Intraoperative radiographs for placing acetabular components in hip resurfacing arthroplasty.
BACKGROUND
Various clinical and biomechanical studies suggest certain acetabular positions may be associated with higher wear and failure rates in modern metal-on-metal hip resurfacing arthroplasties. However, there are no widely available, reliable, and cost-effective surgical techniques that ensure surgeons are able to place an acetabular component within the safe range of inclination angles after hip resurfacing surgeries.


OBJECTIVE
We investigated the accuracy of intraoperative radiographs to determine the acetabular inclination angle in resurfacing arthroplasty procedures.


METHODS
The study group included the first 100 resurfacing arthroplasties performed after we started routinely checking the intraoperative acetabular inclination angles. The acetabular component was repositioned if the intraoperative acetabular inclination angle was out of the target range of 30° to 50°. The control group included the previous 100 resurfacing arthroplasties performed without the benefit of intraoperative radiographs. A posterior minimally invasive surgical approach was used in both groups. Demographics and diagnoses were similar in both groups.


RESULTS
The average (± SD) difference between the intraoperative and 6-week radiographs was 2.7° ± 2.5°. The acetabular inclination angles at 6-week followup were within the targeted range more frequently in the study group than in the control group (outliers: 4% versus 29%).


CONCLUSIONS
These data suggest a single intraoperative radiograph is a quick, reliable, and cost-effective method for ensuring the acetabular inclination angle is within the targeted range.
Midlands Orthopaedics, p. a., 1910 Blanding Street, Columbia, SC 29201-3520, USA.
Thomas P
TP
Gross
Fei
F
Liu
Lee
L
Webb
D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000601:surgery; D011474:Prosthesis Design; D011859:Radiography; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013499:Surface Properties; D016896:Treatment Outcome