[Peri-lunate wrist dislocation: long-term outcome].

PURPOSE OF THE STUDY

We report our experience with 25 peri-lunate posterior wrist dislocations and compare outcome with data in the literature searching for prognostic factors.

MATERIAL AND METHODS

Our series included 24 men and one woman, mean age 36 years. Twenty-three patient were less than 50 years old at the time of the accident. Diagnosis was established late in five patients. All patients were reviewed clinically and radiologically with a mean follow-up of 57 months. We differentiated pure dislocations (n=16) from trans-scapho-lunate dislocations (n=9). The pure dislocations included six type 1 and ten type 2 in the Witvoët and Allieu classification. We also distinguished groups by open or closed treatment, with or without pinning, and with or without suture of the scapho-lunate ligament. Screw fixation was used in case of scaphoid fracture. Post-operative cast immobilization was 45 days on the average, followed by three months of rehabilitation exercises.

RESULTS

Residual pain of variable intensity was reported by 22 patients but subjectively, 21 patients considered outcome to be good or very good. Wrist movement was greatly impaired in eight patient with a 60 degrees flexion-extension arc. All patients had a 20% reduction in force compared with the healthy side. According to the Green and O'Brian functional score, outcome was poor in four wrists. The scapholunate space and the sapholunate angles were abnormal in seven wrists. Reduction was insufficient in only one case with the scapholunate space measuring 5 mm after trans-scapho-lunate dislocation. In most of the cases, these poor functional and/or radiographic results coincided with carpal instability which developed early or late after trauma. The most bothersome element in other cases was wrist stiffness. The trans-scapho-lunate dislocations appeared to evolve more favorably than the pure dislocations, but could also cause carpal instability.

DISCUSSION

There is a real functional impairment after posterior peri-lunate dislocation. The differences in outcome we observed were not statistically correlated with type of treatment, probably because of the small number of patients, but did reveal certain tendencies. Closed reduction did not always avoid the development of carpal instability and gave only average results. Percutaneous pinning or open reduction did not improve outcome in pure dislocations. It might be good to use scapho-lunate suture more often to obtain better healing and reduce the risk of carpal instability, as has been suggested by certain teams.