In the office, the third dorsal compartment was aspirated after skin preparation with povidone-iodine. The Lister tubercle is typically palpable along the dorsal distal radius and is aligned with the cleft between the index and long fingers. Aspiration with an 18-gauge needle is performed just ulnar to the Lister tubercle in the EPL sheath, and hematoma is evacuated. The patient is then placed back into a long-arm cast or splint per the clinical situation.
Results
Patient age ranged from 17 to 81 years. Eight (1 male, 7 female) patients sustained an EPL rupture a mean of 46 days after initial trauma (range, 21-118 days). Two patients were treated with a prophylactic EPL transposition secondary to clinically apparent impending rupture, and 4 were treated with prophylactic needle decompression of the third compartment. Ruptures were treated with EIP-to-EPL transfers.
As in other studies, each patient’s radiographs showed a nondisplaced fracture and a transverse fracture line. Six patients also had a longitudinal, intra-articular fracture line that exited in a common spot between the scaphoid and the lunate facet.
Results in our cadaveric model were consistent with those in in vitro decompression of the third dorsal compartment (Table 1). In the cadaver model, mean (SD) initial third dorsal compartment pressure was 0.77 (0.88) mm Hg. Mean (SD) pressure after osteotomy and Hypaque injection was 25.5 (11.11) mm Hg. After simulated therapeutic aspiration, mean (SD) pressure decreased to 1.61 (1.40) mm Hg. Mean change in pressure from after injection to after aspiration was 23.89 mm Hg (P = .000388) (Table 2).
Information from other studies and from Dr. Lourie’s experience was used to identify patients at significant risk for EPL ruptures in association with distal radius fractures. Four patients in Dr. Lourie’s practice between 2004 and 2009 had characteristic findings, including a nondisplaced distal radius fracture, localized swelling over the third dorsal compartment, and pain with resisted active EPL extension. Prophylactic aspiration and hematoma evacuation were performed in this series, yielding a mean hematoma amount of 2 mL (Table 3).
For all 4 patients, aspirations were performed within 2 weeks of injury. Subjectively, these patients described almost immediate pain relief and less discomfort with EPL motion after aspiration. Three of the 4 reported sustained pain relief on close follow-up 7 and 14 days after aspiration. The fourth patient continued to have pain over the third dorsal compartment, though she described it as significantly improved. Her initial fracture contained about 50% dorsal comminution, and she began to have a significant callus response. After 2 months of continued symptoms, and out of concern about consequences of an impending rupture, open decompression and transposition of the EPL were performed. In follow-up over 29 months, this patient continued to do well and had full EPL function. The 3 patients treated with aspiration alone have not had an EPL rupture (range of follow-up, 29-89 months).
Discussion
Distal radius fractures are very common injuries, and treating physicians must attempt to prevent possible complications. EPL tendon ruptures continue to be rare events (incidence, <1%) in association with distal radius fractures. Although statistics vary, studies have found a higher incidence in nondisplaced (vs displaced) distal radius fractures.5,7,10 Ruptures in nondisplaced fractures occur within 2 weeks to 3 years after injury but typically an average of 6 weeks after injury.2,4,7-9 Prodromal symptoms often include tenderness and swelling around the dorsal distal radius region around the Lister tubercle.7,11,12 Patients may complain of pain with active thumb extension or passive thumb range of motion.11 Rupture is indicated by an inability to actively extend the thumb.
Studies have shown that the tendon rupture site is around the Lister tubercle.7 No single cause for EPL ruptures has been confirmed, and the etiology is likely a mix of factors in relation to the clinical situation. Two theories have been espoused for the relation between EPL ruptures and distal radius fractures. The mechanical theory involves a prominent spicule of bone abrading the tendon and subsequently causing rupture.5,9 This seems less likely for nondisplaced fractures. The vascular theory centers on a watershed region of the EPL tendon around the Lister tubercle. Studies have found microangiographic evidence of a 5-mm portion of tendon around the Lister tubercle that has no mesotenon and poor vascularity.7,9 The tendon in this section may be reliant on synovial diffusion for nutrition,7 but hematoma may displace synovial fluid, interfering with tendon nutrition.
Researchers have studied the third dorsal compartment in patients with impending or established ruptures. In a series by Hirasawa and colleagues,7 11 patients with a nondisplaced fracture and a tendon rupture had an intact retinaculum and smooth bony surfaces on the dorsal radius. Periosteal hypertrophy and narrowing of the third compartment were noted. In another series, Helal and colleagues5 reported on 16 patients (nondisplaced and displaced fractures) who had possible EPL ruptures over a 4-year period. In all cases, the extensor retinaculum was intact. Likewise, the 7 patients with EPL ruptures in a series by Bonatz and colleagues4 had an intact extensor retinaculum. On exploration, Bunata10 noted fluid collections, including hematomas, within the sheath, as well as a lack of bony prominences. Simpson12 explored 2 cases of blunt trauma, no fracture, and subsequent EPL rupture. Clinically these 2 patients had swelling in the region of the Lister tubercle, and surgically they were found to have a distended, blood-filled sheath. These ruptures may correlate with nondisplaced distal radius fractures and provide further evidence supporting the vascular theory of ruptures. The combination of intact compartment and volume overload presents a situation akin to compartment syndrome. Acute compartment decompression with needle evacuation would theoretically relieve the vascular insult.