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The Modular Control of Walking in Patients with Knee Osteoarthritis

Investigators closely examine the differences between neuromuscular changes associated with normal aging and those associated with age-related disorders and how they affect individuals with knee osteoarthritis.

Results from a new study indicated that modular control of gait may become impaired due to the combined effects of knee osteoarthritis (KOA) and aging.

The study, “Effects of age and knee osteoarthritis on the modular control of walking: A pilot study” was conducted by a team led by Sarah Roelker, PhD, Department of Kinesiology, University of Massachusetts Amherst.

Reduced locomotor function and altered muscle activity is usually exhibited in older adults with knee osteoarthritis. The prevalence of gait impairment increases with age and is found in 32% of older adults.

The Motivation

Investigators aimed to identify changes to the modular control of gait that are related to age and knee osteoarthritis in order to gain insight into the neurological mechanisms underlying reduced walking performance in these populations.

The objective of this pilot study was to determine if there are differences between the modular control of walking in younger and older adults without knee osteoarthritis as well as adults with end-stage knee osteoarthritis.

Previous data has shown that functional limitations in older adults is predictive of future disability, falls, pain, and medical expenses. These limitations include difficulty walking, climbing stairs, or crouching.

The age-related changes in muscle function that lead to functional limitations like these are caused by impaired neuromuscular activity. Investigators emphasized the difference between neuromuscular changes associated with normal aging and those associated with age-related disorders.

The Study

In this cross-sectional study, the groups of participants consisted of 10 younger adults without knee osteoarthritis, 10 older adults (55-75 years of age) without knee osteoarthritis, and 10 adults with primarily medial compartment knee osteoarthritis.

Investigators collected kinematic, kinetic, and electromyography data as a secondary analysis of previously reported data that assessed how the individuals walked at their self-selected speed.

Orthopedic surgeons identified potential participants for the cohort of individuals with knee osteoarthritis based on consultation for a total knee arthroplasty. These individuals were a subset of participants from another study that investigated gait biomechanics before and after total knee arthroplasty.

Among the requirements for inclusion were a body mass index (BMI) less than 45, ability to walk 20 meters without assistance, and no history of osteotomy or total knee arthroplasty.

The number of modules required to reconstruct each individual’s electromyography was determined by separate non-negative matrix factorizations of 500 bootstrapped samples.

The Results

The younger adults required a greater number of modules than the adults with knee osteoarthritis. Neither of these cohorts resulted with a significant difference in the required number of modules from the older adults without knee osteoarthritis.

However, a significant association was displayed between module number and walking speed. Individuals with knee osteoarthritis walked significantly slower than the younger adults.

Altered module activation patterns and composition, were also observed in individuals with knee osteoarthritis compared with the older adults without knee osteoarthritis.

“These findings suggest aging alone may not significantly alter modular control,” investigators wrote, “however, the combined effects of knee osteoarthritis and aging may together impair the modular control of gait.”

The study, “Effects of age and knee osteoarthritis on the modular control of walking: A pilot study” was published in PLOS One.