Ideal Timing for Knee Replacements Can Be Tricky

 In Blog

Knee replacement procedures have become extremely commonplace as it is projected that there are more than 600,000 per year in the US alone.1 However, for a surgeon, it can be challenging to decide when the timing is exactly right for patients to undergo the procedure.

A recent study published in The Journal of Bone and Joint Surgery found that most patients who undergo knee replacement for osteoarthritis (OA) do not have the procedure at the best time. The problem is twofold, according to the researchers: “Patients with knee osteoarthritis may undergo total knee replacement too early or may delay or underuse this procedure. We quantified these categories of total knee replacement utilization in 2 cohorts of participants with knee osteoarthritis and investigated factors associated with each category.”2

Two cohort studies were evaluated for data which included demographic, patient-reported radiographic, clinical examination, and total knee replacement (TKR) utilization information. Patients who had or were at risk for knee OA were followed for eight years. TKR appropriateness criteria were applied to stratify patients into two groups: potentially appropriate or likely inappropriate for TKR. Those who received TKR were further stratified: timely (the patient received TKR within two years of the procedure becoming potentially appropriate), potentially appropriate but knee not replaced (TKR remained unperformed for more than two years after the procedure had become potentially appropriate), and premature (TKR was likely inappropriate but had been performed).2

Of 8,002 total patients, 3,417 were eligible for inclusion and stratified into one of the three utilization categories: timely, n = 290 (8% of the total, 9% of the potentially appropriate knees); potentially appropriate but not replaced, n = 2,833 (83% of the total, 91% of the potentially appropriate knees); and likely inappropriate but received TKR prematurely, n = 294 (9% of the total, 26% of TKRs performed). Among the potentially appropriate but not replaced knees, 1,204 (42.5%) had severe symptoms.2

“Compared with the patients who underwent timely total knee replacement, the likelihood of being classified as potentially appropriate but not undergoing total knee replacement was greater for black participants and the likelihood of having premature total knee replacement was lower among participants with a body mass index of >25 kg/m2 and those with depression,” the study authors found.2

“As the number of surgeries rises, we need to make sure the timing is optimal for patients to obtain the most benefit and to keep health care costs down,” Dr. Ghomrawi added. “Because knee replacement is an elective procedure, the timing of surgery is susceptible to not just clinical factors but also demographic, socioeconomic and sociocultural ones. We need to develop a better understanding of these factors to improve timing of surgery.”2

Luckily, new technology has already been designed to help surgeons better decipher the best timing for a patient to undergo knee replacement surgery. TracPatch monitors and records patient-specific, objective, pre-op baseline range of motion mobility trends through two surface sensors that adhere to the patient’s leg. This technology may be just what is needed for surgeons to capture the individual baseline data to help them uncover when the optimal time is for their patients to undergo a procedure. For more information about TracPatch contact us today.


  1. Total Knee Replacement – OrthoInfo – AAOS. Retrieved January 15, 2020, from
  2. D’Onofrio, K. (2020, January 14). Too Soon, Too Late, Just Right: Ideal Timing for Knee Replacements. Retrieved January 15, 2020, from
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