Knee osteoarthritis (KOA) is a degenerative knee disease associated with pain, swelling, stiffness, limited ambulation, and declined balance function [
The primary component of exercise training focuses on improving muscles strength; however the balance deficits and stress management are often overlooked [
Relevant articles were identified using the following databases: Medline (1966 to Jul 2015; via Ovid), EMBASE (1980 to Jul 2015; via Ovid), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 7 of 12 Jul 2015), Pubmed (1966 to Jul 2015), and Physiotherapy Evidence Database (PEDro) (1929 to Jul 2015; via website). Key words included osteoarthritis, knee, yoga, randomized controlled trial, trial, pain, mobility, balance, symptoms, and quality of life. The last search was conducted on December 6, 2015.
Articles were considered included when they met the following criteria: (1) studies were published in English; (2) the patients had clear diagnostic criteria of KOA; (3) the intervention type of experimental group is yoga. Articles were excluded if they were (1) patients diagnosed with secondary KOA; (2) animal studies; (3) published as conference processing.
The following pieces of information were extracted from each article: the demographic characteristic of patients, type of study, description of both experimental and control interventions, duration of trial period, and outcome measure. Two authors independently extracted the date and disagreement was resolved by discussion with the third author.
The methodological quality was assessed using the Downs and Black’s Quality Index which has well-established validity for both randomized and nonrandomized studies [
We obtained 71 articles initially, of which 13 articles were excluded for duplication and 47 records were excluded after reading the title and abstracts. After in-depth screening of the remaining 11 articles, two studies were eliminated owing to unpublished conference reports [
Search strategy and flow chart for this review.
The characteristics of 9 (6 studies) articles are given in Table
Characteristics of included studies in this review.
Study | Study design | Number of Participants | Analyzed number of participants | Duration of KOA (yrs) | Age of the participants |
Gender (F/M) |
---|---|---|---|---|---|---|
Ebnezar et al., 2012 [ |
RCT |
|
|
<1 yr/1-2 yrs/>2 yrs = 121/79/50 |
|
174/76 |
|
||||||
Ebnezar et al., 2012 [ |
RCT |
|
|
<1 yr/1-2 yrs/>2 yrs = 121/79/50 |
|
174/76 |
|
||||||
Ebnezar and Yogitha, 2012 [ |
RCT |
|
|
Unclear |
|
Unclear |
|
||||||
Cheung et al., 2014 [ |
RCT |
|
|
At least 6 months |
|
All females |
|
||||||
Kolasinski et al., 2005 [ |
Single group pre-post study |
|
|
At least 6 months |
|
All females |
|
||||||
Brenneman et al., 2015 [ |
Single group pre-post study |
|
|
Unclear |
|
All females |
|
||||||
Ebnezar et al., 2012 [ |
RCT |
|
|
<1 yr/1-2 yrs/>2 yrs = 121/79/50 |
|
174/76 |
|
||||||
Nambi and Shah, 2013 [ |
RCT |
|
|
At least 6 months |
|
13/17 |
|
||||||
Ghasemi et al., 2013 [ |
Quasi-RCT |
|
|
Unclear |
|
All females |
Study | Comparison Intervention | Intervention of control group | Intervention of yoga group | Yoga therapy practice | Main outcomes | Time point |
---|---|---|---|---|---|---|
Ebnezar et al., 2012 [ |
Yoga + PT versus PT | PT (20 minutes/day/2 weeks) |
PT (20 minutes/day/2 weeks) |
Yogic sukshma vyayamas |
Walking pain |
14 weeks |
|
||||||
Ebnezar et al., 2012 [ |
Yoga + PT versus PT | PT (20 minutes/day/2 weeks) |
PT (20 minutes/day/2 weeks) |
Yogic sukshma vyayamas |
QOL (SF-36) | 14 weeks |
|
||||||
Ebnezar and Yogitha, 2012 [ |
Yoga + PT versus PT | PT (20 minutes/day/2 weeks) |
PT (20 minutes/day/2 weeks) |
Yogic sukshma vyayamas |
Walking pain |
14 weeks |
|
||||||
Cheung et al., 2014 [ |
Yoga versus Usual care (8 weeks) |
Another program (8 weeks) |
Hatha yoga (60 minutes/week/8 weeks) |
Asanas |
WOMAC |
20 weeks |
|
||||||
Kolasinski et al., 2005 [ |
Yoga versus control (no specific exercise) | Modified Iyengar yoga (90-minute classes/week/8 weeks) | Asanas | WOMAC |
8 weeks | |
|
||||||
Brenneman et al., 2015 [ |
Yoga versus control (no specific exercise) | Yoga (60 minutes/sessions/3 sessions/week/12 weeks) | Unclear | VAS |
12 weeks | |
|
||||||
Ebnezar et al., 2012 [ |
Yoga + PT versus PT | PT (20 minutes/day/2 weeks) |
PT (20 minutes/day/2 weeks) |
Yogic sukshma vyayamas |
Anxiety scores |
14 weeks |
|
||||||
Nambi and Shah, 2013 [ |
Yoga + EMG biofeedback + Knee strengthening exercise + TENS versus EMG biofeedback + Knee strengthening exercise + TENS | EMG biofeedback (3 times/week/8 weeks) |
Iyengar yoga (90 minutes/session, 3 times/week/8 weeks) |
Asanas | VAS |
8 weeks |
|
||||||
Ghasemi et al., 2013 [ |
Yoga versus ordinary daily activities | Ordinary daily activities | Hatha yoga (60 minutes/session, 3 times/week/8 weeks) |
|
VAS |
8 weeks |
WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index (lower scores = better state); SPPB: Short Physical Performance Battery (higher scores = better state); QOS: quality of sleep; QOL: quality of life; PSQI: Pittsburgh Sleep Quality Index (lower scores = better state); SF-12: Health Related Short Form 12 (higher scores = better state); PCS: physical component summary; MCS: mental component summary; Cantril current and 5 years (higher scores = better state); AIMS2: Arthritis Impact Measurement Scale 2; GA: Global Assessment; ADL: Activities of Daily Life; VAS: Visual Analog Scale; KOOS: Knee Injury and Osteoarthritis Outcome Scale; KAM: knee adduction moment; PT: physiotherapy; EMG: electromyography.
The consequence of quality assessment about the 9 articles (6 studies) is present in Table
Quality of article included in this review using Downs and Black scale.
Measures | Ebnezar et al., 2012 [ |
Ebnezar et al., 2012 [ |
Ebnezar and Yogitha, 2012 [ |
Cheung et al., 2014 [ |
Kolasinski et al., 2005 [ |
Brenneman et al., 2015 [ |
Ebnezar et al., 2012 [ |
Nambi and Shah, 2013 [ |
Ghasemi et al., 2013 [ |
---|---|---|---|---|---|---|---|---|---|
|
|||||||||
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
|
|||||||||
(1 |
0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
( |
0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
( |
0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 |
|
|||||||||
( |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
( |
0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
( |
0 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 |
|
|||||||||
( |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
( |
1 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 0 |
( |
1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 |
( |
1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 |
( |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
( |
1 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 0 |
|
|||||||||
( |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Total score (maximum 32) | 17 | 17 | 17 | 23 | 18 | 16 | 17 | 11 | 13 |
A score of 23 or higher indicates good-quality article with low risk of bias.
A score between 22 and 13 indicates medium-quality article with moderate risk of bias.
A score of 12 or lower represents a poor-quality article with high risk of bias [
Among included studies, three of them had control group which does conventional exercise during the experimental time [
The yoga group received yoga exercise for 8 weeks in three studies [
Two outcome measurements were used to test the pain change in five studies [
Two studies used WOMAC as an outcome measure to assess the effects of yoga exercise on pain relief for people with KOA [
Four studies used VAS assessed pain in people with KOA [
Three studies assessed mobility in many ways [
Four studies assessed the quality of life (QOL) as an outcome [
The purpose of this review is to evaluate the effect of yoga on pain, mobility, and QOL in people with KOA. Although majority of these studies seem to exhibit a favorable effect after yoga intervention, there are still some inconsistent findings in this review.
Pain is a major symptom for osteoarthritis [
The symptoms of KOA, like pain and stiffness, can cause a series of consequences, such as limited ambulation, and worsen quality of life [
Our review show that yoga has positive effect on mobility in two studies [
Subjects in Kolasinski et al. reported that they had heightened awareness of how they were positioning their bodies in space after yoga intervention [
In addition to a lot of disturbing symptoms that KOA have, the most important thing is that it greatly affects the quality of life of patients with KOA [
The present systematic review showed that yoga intervention has positive effect on QOL based on three studies [
In addition to the physical health we discussed above, we believe that the mental health also have a great impact on QOL. Previous studies showed that yoga has positive effect on depression, anxiety, and stress reducing [
Yoga may be a safe and tolerable exercise for patients with KOA since no studies reported adverse event both during and after yoga intervention.
Three limitations could be found in this systematic review. First, we would not conduct quantitative research by performing a meta-analysis because of the heterogeneity of the studies and missing data of some important outcomes. Second, excluded non-English language studies and unpublished articles and conference processing may result in bias. Thirdly, just small amount of RCTs were focused on this area and were included in this review; the lower quality of the studies will limit the power of drawing any conclusion.
This systematic review showed that yoga has positive effect on pain relief on people with KOA with good evidence. A relative long period (12 weeks) of yoga intervention may help to improve the short-distance mobility in patients with KOA. More RCTs with high quality and larger sample size are needed. Further work will be needed to address the mechanisms of yoga effect on KOA people and more specific outcomes are needed to concern psychological issues.
The authors declare that they have no competing interests.