The Hook Test Is More Accurate Than the Trampoline Test to Detect Foveal Tears of the Triangular Fibrocartilage Complex of the Wrist

Purpose: To evaluate the accuracy of the trampoline and hook tests, used in the arthroscopic assessment of triangular fibrocartilage complex (TFCC) tears compared with arthroscopic direct visualization of the radiocarpal joint (RCJ) and of the distal radial ulnar joint (DRUJ). Methods: In total, 135 patients (97 male, 38 female, mean age 43.5 years) were divided into 2 groups: (1) 80 patients with chronic ulnar-sided wrist pain and positive fovea sign and (2) 55 patients with other complaints. TFCC was assessed by RCJ and DRUJ arthroscopy and by the trampoline and hook tests to detect rupture of distal and proximal components of the TFCC. Accuracy, specificity, sensitivity, and likelihood ratio of the 2 diagnostic methods were measured and compared, using RCJ and DRUJ arthroscopy as reference. Results: The trampoline and the hook tests showed an overall accuracy of 70.37% and 86.67%, respectively. The accuracy of the trampoline test was similar for distal (69%), proximal (66%), and complete (73%) TFCC tears. The hook test was more accurate when evaluating proximal (97%) and complete (98%) tears, rather than distal lesions (75%). Sensitivity for the trampoline and hook tests was 75.00% and 0.00% (P <.001) for distal tears and 78.85% and 100.00% (P <.001) and 58.33% and 100.00% (P <.001) for complete or isolated proximal tears, respectively. Specificity for the trampoline and hook tests was 67.27% and 96.36% (P <.001) respectively. Conclusions: The trampoline and hook tests can assure accurate diagnosis of peripheral TFCC tear. The hook test shows greater specificity and sensitivity to recognize foveal TFCC tears. Values of positive likelihood ratio suggest a greater probability to detect foveal laceration of peripheral TFCC for the hook test than for the trampoline test. These findings suggest that DRUJ arthroscopy is not necessary to confirm foveal incompetence of the TFCC, if the hook test is positive. Level of Evidence: Level II, retrospective diagnostic trial.