Total Hip Arthroplasty in Under-21-years-old Patients?

A new and intriguing piece of research from New York’s Hospital for Special Surgery (HSS), Weill Cornell Medicine, and Stanford University looks at this thought-provoking question. The study, “Use of Total Hip Arthroplasty in Patients Under 21 Years Old: A US Population Analysis,” was published in the December 2021 edition of The Journal of Arthroplasty.

The number of total hip arthroplasties (THA) performed on the under-21-years-old population is small but growing at a notable rate. Between 2000 and 2016, the weighted average total number of hip arthroplasties performed increased from 347 in 2000 to 551 in 2016. (Source: Kids' Inpatient Database – approximately 4,200 hospitals in 46 states.)

According to the researchers, the most frequent diagnoses were osteonecrosis, osteoarthritis, and/or inflammatory arthritis. Of those diagnostic categories, the decision to then use arthroplasty to treat these young patients increased the fastest for osteonecrosis (moving from 24% of the patients in the study in 2000 to 38% in 2016). The decision to use arthroplasty for inflammatory arthritis decreased from 27% of the studied population in 2000 to 4% in 2016.

Co-author Bella Y. Mehta, M.B.B.S., M.S., a rheumatologist at Hospital for Special Surgery, explained to OTW that, “In patients under 21, THA is a fairly rare procedure. Further, only a few specialized centers/surgeons perform THA in young patients, thus little is known about it.”

“In this nationwide analysis of THA utilization in patients under 21 years of age, we found that the number of THAs performed in this population increased from 2000 to 2016, despite a decrease in the use of THA for inflammatory arthritis.” This decrease, the authors noted, “likely reflects improvements in medical management during the study period.”

While the authors found that the cause(s) for the population-level increase in hip arthroplasty in these young patients are unknown, they “may reflect the wide body of evidence showing increased longevity and decreased wear rates of hip arthroplasty implants which use highly cross-linked polyethylene liners, which came into widespread use in the early 2000s, as well as high durability of uncemented implants. Additionally, increased patient awareness of and access to THA may have contributed to increase in THA utilization.”

Looking forward, said Dr. Mehta to OTW, “Knowledge of the epidemiology of total hip arthroplasty utilization in this population may help to guide health policy and future research into the indications, outcomes and failure modes of THA in young patients.”