Background

On 22 July 2011 Norway was subjected to two terrorist attacks by a right-wing extremist. The first attack was an explosion from a car bomb against the Government Building (GB) in Oslo. The second attack occurred less than two hours later at a summer camp on the island Utøya, outside Oslo, where 600–700 young members of the Labour Party hold their annual summer camp. The car bomb killed 8 people and 69 persons were shot and killed at Utøya. All seriously injured patients came to Oslo University Hospital, Ullevål (OUH).

This paper investigates the association between risk factors recorded prospectively before primary total hip arthroplasty (THA) and the risk for later revision surgery. The National Health Screening Service in Norway invited 56 818 people born between 1925 and 1942 to participate in an investigation of risk factors for cardiovascular disease and 92% participated. Matching these screening data with data from the Norwegian Arthroplasty Register about primary THA and revision THA, we identified 504 men and 834 women who had undergone primary THA at a mean age of 62 years. Of these, 75 and 94 were revised during follow-up. The mean age at screening was 49 years and the mean age at censoring was 68 years. The mean age of those who underwent revision THA was 57 years. Men had a 1.9 times higher risk of undergoing hip revision during follow-up (95% CI). For each year’s increase in age at primary THA, the risk of revision THA during follow-up decreased by 14% for men and 17% for women. Men who at screening had the highest level of physical leisure activities had 5.5 times the risk of later revision than those with the lowest level of physical activity (95% CI).

Men have a higher risk for revision THA. The older the patient, the lower the risk for revision. Men with intense physical activity in middle age are at increased risk of undergoing revision THA before they reach 70.

Aims: We wanted to investigate the association between risk factors recorded prospectively before primary hip replacement, and the risk for later revision hip surgery. Methods: During the years 1977–83 The National Health Screening Service in Norway conducted an investigation of risk factors for cardiovascular disease. 56,818 persons born 1925–42 were invited, and 92% participated. We matched these screening data with data from the Norwegian Arthroplasty Register concerning primary and revision hip arthroplasty. Results: We identified 504 men and 834 women who had received a primary total hip replacement after the screening. Of these 75 and 94 were revised during follow-up. Mean age at screening was 49 years; mean age at primary hip replacement was 62 years. Mean age at censoring was 68 years. Men vs women had a relative risk of 1.9 of undergoing hip revision during follow-up (95% CI 1.3–2.8). For each years increase in age at primary hip arthroplasty, the risk of revision surgery during follow-up decreased with 14% for men and 17% for women. Men who at screening had the highest level of physical activity during leisure had 5.5 times the risk of later revision, relative to those with the lowest level of physical activity (95% CI 1.0–31.9). Conclusions: Men have a higher risk for revision hip surgery. There is less risk of revision the older the patient is at primary hip arthroplasty. Men with intense physical activity at middle age are at increased risk of undergoing revision hip surgery before they are 70 years old.