Linear and Curvilinear Relationship between Knee Range of Motion and Physical Functioning in People with Knee Osteoarthritis: A Cross-Sectional Study

Abstract

BackgroundKnee range of motion (KROM) is associated with the ability to perform daily activities in people with knee OA. However, this association is weak, possibly through the use of linear analyses. Curvilinear associations appear much more relevant, as these allow the determination of relevant clinical thresholds in KROM. The goal of this study is to assess the curvilinear association between KROM and daily activities (self-reported and observed) in people with knee osteoarthritis (OA).MethodsDemographic, functional and KROM (flexion and extension) data were collected from a convenience sample of people with knee OA awaiting total knee arthroplasty. Self-reported functioning was measured by use of the Knee Osteoarthritis Outcomes Scale and observed functioning with the timed up and go and six-minute walk test. The presence of curvilinear relationships between KROM and measures of functioning were tested by generalized additive modeling, piecewise regression modeling and receiver operated curves.ResultsData from 110 participants (mean age ± standard deviation: 65 ± 9 and female: 54%) with knee OA were evaluated. Statistical modeling did not reveal linear nor curvilinear associations between KROM and self-reported or observed measures of functioning; except for statistical significant associations between reduced knee flexion and major difficulties standing (p<=0.01). However, further modeling did not provide convincing evidence for relevant clinical associations and thresholds.ConclusionsNo clinically relevant relationship between KROM and self-reported or observed measures of physical functioning could be established, indicating that the limitations in range of motion in the affected knee OA alone do not contribute to poorer functional performance.

Factors associated with poor self-reported function and quality of life in patients with end-stage knee or hip osteoarthritis immediately prior to total joint arthroplasty

“…It is also important to emphasize that in all studies flexion was measured actively, except for the study of Pua et al [20], where flexion was measured passively. However, it is important to point out that only a few of the above-mentioned studies dealt with end-stage knee or hip OA [31,32,34].…”

“…[ 20 ], where flexion was measured passively. However, it is important to point out that only a few of the above-mentioned studies dealt with end-stage knee or hip OA [ 31 , 32 , 34 ].…”

“…Numerous studies have referred to factors related to poor function and HRQoL, where knee OA was more frequently evaluated than hip OA [1,3,5,7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], suggesting that contributions of these factors to disability remain controversial. However, there is limited research referring to the association of different factors with function and HRQoL in end-stage knee or hip OA [29][30][31][32][33][34][35].…”

Modern Trends in Total Knee Arthroplasty

“…Prior to surgery, knee arthritis symptoms can be ameliorated via methods such as exercise, physical therapy, ambulatory assist devices, NSAIDs, and intra-articular injections [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Exercise therapy was found to improve pain levels by 34%, while the new AAOS guidelines for treatment of knee OA no longer supports intra-articular hyaluronic acid injections, as they believe the studies supporting hyaluronic acid to be publication-biased, and that the results were not clinically significant [6,22,25,26].…”

“…Low impact-exercise and physical therapy is often used to manage knee arthritis-related pain and improve function in patients with knee arthritis [14][15][16][17][18]. Fatigue of the quadriceps femoris muscle was found at a much higher rate in patients with knee OA.…”