Malunion of the distal radius is one of the most common complications of distal radius fractures. Rates of malunion in these fractures appear to be higher in those injuries that are treated nonoperatively (1). The typical distal radius malunion involves loss of radial height, radial inclination, and volar tilt. Although in elderly, low-demand patients, malunion can be well tolerated, studies have shown that malunion alters the normal mechanics at both the radiocarpal and the distal radioulnar joint (2,3).

General radiographic indications for operative intervention include dorsal tilt of 20 degrees or more, articular step-off of 2 mm or greater, radial shortening of 2 mm or greater, or subluxation of the radiocarpal or radioulnar joint (4). However, there are no absolute indications for operation. The activity level of the patient, severity of symptoms, and degree of functional impairment must be taken into consideration before embarking on a course of operative treatment. The patient’s comorbidities and risks of surgery must also be carefully weighed. Furthermore, age itself is not an absolute indication or contraindication, since active seniors in their 70s may have significant disability from a malunion whereas a sedentary 50-year-old with several other comorbidities may have very little functional impairment. Common symptoms of malunion include pain, decreased range of motion (particularly with pronation and supination), arthritis, instability, and deformity.

Timing of treatment of distal radius malunion is also somewhat subjective. Although good results for correction of malunions can be obtained after bony consolidation is achieved, the surgery is much technically easier in the first couple of months when the fracture site is still visible (5). However, patients at this point in treatment may still be asymptomatic because they have not returned to their full activities. Regardless, early operative correction may be indicated in a younger or active patient who meets the radiographic criteria for malunion and will predictably go on to be symptomatic (4).

The major contraindication to distal radius osteotomy for malunion is the presence of advanced radiocarpal or intercarpal arthritis. Advanced degenerative changes are better treated with some type
of salvage operation. In addition, patients with fixed carpal malalignment are also better served with a salvage procedure. Low-demand patients or patients who are unable to comply with the postoperative regimen are also poor candidates. The procedure may be delayed in patients who are medically unstable or unable to tolerate anesthesia until their risk of surgery is improved. Finally, the results of distal radius osteotomy in patients whose primary complaint is pain rather than limitation of function are less predictable (4).

Take a detailed history to ascertain the mechanism of injury and any significant comorbidities. Note any prior treatment, including attempts at closed reduction and casting. Document the patient’s smoking history or significant drug or alcohol use. The patient should attempt to quit or cut back before embarking on treatment. In addition, careful documentation of the patient’s current symptoms is necessary, paying particular attention to disability and difficulty with activities of daily living.

Physical examination includes careful inspection of the skin and soft tissues. A meticulous neurologic exam as well as examination of tendon function is critical in knowing whether other injuries need to be addressed surgically in addition to the bony deformity. Finally, measure and record active and passive motion in pronation/supination, flexion/extension, and radial/ulnar deviation for both the injured and normal side. Also record grip strength.

Radiographic evaluation should include posteroanterior, lateral, and oblique films to determine the extent of deformity (Fig. 11-1). Computed tomography scans are not routinely obtained but may be useful to determine the amount of bony healing or the degree of intercarpal malalignment. Magnetic resonance imaging is also not routinely necessary but may be useful in assessing arthritic changes and ligamentous integrity. Radiographs of the uninjured side are also useful to determine the amount of ulnar variance, radial inclination, and volar tilt. This side can then be used as a template for the osteotomy.

Tracing paper or a computer program is useful in templating the length, angle, size, and approach for the osteotomy. Once these factors are determined, the need for bone graft can be ascertained. The need for ulnar-sided procedures can also be assessed based on the quality and integrity of the distal radioulnar joint. Internal plating has been the standard for stabilization of distal radius malunions following osteotomy. Volar fixed-angle plating in particular has been successfully used for both dorsal and volar deformities. Furthermore, because the majority of orthopaedists are now comfortable with its use, it has become the standard of fixation in treating these deformities.

Determining the age of the injury and extent of bony union are also critical in preoperative planning. Nascent malunions, as described by Jupiter and Ring as being around 8 weeks or less in age, do not have bony union (5). Thus, the fracture site is still visible on routine radiographs and can be “taken down” and used as the site of the osteotomy. In addition, structural autograft is often not needed, and a combination of local bone graft from the fracture site as well as allograft can be used. Mature malunions require more preoperative planning to determine the optimum site of osteotomy. These may need structural autograft from the iliac crest to support correction of the osteotomy. However, given the excellent rigidity of currently available volar fixed-angle plates, most osteotomies can be supported with cancellous bone, and structural auto-graft is rarely a necessity.