Healio
Healio
September 11, 2009
2 min read
Save

CT scan performed 4 weeks after treatment of undisplaced scaphoid fractures can help orthopedists predict outcome

SAN FRANCISCO — Orthopedists can predict the outcomes of undisplaced scaphoid fractures treated nonoperatively with reasonable accuracy by assessing fracture union on a CT scan done at 4 weeks, according to a study presented here.

“Studies which have used CT to define displacement have reported very high rates of union for undisplaced fractures with nonoperative treatment,” Tim R.C. Davis, FRCS, said at the Combined Annual Meeting of the American Society for Surgery of the Hand and the American Society of Hand Therapies, here.

“This led us to think: Are undisplaced scaphoid fractures a benign injury we’ve been overtreating for years because we’ve been unable to accurately distinguish them from displaced fractures because CT hasn't been available? And if that’s the case, do they really need 6 weeks or more in plaster to unite?”

Study parameters

Davis and his colleagues from Nottingham, England, compared 59 scaphoid fractures in 57 patients, and all fractures underwent CT scans at 4 weeks. The CT scans demonstrated that 43 (73%) of the fractures were undisplaced.

Two independent observers assessed these 43 fractures, with the reproducibility of their assessments being determined through Cohen’s cappa values. There was a mean of 112 days radiographic follow-up for all of the fractures.

The duration of nonoperative treatment was determined by the treating surgeon. Twenty-six fractures were mobilized at 4 weeks, two at 5 weeks, four at 6 weeks, one at 7 weeks, and 11 at 8 weeks.

CT scan proves effective

According to the study, a comparison of the two observers’ assessments of union revealed good reproducibility. Thirty-seven of the 43 undisplaced fractures were classed as “united” on their respective week 4 CT scans, and all 37 of these fractures were united, despite 25 of those fractures only being immobilized for 4 weeks.

Davis also noted that only one of the six undisplaced fractures classed as “not yet united” on the week-4 CT scan failed to unite. The week-4 CT scan had 88% sensitivity, 100% specificity, and 100% positive and 17% negative predictive values in predicting the outcome of the undisplaced fractures.

He said the 4-week CT scan of the one undisplaced fracture that developed a nonunion clearly showed that the fracture had not yet united.

“A 4-week scan does predict union. If it looks united, we think the fracture will unite, but it is not so good at predicting nonunion," Davis said.

Moderator question

Moderator Scott W. Wolfe, MD, commended the researchers’ efforts.

“This paper certainly outlines the difficulty in generalizing our treatment of the scaphoid and confirms that there is a subset of nondisplaced fractures that have a likelihood to heal within 4 weeks,” he said. Still, “This study was performed 6 years ago. Have you changed your management? Do you obtain a CT scan on all of your scaphoid fractures, and is 4 weeks still your optimal period of time?”

“We still do a CT scan at 4 weeks, but we’re contemplating just doing one initially and treating according to [the scan results],” Davis said. “If we can just distinguish them as displaced or undisplaced initially and treat them in plaster for 4 weeks, that would be OK.”

Reference: