Abstract
Background
Scaphoid fracture malunion with flexion and shortening results in the ‘humpback deformity’. This is thought to be associated with poor clinical results when assessed with the lateral intra-scaphoid angle and the Green and O'Brien wrist evaluation scale. This method of deformity measurement is now considered unreliable and the functional score has not been validated in the setting of scaphoid fractures.
Aims & objectives
To assess the outcome of scaphoid malunion at one year using the height to length ratio, a reliable measure of deformity, and the Patient Evaluation Measure (PEM), a functional assessment validated specifically for scaphoid fracture outcome.
Material & methods
Forty-two consecutive patients with a united scaphoid fracture were prospectively evaluated one year following injury. All had been treated in a below elbow colles plaster for up to 12 weeks. Fracture union was confirmed at 12-18 weeks post-injury with longitudinal CT scans. Scaphoid malunion was quantified with the height to length ratio measured on CT images by two observers. A blind clinical assessment was made and all patients completed the PEM questionnaire. The group consisted of 38 males and 4 females with a mean age of 31 years at the time of injury.
Results
23 out of 42 patients were judged to have scaphoid malunion. Grip strength, range of motion and PEM scores were not significantly different between the malunited fractures and those fractures that united without deformity (Grip Strength: 95% vs. 100% of the normal side; ROM: 98% vs. 99% and PEM: 7% vs. 10% respectively, p>0.066).
Conclusions
We found scaphoid fractures that had united with a humpback deformity resulted in a 5% reduction in hand grip strength, but no significant reduction in range of motion or functional impairment using the validated PEM.
