Arthroscopy best for scaphoid fracture assessment

By Lynda Williams, Senior medwireNews Reporter

Research shows that radiographs and computed tomography (CT) cannot replace arthroscopy for the diagnosis of unstable and displaced fractures of the scaphoid wrist.

Compared with intraoperative arthroscopy under 5 kg of traction, radiographs of 44 patients were just 45% sensitive, 95% specific, and 70% accurate for the detection of displacement, with corresponding values of 34%, 93%, and 55% for detection of intraoperative instability.

Although CT imaging was significantly better than radiography, it remained poor compared with arthroscopy, being 77% sensitive, 86% specific, and 82% accurate for the detection of displacement, and 62% sensitive, 87% specific, and 70% accurate for intraoperative instability.

When assuming a 10% prevalence of displacement and instability, the positive and negative predictive values for displacement using radiographs were 53% and 94%, and for instability 36% and 34%. For CT, the positive and negative predictive values for displacement were 39% and 97%, and for instability 34% and 95%, respectively.

"We conclude that radiographs or CT scans do not accurately diagnose intraoperative fracture displacement and instability of acute scaphoid waist fractures," report David Ring (Massachusetts General Hospital, Boston, USA) and co-workers.

"We do not believe that the results of this study should alter management," they write in the US edition of the Journal of the Bone and Joint Surgery.

Preoperative images were examined for 44 patients who underwent arthroscopy-assisted surgery for scaphoid wrist fracture between 2004 and 2010, an average of 9 days after injury.

Arthroscopy revealed 22 displaced fractures, all unstable, as well as 22 nondisplaced fractures, seven of which were unstable. Displacement was demonstrated by radiography in 25% of patients and by CT in 45% of patients.

While the results show that arthroscopy and CT are significantly better than radiography for assessing the likelihood of displacement and instability, the team comments: "We do not know if instability of a scaphoid fracture that is not seen to be displaced on radiographs is associated with adverse outcomes, nor do we know if routine CT or arthroscopy improves management.

"Fracture displacement is a known risk factor for nonunion, but additional research is necessary to determine the relationship between scaphoid fracture instability and nonunion."

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