Asymptomatic and symptomatic individuals with the same radiographic evidence of knee osteoarthritis walk with different knee moments and muscle activity

Abstract

There is an established discordance between the structural joint damage and clinical symptoms of knee osteoarthritis; however, there has been little investigation into the differences in joint level biomechanics and muscle activation patterns during gait between symptomatic and asymptomatic individuals with the same radiographic evidence of osteoarthritis. The objective of this study was to examine three-dimensional knee joint biomechanics and muscle activation differences during gait between asymptomatic and symptomatic individuals with radiographic knee osteoarthritis. A total of 54 asymptomatic and 59 symptomatic individuals with a Kellgren-Lawrence osteoarthritis radiographic grade of 2 underwent a comprehensive gait analysis to examine differences in the magnitude and patterns of the knee flexion angle, three-dimensional net resultant moments, and electromyography of the quadriceps, hamstrings, and gastrocnemii during over ground walking between the two groups. The symptomatic group walked with significantly higher overall magnitudes and less mid-stance unloading of the net resultant knee adduction moment, lower peak flexion moments, and higher lateral hamstrings and quadriceps activity during stance than the Asymptomatic group (p < 0.05, sex-adjusted analysis), with a trend (p = 0.07) toward greater transverse plane range of moment over stance. The differences found suggest a "stiffer" frontal and sagittal plane pattern with symptomatic individuals, but with more muscle activity and a trend toward more torsional loading in the transverse plane, which may have implications for shear loading of the joint. This is the first evidence of differences in three-dimensional knee joint biomechanics and muscle activation between asymptomatic and symptomatic individuals with the same radiographic grade. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1661-1670, 2017.

Baseline Gait Muscle Activation Patterns Differ for Osteoarthritis Patients Who Undergo Total Knee Arthroplasty Five to Eight Years Later From Those Who Do Not

“…Our study also identified prolonged quadriceps activity, which is a feature not previously associated with structural progression. This prolonged quadriceps activity and increased, prolonged LH activity combination was previously found in symptomatic versus asymptomatic groups with similar radiographic OA (20) and in clinically severe versus moderate OA groups (25), suggesting a relationship between prolonged muscle activity and symptoms. TKA decision‐making is multifactorial, where symptomatic changes are considered (13,14), and thus, these changes suggest 1 potential mechanism by which prolonged muscle activation could lead to TKA.…”

“…The second unique feature captured the difference between KFM in early‐stance and late‐stance knee extension moment (10). Smaller differences for both features indicated less unloading, consistent with a stiff leg gait pattern (20), where the TKA group had reduced unloading of the knee (10). This sustained loading pattern is comparable to animal models showing that static loads produce significantly more tissue damage than dynamic loads of similar magnitude (21), and to human research showing that asymptomatic participants with cartilage loss have smaller late‐stance maximum external knee extension moments and higher serum proinflammatory cytokine concentrations than controls (22).…”

“…Cross‐sectional studies show that those with knee OA have higher, prolonged quadriceps and higher lateral hamstrings (LH) activity than asymptomatic controls (25,26). Furthermore, these alterations were related to knee OA symptoms (20). Muscle activity and structural progression have been examined where longer duration medial muscle coactivation was correlated with decreased medial knee cartilage volume at 2‐year follow‐up (27).…”

Discordance between radiographic findings, pain, and superficial temperature in knee osteoarthritis

“…Our data also confirmed the discordance between pain perception (VAS) and Kellgren-Lawrence classification, previously observed by several studies [1,5,6]. Thus, self-reported knee pain is an imprecise marker of radiographic knee OA [1].…”

“…Standard assessment of joint degeneration is usually made by radiographic images that evaluate the presence of osteophytes and joint space narrowing [5]. However, individuals presenting knee pain do not always have radiographic evidence of OA, and many asymptomatic patients may have severe structural damage in the knee joint [6].…”