88 Distal Radius Fracture Nonunion
88.1 Patient History Leading to the Specific Problem
A 78-year-old woman suffered a left distal radius fracture 25 months ago. She was initially treated with cast immobilization. She has noticed progressive deformity in the left wrist, which is now flexed and radially deviated (▶Fig. 88.1a). She had pain and crepitus over the distal radius, 5% grip strength compared to the right hand, and limited ability to rotate, flex, or extend the wrist. Radiographs showed an atrophic, ununited, extra-articular fracture of the distal radius with volar and radial angulation (▶Fig. 88.1b).
88.2 Anatomic Description of the Patient’s Current Status
This patient has distal radius fracture nonunion and a deformity consistent with posttraumatic radial club hand. Historically, nonunion of the distal fracture is quite rare comprising 0.0003 to 0.2% of distal radius fractures. Injury factors associated with nonunion of long bones are open fracture, high-energy fracture, soft-tissue interposition, infection, and pathologic fracture. Concomitant ulna fracture may also increase the risk of nonunion in the radius due to a more global injury associated with greater forearm instability. Patient comorbidities, tobacco use, and alcoholism may additionally affect healing. Potential iatrogenic causes for nonunion include inadequate immobilization, over-distraction with external fixation, devascularization of bone fragments during surgery, inadequate reduction or fixation, and failure to bone graft large comminuted defects.
Most individuals achieve bone union by 3 months. A surgeon should suspect distal radius nonunion if continued pain and progressive deformity in the wrist are observed. Failure of the bone to achieve union by 4 months is considered a delayed union, while failure at 6 months is considered a nonunion. Stable, fibrous nonunions may be asymptomatic but have persistent fracture lines on radiography. Unstable, synovial nonunions are often painful, unstable, and associated with soft-tissue contracture, weakness, and deformity; radiographs show bone loss and atrophy. Unstable or symptomatic nonunions may be considered for surgical correction.
88.3 Recommended Solution to the Problem
Given the significant limitation of function, nonoperative management is only reserved for ill or elderly patients. Some surgeons have recommended wrist arthrodesis, especially if less than 5 mm of subchondral bone is supporting the lunate facet in the distal fragment. However, Prommersberger et al reported encouraging outcomes irrespective of size. While a smaller distal fragment certainly increases the technical difficulty of the surgery, the radial column often has sufficient mass, and purchase can be enhanced by angular stable implants and orthogonal plates. As the radiocarpal and midcarpal joints are often undisturbed, wrist motion can be preserved by restoring the radius; we therefore recommend reserving wrist arthrodesis for lower demand patients or failed nonunion surgery.
Presurgical planning should include orthogonal radiographs at minimum. Stress views in flexion and extension may show motion of the fragments at the fracture site. Additionally, a CT scan can be helpful for diagnosis and presurgical planning. The size and quality of the bone fragments should also be noted. The surgeon should note the disturbance in normal radiographic parameters of radial height, inclination, volar tilt, and ulnar variance, and plan realignment by templating from normal radiographs of the contralateral wrist. An extensile approach with soft-tissue releases should be anticipated. A small skeletal distractor may be required for excessive shortening. Lengthening of the radius may be performed as a one- or two-staged procedure. Bone loss should also be anticipated and may be replaced with graft using iliac crest or the resected distal ulna. Surgeons may decide to use a variety of fixation strategies, which include external fixation, volar plating, dorsal plating, orthogonal plating, or bridge plating. Currently, our preferred fixation method is orthogonal plating with fixed angle implants. After fixation, attention should be turned to the ulna and distal radioulnar joint (DRUJ). Stability from lengthening and aligning the radius is possible but often difficult. Options for addressing the ulna most commonly include ulnar-shortening osteotomy, hemiresection/interposition (Bowers’ arthroplasty), and resection arthroplasty (Darrach’s procedure).
