Home-based motor imagery intervention improves functional performance following total knee arthroplasty in the short term: a randomized controlled trial

Armin H Paravlic,Rado Pisot,Simon Kovač,Nicola Maffulli

doi:10.1186/s13018-020-01964-4

Abstract

BackgroundMotor imagery (MI) is effective in improving motor performance in the healthy asymptomatic adult population. However, its possible effects among older orthopaedic patients are still poorly investigated. Therefore, this study explored whether the addition of motor imagery to routine physical therapy reduces the deterioration of quadriceps muscle strength and voluntary activation (VA) as well as other variables related to motor performance in patients after total knee arthroplasty (TKA).MethodsTwenty-six patients scheduled for TKA were randomized to either MI practice combined with routine physical therapy group (MIp) or to a control group receiving physical therapy alone (CON). MIp consisted of maximal voluntary isometric contraction (MViC) task: 15 min/day in the hospital, then 5 times/week in their homes for 4 weeks. MViC and VA of quadriceps muscle, knee flexion and extension range of motion, pain level, along with a Timed Up-and-Go Test (TUG) and self-reported measure of physical function (assessed using the Oxford Knee Score questionnaire [OKS]) were evaluated before (PRE) and 1 month after surgery (POST).ResultsSignificantly better rehabilitation outcomes were evident on the operated leg for the MIp group compared to CON: at POST, the MIp showed lower strength decrease (p = 0.012, η2= 0.237) and unaltered VA, significantly greater than CON (p = 0.014, η2= 0.227). There were no significant differences in knee flexion and extension range of motion and pain level (p > 0.05). Further, MIp patients performed better in TUG (p < 0.001, η2= 0.471) and reported better OKS scores (p = 0.005, η2= 0.280). The non-operated leg showed no significant differences in any outcomes at POST (all p > 0.05). In addition, multiple linear regression analysis showed that failure of voluntary activation explained 47% of the quadriceps muscle strength loss, with no significant difference in perceived level of pain.ConclusionMI practice, when added to physical therapy, improves both objective and subjective measures of patients’ physical function after TKA, and facilitates transfer of MI strength task on functional mobility.Trial registrationRetrospectively registered on ClinicalTrials.govNCT03684148

Highlights

Osteoarthritis (OA) is a major cause of disability [1, 2]
We aimed to explore whether Motor imagery (MI), when added to routine physical therapy, may reduce deterioration of maximal voluntary isometric strength (MViC), voluntary activation (VA), and other variables related to motor performance, such as functional mobility, the range of motion, and self-reported physical function
Three hundred six patients were excluded: 286 did not satisfy the inclusion criteria, 7 patients declined to participate, and 23 patients were excluded for various other reasons

Summary

Introduction

Osteoarthritis (OA) is a major cause of disability [1, 2]. Total knee arthroplasty (TKA) successfully relieves pain, corrects deformity, and improves function [3, 4]. In older patients following end-stage OA, combining MI with RPT produces positive effects on motor performance following total hip arthroplasty [20] and TKA [21, 22]. An explanation for these apparently contradictory findings may be ascribed to the different MI intervention approaches used, including sample characteristics (e.g., age and individual ability to undertake MI) and/or the primary outcome measures used. This study explored whether the addition of motor imagery to routine physical therapy reduces the deterioration of quadriceps muscle strength and voluntary activation (VA) as well as other variables related to motor performance in patients after total knee arthroplasty (TKA)

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