Reliability of the radiological assessments of radiolucency and loosening in total hip arthroplasty using PACS.

We evaluated the reliability of three commonly used radiological assessments of total hip arthroplasty (THA) using the electronic picture archiving and communications system (PACS). Thirty-three patients were selected at random at a mean of 7.2 years after THA. The Barrack, Gruen and Hodgkinson evaluations of cementing quality, loosening/radiolucency were graded. Three observers assessed each radiograph (one consultant orthopaedic surgeon, one senior orthopaedic registrar and one senior house officer). Four weeks after the initial assessment, each radiograph was reviewed a second time. The findings indicated that the intra- and inter-observer reliability of the Barrack, Gruen and Hodgkinson methods were questionable. Inter-observer reliability using the Gruen system was poor, using the Barrack system it was moderate to good, and fair to good using the Hodgkinson assessment. Intra-observer reliability was moderate to good for Barrack assessment, poor to good using Gruen zone assessments, but good to very good for the Hodgkinson assessment. The use of Barrack, Gruen and Hodgkinson assessments to evaluate femoral and acetabular loosening should be questioned since these exhibit limited inter- and intra-observer reliability on PACS radiographs, but of the three, the Hodgkinson system is the most reliable.