Bi- and trimalleolar ankle fractures operated with nonrigid internal fixation.

The results of bi- and trimalleolar fractures treated with nonrigid internal fixation were analyzed in 134 patients. The fractures were of both pronation and supination type. The operative success was evaluated in terms of congruency as seen on the post-operative radiographs. The congruency was classified as either congruent, small, or grave displacement respectively. At follow-up evaluation, four variables were recorded: a linear analogue scale, an ankle score, range of motion, and presence of osteoarthritis. Fifty percent had congruent joints, 20% had small, and 30% had grave displacements. At follow-up examination those with congruent joints had significantly better function than those with displacements in all four variables. There were only minor differences between the two displacement groups. The nonrigid technique seems inadequate in retaining congruency of the unstable bi- and trimalleolar fractures. Congruency is the key to good prognosis. Even minor displacement significantly increases the risk of impending disability.