Outco
me after total hip arthroplasty (THA) depends on several factors related to the patient, the surgeon and the i
mplant. It has been suggested that the annual nu
mber of procedures per hospital affects the prognosis. We ai
med to exa
mine if hospital procedure volu
me was associated with the risk of revision after pri
mary THA in the Nordic countries fro
m 1995 to 2011.
Design
The Nordic Arthroplasty Register Association database provided information about primary THA, revision and annual hospital volume. Hospitals were divided into five volume groups (1–50, 51–100, 101–200, 201–300, >300). The outcome of interest was risk of revision 1, 2, 5, 10 and 15 years after primary THA. Multivariable regression was used to assess the relative risk (RR) of revision.
Results
417,687 THAs were included. For the 263,176 cemented THAs no differences were seen 1 year after primary procedure. At 2, 5, 10 and 15 years the four largest hospital volume groups had a reduced risk of revision compared to group 1–50. After 10 years RR was for volume group 51–100 0.79 (CI 0.65–0.95), group 101–200 0.76 (CI 0.61–0.95), group 201–300 0.74 (CI 0.57–0.96) and group >300 0.57 (CI 0.46–0.71). For the uncemented THAs an association between hospital volume and risk of revision were only present for hospitals producing 201–300 THAs per year, beginning at years 2 through 5 and in all subsequent time intervals to 15 years.
Conclusion
Hospital procedure volume was associated with a long term risk of revision after primary cemented THA. Hospitals operating 50 procedures or less per year had an increased risk of revision after 2, 5, 10 and 15 years follow up.