Exercise as it relates to Disease/Interventions for obese patients with knee osteoarthritis - Underwater vs. home exercise?

Original research article: 'Is four-week underwater treadmill exercise regimen compared to home exercise efficacious for pain relief and functional improvement in obese patients with knee osteoarthritis?'

What is the background to this research?

Knee osteoarthritis is a chronic, musculoskeletal disease that results in knee joint degeneration, causing pain and adverse functioning. The degradation of articular cartilage causes the joint to stiffen, reducing motility and creating discomfort. The condition affects an individual's ability to perform everyday activities, leading to decreased physical activity levels and increased weight gain. Obesity and major knee injury are primary risk factors for knee osteoarthritis within older adults. A 2016 Cochrane Systematic Review evaluated a 12-week aquatic exercise program. Cochrane reviews are prepared by researchers and evaluate research articles findings, aimed at minimizing bias and producing reliable conclusions to inform decision making. Bartels et al. found that aquatic exercise reduces pain significantly in individuals with knee or hip osteoarthritis. This finding together with others, ignited investigation into a research gap regarding a newer exercise intervention. This being the underwater treadmill (UTM), as an alternative rehabilitation technique for knee osteoarthritis.

Where is the research from?

The study was conducted in Bangkok, at Thailand's largest national referral centre; the rehabilitation department of the Siriraj Hospital. This research study was financially supported by a grant from the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. However, the authors have declared no potential conflicts of interest with respect to the research, authors or publication of the article. Author Vilai Kuptniratsaikul is an Associate Professor at Mahidol University, Bangkok, and expert in geriatrics and clinical rehabilitation. She has published many research studies investigating issues within this area, such as a well-known study that evaluated pharmaceutical efficacy and safety of Curcuma domestica extracts against ibuprofen, in patients with knee osteoarthritis.

What kind of research was this?

This research study was conducted using a randomized controlled trial (RCT). The design of this study type is to randomly assign participants into two or more intervention groups, in order to reduce bias. RCTs are considered a gold standard within research studies and a deliver high levels of evidence. They are beneficial for evaluating efficacy and safety of new treatments, and useful for comparing data between multiple groups. RCTs are best suited for this study, to contrast the effectiveness of UTMs against home exercise interventions.

What did the research involve?

Participants were selected based on inclusion criteria (conditions of acceptance, targeting characteristics being assessed by the study): aged 50–80 years, primary knee osteoarthritis, rating ⩾5 mild-moderate knee pain, and a body mass index value of ⩾ 25 kg/m2. Eighty participants were chosen and randomly allocated into the study or control group. The control group were given exercise brochures and instructed to perform daily quadriceps exercises, at home for 30 minutes. The study group participated in three 30-minute UTM sessions per week, at the hospital pool. Baseline measures of pain score, quadriceps strength, body weight and six-minute walking distance, were taken prior to and following the four-week research period. Global assessment, adverse events and satisfaction were also assessed following the study. The research study consisted of many limiting factors. The researchers refer to the home exercise group as the 'control' group; however, by definition, a control group is an experimental group that receives no treatment. Yet this group is an intervention group used as a standard for comparison to contrast UTM aquatic exercise. The inconvenience of participants travelling to attend hospital for UTM sessions, resulted in 5 participants withdrawing. The study includes only exercise based and no dietary based interventions. The study had no long-term follow-up, which would have been beneficial for assessing if participants continued performing an exercise intervention. A longer research period would have given a better indication of weight loss and fat-mass reduction.

What were the basic results?

The main findings of the study were that all patient outcomes improved by the end of the study, with the exception of body weight. Compliance did not differ between groups and there was no significant difference between joint or muscle pain, or pain medication consumption between the two groups. Those in the study group recorded higher patient satisfaction compared to those in the control group. This is not surprising as participating in a UTM program would be new and exciting. The researchers used the results to assess each intervention in terms of pain management and functional improvement and compare the benefits and limitations of implementing the exercise regimes within the target population.

What conclusions can we take from this research?

From this study it can be acknowledged that a UTM exercise regime proves to be just a effective as a home exercise program, in reducing pain associated with knee arthritis in obese individuals. However, it was concluded that UTM does not lead to short-term symptomatic functional benefits, but suggests further research would be required to prove this long term. The exercise intervention used is not crucial to the condition management with each having advantages and disadvantages. Aquatic UTM exercise offers variety, yet is situated at a public pool and can be expensive. Home exercises are convenient and easy to perform, but are not professionally supervised and patients can become unmotivated, and exercises repetitive. Therefore patients may choose an avenue best suited to their preference, situation and personal circumstances.

Practical advice

The study demonstrates that land-based and aquatic interventions are effective for pain management and improving knee function of obese osteoarthritis patients. Various exercise regimes have both benefits and limitations, so individuals should choose a regime best suited to them. Those suffering should consult an appropriate healthcare professional, such as a doctor or physiotherapist, before commencing any exercise regime to ensure it is catered to their individual needs, they understand the program and are able perform it safely.

Further Information

• Information about managing osteoarthritis, resources and support, can be found on the Arthritis Australia website: https://arthritisaustralia.com.au/ and the website of the arthritis organisation of each state/territory.
• Inspire Arthritis Foundation - online arthritis support group/discussion community: https://www.inspire.com/groups/arthritis-foundation/