The radiological features of the cement mantle around total hip replacements (THRs) have been used to assess aseptic loosening. In this case-control study we investigated the risk of failure of THR as predictable by a range of such features using data from patients recruited to the Trent Regional Arthroplasty Study (TRAS).

An independent radiological assessment was undertaken on Charnley THRs with aseptic loosening within five years of surgery and on a control group from the TRAS database. Chi-squared tests were used to test the probability of obtaining the observed data by chance, and odds ratios were calculated to estimate the strength of association for different features.

Several features were associated with a clinically important increase (> twofold) in the risk of loosening, which was statistically significant for four features (p < 0.01). Inadequate cementation (Barrack C and D grades) was the most significant feature, with an estimated odds ratio of 9.5 (95% confidence interval 3.2 to 28.4, p < 0.0001) for failure.

We have assessed the usefulness of a regional hip register in the assessment of the outcome of primary total hip replacement (THR). Over 97% of THRs performed in the Trent region in 1990 were captured onto the register and the inaccuracies recorded were less than 1.8%. In an independent assessment of 2111 patients five years after THR, 85.9% of those available for assessment responded, and 66.8% agreed to an assessment.

The cost of this independent assessment at five years, utilising a regional hip register, was approximately £50 per implant. This is a reasonable outlay to identify problems early. Some form of registration and outcome assessment should be performed on a national level.

Using a regional arthroplasty register we assessed the outcome at five years of 1198 primary Charnley total hip replacements (THRs) carried out in 1152 patients across a single UK health region in 1990. Information regarding outcome was available for 1080 hips (90%) and 499 had an independent clinical and radiological assessment.

By five years the known rate of aseptic loosening was 2.3%, of deep infection 1.4%, of dislocation 5.0% and of revision 3.2%. The radiological assessment of 499 THRs revealed gross failure in a further 5.2%, which had been previously unrecognised. The combined rate of failure of nearly 9% is higher than those published from specialist centres and surgeons, but is probably more representative of the norm.

Our study supports the need for a national register and surveillance of THRs. It emphasises that all implants should be followed, and suggests that the results of such surgery, when performed in the general setting, may not be as good as expected.

We calculated the rates for perioperative mortality and fatal pulmonary embolism (PE) after primary total hip replacement in a single UK health region, using a regional arthroplasty register and the tracing service of the Office of National Statistics. During 1990, there were 2111 consecutive primary replacements in 2090 separate procedures. Within 42 days of operation a total of 19 patients had died (0.91%, 95% CI 0.55 to 1.42). Postmortem examination showed that four deaths (0.19%, 95% CI 0.05 to 0.49) were definitely due to PE.

The overall perioperative mortality and fatal PE rates are low and in our study did not appear to be altered by the use of chemical thromboprophylaxis (perioperative mortality rate: one-tailed Fisher’s exact test, p = 0.39; fatal PE rate: one-tailed Fisher’s exact test, p = 0.56).

The routine use of chemical thromboprophylaxis for primary THR is still controversial. The issue should be addressed by an appropriate randomised, prospective study using overall mortality and fatal PE rate as the main outcome measures, but the feasibility of such a study is questioned.