Abstract
Introduction
Total hip replacement (THR) is one of the most widely used and most successful orthopedic procedures performed in developed countries. The burden of revision surgery, however, has become a major issue in terms of both volume and cost. Technical errors at the time of the index operation are known to be associated with an increased rate of revision.
Statistical methods, such as the CUSUM test, which have been developed for the manufacturing industry to monitor the quality of products, have come to the attention of health-care workers as a result of centers with protracted periods of inadequate performance. In orthopedics, these methods have been used to monitor the quality of total hip replacement in a tertiary care department using conventional imaging techniques.
Biplane low-dose X-ray imaging (EOS) may allow an easy, patient-friendly, way to retrieve data on the position of implants immediately postoperatively. Therefore real-time feedback is provided to surgeons and performance adjusted accordingly
Objectives
To assess the usefullness of EOS imaging in providing the position of implants immediately postoperatively
Methods
Thirty-six patients who underwent a primary hip replacement at a tertiary care department had a standing EOS acquisition before discharge (around day 5). The following parameters were collected: cup abduction, cup anteversion, leg length, stem anteversion, stem inclination. Cup inclination was considered inadequate if more than 55 degrees or less than 35 degrees; cup abduction was considered inadequate if more than 30 degrees or less than 0 degrees; leg length was considered inadequate if more than 1cm; stem anteversion was considered inadequate if more than 30 degrees of less than 0 degrees; stem inclination was considered inadequate if more than 4 degrees varus or valgus. A procedure was considered inadequate if any criterion was outside the appropriate range.
A CUSUM test was used to detect inadequate performance for each criterion and for the whole procedure (more than 20% of the implants poorly positioned).
Results
On this preliminary sample of 36 patients only cup inclination demonstrated to be inadequate. Other parameters were within the expected limits. The acquisition of images proved to be easy, without interrupting the flow of patient care and physician work.
Conclusions
Biplane low-dose X-ray imaging (EOS) provides an easy way to continuously evaluate the quality of THR implant positioning at a tertiary care department.
