Specific and general adaptations following motor imagery practice focused on muscle strength in total knee arthroplasty rehabilitation: A randomized controlled trial

Abstract

Background Motor imagery (MI) has been a widely used strategy in the past two decades to enhance physical capabilities among orthopaedic patients. However, its effectiveness is still questioned, since the demonstrated effects were likely task-dependent, with little evidence of transfer to tasks not specifically trained with MI. Objective The aim of this study was to investigate whether an MI practice focused on maximal isometric knee extension strength, causes additional specific and general adaptations upon neuromuscular and functional variables when compared to conventional rehabilitation only, in patients submitted to total knee arthroplasty (TKA). Design Parallel group randomized controlled clinical trial. Participants Thirty-four patients (56% man) submitted to TKA. Program Patients were randomly assigned to an MI practice group (MIp: 15 minutes per day/5 days per week in addition to routine physical therapy) or control group (CON) that performed routine physical therapy alone for four weeks. Outcome measures The maximal isometric knee extension strength of the operated leg was defined as the primary outcome. Secondary outcomes were spatial and temporal gait parameters, 30-second chair sit-to-stand performance, a self-reported physical function assessed by the Lower Extremity Functional Scale (LEFS) questionnaire, and an MI ability score. All measurements were conducted before and one month after TKA. Results Significant differences in treatment effects were observed for the MIp group compared to CON: the MIp showed less strength decrease (ES = 1.15, 95% CI: 0.32, 1.99, p = 0.022); faster self-selected speed under single (ES = 2.12, 95% CI: 1.16, 3.08, p = 0.001) and dual task (ES = 1.59, large, 95% CI: 0.67, 2.50, p = 0.002) conditions; brisk-pace gait speed during single (ES = 1.32, 95% CI: 0.47, 2.17, p = 0.020) and dual task conditions (ES = 1.31, large, 95% CI: 0.38, 2.23, p = 0.013); improved chair sit-to-stand (ES = 1.45, large, 95% CI: 0.58, 2.31, p = 0.004) performance; and a higher score on MI ability questionnaires for kinaesthetic imagery (KI) (ES = 0.55, 95% CI: -0.23, 1.34, p = 0.010) and internal visual imagery (EVI) (ES = 0.99, 95% CI: 0.18, 1.80, p = 0.039) scales, respectively. In addition, only MIp showed unaltered single and double support periods, as well as stride length and cadence during single task self-selected gait condition. Finally, analysis showed that the improved MI ability score achieved at the end of MI training was significantly correlated with the changes in the strength of the operated leg (kinaesthetic imagery: r = 0.741, p = 0.004; and internal visual imagery: r = 0.623, p = 0.023). Conclusions MI training, when added in a corollary to routine physical therapy, led to improvements in both specific and general adaptations that were related to patients’ physi...

Motor imagery training speeds up gait recovery and decreases the risk of falls in patients submitted to total knee arthroplasty

“…As one could have anticipated, our MI training improved the quality of motoric imagery abilities expressed as the coupling between actual motor execution of a classical clinical task, the TUG task, and MI times for the same task (MIQI index): in the experimental group, the value of the index became lower, indicating a training-induced improvement of the ability to efficiently evoke gait motor representations. In contrast with previous reports on post-TKA acute phase 16,17 , where the MI training only improved lower limbs muscular strength, our MI improvement generalized to real walking, with better recovery of motor performance for actual gait, as measured by the TUG test. The difference with previous studies is perhaps less than surprising, because in these experiments patients were instructed only to imagine maximal voluntary isometric contractions of the quadriceps 16,17 or simple knee extension-flexion 18 .…”

“…In contrast with previous reports on post-TKA acute phase 16,17 , where the MI training only improved lower limbs muscular strength, our MI improvement generalized to real walking, with better recovery of motor performance for actual gait, as measured by the TUG test. The difference with previous studies is perhaps less than surprising, because in these experiments patients were instructed only to imagine maximal voluntary isometric contractions of the quadriceps 16,17 or simple knee extension-flexion 18 . On the contrary, we specifically asked our patients to imagine complex gait behaviours, like walking in ecological settings: this, if anything, shows that a specific form of mental motor training should be used to achieve the desired results for complex outcomes like measures of gait.…”

“…For what concerns knee surgery, to date only two studies tested the possible clinical efficacy of MI training in post-surgery rehabilitation during the acute phase 16,17 . They reported encouraging results in terms of isometric knee extension 16 and perceived pain 17 .…”

“…For what concerns knee surgery, to date only two studies tested the possible clinical efficacy of MI training in post-surgery rehabilitation during the acute phase 16,17 . They reported encouraging results in terms of isometric knee extension 16 and perceived pain 17 . Mourzarkel and colleagues 18 demonstrated the efficacy of MI training also in the chronic post-operative phase (six months after the surgery), for what concerns quadriceps muscle strength of the operated knee, active knee flexion measured with gait analysis and speed in climbing and descending stairs 18 .…”

Core Outcome Measurement Instruments for Clinical Trials of Total Knee Arthroplasty: A Systematic Review

“…Eleven trials were considered high quality (PEDro score >5/10), with a mean score of 5.9/10 across all trials ( Table 1 and Table A2 ). The total PEDro scores were 8 for 1 trial [ 53 ], 7 for 8 trials [ 1 , 23 , 44 , 49 , 58 , 59 , 61 , 74 ], 6 for 2 trials [ 45 , 46 ], 5 for 6 trials [ 11 , 20 , 25 , 50 , 83 , 84 ] and 4 for 3 trials [ 41 , 85 , 86 ]. The items of the PEDro scale the most frequently found were eligibility criteria, outcome obtained in more than 85% of participants, the use of similar groups at baseline, measurements of variability for at least one key outcome, and between-group comparisons, which were evident in almost all reports.…”