A novel fluoroscopic approach to assessing patient positioning in total hip arthroplasty: accuracy and the influence of body mass index



Accurate prosthetic cup placement is important in total hip arthroplasty (THA) and can be influenced by patient positioning. This study aims to assess the accuracy of patient positioning prior to THA, describe a new technique of assessment, and evaluate the influence of body mass index (BMI) on positioning error.


A consecutive series of 37 patients undergoing unilateral THA were investigated. After patient positioning in lateral decubitus, a lateral fluoroscopic image through the table was taken. The C-arm of the image intensifier was manipulated in 2 planes (coronal, transverse) until a perfect lateral view of the pelvis was obtained, defined as when the native acetabulae were superimposed. Degrees of positioning error in the 2 planes were recorded, along with patient BMI.


There were 6 patients (16%) positioned within 2° of true lateral in both planes. A further 21 patients (57%) had an error of 5° or more in at least 1 plane. Mean absolute positioning error was 3.0° (SD 2.2°; range 0°-9°) and 3.0° (SD 3.2°; range 0°-13°) in the transverse and coronal planes respectively. Pelvic adduction in the coronal plane was 4.5 fold more likely than abduction (49% vs. 11%). Correlation was shown between patient BMI and the combined error in the 2 planes (R = 0.48, p = 0.001).


Fluoroscopic positioning assessment prior to THA demonstrates that significant malpositioning is common and more likely with increasing BMI. This technique may be particularly useful for patients with a BMI of >30 kg m-2.

Hip Int 2016; 26(6): 550 - 553




Anton P. Lambers, Robert Jennings, Andrew T. Bucknill

Article History


Financial support: None.
Conflict of interest: None.

This article is available as full text PDF.

  • If you are a Subscriber, please log in now.

  • Article price: Eur 36,00
  • You will be granted access to the article for 72 hours and you will be able to download any format (PDF or ePUB). The article will be available in your login area under "My PayPerView". You will need to register a new account (unless you already own an account with this journal), and you will be guided through our online shop. Online purchases are paid by Credit Card through PayPal.
  • If you are not a Subscriber you may:
  • Subscribe to this journal
  • Unlimited access to all our archives, 24 hour a day, every day of the week.



  • Royal Melbourne Hospital, Melbourne, Victoria - Australia
  • Department of Surgery, University of Melbourne, Melbourne, Victoria - Australia
  • University Hospital Southampton, Southampton - UK

Article usage statistics

The blue line displays unique views in the time frame indicated.
The yellow line displays unique downloads.
Views and downloads are counted only once per session.

No supplementary material is available for this article.