[Wrist stability after experimental traumatic triangular fibrocartilage complex lesions].

OBJECTIVE: To evaluate the changes in stability of the wrist after experimental traumatic triangular fibrocartilage complex (TFCC) lesions, and to provide basic theoretical criteria for clinical treatment.

METHODS: Fourteen adult cadaver upper extremities specimens were included. Two of 14 specimens were tested in pre-experiment. The specimens were tested in a INSTRON 8874 biomechanics measuring instrument. First a dorsal arthrotomy (ART) was performed, and second test was with 1 of 4 different experimental lesions according to Palmer's classification of traumatic TFCC lesions (n=3). 1A: central perforation; 1B: ulnar avulsion with or without fracture of processus styloideus ulnae; 1C: distal avulsion with ligament injury; 1D: radial avulsion. Forced internal external rotation torque were recorded in the interval -60 degrees to 60 degrees of flexion.

RESULTS: The average torque of the dorsal ART was (0.713 +/- 0.121) Nm, and the 1B-1 lesion (ulnar avulsion without ulnar styloid fracture) was (0.709 +/- 0.134) Nm, the 1B-2 lesion (ulnar avulsion with ulnar styloid fracture) was (0.409 +/- 0.113) Nm. The difference between the 1B-1 lesion and the dorsal ART was not significant but the difference between the 1B-2 lesion and the dorsal ART was significant (P < 0.05). The average torque of the 1C lesion in about 45 degrees of wrist extension and flexion were (0.878 +/- 0.184) Nm and (0.988 +/- 0.197) Nm, and the dorsal ART were (1.510 +/- 0.173) Nm and (1.540 +/- 0.093) Nm. The difference between the two groups was significant (P < 0.05). The 1A lesion and 1D lesion did not alter significantly wrist stability.

CONCLUSION: The 1B-2 lesion and 1C lesion alter significantly the stability of the wrist.