Exercise as it relates to Disease/Effectiveness of Aquatic Physical Therapy for the Improvement of Osteoarthritis of the Hip and Knee

Osteoarthritis is characterised by joint stiffness, pain, loss of mobility and reduced muscle strength which is due to the degeneration of the articular cartilage of the joints. As the population continues to age, it is expected that osteoarthritis prevalence is going to increase and continue to be one of the most prevalent musculoskeletal conditions for those aged over 65.

Physical therapy in general aims to manage symptoms by increasing muscle strength, balance and joint mobility. A common prescription is aquatic physical therapy and is used for the management of symptoms in patients with osteoarthritis of the hip and knee. This study aims to verify the effectiveness of aquatic therapy in managing symptoms and determine how sufferers might incorporate it into their management regimen.

The Research

This study was published in an online journal that came from the Centre for Health Exercise and Sports Medicine from the University of Melbourne in Victoria, Australia. This study was conducted by Rana S Hinman, Sophie E Heywood and Anthony R Day.

Research Type

This randomized control trial was conducted using quantitative data collection to determine the objective effects that aquatic therapy had on the common symptoms of osteoarthritis. It also used qualitative data in the way of questionnaires to determine the subjective measures of perceived improvements.

Research Protocol

This study was conducted on participants over 50 years of age with either hip or knee osteoarthritis as determined by the American College of Rheumatology classification criteria. A cohort of 71 participants met the criteria required and from that, 36 were randomly assigned to twice a week sessions for a period of 6 weeks of aquatic based therapy. The remaining 35 were assigned to a control group who would not take part in the intervention.

Both sets of subjects were assessed prior to the 6 week period and again at the end using the VAS pain scale to assess pain with movement. Secondary tests involved:

• WOMAC questionnaire for perceived pain and stiffness
• Isometric muscle tests for hip abduction and knee extension
• Dynamic step test for balance
• Timed “Up and Go” test to determine functional capacity to get in and out of an armchair
• 6 minute walk test to determine the capacity to walk as far as possible in the time period

Subjects were retested 6 weeks post intervention to determine the retention of any short term benefits experienced.

Results of the Study

Primary outcomes showed that at the end of the therapy the aquatic group on average reported a 33% reduction in pain with joint movement from their original assessment. Also in regards to overall pain, joint stiffness and physical function, the participants were 12 times more likely to report improvements than those who did not participate in the therapy. Secondary outcomes of hip muscle strength and quality of life were improved. However, quadriceps strength, balance step test and timed “Up and Go” tests did not report significant improvements over the control group. These results also appeared to remain 6 weeks post therapy cessation.

Interpretation of the Results

The researcher’s overall interpretation of the results indicated that the improvements in physical function, joint stiffness and reduction in pain were believed to be primarily attributed to the marginal increase in quadriceps strength and the larger increase in hip muscle strength. Hip muscle strength is seen to be correlated with improved pelvis stability while walking and quadriceps femoris strength is associated with decreased knee pain severity. Continuous supervision and minimal equipment were factors that contributed significantly to adherence. Factors such as warm water temperature and water pressure may have in part contributed to the reduction in pain and joint stiffness. The reduced loading on affected joints due to buoyancy may also have been a contributing factor that increased the ability to perform activities and increased adherence.

Conclusions

The conclusions that should be taken away from this research are that aquatic based therapy will show for improvements in:

• Joint Stiffness
• Physical Function
• Pain Reduction
• Hip Muscle strength
• Quality of life

It is important to note that along with therapy other factors associated with warm water immersion may also help to reduce pain and improve movement.

Practical Implications

Research suggests that aquatic based therapy 2-3 times a week is a good mechanism to improve symptoms and quality of life for sufferers with osteoarthritis of the hip or knee. This may make it a viable option over land based therapy in sufferers that have difficulty in performing exercise and poses as a stepping stone to progressing to exercise on land. There has been little evidence to suggest that aquatic based therapy is more effective than a gym based program with other studies showing larger increases in muscle strength with land based activities. However pain is a limiting factor in performing exercise of which can be minimised through aquatic therapy, therefore a preferred exercise regimen would be a combination of both.

Other studies showed that in 6 month follow ups the benefits of therapy did not continue to be apparent. This indicates that aquatic therapy must be maintained consistently for long term improvements to be retained. Compliance to any regime becomes important and this is increased with aquatic therapy as it makes performing exercises less painful and has minimal adverse effects.

Limitations of the Study

This study did not have the capacity to separate the benefits of therapy for hip or knee osteoarthritis therefore highlighting the need for further research on joint specific measures. The absence of a placebo control as well as a relatively short follow up period may have reduced its capacity to predict long term effects. This study also used very minimal equipment and in future research the use of resistance aids may contribute to an increase in muscle strength and positive results.

Further reading

Osteoarthritis, Causes, Symptoms, Treatments

Aquatic Therapy Overview

Benefits of Aquatic Therapy

Types of Aquatic Therapy