Abstract
We determined the survival of primary total hip and knee replacements and patients who had undergone surgery between 1989 and 2007 in Dunedin with the aim to using these figures to provide information on
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whether our arthroplasty population is changing,
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what the likely future demands are on follow-up services,
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whether we can predict which patients will require follow-up.
The initial search using records held by the audit department at Dunedin Hospital returned 6,328 patient records with total hip and knee arthroplasty between 1988 and 2007. These reports however, included many procedures which were neither hip/knee nor primary/revision total joint arthroplasty. The data was filtered, resulting in 4,773 hip and knee arthroplasties. The final data included 3194 primary total hip replacements and 1579 primary total knee replacements. Comorbidity scoring of these patients was also undertaken.
The mean age of patients who underwent primary hip replacement was 67.6 yrs (SD 12.4) and the mean age of patients who underwent a primary knee replacement was 70.8 yrs (SD 9.8). Around 25% of patients who have had a primary joint replacement died after a mean of 10 yrs after the operation. In the group of patients who died after 10 years, the mean age at surgery was around 74 years. The mean age at the time of death was around 80 years. No difference was found in the death rate, revision rate, and the combined outcomes with death or revision as the end point with respect to the following-THRs. TKR, the grade of the surgeon, the comorbidity score or in men vs. women as compared to the general population.
Patients over 59 years of age at time of primary arthroplasty have a > 90% chance of dying before the need for revision surgery. Patients of less than 51 years of age have a > 90% chance of requiring revision surgery. Patients of 55 years of age have a 50% chance of requiring revision surgery. In a setting of ongoing scarce resources symptomatic/questionnaire targeted follow-up with radiology may be the only long term viable solution.
Correspondence should be addressed to Associate Professor N. Susan Stott, Orthopaedic Department, Starship Children’s Hospital, Private Bag 92024, Auckland, New Zealand.
