Socket wear assessment. A comparison of three different radiographic methods

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Radiology

Background:

• Total hip replacement (THR) is a common procedure to alleviate pain and restore function.
• Accurate measurement of polyethylene wear in THR sockets is crucial for assessing implant longevity and patient outcomes.
• Radiographic methods offer a non-invasive approach to monitor wear, but their accuracy varies.

Purpose of the Study:

• To compare the accuracy of three radiographic methods for measuring polyethylene wear in retrieved total hip sockets.
• To determine the most reliable radiographic technique for assessing socket deformity and wear rate.
• To identify prerequisites for accurate radiographic wear assessment.

Main Methods:

• Direct measurement of internal deformity in 28 retrieved hip sockets using a coordinate measuring machine (CMM) as the gold standard.
• Comparison of CMM results with measurements from three radiographic techniques: uni-radiographic, duo-radiographic, and center-to-center (CEN) distance.
• Statistical analysis to assess the correlation between radiographic methods and CMM measurements.

Main Results:

• All three radiographic methods (uni-radiographic, duo-radiographic, CEN) showed significant correlation with CMM measurements for non-loose sockets.
• The CEN method demonstrated the highest accuracy among the tested radiographic techniques.
• The accuracy of radiographic measurements was dependent on the absence of radiolucent lines indicating loosening.

Conclusions:

• The center-to-center (CEN) radiographic method is the most accurate for measuring polyethylene wear in total hip sockets.
• Radiographic assessment of socket wear is reliable only when the sockets are radiographically intact and not loose.
• Accurate estimation of socket wear rate necessitates utilizing observations from intact sockets on plain radiographs.