Comparing radial styloid size between osteoarthritic and healthy wrists: a pathoanatomical three-dimensional study

Radial styloid pointing due to spur formation is considered an early sign of osteoarthritis, but is sometimes difficult to distinguish from normal anatomic variation. In this pathoanatomical study we used three-dimensional imaging techniques to evaluate quantitatively whether the styloid size is larger in wrists with scaphoid non-union than in healthy wrists. We compared these findings with duration of the non-union and with the scaphoid non-union advanced collapse classification, which was based on radiographic assessment of the general level of wrist osteoarthritis. In 31 patients, the injured styloid was consistently larger than the contralateral healthy styloid. In 74% of the patients this pathoanatomical difference (maximum 5 mm) exceeded anatomical left-to-right variation in styloid size (maximum 2 mm), indicating significant pointing. Increased styloid pointing was associated with older non-unions, and with more severe osteoarthritis. Three-dimensional styloid pointing analysis is an objective method to assess osteoarthritic progression. Combining traditional qualitative evaluation and quantitative measurements may improve the classification of wrist osteoarthritis.

Level of evidence: IV