FOUR-YEAR OUTCOME OF RECENT TRANSSCAPHORETROLUNATE CARPAL DISLOCATION: 16 CASES

Abstract

Purpose: Transscaphoretrolunate dislocation is the most frequent perilunate dislocation of the carpus (65% according to Herzberg). Treatment remains controversial. The aim of this work was to analyse functional outcome in a homogeneous series of 15 patients treated by open reduction and fixation.

Material and methods: This retrospective analysis of 15 patients, mean age 34 years was conducted at four years follow-up. Clinical outcome was based on the Cooney clinical scoring chart. Static and dynamic x-rays of the wrist were studied. The dislocations were: type I=9, type IIa=5, type II=1 according to the Alnot classification. The scaphoid fractures were: types III and IV=13, type II=2. A dorsal approach was used for six cases, an anterolateral approach for four and a double approach for five. The carpal tunnel was opened in seven cases. The scaphid fracture was fixed by pins in eleven cases, by screws in four, and associated with a corticocancellous graft in five. The carpus was fixed in seven cases with scapholunate pins, with lunotriquetral pins in seven, and radiolunate pins in three.

Results: Mean score was 70±20% with mean flexion 50±17° and mean extension 54±20°. Grip force was 32/45±11 (Jamar). The thumb-index force was 14±5.1. Pain was negligible in 33% of the patients and was disabling in 17%. Climatic pain was reported by 50% of patients; 75% were able to resume their occupational activities. Radiographically we found osetonecrosis of the lunate (n=1), osteonecrosis of the proximal pole of the scaphoid (n=2), non-union of the scaphoid (n=3), radiocarpal osteoarthritis (n=4), SLAC (n=1) and SNAC (n=2).

Discussion: Our outcomes were slightly less favourable than those reported in the literature concerning joint motion. Conversely, for pain, duration of sick leave, and percentage of occupational reclassing, our results were the same as reported in the literature. The series shows that radiographic outcome was favourable with 13% radiocarpal osteoarthritis (38% for Herzberg in 2002 at 96 months. The stability of the scaphoid osteosynthesis remains the key to success (two nonunions for four single pin fixatons). A new analysis at longer follow-up would be interesting to determine the arthrogenic results.