External fixators, both spanning (crossing the radiocarpal joint) and nonspanning, have been and continue to be used successfully in the treatment of distal radius fractures. Of late, the preferred technique for the reduction and stabilization of displaced distal radius fractures is the application of a volar locking plate. Similarly, new low-profile precontoured locking plates have been designed to buttress displaced facets of the radial and dorsal columns of the distal radius. Despite this popular shift in therapeutics, recent randomized clinical trials^1,2,3 have demonstrated equivalent successful patient outcomes with either technique if equivalent fracture reduction is obtained.

In short, it is all about the reduction. Certainly, external fixation has traditionally been useful in open fractures with significant soft-tissue injury, and as an adjunct to neutralize deforming muscle forces associated with complex fractures despite internal fixation with locking plates. Some of these fractures involve shearing of the volar radial rim, which disrupts the capsular ligament stability of the carpus. These fractures are very distal and comprise a small amount of the distal radius volar rim precluding the application of traditional volar locking plates. Also, the articular impaction fracture, or die punch injury of either the dorsal or palmar articular facet, is difficult to reduce with plating alone and is uniquely suited to a limited open elevation of the articular segment followed by a spanning external fixation frame to protect against re-displacement. The advent of popularity to use spanning dorsal plates (internal external fixator) for highly unstable distal radius fracture is but another way to provide the stability of a spanning external fixation frame. The advantage of the frame is the ease of removal and avoidance of the expense and time for a formal second surgery to remove the plate.

Even with the wave of enthusiasm of distal radial plating, the option of combining internal fixation and external fixation is logical and will protect against late loss of reduction because of poor bone quality, despite modern locking screw technology. The precept has been extended to the use of the dorsal spanning plate, which is no more than a spanning external fixator which is buried. The external fixator can be easily removed after bony healing in the office without a second surgical intervention. Geographic variation in surgical practice in terms of training, resources, and economics means that this treatment remains a useful one globally.

External fixation of distal radius fractures can consist of spanning and nonspanning constructs. More commonly, spanning external fixation is an adjunctive technique used to help reduce and maintain a reduction that is obtained by manipulative reduction and often includes Kirschner wire (K-wire) fixation, via either a transradial styloid or the Kapandji intrafocal technique. Arthroscopic-assisted articular facet reduction can be combined with spanning external fixation, as can the application of fragment-specific mini-plates. In high kinetic-energy fractures or in severe cases of osteopenia, the metaphyseal void created by impaction requires filling with either allograft or bone cement substitutes.⁴ This is necessary because the removal of fixators typically at 6 to 8 weeks may not allow for sufficient subchondral healing to resist remodeling changes over the ensuing 3 to 6 months, which can lead to articular facet subsidence. In short, traction alone will not in most instances adequately reduce articular fractures. Spanning fixators using ligamentotaxis alone cannot restore physiologic volar tilt due to symmetric tensioning of the dorsal and palmar capsular ligaments. A frequent but unsuccessful tactic is to overdistract to achieve reduction. Spanning fixators with excessive traction will not reduce displaced and translated articular fragments and can actually reduce wrist
mobility, create metacarpophalangeal stiffness, and incite causalgia or complex regional pain syndrome.^5,6,7

A nonspanning external fixator can be a powerful tool to reduce articular facets and allow restoration of a more normal distal radial architecture. It does require an adequate distal radial segment of approximately 10 mm and adequate bone quality to place pins in a subchondral position, which will allow “joystick” reduction and then frame assembly to lock in the position without subsequent loss of fixation. It can also be linked to spanning pins in the second metacarpal shaft so that they can be sequentially deconstructed. Non-joint-spanning external fixation is for relatively simpler articular and nonarticular fractures of the distal radius.

This chapter will focus on the application of spanning external fixators and touch on the nuances of the use of nonspanning fixators.

AP, lateral, and oblique radiographs are obtained to evaluate the wrist before (Figure 1, A and B) and after reduction. Assessment of both of these series is extremely valuable because it allows pattern identification and recognition of articular facet displacement, thereby influencing the surgical approach and implant choice. Radiographs of the uninjured contralateral wrist can be helpful for determining the patient’s normal anatomy as an aid to evaluating the quality of reduction. Traction radiographs of the wrist are essential to understand the complexity of fracture fragment displacement and in alerting the surgeon to possible capsuloligamentous injuries in the carpus such as scapholunate ligament injury. These examinations are sometimes performed in the operating room after anesthesia is administered. Combined wrist and forearm patterns, seen in Galeazzi, Monteggia, or Essex-Lopresti injuries, must always be considered. CT scans of the distal radius can be helpful to further delineate fragment displacement, but the cost and the fact that they are performed without traction often limit their utility (Figure 1, C through E).

VIDEO 42.1 External Fixation of Distal Radius Fractures. Jonathan R. Danoff, MD; Michael V. Birman, MD; Neil J. White, MD, FRCS; Melvin P. Rosenwasser, MD (7 min)