Relative difference in muscle strength between patients with knee osteoarthritis and healthy controls when tested bilaterally and joint-inclusive: an exploratory cross-sectional study

Abstract

BackgroundTo improve the goal-directedness of strength exercises for patients with knee osteoarthritis (KOA), physical rehabilitation specialists need to know which muscle-groups are most substantially weakened across the kinetic chain of both lower extremities. The purpose was to improve the knowledge base for strength exercise therapy. The objective was to explore the relative differences in muscle strength in the main directions bilaterally across the hip, knee, and ankle joints between patients with light-to-moderate symptomatic and radiographic KOA and people without knee complaints.MethodsThe design was an exploratory, patient vs. healthy control, and cross-sectional study in primary/secondary care. Twenty-eight patients with mild to moderate KOA (18 females, mean age 61) and 31 matched healthy participants (16 females, mean age 55), participated. Peak strength was tested concentrically or isometrically in all main directions for the hip, knee, and ankle joints bilaterally, and compared between groups. Strength was measured by a Biodex Dynamometer or a Commander II Muscle Tester (Hand-Held Dynamometer). Effect sizes (ES) as Cohen’s d were applied to scale and rank the difference in strength measures between the groups. Adjustment for age was performed by analysis of covariance.ResultsThe most substantial muscle weaknesses were found for ankle eversion and hip external and internal rotation in the involved leg in the KOA-group compared to the control-group (ES [95% CI] −0.73 [−1.26,-0.20], − 0.74 [−1.26,-0.21], −0.71 [−1.24,-0.19], respectively; p < 0.01). Additionally, smaller but still significant moderate muscle weaknesses were indicated in four joint–strength directions: the involved leg’s ankle inversion, ankle plantar flexion, and knee extension, as well as the uninvolved leg’s ankle dorsal flexion (p < 0.05). There was no significant difference for 17 of 24 tests.ConclusionsFor patients with KOA between 45 and 70 years old, these explorative findings indicate the most substantial weaknesses of the involved leg to be in ankle and hip muscles with main actions in the frontal and transverse plane in the kinetic chain of importance during gait. Slightly less substantial, they also indicate important weakness of the knee extensor muscles. Confirmatory studies are needed to further validate these exploratory findings.

WITHDRAWN: Predictive potentials of 8 muscle strength actions, KOOS-pain, and Örebro-psychosocial difficulties on self-reported activities-of-daily-life function in patients with knee osteoarthritis: an exploratory regression-based cross-sectional study

“…For a full description of the 12-variable strength-testing procedure, cf. our discriminative strength study (28). Here we present procedures for the 8 strength actions in the current study.…”

“…However, the importance of muscle strength deficits in various joint─strength directions between patients and healthy controls shown in a recent meta-analysis (19) has yet to be evaluated in clinical trials. Adding to the strength discrimination knowledge, we just presented the apparently first study (28) to compare a comprehensive list of lower-limb strength actions between patients with KOA and healthy controls. The most substantive relative strength deficits were indicated for the hip rotator muscles, closely followed by that of the ankle invertor-evertors, and the knee extensor muscles.…”

“…However, according to systematic reviews (21,36) neither existing cross-sectional relational nor prospective studies has yet systematically explored the predictive potential/cross sectional relationships of the most discriminative joint─strength actions (28) towards the primary KOA-outcome SR-ADL function. Especially not so when adjusted for prior known important predictive variables.…”

Wireless Motion Sensors—Useful in Assessing the Effectiveness of Physiotherapeutic Methods Used in Patients with Knee Osteoarthritis—Preliminary Report

“…Although all assessed parameters are relevant, a truly comprehensive assessment of OAK patients would require an evaluation of other biomechanical parameters. Other authors have focused on muscle activation patterns and strength measured by EMG [54][55][56] and dynamometers [57,58], as well as gait analysis, measured via visual or inertial motion capture systems [59][60][61][62].…”

Effects of a foot-ankle strengthening programme on clinical aspects and gait biomechanics in people with knee osteoarthritis: protocol for a randomised controlled trial

“… 15 16 However, previous studies on KOA reported that weak foot-ankle muscles cause kinetic alterations in the frontal and transverse planes during gait. 17 Moreover, Røsland et al 18 observed that foot muscle strength deficits in individuals with KOA were directly related to increased knee pain and stiffness, decreased physical function and more severe KOA. Uritani et al 19 also demonstrated that women with KOA have less plantar grip strength, a deficit which may contribute to changes in the kinetic chain of the lower limb during gait.…”