34th Annual Scientific Meeting proceedings

Objectives:

To assess changes in patient positioning prior to acetabular cup impaction during total hip arthroplasty procedures in dogs.

Methods:

Client-owned dogs were evaluated for change in patient positioning during total hip arthroplasty (THA). Following initial patient positioning in true lateral recumbency, fluoroscopic measurement of changes in patient positioning was performed for each plane at two separate time points: (M1) after draping and (M2) immediately prior to cup impaction.

Results:

Patient positioning was significantly altered at time point M1 in the transverse plane with a mean change of 2.78 degrees. This change in position was most often towards the dorsum, with dorsal shift occurring in 16/26 cases (62%). Significant shifting was also found at time point M2 in the transverse plane with a mean change of 2.56 degrees. This change, however, did not significantly correlate with a dorsal or ventral direction and probability of occurrence in a particular direction was low. No additive effect was seen at M1 or M2 in either plane. Body condition score had no effect on shifting found at M1 or M2 in either plane.

Conclusions:

Perfect patient positioning is not maintained with the use of bean bag positioners. Surgeons should be aware that, despite accurate initial positioning and the use of this positioning device, shifting can and does occur. Adjustment of patient positioning may be necessary to ensure appropriate acetabular component insertion angles.