In the current issue of JBJS, Hailer et al. report on an investigation in Sweden in which they analyzed genetic susceptibility to hip and knee osteoarthritis necessitating total hip arthroplasty (THA) or total knee arthroplasty (TKA), and whether body mass index (BMI) moderates the heritability of these outcomes.
Although the need for THA or TKA is not a perfect indicator of osteoarthritis (osteoarthritis does not always become symptomatic enough to warrant total joint arthroplasty), this large study offers further data on the question of genetic susceptibility to the development of osteoarthritis. Understanding the influence of obesity (a modifiable risk factor) becomes increasingly important and warrants continued investigation in studies exploring heritability in relation to orthopaedic conditions.