[Pseudarthroses after distal radius fractures. What is the role of the distal radioulnar joint?].

Non-union following distal radial fracture is extremely rare. Therefore, the patterns are not completely understood. Recently, it was suggested that an associated distal ulna shaft fracture increases the risk to develop a non-union for comminuted fractures of the distal radius. The purpose of this study was to review our 15 cases with this condition to investigate the role of an associated distal ulna shaft fracture and/or an associated lesion of the distal radioulnar joint. The second goal was to evaluate the success of the surgical treatment in relation to the extent of the metaphyseal subchondral bone supporting the articular surface distal to the site of the non-union. We reviewed our 15 cases which were operated on for non-union of the distal radius since 1992. In all cases, the radiographs could be reviewed. Twelve patients could actually be re-examined. The investigated criteria were: initial, pre- and postoperative X-ray findings, other medical conditions, range of motion, grip strength, and pain relief. Clinical outcome was evaluated using the DASH-questionnaire. According to the AO classification system, there were two type A3 and 13 type C3 fractures. There were seven associated distal ulna fractures. The distal radioulnar joint was involved in twelve cases. The other medical conditions in the patients with non-union after distal radial fracture included allergy, hypothyroidism, diabetes mellitus, peripheral neuropathy, and bronchial asthma. Four patients were tobacco smokers. Only one patient was initially treated non-operatively. In all cases, the distal radius was restored preserving wrist motion. Bony union was achieved in 14 cases. The range of motion has improved in all planes. Grip strength increased but still remained over 50% below the level of the opposite side. Postoperatively, the majority of patients was pain free. In four cases, complications were seen postoperatively. Three of these patients had less than 6 mm of metaphyseal subchondral bone beneath the articular surface. Three of the four patients were tobacco smokers. Inadequate treatment of a comminuted distal radial fracture associated with a special local situation--such as an additional distal ulna shaft fracture and/or an associated lesion of the distal radioulnar joint--combined with a general medical condition, adversely affects fracture healing, increasing the risk for non-union. From the review of the records of these 15 cases, we recommend that non-union with more than 5 mm of subchondral bone supporting the articular surface distal to the non-union site undergo reconstruction of the radius. Non-union with less than 5 mm subchondral bone supporting the articular surface requires an individual decision. A good bone stock and stable fixation allows for reconstruction of the radius, otherwise wrist fusion is a useful salvage procedure.