Knee osteoarthritis (OA) is a painful condition that can substantially interfere with peoples’ daily activities. It will affect one in two people over their lifetime and is more likely in people who are overweight (Murphy et al., 2008).
In light of the existing literature regarding joint function in people with knee osteoarthritis, we wrote a recent editorial on a study by researchers from The University of Delaware (Kumar et al., 2014) to discuss some of the points raised.
WHAT DID WE DISCUSS?
The study investigated the sense of movement (termed Proprioception) in people with knee osteoarthritis to see if proprioception is accompanied by functional deficits in the ability to detect and respond to disturbances to balance.
Despite the common practice of clinicians to prescribe exercise intended to improve proprioception, there is mixed evidence regarding whether deficits exist in knee osteoarthritis and how this relates to disease progression and peoples’ function.
Proprioception is one of several factors important to balance and avoiding falls. Though the risk of falls is known to be greater for people with knee OA (Sturnieks et al., 2004), the authors unexpectedly found a remarkable similarity between people with knee osteoarthritis and healthy controls in their ability to respond and adapt to simulated slips while walking.
This was tested by having people walk over a platform that was moved when they planted their foot and repeated over multiple trials to see if people learnt to adapt. Separate, specific measures of proprioception at the knee joint were also made, but were limited somewhat by the particular methods used (Proske & Gandevia, 2012).
SIGNIFICANCE AND IMPLICATIONS:
There is evidence that altered joint function, which may change the way force is applied across the joint, contributes to the development and progression of knee osteoarthritis. This has prompted exercise interventions that are tailored to alter joint function.
The study by Kumar et al. (2014) adds to the existing literature that suggests that such tailored training may not be needed.
Barry BK, & Sturnieks DL (2014). How important are perturbation responses and joint proprioception to knee osteoarthritis? J Appl Physiol, 116, 1–2.
Kumar D, Swanik CB, Reisman DS, Rudolph KS (2014). Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments. J Appl Physiol 116,13-23.
Murphy L, Schwartz TA, Helmick CG, Renner JB, Tudor G, Koch G, Dragomir A, Kalsbeek WD, Luta G, and Jordan JM (2008). Lifetime risk of symptomatic knee osteoarthritis. Arthritis Rheum 59, 1207-1213.
Proske U, and Gandevia SC (2012). The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force. Physiol Rev 92, 1651-1697.
Sturnieks DL, Tiedemann A, Chapman K, Munro B, Murray SM, and Lord SR (2004). Physiological risk factors for falls in older people with lower limb arthritis. J Rheumatol 31, 2272-2279.