Socket wear assessment. A comparison of three different radiographic methods

Three different methods to measure wear of total hip sockets from plain radiographs were compared with the results obtained by direct assessment of the internal deformity of 28 retrieved sockets by means of a coordinate measuring machine. The values obtained by the uni-radiographic, the duo-radiographic, and the radiographic methods based on the change of distance between the centers of the socket and the prosthetic head (CEN) all correlated significantly with the standard obtained by the coordinate measuring machine, provided the sockets were not loose. The most accurate radiographic measurements were obtained with the CEN method. A prerequisite for a reliable estimation of socket wear rate is that it be based on observations of radiographically intact sockets.