Literature Search
Study Characteristics
A total of 739 patients were included in the 10 studies, including 412 patients in the experimental group and 414 patients in the control group. The minimum sample size was 10 and the maximum sample size was 86. Table 1 showed the detailed characteristics and main conclusions of all studies. Table 2 summarized the intervention measures for each study and the results of the outcome indicators.
Table1. Characteristics of the studies in meta-analysis.
Study
|
Year
|
Country/Region
|
Journal
|
Study type
|
Level of
Evidence
|
Sample size(T/C) *
|
Gender (M/F)
|
Median age
(T/C) *
|
BMI*
(T/C) *
|
Length of follow-up
|
Hunter [15]
|
2012
|
Australia.
|
Ann Rheum Dis
|
RCT
|
Ⅰ
|
29/27
|
30/50
|
63.0/60.0
|
32.7 /34.7
|
30weeks
|
van Raaij [19]
|
2010
|
Netherlands
|
Clin Orthop Relat Res
|
RCT
|
Ⅰ
|
46/45
|
46/45
|
54.9 /54.4
|
29.0 /29.4
|
26weeks
|
YU [20]
|
2016
|
Australia.
|
Int J Rheum Dis.
|
RCT
|
Ⅱ
|
86/68
|
54/100
|
67.7/67.0
|
30.7 /33.2
|
52weeks
|
Dammere [21]
|
2018
|
Austria
|
Knee Surg Sports Traumatol Arthrosc
|
RCT
|
Ⅰ
|
21/21
|
22/20
|
50.6/53.3
|
24.7/26.5
|
52weeks
|
Thoumie [22]
|
2018
|
France
|
Sci Rep.
|
RCT
|
Ⅰ
|
32/35
|
23/44
|
64.8/ 66.6
|
29.2/28.1
|
6weeks
|
Jones [23]
|
2012
|
UK
|
Gait Posture
|
RCT
|
Ⅰ
|
28/28
|
NA
|
NA
|
NA
|
2weeks
|
Callaghan [24]
|
2015
|
USA
|
Ann Rheum Dis
|
RCT
|
Ⅰ
|
56/61
|
NA
|
NA
|
NA
|
6weeks
|
Muller [25]
|
2011
|
Germany
|
Z Orthop Unfall.
|
RCT
|
Ⅰ
|
13/10
|
16/7
|
49.8 /57.4
|
27/28
|
16weeks
|
Niazi [26]
|
2014
|
Pakistan
|
Pak J Med Sci
|
RCT
|
Ⅰ
|
56/53
|
NA
|
NA
|
NA
|
26weeks
|
Arazpour [27]
|
2013
|
Iran
|
Prosthet Orthot Int
|
RCT
|
Ⅰ
|
12/12
|
9/15
|
58.75/59.83
|
27.30/26.71
|
6weeks
|
*T Experimental group, C Control group, BMI Body mass index, NA not applicable.
Table2. Study Interventions and Outcome indicators
Lead Author
|
Intervention(T)*
|
Intervention(C)*
|
Outcome indicators*
|
Hunter [15]
|
Valgus knee brace
|
a neutral knee brace (no valgus angulation)
|
②
|
van Raaij [19]
|
Valgus knee brace
|
Laterally
wedged insole
|
①②
|
YU [20]
|
Valgus knee brace
|
no bracing
|
①③④
|
Dammere [21]
|
Valgus knee brace
|
a custom-made wedge insole
|
③④
|
Thoumie [22]
|
Valgus knee brace
|
no bracing
|
①
|
Jones [23]
|
Valgus knee brace
|
Laterally wedged insole
|
①②
|
Callaghan [24]
|
Valgus knee brace
|
no bracing
|
①④
|
Muller [25]
|
Valgus knee brace
|
an elastic knee bandage
|
①②
|
Niazi [26]
|
Valgus knee brace
|
Laterally wedged insole
|
①
|
Arazpour [27]
|
Valgus knee brace
|
Laterally wedged insole
|
①
|
*T Experimental group, C Control group. ①VAS(visual analog scale)
②WOMAC(Western Ontario and McMaster Universities Osteoarthritis Index)
③KOOS(Knee Injury and OsteoarthritisOutcome Score)
④KOOS-ADL(KOOS activities of daily living)
Quality Assessment
Using Cochrane Handbook 5.0.1 RCT bias risk assessment tool to evaluate the quality of 10 studies, the results were shown in Figure 2/3. The figure showed a total of one high risk, and the rest were unclear or low risk. Overall, the quality of the literature was at the upper-middle level.
Primary Outcome Measures
VAS pain score
A total of eight studies reported the impact of valgus knee bracing on the VAS pain score of patients with KOA. The heterogeneity test results of the eight included studies was I2 = 88%> 50%, the random effect model was selected. The results showed that RR = -0.29, 95% CI [-0.73, 0.15], and the combined effect test Z = 1.28. P = 0.20 (Figure 4), indicating that the experimental group compared with the control group had no statistically significant difference in improving knee VAS pain scores significance.
WOMAC function score
A total of four studies reported the effect of valgus knee bracing on the WOMAC function score of KOA patients. The heterogeneity test results of these four studies was I2 = 0 <50%, so the fixed effect model was selected. As shown in Figure 5, RR = -0.15, 95% CI [-0.41,0.11], the combined effect Z = 1.12.P = 0.26. This indicated that valgus knee bracing had no statistically significant difference in improving knee WOMAC function score.
Secondary Outcome Measures
KOOS score
A total of two studies reported the impact of valgus knee bracing on the KOOS score of KOA patients. The heterogeneity test results of these two studies was I2 = 0 <50%, so the fixed effect model was chosen. The results can be obtained from Figure 6: RR = 0.58, 95% CI [-4.25, 5.42], the combined effect Z = 0.24. P = 0.81. The results showed that the experimental group and the control group had no statistically significant difference in KOOS score.
KOOS-ADL
A total of 3 studies reported the influence of valgus knee bracing on the KOOS-ADL score of KOA patients. The heterogeneity of the 3 studies was I2 = 87% > 50%, so the random effect model was elected. The specific results were shown in Figure 7:RR = 0.04, 95% CI [-0.62,0.69], the combined effect Z = 0.11.P = 0.91. The results showed that the difference between the KOOS-ADL scores of the experimental group and the control group was not statistically significant .
Subgroup Analysis
As can be seen from the above results, there were two outcome indicators with high heterogeneity, which were VAS pain score and KOOS-ADL score. However, it is considered that the KOOS-ADL score was included in fewer studies, the VAS score had the value of subgroup analysis. Through analysis of 8 studies that reported the impact of valgus knee bracing on VAS scores of KOA patients, it was found that the follow-up time of these 8 studies was very different, so we conducted a subgroup analysis of follow-up time. In the process of subgroup analysis, it was found that the calculation method of VAS score in Thoumie's[22] study is very different from other studies. After using or excluding this study, the heterogeneity had changed greatly. Therefore, the subgroup analysis excluded the Thoumie's[22] study.
The results of the subgroup analysis of the follow-up time were shown in Table 3 and Figure 8. When the follow-up time was greater than 52weeks: only one study was included, there was no results of the heterogeneity; when the follow-up time was less than 24weeks, the heterogeneity was I2 = 35%; when the follow-up time was between 24-48 weeks, the heterogeneity was I2 = 7%; the results showed that the follow-up time was the source of the heterogeneity of the VAS pain score.
Adverse Reactions
None of the 10 articles included in this study reported adverse reactions.
Table 3
Subgroup analysis of follow-up time of VAS score
Subgroup
|
Results of subgroup analysis
|
follow-up time
|
Number of studies
|
MD*value(95%CI)
|
Pvalue
|
I²/%
|
a*<24weeks
|
4[21-24]
|
-0.41[-0.78,-0.05]
|
=0.03
|
35%
|
24weeks<a*<48weeks
|
2[17,25]
|
-0.20[-0.49,0.09]
|
=0.17
|
7%
|
a*>48weeks
|
1[18]
|
0.64[0.32,0.97]
|
=0.0001
|
-
|
*afollow-up time,MD mean difference. |