The Effect of Radial Inclination on the Stage of Kienbock Disease at the Time of Initial Diagnosis.

ABSTRACT

BACKGROUND: Negative ulnar variance is a widely accepted risk factor for the development of Kienbock disease (KD). Variation in radial inclination has been proposed as a risk factor, but evidence thus far has been inconclusive. We aim to clarify the relationship between radial inclination and KD. METHODS: A retrospective analysis of all KD patients from a single institution from 2007 to 2021 was conducted. Radiographs were reviewed to measure anatomic parameters and stage of disease. An exploratory multinomial regression model was created to examine the association of patient age, radial height, ulnar variance, radial inclination, volar tilt, scapholunate angle, duration of symptoms prior to evaluation, history of wrist trauma, and diagnosis of diabetes with stage of disease. RESULTS: Fifty-seven cases of KD were identified, with a mean duration of disease of 33.3 months. A history of trauma to the wrist was common (53%) and significantly associated with stage of disease at initial presentation. Twenty-seven cases (47%) were stage IIIB or greater. The average initial radial inclination, radial height, and ulnar variance was 21.9°, 10.7 mm, and -1.23 mm, respectively. A multinominal logistic regression model revealed decreased initial radial inclination is associated with Lichtman stage IIIB or greater at the time of initial patient presentation. CONCLUSIONS: A correlation exists between decreased radial inclination and more advanced KD at presentation, suggesting this may be a risk factor for disease progression. This correlation is strengthened by our finding of decreased ulnar variance being associated with later stage at presentation, which is one of the most widely accepted proposed risk factors for development and progression of disease. LEVEL OF EVIDENCE IV.