Distal radius fractures are among the most common upper extremity injuries. A Swedish study noted that 75% of forearm fractures involve the distal radius.1 Extensor pollicis longus (EPL) ruptures are a well-documented complication (0.3% incidence2) of distal radius fractures.
The first description of EPL ruptures is attributed to Duplay in 1876 and was termed drummer boy’s palsy.3 Spontaneous EPL ruptures are often described in the setting of acute or chronic tenosynovitis.4,5 Beginning in the early 1930s, multiple case reports began to connect distal radius fractures with EPL ruptures.6 Although EPL ruptures are rare, their consequences are substantial and typically necessitate reconstructive procedures. Extensor indicis proprius (EIP)-to-EPL tendon transfer has become a common surgical treatment for this complication. Increasing our knowledge of several characteristics associated with this complication may help clinically in preventing EPL ruptures.
Multiple studies have indicated that EPL ruptures occur more often in nondisplaced fractures and often occur between 6 and 8 weeks after injury.2,5,7,8 Several factors are implicated in the etiology of EPL ruptures in distal radius fractures. The classic 1979 study by Engkvist and Lundborg9 showed that the EPL tendon has an area of poor vascularity around the Lister tubercle. Explorations of nondisplaced distal radius fractures have shown an intact extensor retinaculum that allows the tendon to continue to travel through an enclosed space.4,5,7 In the setting of distal radius fracture, hematoma may contribute to tendon ruptures secondary to increased pressure within an intact third dorsal compartment, which further compromises vascularity in this region of the EPL tendon.
Recognition and prevention of an impending EPL rupture may help avoid the significant consequences of this complication. Decompression and release of the third dorsal compartment have been described as constituting a prophylactic surgical option.10,11 Early thumb range of motion is also advocated to help prevent EPL rupture.9 However, results reported in the literature are inconclusive as to the effectiveness of these or indeed any preventive procedures. Dr. Lourie uses a novel technique that involves aspiration of the third dorsal compartment in patients with clinical symptoms associated with impending EPL rupture. Needle decompression, a less invasive option, can be quickly performed in an office, and it is hypothesized that removal of the hematoma may prevent EPL ruptures.
In the present study, we retrospectively reviewed Dr. Lourie’s records of patients with EPL ruptures in association with distal radius fractures to help delineate which radiographic and clinical characteristics identify patients at risk for these ruptures. A cadaveric model of a nondisplaced distal radius fracture was then created in order to simulate a change in third compartment pressures before and after needle decompression. We present preliminary outcomes on a case series of 4 patients who underwent aspiration of the third compartment and who were thought to be at risk for EPL rupture.
Materials and Methods
Institutional review board approval was obtained for this study. From Dr. Lourie’s records, 19 patients treated between 1998 and 2009 were identified as having confirmed or clinically impending EPL ruptures in association with nonoperative treatment of distal radius fractures. Prodromal symptoms that were used to diagnose impending EPL ruptures included pain with resisted active EPL extension, pain with passive flexion of the thumb interphalangeal joint, and localized swelling over the third dorsal compartment of the wrist.5,7,10,12 Eleven patients had complete radiographs, which were reviewed for radiographic characteristics. Posteroanterior (PA) and lateral radiographs of the injured wrist were reviewed. On the PA radiographs, fraction location was measured from the tip of the radial styloid using a line perpendicular to the radial shaft. Fractures were also evaluated for displacement and intra-articular involvement.
A cadaveric model was developed to evaluate compartment pressures in the EPL sheath in a simulated distal radius fracture. Six fresh-frozen cadaveric forearms were used after being thawed at room temperature. The cadavers were radiographically evaluated to determine that there was no evidence of prior fracture. A Stryker compartment pressure monitoring system (Stryker, Kalamazoo, Michigan) was used to take initial pressure readings in the third dorsal compartment slightly ulnar to the Lister tubercle (preinjection readings). A limited volar approach was then created. Under fluoroscopy, a half-inch osteotome was used to make an extra-articular fracture line in the distal radius, in the region of the Lister tubercle. The osteotomy was a mean of 1.2 cm from the distal aspect of the radius. The osteotomy site was then injected from the volar aspect with 5 mL of radiopaque (Hypaque) dye (Figure 1). Fluid extravasation into the third dorsal compartment was visualized under fluoroscopy (Figures 2–4). The monitor was then reinserted into the EPL sheath, and once again pressures were measured (postinjection readings). An 18-gauge needle was then used to aspirate the compartment just ulnar to the Lister tubercle. Compartment pressures were measured a final time (postaspiration readings). For all readings, 3 pressure measurements were recorded and then averaged. Pressure measurements were compared using t test.
