Humback Deformity

Measurement of the scaphoid humpback deformity using longitudinal computed tomography: intra- and interobserver variability using various measurement techniques

Bain GI, Bennett JD, MacDermid JC, Slethaug GP, Richards RS, Roth JH

Department of Surgery, University of Western Ontario, London, Canada.

The intra- and interobserver variability of 3 techniques for measuring the humpback deformity of 37 scaphoids using longitudinal computed tomography was assessed. The 3 measuring techniques were the lateral intrascaphoid angle, the dorsal cortical angle, and the height-to-length ratio.

The intraobserver reliability of the intrascaphoid angle was poor; the dorsal cortical angle was moderate to excellent, and the height-to-length ratio was excellent. The interobserver reliability of the intrascaphoid angle was poor to moderate, the dorsal cortical angle was moderate to excellent, and the height-to-length ratio was moderate to excellent.

For all 3 observers, the intra- and interobserver reliability was the best for the height-to-length ratio and worst for the intrascaphoid angle.

The height-to-length ratio is the most reproducible method of assessing the humpback deformity. Clinical correlation is required to establish whether the height-to-length ratio will be of value in predicting the outcome of fractures of the scaphoid.

J Hand Surg [Am] 1998 Jan;23(1):76-81