We identified 1305 femoral impaction bone grafting revisions using the Exeter stem performed between 1989 and 2002 in 30 hospitals throughout Sweden. There were 1188 patients with a mean age of 71 years (29 to 94) followed up for between five and 18 years.

The participating departments reported 70 further revisions in total, of which 57 could also be identified on the Swedish National Arthroplasty Registry.

Kaplan-Meier survivorship for all causes of failure was 94.0% (95% confidence interval (CI) 92 to 96) for women and 94.7% (95% CI, 92 to 96) for men at 15 years. Survivorship at 15 years for aseptic loosening was 99.1% (95% CI 98.4 to 99.5), for infection 98.6% (95% CI 97.6 to 99.2), for subsidence 99.0% (95% CI 98.2 to 99.4) and for fracture 98.7% (95% CI 97.9 to 99.2)

Statistically significant predictors of failure were the year in which revision was conducted (p < 0.001). The number of previous revisions was slightly above the level of signifance (p = 0.056). Age, gender, the length of the stem and previous septic loosening were not predictors of failure (p = 0.213, p = 0.399, p = 0.337, p = 0.687, respectively). The difference in survivorship between high- and low-volume departments was only 3% at ten years.

We conclude that impaction bone grafting with the Exeter stem has an excellent long-term survivorship following revision arthroplasty. The technique of impaction grafting appears to be reliable, can be learned rapidly and produces a predictably low incidence of aseptic loosening.

A total of 10474 unicompartmental knee arthroplasties was performed for medial osteoarthritis in Sweden between 1986 and 1995. We sought to establish whether the number of operations performed in an orthopaedic unit affected the incidence of revision. Three different implants were analysed: one with a high revision rate, known to have unfavourable mechanical and design properties; a prosthesis which is technically demanding with a known increased rate of revision; and the most commonly used unicompartmental device.

Most of the units performed relatively few unicompartmental knee arthroplasties per year and there was an association between the mean number carried out and the risk of later revision. The effect of the mean number of operations per year on the risk of revision varied. The technically demanding implant was most affected, that most commonly used less so, and the outcome of the unfavourable design was not influenced by the number of operations performed.

For unicompartmental arthroplasty, the long-term results are related to the number performed by the unit, probably expressing the standards of management in selecting the patients and performing the operation.