Persistent pain following knee arthroplasty.

BACKGROUND AND OBJECTIVE: The prevalence of persistent pain after orthopaedic surgery has been the subject of only few studies and the risk factors for persistent pain have been evaluated even more rarely. The purpose of the present study was to evaluate the degree and the risk factors of persistent pain after knee arthroplasty. METHODS: The prevalence of persistent postoperative pain after knee replacement was evaluated with a questionnaire in a large, register-based cross-sectional prevalence study. The main hypothesis was that the type of operation (primary, bilateral, revision) would influence the prevalence of persistent postoperative pain. Logistic regression analysis was performed to test the hypothesis and to find other possible risk factors for the development of persistent pain. RESULTS: The total number of patients was 855. The operation was a primary arthroplasty in 648 patients (75.7%), a bilateral arthroplasty in 137 patients (21.1%) and a revision arthroplasty in 70 patients (8.2%). The response rate was 65.7%. The type of operation was not associated with the prevalence of persistent pain, but the degree of early postoperative pain was the strongest risk factor. If the degree of pain during the first postoperative week was from moderate to intolerable, the risk for the development of persistent pain was three to 10 times higher compared with patients complaining of mild pain during the same period. Other risk factors were the long duration of preoperative pain and female sex. CONCLUSION: Intensity of early postoperative pain and delayed surgery increase the risk of the persistent pain after knee arthroplasty.

Standardized incidence rates of total hip replacement for primary hip osteoarthritis in the 5 Nordic countries: similarities and differences.

BACKGROUND: The national hip registers of the Nordic countries provide an opportunity to compare age- and sex-standardized annual incidence of primary total hip replacement (THR) and types of implants used for primary hip osteoarthritis (OA) in Denmark, Finland, Iceland, Norway and Sweden. METHODS: The data on THR were from the national total hip replacement registries, and population data were from the national statistics agencies. Annual incidence density per 100,000 was calculated for each 5-year age group and it was age-standardized using the WHO European standard population. RESULTS: Crude country-specific annual incidence (all ages) for 1996-2000 varied between 73 and 90. WHO age-standardized annual incidence (all ages) varied between 61 (Finland) and 84 (Iceland). For the ages 50-89, comprising 94-98% of all THRs for OA, annual incidence varied between 217 (Finland) and 309 (Iceland). For Norway, the sex incidence ratio (women/men) was 2, and for the other countries it was between 1.1 and 1.3. The use of uncemented and hybrid replacements was considerably higher in Finland and Denmark than in the other countries. INTERPRETATION: We found overall similarity in THR incidence between the 5 Nordic countries, but substantial differences between women and men, and in the use of different types of implant. Population-based, age-standardized and disease-specific information on THR incidence is required in order to properly explore the causes of differences in provision and practice of THR in different countries, regions and groups, and it will aid in projecting future needs.

Periprosthetic fractures in total hip arthroplasty: an epidemiologic study.

This study was based on data from the Finnish Arthroplasty Register. From 1990 to 1999, 33,154 primary hip arthroplasties were performed in Finland. Only periprosthetic fractures treated by a revision arthroplasty were registered. The six most used femoral components were compared using survival analysis and Cox's regression model. The incidence of periprosthetic fractures was calculated separately for the years 1990-1994 and 1995-1999. The incidence in the first period was greater than in the latter. Survival analysis and Cox's regression model showed that gender, prosthesis type and age were of no significance as risk factors for periprosthetic fractures.