More than one-third of total knee arthroplasties (TKAs) in the US could be "inappropriate," according to a new study whose lead author is a Catherine Worthingham Fellow. Researchers involved in the study believe that reducing that rate will require "a consensus-based appropriateness classification system for US patients" for a procedure that is currently "highly reliant on subjective criteria."
The analysis, e-published ahead of print in the June 30 Arthritis & Rheumatology (abstract only available for free), looked at data from 205 individuals who received TKA for a 5-year span leading up to the surgery. Using a modified assessment system developed in Spain, researchers evaluated radiographic evidence, knee motion and laxity, and scores on the Western Ontario and McMaster Universities Arthritis Index (WOMAC) to arrive at classifications of "appropriate," "inconclusive," or "inappropriate" for the patients. Lead author for the study was Daniel L. Riddle, PT, PhD, FAPTA.
The subjects studied were drawn from participants enrolled in the Osteoarthritis Initiative (OAI), a 5-year study of individuals at high risk of developing knee osteoarthritis (OA). For the TKA study, authors excluded participants who had rheumatoid arthritis, bilateral knee arthroplasty (or plans to obtain one in the next 3 years), or bilateral end-stage radiographic knee OA; used ambulatory aids other than a straight cane; or were men who weighed over 286 pounds or women over 251 pounds. The 205 individuals included in the final study were on average 67 years old at the time of TKA, with females making up 60% of the group.
Authors classified 44% of surgeries as appropriate, given imaging evidence, WOMAC scores, and motion analysis, with 34.3% of surgeries found to be inappropriate, and 21.7% designated as "inconclusive." Going into the study, researchers expected the "inappropriate" rate to be closer to 20%.
According to the study, subjects classified as inappropriate generally had either mild or moderate symptoms as measured via WOMAC or low scores on the Kellgren and Lawrence (KL) scale classifying arthritis pattern and severity. "Given that most of these subjects either had pain and functional loss profiles that were less than half that of typical patients undergoing TKA or they had no joint space narrowing, it seems reasonable to question whether TKA was the most appropriate intervention for this subgroup," authors write.
The study acknowledges that this kind of analysis should not be applied to individual patients, but could be appropriate across patient groups. Use of analyses like the one studied could help to lessen the "extensive variation among TKA patients' characteristics," they write, adding that "it is likely this variation will continue until consensus is reached on the key criteria that drive decisions to recommend TKA to patients."
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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