mHealth Research Daily with Tim Bredrup

In a recent study, a novel system is described that uses both the camera and the accelerometer functions of the iPhone to improve the process of acetabular cup placement in total hip arthroplasty.

The accelerometer function senses changes in movement and is used in a number of other iPhone apps.  To further assist in achieving proper acetabular cup placement, a level indicator app and protractor app were downloaded to the iPhone and also effectively used.

This new system offers an alternative to the conventional techniques and computer-assisted surgery that according to the study’s authors “are the two most popular methods for proper placement of the acetabular cup in Lewinnek’s safe zone of orientation.(anteversion 15° ± 10° and lateral inclination 40° ± 10°)”

The authors state that the new approach is accurate and quick.  Fifty prospective case studies showed good early results  “with all our acetabular cups being placed within a narrow range in the safe zone and with less than 5% difference between the preoperative, intraoperative, and postoperative acetabular inclinations.”

Given the small sample size and novelty of this approach, more research is needed to determine its clinical validity and utility.

For more research on this topic, see “Poor accuracy of freehand cup positioning during total hip arthroplasty” and also “Computer-assisted cup placement techniques in total hip arthroplasty improve accuracy of placement”.

Authors: Peters FM, Greeff R, Goldstein N, Frey CT

Original Abstract: link