New 5-Point Scoring System Guides Knee Surgery Timing

New work from the Department of Orthopaedic Surgery at the Singapore General Hospital has attempted to shine a light on the ideal timing of knee arthroplasty—based on patient-reported outcome measures (PROMs).

Their paper, “A Weighted Scoring System Based on Preoperative and Long-Term Patient Reported Outcome Measures to Guide Timing of Knee Arthroplasty,” was published in the August 9, 2021, edition of The Journal of Arthroplasty.

The researchers collected data on 766 total and 382 unicompartmental knee arthroplasty (TKA and UKA), with PROMs assessed preoperatively and at 10 years using the Knee Society Score, the Oxford Knee Score and the Short Form-36 physical component scores.

Lead author Yong Zhi Khow, told OTW, “Patient reported outcome measures (PROMs) have been around for a long time to [help us] understand surgical outcomes more holistically. Our centre routinely collects PROMs to track postoperative improvements. Deciding when to proceed for knee arthroplasty is a shared decision between both surgeon and patient.”

“However, given that radiographs correlate poorly with symptoms, and patients are unsure at what point their symptoms are severe enough to request surgery, timing of knee arthroplasty can be subjective. Given that preoperative PROMs are known to predict postoperative outcomes, we were curious about the potential for preoperative PROMs to guide optimal timing of knee arthroplasty.”

Indeed, worse baseline PROMs did signal 10-year clinically meaningful improvements.

Corresponding author, Lincoln Ming Han Liow, MBBS explained to OTW, “Patients with poorer baseline PROMs experienced greater improvements 10 years after unicompartmental knee arthroplasty and total knee arthroplasty. Precise thresholds for each PROM that reliably predicted patients who experienced clinically meaningful improvements in outcome after knee arthroplasty were identified.”

“These thresholds were synthesized to create a novel weighted scoring system to score patients on a 5-point scale. The final score from scoring patients using this novel scoring system went on to demonstrate a strong correlation with the magnitude of postoperative improvements 10 years after primary knee arthroplasty.”

Triage tool?

Seng Jin Yeo, MBBS, director of the Adult Reconstruction Service at Singapore General Hospital, was senior author on the paper and explained to OTW how this score can be used: “The final score from this novel weighted scoring system essentially grades the severity of patients’ preoperative state, which also underscores their potential for long-term benefits from knee arthroplasty.”

“This score can help guide both surgeons and patients on the appropriate time from which knee replacement will reliably lead to clear and long-lasting clinical benefits. Moreover, in an era where waiting time for surgery can be long due to high patient volumes and limitations in operating theatres, recently exacerbated by COVID-19 pandemic measures, scoring patients can help prioritize patients who are waiting to receive surgery. Such a system could ensure the right candidates proceed for knee arthroplasty at the right time, to maximize surgical outcomes and overall patient experience.”