Summary

The present review highlights wide heterogeneity in the literature on knee replacement in reporting functional outcomes.

Abstract

Introduction

Recently, an OMERACT core domain set for knee total joint replacement (TJR) trials has been defined. Function, together with pain, patient satisfaction, revision surgery, adverse events and deaths, were included in the inner circle, meaning the core domains that should be mandatorily used in every trial. Furthermore, it is of upmost importance that all authors of clinical trials on this topic adopt the same sets of domains and measure of outcomes, so that it will be easier to summarize the evidence comparing knee arthroplasty clinical trials. The purpose of our study was to summarize the current trends in the literature in terms of outcome measurements for evaluating physical function.

Methods

MEDLINE, Cinhal, Web of Science and Cochrane library were queried utilizing keywords pertinent to TKA, UKA, physical function, clinical trials, measures of outcome. Clinical trials on knee joint replacement were included only if published in the last 5 years and reporting data on functional outcomes and pain. Articles that had as a main topic anesthesia, tourniquet use, or tranexamic acid were excluded. Descriptive statistics was used to summarize the evidence.

Results

One-hundred-and-eighty-one articles met the inclusion criteria. Overall, 50 different outcome measurements were used among the studies to evaluate clinical outcomes after knee arthroplasty. The most adopted Patient Reported Outcomes measures were Knee Society Score (KSS) in 78 (43,1%) studies, Western Ontario and McMaster Universities Arthritis Index (WOMAC) in 62 (34,3%) articles, Oxford Knee Score (OKS) in 51 (28,2%) and Knee Injury and Osteoarthritis Outcome Score (KOOS) in 36 (20%). The most used Performance-Based Outcomes (PBO) were Time-up and go test in 30 studies (16,6%) and 6-minute walk test in 21 articles (11,6%). Range of motion was used by 74 studies (40,9%). Papers focused on rehabilitation programs were more prone to use PBO compared to those on the surgical procedure (68,9% vs. 7%). Only 51,4% of the articles reported any adverse events occurred to participants.

Discussion

The main finding of this review was that there is still a wide heterogeneity in the literature on knee replacement in reporting functional outcomes. Physical function is a domain that is critical for a successful arthroplasty and can be measured both with subjective and objective assessments. None of the measurements of outcome included in this review has showed some superiority compared to the others. It is critical that in the next years the community will reach a consensus on how to measure physical function.