Exercise as it relates to Disease/Can home-based exercises help reduce knee pain?

This is a critique of the article "Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial" KS thomas, et al (2002) 
What is the background to this research?
Knee pain caused by knee osteoarthritis is the single most common cause of disability in older adults. The aim of this research was to determine if there would be a reduction in knee pain by simply introducing a 20 to 30-minute exercise intervention in people with knee pain. Although exercise is a common treatment for knee osteoarthritis, patients often seek the attention of physiotherapists. As knee pain is a common problem a less expensive more accessible treatment is ideal. Knee osteoarthritis is a result of the loss of articular cartilage typically found in elderly population. It can also result from wear and tear in the knee joint as people age or from abnormal concentration of force across the knee. Knee osteoarthritis is the most diagnosed type of arthritis and is only set to rise as life expectancy and obesity in people increases.
Where is the research from?
This research was conducted through two general practices in Nottingham where a postal survey was sent to male and females over the age of 45. The authors of the research had backgrounds in rheumatology and access to funding from the department of health.
What kind of research was this?
The research was a randomised controlled trial over two years. Participants were divided into four groups as follows:
1. Three groups received an intervention:
a. One group engaged in an exercise program;
b. One group received a monthly telephone call; and
c. One group received both an exercise program and a monthly telephone call.
2. The fourth group received no intervention.
Participants in the exercise and telephone call group and participants in the no intervention group were randomised to receive or not receive a placebo health food tablet.
What did the research involve?
The research involved participants aged 45 years old and over who were required to meet the following requirements:
1. They had not had a total knee replacement, lower limb amputation or a permanent cardiac pacemaker;
2. They provided informed consent; and
3. Had experienced no knee pain within the previous week.
786 people were recruited for the research – 470 for the exercise group and 316 for the non-exercise group. A limitation of this group of people is that all participants were recruited from two family practices in Nottingham. This does not provide a broad representation of the population, noting that low socioeconomic status is associated with a higher risk of developing arthritis. 
While the research points to exercise as being beneficial in reducing knee pain, there are limitations to people’s ability to exercise. For example, a person’s socioeconomic status and environmental factors can influence and reduce their ability to exercise.
The research was carried out over two years and the results recorded in six-month intervals. The participants who were assigned exercise intervention were required to perform a 30-minute exercise using both legs, increasing repetitions up to a maximum of 20 repetitions per leg. The programme was designed to strengthen the muscles around the knee and to increase range of motion. The authors did not go into detail about the exercises performed, stating only that the use of graded exercise bands was used. Having not stated the exact exercise interventions performed makes it difficult for the reader to understand and draw their own conclusion from the results.
What were the basic results?
Results were self-reported using a knee specific questionnaire from the Western Ontario and McMaster University (WOMAC) Osteoarthritis Index. The Osteoarthritis Index is based on pain, stiffness, and physical function. The pain score ranges from 0-20 with the higher score being more painful. The results showed the exercise intervention group did have an average of 12% reduced pain over the two-year period.
What conclusions can we take from this research?
The study was aimed at measuring the effect of prescribed home-based exercise on reducing knee pain in adults 45 years and older. There was a reduction in self-reported knee pain in exercise group compared with the non-exercise group. Although there was a reported reduction in pain, a large percentage of participants did not complete the two-year intervention with only 48.1% of the exercise group (226 people) completing the programme.
Practical advice.
Aerobic and strength home based exercise can help manage and reduce knee pain. It is important to maintain a fit and healthy body to reduce immobility. Low impact aerobic exercises such as cycling, and walking are a great way for the elderly population to maintain fitness. Strength training for the muscles surrounding the knee joint is important for older people and in particular those with knee pain. Simple exercises such as sitting then standing (sit/stands – where the person sits on a chair, stands, and then sits on the chair until the desired amount of repetitions is reached) and leg crosses can be beneficial and performed in a safe manner. Leg crosses require the person to sit on the edge of a table, bed or seat. The person then crosses their ankles with straight legs and pushes their front leg backwards and the back leg forward until the thigh muscles become tense. This exercise can be held for one minute and then the person may rest for two minutes, and then the exercise repeated a further two times before switching legs.
Further information/resources.
https://www.arthritis.org/home
https://www.versusarthritis.org/about-arthritis/conditions/osteoarthritis-of-the-knee/