To assess the evidence for the efficacy of the following interventions for improving clinical outcomes in adults with osteoarthritis (OA) of the knee: cell-based therapies; glucosamine, chondroitin, or glucosamine plus chondroitin; strength training, agility, or aerobic exercise (land or water based); balneotherapy, mud bath therapy; electrical stimulation techniques (including transcutaneous electrical stimulation [TENS], neuromuscular electrical stimulation, and pulsed electromagnetic field therapy [PEMF]); whole body vibration; heat, infrared, or ultrasound; orthoses (knee braces, shoe inserts, or specially designed shoes); weight loss diets; and home-based therapy or self-management.
PubMed, Embase, the Cochrane Collection, Web of Science, and the Physiotherapy Evidence Database (PEDRO) from 2006 to September 2016, and ClinicalTrials.gov and the proceedings from the 2015 American College of Rheumatology annual meetings.
We included randomized controlled trials conducted in adults 18 years or over diagnosed with OA of the knee, comparing any of the interventions of interest with placebo (sham) or any other intervention of interest that reported a clinical outcome (including pain, function, and quality of life). We also included single-arm and prospective observational studies that analyzed the effects of weight loss in individuals with OA of the knee on a clinical outcome. Standard methods were used for data abstraction and analysis, assessment of study quality, and assessment of the quality of the evidence, according to the Agency for Healthcare Research and Quality Methods Guide. Findings were stratified according to duration of interventions and outcomes: short term (4–12 weeks), medium term (12–26 weeks), and long term (>26 weeks).
Evidence was insufficient to draw conclusions about the effectiveness of many interventions, largely due to heterogeneous and poor-quality study design, which limited the number of studies that met inclusion criteria and could be pooled. Interventions that show beneficial effects on short-term outcomes of interest include TENS for pain (moderate strength of evidence [SoE]); strength and resistance training on Western Ontario and McMaster University Arthritis Index (WOMAC) total scores; tai chi on pain and function; and agility training, home-based programs, and PEMF on pain (low SoE). Interventions that show beneficial effects on medium-term outcomes include weight loss for pain (moderate SoE) and function, of life, , general exercise programs on pain and function, tai chi on pain and function, whole-body vibration on function, and home-based programs on pain and function (low SoE). Interventions that show beneficial long-term effects include agility training and general exercise programs for pain and function, and manual therapy and weight loss for pain (low SoE). Moderate SoE supports a lack of long-term benefit of glucosamine-chondroitin on pain or function, and glucosamine or chondroitin sulfate alone on pain. No consistent serious adverse effects were reported for any intervention. Almost no studies conducted subgroup analysis to assess the participant characteristics associated with better outcomes, and few studies systematically compared interventions head to head. Additional limitations included lack of blinding and sham controls in studies of physical interventions and the potentially limited applicability of study results to patients seen in nonacademic health care settings.
A variety of interventions assessed for their efficacy in treating OA of the knee in this review demonstrate shorter term beneficial effects on pain and function. With the exception of weight loss, agility training, and general exercise programs, few have been tested for or show long-term benefits. Larger randomized controlled trials are needed, with more attention to appropriate comparison groups and longer duration, to assess newer therapies and to determine which types of interventions are most effective for which patients.
