Femoral prosthesis version angle calculation from a sagittal plane radiographic projection of the femur.

OBJECTIVE: To investigate a technique for determination of femoral prosthesis version using a mediolateral radiographic projection of the sagittal plane of the implanted femur. STUDY
DESIGN: In vitro radiographic study.
METHODS: Femoral prostheses from BioMedtrics (cemented [CFX™] and biologic fixation [BFX™]), and Kyon uncemented were secured in prepared Sawbones® at various angles of version. Axial and mediolateral radiographs of the implanted femurs were taken at each angle of version. Angles of version were determined by direct measurement from the axial view, and then calculated from measurements made on the lateral view by 2 separate observers blinded to the axial measurement. Accuracy of the technique was evaluated individually for each observer using regression analysis. Inter-observer mean values were assessed with a paired t-test, and the within and between operator error was evaluated using percent coefficient of variance (%CV).
RESULTS: There was no significant difference between the directly measured prosthesis version and the calculated prosthesis version (P > .05). There was no significant difference between the mean measured inclination angle (MIA) measured by each observer (P = .204). Mean version angles measured were accurate at all version angles for both observers; %CV < 15%.
CONCLUSION: Femoral prosthesis version angles can be accurately determined using this technique. © Copyright 2012 by The American College of Veterinary Surgeons.