We have assessed the relative value of various outcome measures after THR, by the analysis of follow-up data from over 2000 patients. They had been reviewed clinically and radiologically six months after operation, at one year, and then every two years, some for 16 years. At each review their pain level, stiffness and opinion of progress were scored and a radiograph taken.

We found that pain level was the most informative outcome as a predictor of revision and correlated well with the patients’ opinions.

We made a comparison between the six types of implant in the series, using survival analysis and log-rank testing with different pain levels as endpoints. This analysis revealed differences which were not detected by survival analysis using the traditional endpoint of revision.

We therefore recommend the use of different levels of pain as the main outcome measures after total hip replacement.

We reviewed the records of the long-term outcome of 208 Charnley and 982 Stanmore total hip replacements (THR) performed by or under the supervision of one surgeon from 1973 to 1987. The Stanmore implant had a better survival rate before revision at 14 years (86% to 79%, p = 0.004), but the difference only became apparent at ten years.

The later Stanmore implants did better than the early ones (97% to 92% at ten years, p = 0.005), the improvement coinciding with the introduction of a new cementing technique using a gun. Most of the Charnley implants were done before most of the Stanmore implants so that the difference between the results may in part be explained by improved methods, but this is not the complete explanation since a difference persisted for implants carried out during the same period of time.

We conclude that improved techniques have reduced failure rates substantially. This improvement was much greater than that observed between these two designs of implant. Proof of the difference would require a very large randomised controlled trial over a ten-year period.

We studied the migration of 58 cemented Hinek femoral components for total hip replacement,using roentgen stereophotogrammetric analysis over four years. The implants migrated faster during the first year than subsequently, and the pattern of migration in the second period was very different. During the first year they subsided, tilted into varus and internally rotated. After this there was slow distal migration with no change in orientation. None of the prostheses has yet failed.

The early migration is probably caused by resorption of bone damaged by surgical trauma or the heat generated by the polymerisation of bone cement. Later migration may be due to creep in the bone cement or the surrounding fibrous membrane.

The prosthesis which we studied allows the preservation of some of the femoral neck, and comparison with published migration studies of the Charnley stem suggests that this decreases rotation and may help to prevent loosening.