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Posted By: Richard S. Pope, PA-C, MPAS
May 28, 2021
Osteoarthritis (OA) of the knee is one of the most common musculoskeletal conditions treated in this country. According to NIH statistics, in 2005 there were 26.9 million adults with clinical OA, which includes those with knee OA. There are multiple causes of knee OA, including biomechanical imbalances, peripheral neuropathy, central nerve processing, inflammation, prior injury and/or surgery, weight management, poor muscle strength, genetics, metabolic conditions, and overuse. In addition to those possible causes, we must consider the patient's emotional status, subjective pain sensitivity, occupation, comorbid conditions, and living space.
As a rheumatology PA, I am interested in low-tech, high-value management techniques for OA, 2 of which have emerged recently. The first is the role of gardening in association with knee pain. A retrospective, cross-sectional study was published in Osteoarthritis and Cartilage in 2018. Though it involves bending at the waist, kneeling, and lifting heavier weights, during the study period, a 20% improvement in knee OA pain was seen in the gardening group. It is not clear exactly what led to this reduction in pain, but I believe it was likely due to slightly lower body weight along with decreased levels of depression in the gardening group.
A second study published in 2020, referred to as BIOTOK, was a randomized clinical trial initiated through a Swiss university hospital that employed an advanced orthotic for knee OA (designed by AposTherapy, APOS Medical Assets). In the trial, 220 participants with radiologic evidence of knee OA and knee pain were randomized in a 1:1 ratio to treatment (n = 111; an orthotic with adjustable external convex pods attached to the outsole) or control (n = 109; footwear that had visible outsole pods that were not adjustable and did not create a convex walking surface). Participants were stratified based on affected compartment (medial or lateral).
The primary outcome was knee pain at 24 weeks; pain was measured using a Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain score from 0 (no symptoms) to 10 (extreme symptoms). A 30% reduction in WOMAC pain score was seen in 92% of the biomechanical intervention group vs 58% in the placebo group; a 50% reduction in WOMAC pain score was seen in 83% of the intervention group vs 42% of the placebo group. This study hypothesized that with specific orthotic adjustments to accommodate the painful arthritic knee, one could recondition the neuromuscular system and improve pathologic gait patterns—thereby reducing pain.
So, with a few changes in lifestyle (eg, gardening along with adjustable, convex-surfaced orthotic footwear) individuals with knee OA could sustain a significant improvement in pain and overall functioning. The question that remains is whether these low-tech, high-value adjustments could stave off knee surgery. Future studies will be needed to address this.
- Lawrence RC, et al. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis Rheum. 2008;58:26.
- Lo G, et al. Gardening associates with less knee pain: data from the osteoarthritis initiative. Osteoarthritis and Cartilage. 2018;26:S246.
- Reichenbach S, et al. Effect of biomechanical footwear on knee pain in people with knee osteoarthritis: The BIOTOK randomized clinical trial. JAMA. 2020;323:1802.