Assessing neuromuscular control in knee osteoarthritis

Background: Individuals with knee osteoarthritis (KOA) exhibit reduced muscle strength and proprioception (biomechanical impairments) (1). These biomechanical impairments have been shown to be predictive of functional outcomes, where by it is thought that poor muscle strength and proprioception impairs neuromuscular control (NC), negatively impacting on functional outcomes in KOA (2). The purpose of this study was to assess how biomechanical impairments determine the loss of NC and subsequently impacts on disease severity in KOA.

Methods or theme: Biomechanical impairments of 77 symptomatic KOA participants (62.5¿±¿8.1 yrs; 29.4¿±¿6.0¿kg/m2) and 18 controls (62.5¿±¿10.4 yrs; 24.3¿±¿3.7¿kg/m2), were assessed, including muscle strength of the knee flexors and extensors, and passive position sense (proprioception). NC was determined from submaximal force accuracy and steadiness (3,4) and muscle co-activation(CI) (5) during gait for anterior-posterior and medial-lateral muscles. MRI Boston Leeds Osteoarthritis Knee Score (BLOKS) were used to assess disease severity Linear regression and Pearson correlations were performed to assess the relationships between biomechanical impairments, neuromuscular control and health outcomes.

Results: Biomechanical impairments (muscle strength and proprioception) and their interactions significantly predict loss of NC. Muscle CI, but not force accuracy or steadiness was weakly correlated with cartilage damage and osteophyte formation.

Conclusions: Muscle weakness and poor proprioception predict the loss of NC in participants with KOA, suggesting both passive and active joint structures may influence NC. When looking at the impact of loss of NC muscle CI measures showed weak relationships with structural damage for both KOA and control participants.