Fig. 1 Volar tilt (left) was measured as the difference in subtracting the angle formed by lines A and B from 90 degrees. Radial height (right) was measured as the distance between lines D and E while ulnar variance (right) was measured as the difference between C and E.
Courtesy of Joey LaMartina II, MD

AAOS Now

Published 1/1/2014
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Maureen Leahy

Predicting Displacement After Closed Treatment of Distal Radius Fractures

Study finds that majority of reduction loss occurs within 6 weeks, continues for many months

The majority of displacement in distal radius fractures treated with closed reduction and casting occurs within the first 6 weeks of treatment and loss of reduction continues—although at a slower rate—for many months, according to data presented at the Orthopaedic Trauma Association annual meeting.

“Most surgeons immobilize these fractures for 4 to 6 weeks until the fracture is stable enough for a removable splint and range of motion. However, little data exist about when these fractures are most likely to change in alignment and when they ultimately stop moving,” said Joey LaMartina II, MD, of Boston University Medical Center.

Dr. LaMartina and his colleagues analyzed radial height, volar tilt, and ulnar variance in patients with a displaced distal radius fracture who received nonsurgical management to determine when the greatest displacement occurs and when the fracture reduction becomes stable.

Prospective analysis
The researchers prospectively screened 546 consecutive distal radius fracture patients treated at their institution between January 2005 and April 2011. In all, 168 fracture patients were treated nonsurgically to union and met the following inclusion criteria:

  • skeletally mature
  • minimum of 10 degrees of apex volar angulation (20 degrees from normal)
  • adequate radiographs—including a lateral view with 50 percent overlap of the radius and ulna distally—at presentation, postreduction, and follow-up

Distal radius fractures with associated ulnar metaphyseal fractures, partial articular injuries, open distal radius fractures, and fractures that went on to surgical treatment were excluded.

Patients were treated with closed reduction and casting and evaluated every other week for 6 to 8 weeks by an attending orthopaedic surgeon. Patients whose fracture position shifted within the first 2 weeks or who experienced loosening of the cast were recast. Radial height, volar tilt, and ulnar variance were measured on initial reduction and all follow-up radiographs (Fig. 1).

Results
Using regression analysis, functions for radial height, volar tilt, and ulnar variance were determined. Based on those functions, the researchers calculated the number of days when 50 percent, 75 percent, and 95 percent of the alignment was lost relative to one year, when complete healing is presumed.

“Because our primary interest was in patients with longer follow-up, we generated a regression curve for the 116 measurements in patients with more than 150 days of follow-up. To validate our findings, the analysis was repeated with all patients, regardless of length of follow-up,” Dr. LaMartina explained.

Fig. 1 Volar tilt (left) was measured as the difference in subtracting the angle formed by lines A and B from 90 degrees. Radial height (right) was measured as the distance between lines D and E while ulnar variance (right) was measured as the difference between C and E.
Courtesy of Joey LaMartina II, MD

The analysis showed that the majority of radial height, volar tilt, and ulnar variance is lost in the first 6 weeks after reduction, and all 168 patients had almost identical findings (Table 1).

“At 6 weeks, approximately 1 mm of radial height (64 percent), 4.5 degrees of volar tilt (64 percent), and 1.1. mm of ulnar variance (54 percent) are lost,” Dr. LaMartina said. “We also found that fracture position continues to shift for months after cast removal. However, the late shift averaged only 3 degrees and 1 mm.”

The authors acknowledge that the study did have limitations, namely the use of standard clinic radiographs. “Even though we saw small magnitudes of change after 6 weeks, there were some outliers with greater changes. Moreover, these radiographic changes may or may not correlate with function,” Dr. LaMartina added.

Despite these limitations, he noted, the study has important implications for orthopaedic surgeons who treat distal radius fractures. “Because loss of radial height, volar tilt, and ulnar variance have been implicated in long-term wrist dysfunction, this data is important in predicting both immediate and long-term radiographic outcomes for patients and may be important in early discussions regarding treatment,” Dr. LaMartina explained.

Dr. LaMartina’s coauthors of “When Do Distal Radius Fractures Most Likely Displace and When Do They Stop Moving: Long-term Follow-up of Closed Reduction and Casting” are Paul Tornetta III, MD, and Andrew Jawa, MD.

Disclosure information: Dr. Tornetta—Smith & Nephew; Wolters Kluwer Health - Lippincott Williams & Wilkins; Journal of Orthopaedic Trauma; Drs. LaMartina and Jawa—no conflicts.

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom Line

  • Distal radius fractures treated with closed reduction and casting may lose position over time.
  • Most of the displacement in radial height, volar tilt, and ulnar variance occurs in the first 6 weeks after reduction; however, fracture position continues to shift for many months.
  • This information is important in predicting both immediate and long-term radiographic outcomes for patients, and may be important in early discussions regarding treatment.
  • The overall change after cast removal was only 3 degrees of tilt and 1 mm of displacement.