Nonunion of operatively treated capitellum and trochlear fractures.

PURPOSE: To test the hypothesis that comminuted fractures of the capitellum and trochlea with posterior comminution (Dubberley type 3B) have a greater risk of nonunion than other types of capitellum and trochlea fractures.

METHODS: We observed 30 patients with operatively treated fractures of the capitellum and trochlea for an average of 34 months (range, 12-75 mo). We compared 18 fractures with comminution of the capitellum and trochlea and posterior comminution (type 3B according to Dubberley and colleagues) with 12 fractures consisting of single large anterior fracture fragments with (6 patients; Dubberley type 2B) or without (6 patients; Dubberley type 2A) posterior comminution.

RESULTS: Of 18 patients, 8 with type 3B fractures were noted to have nonunion. No patients with type 2 fractures had a nonunion.

CONCLUSIONS: Fractures of the capitellum and trochlea are prone to nonunion when they create multiple articular fragments and there is posterior comminution (Dubberley type 3B).