The rate of total knee arthroplasty (TKA) in adults has surpassed the rate of total hip arthroplasties (THA) over the past 20 years, and researchers believe overweight and obesity is the reason.
A study published in the June 4 Journal of Bone and Joint Surgery (abstract only available for free) reviewed the rise in hip and knee replacement surgeries and found that while both procedures are occurring at higher rates than 20 years ago, total knee replacements have "far outpaced" hip replacements. In 1993, surgeons performed about 1.16 knee replacements for every hip replacement surgery. By 2009, that rate had increased to 1.60 knee replacements per hip procedure. Over the time period they studied, the THA rate doubled, while the TKA rate more than tripled.
Authors found that when they compared these 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. The number of patients ages 18 to 64 undergoing TKA rose 56% in 20 years—an increase that authors feel is reflective of that same age group's more marked rise in obesity and overweight compared with individuals 65 and older.
At the same time the numbers of procedures were on the rise, physician compensation was falling more or less equally for both replacement surgeries, with per-case reimbursements falling to $1,560 for TKA, and to $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.
Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.
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