Exercise for osteoarthritis of the knee
Abstract
Background
Biomechanical factors, such as reduced muscle strength and joint malalignment, have an important role in the initiation and progression of knee osteoarthritis (OA). Currently, there is no known cure for OA; however, disease‐related factors, such as impaired muscle function and reduced fitness, are potentially amenable to therapeutic exercise.
Objectives
To determine whether land‐based therapeutic exercise is beneficial for people with knee OA in terms of reduced joint pain or improved physical function.
Search methods
Five electronic databases were searched, up until December 2007.
Selection criteria
All randomized controlled trials randomising individuals and comparing some form of land‐based therapeutic exercise (as opposed to exercises conducted in the water) with a non‐exercise group.
Data collection and analysis
Two review authors independently extracted data and assessed methodological quality. All analyses were conducted on continuous outcomes.
Main results
The 32 included studies provided data on 3616 participants for knee pain and 3719 participants for self‐reported physical function. Meta‐analysis revealed a beneficial treatment effect with a standardized mean difference (SMD) of 0.40 (95% confidence interval (CI) 0.30 to 0.50) for pain; and SMD 0.37 (95% CI 0.25 to 0.49) for physical function. There was marked variability across the included studies in participants recruited, symptom duration, exercise interventions assessed and important aspects of study methodology. The results were sensitive to the number of direct supervision occasions provided and various aspects of study methodology. While the pooled beneficial effects of exercise programs providing less than 12 direct supervision occasions or studies utilising more rigorous methodologies remained significant and clinically relevant, between study heterogeneity remained marked and the magnitude of the treatment effect of these studies would be considered small.
Authors' conclusions
There is platinum level evidence that land‐based therapeutic exercise has at least short term benefit in terms of reduced knee pain and improved physical function for people with knee OA. The magnitude of the treatment effect would be considered small, but comparable to estimates reported for non‐steroidal anti‐inflammatory drugs.
PICOs
Plain language summary
Exercise for osteoarthritis of the knee
This summary of a Cochrane review presents what we know from research about the effect of exercise on osteoarthritis (OA).
The review shows that, on average, in people with OA, exercise results in a modest reduction in pain and a modest improvement in physical function.
What is OA of the knee and what is exercise?
Osteoarthritis (OA) is a disease of the joints, such as your knee. When your knee loses cartilage, the bone grows to try and repair the damage. Instead of making things better, however, the bone grows abnormally and makes things worse. For example, the bone can become misshapen and make the joint painful and unstable.
Doctors used to think that osteoarthritis was caused by wear and tear on the cartilage. However, it's now thought that osteoarthritis is a disease of the whole joint.
OA is one of the most common forms of arthritis and affects men and women equally. OA is one of the main causes of disability as people grow older.
Exercise can be any activity that enhances or maintains muscle strength, physical fitness and overall health. People exercise for many different reasons including weight loss, strengthening muscles and to relieve the symptoms of OA.
Best estimate of what happens to people with OA who exercise:
In the short term, a supervised exercise program:
Reduces knee pain by 1 point on a scale of 0 to 20; and
Improves knee function by 3 points on a scale of 0 to 68.
