A recent study published in Journal of Bone and Joint Surgery that reviewed the rise in hip and knee replacement surgeries believe being overweight or obese is the cause. According to a news release from the American Physical Therapy Association (APTA), both hip and knee replacement surgeries are occurring at higher rates than 20 years ago, and total knee replacements (TKR) have “far outpaced” hip replacements. In 1993, surgeons performed about 1.16 knee replacements for every hip surgery, and by 2009, the rate increased to 1.60 knee replacements per hip procedure.
Overall, the rate of total knee arthroplasty (TKA) in adults has exceeded the rate of total hip arthroplasties (THA) over the past 20 years. The APTA news release notes that over the time period studied, the THA rate doubled and the TKA rate more than tripled.
Authors of the study found that when they compared the data with BMI information from individual patients, “individuals with a body mass index of ?25 kg/m2 were responsible for 95% of the differential increase in [TKA] over [THA] volumes.” The rate of growth in TKA rates echoed the increase in overweight and obesity among age groups, as indicated on the APTA news release.
The number of patients ages 18 to 64 years undergoing TKA rose 56% in 20 years, which is an increase that authors feel is reflective of that same age group’s more marked rise in obesity and overweight compared with individuals 65 years and older, according to APTA.
The APTA news release indicates that at the same time the numbers of procedures were on the rise, physician compensation was falling more or less equally for both replacement surgeries. Per-case reimbursements fell to $1,560 for TKA and $1,460 for THA. Authors believe that the similarity in rates makes it unlikely that surgeons are performing TKA more frequently than THA for reimbursement reasons. Researchers also discounted changes in length of stay, and in-hospital mortality as possible reasons for the growth.