Exercise type & dose on pain & disability in knee osteoarthritis

As you know from our previous blogs some of our woodland friends have osteoarthritis of the knee. “Wouldn’t it be good” they said, “if we knew what the best exercise programmes were for reducing pain and improving our function?”

So we set about searching the literature to see if we could find any evidence to help our friends. We found a recent systematic review examining the best type of exercise with a focus on and what intensity length of program, duration of individual supervised sessions, and number of sessions per week.

Here’s what they did

They searched electronic databases (Medline, EMBase, CINAHL, PEDro, and the Cochrane Central Register of Controlled Trials) up until May 2012. They included Randomised Controlled Trials (RCTs) comparing at least one exercise group to a non-exercise intervention control group. Patients had to have osteoarthritis (OA) in either one or both knees, as defined by the American College of Rheumatology (ACR) criteria. The outcomes were pain and disability.

They undertook a meta-analysis using standardized mean differences (SMDs) and study-level covariates were applied in meta-regression analyses in order to reduce between-study heterogeneity.

Here’s what they found

Forty-eight trials comparing 59 exercise interventions with control treatments and 2,732 participants were included.
Age: mean 64.3 (52.2–73.8) years. Gender: 75% (26–100%) women. BMI: 29.1(24.0–34.8). Baseline pain score (transformed to a scale ranging from 0 [no pain] to 100) was 46.3 (23.7–75.2).

Pain:

Similar effects for aerobic, resistance, and performance exercise (SMD 0.67, 0.62, and 0.48, respectively; P = 0.733).
Single-type exercise programs were more efficacious than different exercise types (SMD 0.61 versus 0.16; P < 0.001).
The effect of aerobic exercise increased with an increased number of supervised sessions (slope 0.022 [95% confidence interval 0.002, 0.043]).
More pain reduction occurred with quadriceps-specific exercise than with lower limb exercise (SMD 0.85 versus 0.39; P = 0.005) and when supervised exercise was performed at least 3 times a week (SMD 0.68 versus 0.41; P = 0.017).
No impact of intensity, duration of individual sessions, or patient characteristics was found.

Patient-reported disability: similar effects were found.

The authors concluded

For best results, the exercise program should be supervised and carried out 3 times a week.

Exercise is effective for knee osteoarthritis – for the best result, it should be supervised and carried out 3 times a week.

The Musculoskeletal Elf’s view

Exercise is effective for knee OA, regardless of age, sex, BMI, radiographic status, or baseline pain. This review also demonstrates that programmes focusing on single type of exercise are more efficacious in reducing pain and patient reported disability than those mixing several types of exercise. Furthermore an increased number of supervised sessions enhances the benefits of aerobic exercise.

To allowing pooling and comparison of the various outcomes assessed in individual trials the authors of this review used standardized mean difference (SMD). So how do you interpret the SMD? An SMD of 0.2 is considered small, an SMD of 0.5 moderate (and would be recognized as clinically important), and an SMD of > 0.8 is considered a large effect.

What do you think?

Do you mix or use single exercise types in your exercise programmes? What will you do now?
How many sessions of supervised exercise do you use? What will you do now?
Do you focus on quadriceps-specific exercise rather than lower limb exercise?

Send us your views on this blog and become part of the ever expanding Musculoskeletal Elf community. Post your comment below, or get in touch via social media (Facebook, Twitter, LinkedIn, Google+).

Do you know that there is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses? This is called the Preferred Reporting Items for Systematic Reviews and Meta-Analyses or PRISMA statement and can be accessed through the website of the EQUATOR Network. The Elves use the PRISMA statement for critical appraisal of systematic reviews, although it is not a quality assessment instrument to gauge the quality of a systematic review.