Blog | Wednesday, July 2, 2014

QD: News Every Day--One-third of knee replacements may be inappropriate

About a third of total knee replacements were judged to be inappropriate, a study found.

The authors noted in the study’s introduction that from 1991 to 2010, the annual volume of total knee arthroplasty (TKA) surgeries among Medicare beneficiaries increased 161.5% while per capita utilization increased 99.2%.

To further quantify rates and whether the surgeries could be classified as appropriate, researchers examined a subset of nearly 4,800 people who were enrolled in the Osteoarthritis Initiative, which is a multicenter, prospective, 5-year longitudinal study of persons with or at high risk for knee osteoarthritis (OA). Data from 205 persons with TKA were examined to classify them as appropriate, inappropriate or inconclusive for TKA surgery based on the 16 terminal nodes of the algorithms developed by Escobar et al. Results appeared online June 30 at Arthritis & Rheumatology.

Researchers deemed 44% (95% CI, 37% to 51%) as appropriate, 21.7% (95% CI, 16% to 28%) as inconclusive, and 34.3% (95% CI, 27% to 41%) as inappropriate.

The authors noted that the patients classified as inappropriate generally had either mild or moderate symptoms, or Kellgren and Lawrence scores of 2 or lower. “Patients seek TKA primarily because of their knee pain and the associated impact of pain on daily life,” they wrote. “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.”

The authors also noted that their rate of inappropriate surgery was higher than that found in others studies of about 20%. This could be because of the bias grounding the Escobar et al criteria that persons who are the best candidates for TKA are 55 years and older with severe levels of pain, functional loss and knee osteoarthritis.

“Because there is no consensus in the U.S. on TKA candidacy, extensive variation among

TKA patients’ characteristics exists, particularly with regard to knee pain, OA severity and extent

of functional loss,” the authors wrote. “It is likely this variation will continue until consensus is reached on the key criteria that drive decisions to recommend TKA to patients.”