[Conservative and Surgical Treatment for Distal Ulna Fractures Associated with Distal Radius Fractures].

PURPOSE OF STUDY

Fractures of the distal radius and distal ulna require anatomical reconstruction for good restoration of wrist and hand function. In this study we compared the results of conservative treatment with those of plate osteosynthesis management in distal ulna fractures of patients who had concomitant fractures of the distal radius indicated for plate osteosynthesis. Our objective was to specify indications for plate osteosynthesis of a distal ulna fracture in the case of an associated distal radius fracture.

MATERIAL AND METHODS

A total of 27 patients were evaluated. In 17 of them, distal radius fractures were treated by plate osteosynthesis and distal ulna fractures conservatively (CONS group). In 12 patients, both distal radius and distal ulna fractures were treated by plate osteosynthesis (SURG group). Osteosynthesis was carried out using an APTUS variable-angle locking system (Medartis, Basel, Switzerland). In two SURG group patients with distal radioulnar joint (DRUJ) instability, the radius and ulna in anatomical position were secured with two Kirschner wires.

RESULTS

Fracture union of the distal radius was achieved in all patients. Non-union of the distal ulna was recorded in one patient of each group. No secondary displacement of distal radius fragments during bone union was found in either group. Displacement of fragments during the healing of distal ulna fracture occurred in one (6.7%) patient of the CONS group. Out of the parameters evaluated, the restriction of motion below 80% of the original range in volar flexion, dorsal flection and supination was recorded in three CONS patients (20.0%) and two SURG patients (16.7%). No DRUJ instability was found. Intra-operative swelling preventing closure of surgical wounds was managed by secondary wound suture in one SURG patient (8.3%). There were no other complications.

DISCUSSION

Views vary on whether the distal ulna should be treated by plate osteosynthesis when, after distal radius fixation, its fracture managed by closed reduction heals well. A distal ulna plate often causes pain and has to be removed. The acute cases of DRUJ instability caused by comminuted distal ulna fracture can be treated by osteosynthesis of the distal ulna and two Kirschner wires inserted into the fracture site in an ulnar-to-radial direction. For chronic radioulnar instability, various methods involving free tendon grafts and dynamic tenodesis are used. Other options include the Sauvé-Kapandji procedure based on inducing artificial non-union of the distal ulna diaphysis and radioulnar arthrodesis; in our modification of this technique we use a single cancellous malleolar screw. In severely comminuted fractures of the distal ulna with injury to articular cartilage, ulnar head replacement can be indicated. CONCLUSIONS Distal ulna fractures can be treated conservatively if osteosynthesis of the distal radius in the anatomical position is achieved together with anatomical reduction of bone fragments of the distal ulna. When a distal radius fracture managed by osteosynthesis is not accompanied by anatomical reduction of distal ulna fragments, or the ulna is shorter or longer than the contralateral bone, an open reduction and stabilisation using an angle-stable locking plate, set at an adequate radius-toulna length ratio, is the method of choice.