**3. Results**

**Figure 1** shows the search strategy process followed for the present review. Initially, NO articles were identified by using predefined search criteria. No additional articles were found by using other sources as mentioned above. Following the initial step, duplicate records were removed and reviews were excluded based on their titles and abstracts. Of this NO of full-text reviews were assessed with only three reviews with meta-analysis were included in this study.

### **3.1 Characteristics of the included systematic reviews**

The characteristics of the included reviews are presented in **Table 2**. Current study included 3 systematic reviews with meta-analysis, amounting to 10 original studies (5 overlapping between reviews), 9 RCTs and one non RCT, with a total of 558 participants (Experimental group: 278; Control group: 280 patients). All studies included patients scheduled to total knee arthroplasty, both sexes and aged between 50 and 85 years. In all systematic reviews, the main intervention used MI as adjunct therapy, while two reviews included combination of MI with other cognitive interventions such as action observation and/or guided imagery [9, 11]. Included reviews differed in terms of outcomes assessed. Thus, all reviews assessed affected knee extension strength and timed up to go test. Two reviews assessed pain intensity assessed by Visual Analogue Scale (VAS) [10, 11], while two studies assessed


self-perceived knee function [9, 10], and Paravlic et al. [9] self-selected and brisk walking speed under dual and single tasks.

#### **3.2 Methodological quality assessment and quality of the evidence evaluation**

The methodological quality of the included reviews is presented in **Table 3**. All three reviews were rated as of high quality using the AMSTAR-2 checklist. Reviews did not provide a list of excluded studies justifying the exclusion reasons (Item 7) and the report of sources of funding of the studies included in the review (Item 10). Only one review [10] did not perform sensitivity analysis considering publication bias (Item 15). The quality of evidence assessed by adopted GRADE principles showed that all three included studies were rated as of high quality.

#### **3.3 Results of meta-analyses**

The Egger's test was performed to provide statistical evidence of funnel plot asymmetry. Results indicated no publication bias for two meta-analyses only: strength (p = 0.139) and TUG (p = 0.225), respectively. For self-reported physical function and pain intensity, a publication bias analysis was not performed, due to low number of included studies.

Nine ESs from three included meta-analyses showed *small* effect (random effect: cES = 0.55, 95% CI 0.38 to 0.71, n = 9; p < 0.001; I<sup>2</sup> = 32%; fixed effect: cES = 0.53, 95% CI 0.39 to 0.66, n = 9; p < 0.001; I<sup>2</sup> = 32%;) on measures of physical function in general (**Figure 2A**). Three ESs from all three included reviews showed a *moderate* effect (random effect: ES = 0.85, 95% CI 0.58 to 1.11, n = 3; p < 0.001; I2 = 0%; fixed effect: //) on measures on maximal knee extension strength (**Figure 2B**). Furthermore, three ESs from all three included reviews showed *small* effect (random effect: ES = 0.49, 95% CI 0.25 to 0.73, n = 3; p <sup>&</sup>lt; 0.001; I2 = 0%; fixed effect: //) on measures on timed-up and go test (**Figure 2C**). Summarized effect of MI intervention showed *small* effect (random effect: ES = 0.34, 95% CI 0.07 to 0.61, n = 2; p = 0.015;


*Motor Imagery as Adjunct Therapy for Rehabilitation of Total Knee Arthroplasty Patients… DOI: http://dx.doi.org/10.5772/intechopen.106388*


#### **Table 2.**

*Summary of reviews with meta-analysis that investigated the effects of motor imagery practice on physical rehabilitation outcomes following total knee arthroplasty (TKA).*

*Motor Imagery as Adjunct Therapy for Rehabilitation of Total Knee Arthroplasty Patients… DOI: http://dx.doi.org/10.5772/intechopen.106388*


#### **3.**

*Overall results of the Assessing the Methodological Quality of Systematic Reviews (AMSTAR-2) and adopted Grade of Recommendation, Assessment, Development and Evaluation(GRADE) quality of evidence checklist.*

#### **Figure 2.**

*Summarized effect of MI practice intervention on (A) physical function in general; (B) timed-up to go test; (C) knee extensors strength of the affected knee; and (D) self-reported physical function.*

I <sup>2</sup> = 0%; fixed effect: //) on measures of self-reported physical function (**Figure 2D**). And finally, a *moderate* effect (random effect: ES = 0.67, 95% CI 0.16 to 1.18, n = 2; p = 0.010; I2 = 72%, p = 0.058; fixed effect: ES = 0.64, 95% CI 0.37 to 0.90, n = 2; p < 0.001; I2 = 72%, p = 0.058) was observed for pain intensity. Given there were no differences in the magnitude of the effects when random and fixed effects analyses were applied, these findings can be interpreted as robust (**Figure 3**).

*Motor Imagery as Adjunct Therapy for Rehabilitation of Total Knee Arthroplasty Patients… DOI: http://dx.doi.org/10.5772/intechopen.106388*

#### **Figure 3.**

*Effect of MI practice intervention on the pain intensity of the affected knee.*
