Exercise as it relates to Disease/Just walk it off: The prospect of physical activity reducing osteoarthritic pain

This is an appraisal of the research article ‘Exercise Training in Treatment and Rehabilitation of Hip Osteoarthritis: A 12-Week Pilot Trial’ (2017) Authors: Uusi-Rasi K, Patil R, Karinkanta S, Tokola K, Kannus P, Sievänen H.

What is the background to this research?
There is general consensus that hip osteoarthritic (OA) pain prospectively leads to surgery without considering alternative routes. For some patients the extenuating costs and processes may not be appropriate. Research on aerobic and strength training as the first form of implementation has shown success in mild to moderate cases of knee OA. Similarly, hip OA could benefit from exercise treatment strategies. There are few clinical trials to date that have examined this, however the results are inconsistent. This article examines specific exercise training around the hip to determine its efficacy and compliance.

Where is the research from?
The article was published by the UKK institute, Tampere, Finland. All authors are employed at the UKK institute and are all experienced with highly regarded academia in the area of epidemiology and physical activity.

What kind of research was this?
This 12-week pilot trial was a prospective observational study, testing the safety and feasibility of a specifically designed exercise program targeting hip OA, to relieve related pain and improve physical function. Thirteen female participants were involved; all aged over 65 years with either unilateral or bilateral hip OA pain. Patients presented with moderate to severe restriction in mobility and debilitating pain with everyday activities. Strict exclusion criteria were applied to reduce the impact of confounding results. Associated studies have developed their research around the benefit of physical activity for treatment for knee OA, therefore this study looked to extrapolate this approach to hip OA. Alternative research approaches include differing exercise types such as Thai Chi, aquatic or higher loads of aerobic activity. There has been a universal emphasis on individualising the program to each participant; considering their aerobic fitness, strength and range of motion.

What did the research involve?
At baseline participants went through 3 forms of assessment in order to develop the training program and compare with post intervention results.
 * Anthropometry: (measured only at baseline) included height weight, body composition and femoral neck bone mineral density via a DXA scan.
 * Self-reported hip joint pain and physical function, utilising Western Ontario and McMaster University Osteoarthritis Index (WOMAC) reflecting overall disability; utilised in many related research articles as a prominent indicator. Error may arise as no qualification is required to complete the WOMAC thus questioning the possibility of bias when self-reporting, resulting in over or underestimated results.
 * Strength, balance and mobility: objective quantitative measures. Assessments included were isometric strength measured with a dynamometer, Short Physical Performance Battery, postural balance using a force platform to determine centre of pressure, balance testing with eyes open or closed. Additionally, pedometers were used to collect number of daily steps taken throughout the entirety of 12 weeks.

Methodology
The exercise program consisted of 3 distinct phases that progressed participants through appropriate neuromuscular and strength stages to meet individual goals and limitations. Programs consisted of both aerobic and resistance components. The stages were implemented well, however, certain prescribed exercises did not relate to the assessment measures, challenging the determination of improvement. Furthermore, as the participant group is female, it is unclear whether males will benefit from similar exercise interventions.

What were the basic results?

 * Overall there was adequate participant tolerance and attendance.
 * WOMAC average pain score and total index decreased approximately 30%; however, large variations in individual results were evident.
 * Joint stiffness, function and balance presented inconsequential change.
 * Isometric leg extensor strength increased 3.8N per body weight.
 * ROM: hip extension increased significantly (30%), conversely hip flexion and abduction did not.
 * Observational increase in participant self-efficacy in balance and stability maintenance (not quantified).

The researchers were able to constructively present their findings without statistical exaggeration. They discussed improvements in population outcome in an articulate and objective manner and explored areas for further research. However, no control group was utilised as a comparison. Additionally, it is unclear whether hip extension in ROM, and leg extensor strength is a worthwhile improvement for this condition. Inclusion of abduction and flexion joint actions may have improved the overall result. More isometric or dynamic strength testing may have provided alternative perspectives. Additional advanced balance exercises (single leg activities) may have heightened the chance for improvement.

Anti-inflammatories and other agents that are commonly recommended for OA patients with an ability to alter perception of pain, thus, impacting data particularly in self-reporting WOMAC scale. Changes in OA medication were not recorded during this intervention. Non-steroidal anti-inflammatory drugs were noted as most consumed. No explanation was given as to why medication was not an inclusion in data collection, despite having been considered in other interventions.

What conclusions can we take from this research?
The research of Uusi-Rasi et. al displayed significant correlation between strength improvement and pain reduction in OA of the knee and hip. Thus, similar protocols may provide improvement for females ≥65 years. Conversely, it is inconclusive whether ROM gains will further reduce pain. For subsequent research, a greater age bracket could determine valid treatment methods for a larger population of hip OA patients. The authors also concluded a larger duration and a longer follow-up period would be ideal. Comparing similar articles, varied responses results have emerged on the type of exercise prescribed and approach by researchers when it comes to predominant outcome measures. Nonetheless, common consequences have led to postponing hip replacement surgery due to the alternative physical activity approach.

Practical advice
This research implied resistance and balance exercises has the ability to reduce OA pain and improve some aspects of functionality. However, further research should be done to identify key muscle groups and exercises that provide optimal results. For patients with OA it is ideal to consult with health care and exercise professionals to achieve beneficial results.

Further information/resources
If you wish to extend your knowledge on OA & physical activity, please follow the links below: