IB, ID, complex injuries, and bucket-handle tear were 67-100% and 90-100%, and overall good to perfect interobserver agreements (kappa, 0.64-1.00). The diagnostic performance for the capsular detachment was lower (kappa, 0.38).

CONCLUSION: With high-resolution 3-T MRI, more detailed injury patterns were found including capsular injuries, the horizontal tear of the articular disk, and the bucket-handle tear. It is necessary to refine the classic Palmer classification of TFCC injuries.