Clinical Orthopaedics and Related Research: January 2006 - Volume 442 - Issue - p 180-186 doi: 10.1097/01.blo.0000185032.94102.2b

Correction of Error in Two-dimensional Wear Measurements of Cemented Hip Arthroplasties

The, Bertram*; Mol, Linda†; Diercks, Ron, L*; Ooijen, Peter, M. A. van‡; Verdonschot, Nico†

The irregularity of individual wear patterns of total hip pros- theses seen during patient followup may result partially from differences in radiographic projection of the components between radiographs. A method to adjust for this source of error would increase the value of individual wear curves. We developed and tested a method to correct for this source of error. The influence of patient position on validity of wear measurements was investigated with controlled manipulation of a cadaveric pelvis. Without correction, the error exceeded 0.2 mm if differences in cup projection were as small as 5°. When using the described correction method, cup positioning differences could be greater than 20° before introducing an error exceeding 0.2 mm. For followup of patients in clinical practice, we recommend using the correction method to enhance accuracy of the results.

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