Decreased cancer risk in patients who have been operated on with total hip and knee arthroplasty for primary osteoarthrosis

3 Nordic cohorts of total hip (THA) and total knee arthroplasty (TKA) in patients operated on for primary osteoarthrosis during 1967–1995 were partly adapted and combined for meta-analysis. THA was performed in 49,000 patients and TKA in 24,000 totaling 497,000 person years. The mean and maximum follow-up times were 6.8 and 30 years, respectively. Standardized incidence ratios (SIRs) with 95% confidence intervals (95% CI) were calculated for the observed and expected number of cancers. The expected numbers were based on national incidence rates. The overall SIRs as well as the site-specific ones were similar in the THA and TKA patients. The observed number of cancers at all sites was 7,639 and the expected one was 8,202 (SIR 0.93,95% CI 0.91–0.95).

The SIRs for lung cancer (0.69, 0.64–0.75) and laryngeal cancer (0.64, 0.44–0.92) were reduced. The incidence was also low for cancers of the stomach (SIR 0.76, 0.67–0.84), colon (SIR 0.86, 0.79–0.93) and rectum (SIR 0.89, 0.80–0.98).

Among TKA patients, the only increases in SIRs were seen in cancers of the endometrium (SIR 1.36, 1.05–1.74), prostate (SIR 1.19, 1.02–1.38) and, among both THA and TKA patients, in skin melanoma (combined SIR 1.21,1.03–1.41).