Indications

The ideal candidate for low-profile dorsal plating is a patient with a multifragmented dorsally displaced fracture of the distal radius with dorsal bony defects, due to a high-velocity injury or the presence of osteoporosis. The indications include unstable fractures that have previously undergone closed reduction and splinting with unsuccessful reduction or loss of reduction. This includes extra-articular fractures (AO type A), intra-articular shear fractures (AO type B), and comminuted intra-articular fractures with metaphyseal comminution (AO type C). Some authors use the criteria of more than 20 degrees of dorsal angulation, radial shortening of more than 2 mm, or articular incongruity between 1 and 2 mm.⁶ The age range of patients for the procedure encompasses adolescents at the age of closure of the epiphyses to those in their nineties. It is often better to wait 5 to 7 days after injury to treat these fractures if there is no neurologic or vascular compromise. The reasons are better visualization of the fracture fragments, stabilization of health situations, decrease in the edema of the wrist and fingers, and better understanding of the procedure by patients and their families. We have used the dorsal plates in all types of fractures of the distal radius, including complex intra-articular multifragmented fractures, classified as C1, C2, and C3 by the AO classification system. In C3.3 fractures there might be a call for additional stabilization of the radius shaft fracture component, and we obtain reduction with extra screws taken from the distal radius set or an occasional Kirshner wire.

Contraindications

The only absolute contraindication to dorsal fixation is a distal radius fracture with a large volarly displaced fragment, especially one with minimal dorsal defects. In that case the volar approach is clearly indicated. Relative contraindications have to do with the health status of the patient, which can commonly be corrected during the 7- to 10-day waiting period. Anticoagulation in the elderly always presents a challenge if the patient is on Coumadin or other drugs, so an internal medicine, cardiology, or neurology consultation should be obtained to manage those situations.

Surgical Technique

Under general or brachial block anesthesia, the forearm is prepped and draped to the elbow area. A fluoroscopy preliminary film is obtained to confirm the deformities and the initial impressions. Following that, traction is applied to the index and ring fingers by Chinese finger traps with cords that are attached to a traction apparatus clamped to the operating-hand-procedure side table (Schlein Hand Positioner with rail attachment; Allen Medical Systems, Acton, MA) (Fig. 10-1). In case of doubt and in severe multifragmented fractures, the fluoroscopy film is repeated after traction has been applied. This is a very useful maneuver because in some situations the real severity of the comminution is revealed in this post-traction film rather than in the resting position.

FIGURE 10-1 Setup for open reduction of distal radius fractures with traction apparatus in place.

Under tourniquet control, a 5- to 6-cm dorsal longitudinal incision is made spanning the wrist joint and the distal forearm and deepened to the extensor retinaculum. The third dorsal space is incised obliquely following the direction of the extensor pollicis longus (EPL) tendon (Fig. 10-2). A hematoma is often present in the third dorsal space, and the identification of the tendon direction is facilitated by the presence of blood. At this point, we also open the second dorsal space longitudinally, exposing the extensor carpi radialis longus and brevis and freeing the tubercle of Lister. One of the interesting findings in severely comminuted fractures is that the EPL tendon can be caught between the displaced fracture fragments, and one has to extricate the tendon from the fragments (Fig. 10-3). In those cases, immediate visualization of the tendon is not easy and the surgeon might have to look for the tendon more distally and follow it to the fracture site. That happens in 2% of cases, in our empirical observation, but it is significant because traction applied to the hand and wrist will push the tendon farther into the separation between the fragments, making the reduction of the fracture impossible prior to dissection and extraction of the tendon. This situation would be impossible to recognize if such a fracture were being treated using the volar approach.

FIGURE 10-2 Exposure of the fracture through incision of the third dorsal space following the tendon of the extensor pollicis longus (epl).

FIGURE 10-3 Tendon of the extensor pollicis longus (epl) caught between fracture fragments (Fragment) in a severely comminuted, dorsally displaced fracture of the distal radius.

If the radial fracture fragment is translated toward the radial side and it involves a large portion of the radius styloid, it may not be reducible by traction alone. In these situations, we perform a tenotomy of the brachioradialis tendon as it inserts into the displaced fragment. The first dorsal space tunnel is incised and the contents are exposed. At the floor of that space, one can encounter the tendon of the brachioradialis, which is separate from the extensor pollicis brevis and the abductor pollicis longus.¹⁰ The brachioradialis tendon is tenotomized transversely, which greatly facilitates the reduction maneuvers for that fragment (Fig. 10-4).

FIGURE 10-4 Tenotomy of the brachioradialis tendon (BR) exposed through the first dorsal space.

The dorsal capsule is kept intact if at all possible. It is opened only in the rare instances in which there is a loose dorsal piece of the distal radius that has sheared off the articular surface, and we deem it important to the stability and congruity of the joint. In those cases we use an extender provided in the Locon-T set to capture the fragment.

In sequence, a wide periosteal elevator is used to elevate the periosteum together with the floor of the fourth dorsal space, therefore avoiding entering the space and exposing the finger extensor tendons. With that maneuver, the fracture is completely exposed. Sometimes fragments are still not visualized well enough and they have to be dissected further with a scalpel. Lister’s tubercle can be very prominent, and when that is the case, a rongeur is used to remove the dorsal part of the tubercle. A potential pitfall here is that in an osteopenic patient with multiple fragmentations, it is possible to remove one of the fragments together with the part of the tubercle that is being intentionally removed. Caution and a very shallow resection are strongly advised.

Usually in an elderly patient there is a large bone defect in the dorsal aspect of the radius (Fig. 10-5). For many years now, we have been using iliac crest bone allograft chips previously reconstituted in saline to fill this void (Fig. 10-6). The bone chips are excellent in this situation because they provide internal support and augment the bone stock, preventing collapse of the distal fragments.