Observation on clinical application effect of ankle rehabilitation robot

Xing Lv， Yu-Long Wang ， Jian-Jun Long， Xiao-Ping Li， Li Wan， Fei Yu

Department of Rehabilitation Medicine, Shenzhen second people's Hospital，518035

Keywords:

ABSTRACT

1. Introduction

Hemiplegia, or hemiplegia for short, is the most common complication of stroke patients, accounting for about 20%, with a high disability rate and mortality [1]. Since upper motor neurons are damaged after cerebral ischemia, the patients will lose control of the suppressed primary motor reflex controlled by the lower center, resulting in intermuscular coordination disorder and increased limb muscle tone, further causing abnormal motor patterns [2]. Most patients will experience secondary skeletal musculoskeletal system changes, including increased muscle tone, progressive joint stiffness, and limited range of joint motion [3]. If there is no early effective treatment and intervention, patients will leave cross scissors gait, pointed feet and other postural abnormalities, seriously affecting the normal life of patients, and even lost the ability to move. The ankle joint system is one of the most severely affected joints, with Achilles tendon contracture and triceps spasm of the calf, resulting in joint movement disorder [4]. Therefore, the key to the treatment of patients with hemiplegia is mainly the passive draft of the affected joints, so as to ensure the range of motion of the joints as far as possible, while maintaining good soft tissue ductility to help patients carry out daily activities. But as a result of passive draft will take the cost of a larger and human grasp the drawing strength and duration for therapist has the certain difficulty, can affect the effect of the draft, and can cause discomfort to the patients in the process of drafting, or some pain, so patients often appear psychological resistance, poor treatment adherence and cooperation degree, resulting in rehabilitation treatment effect is not ideal [5]. At the beginning of this century, a series of institutions at home and abroad began to study the use of robots for weight-reducing walking training or auxiliary rehabilitation intervention, and gradually developed into the clinical treatment of neurological injury diseases [6-7]. However, there are few reports on the application of ankle joint rehabilitation robot in the rehabilitation training process of hemiplegia patients in China, so the ankle joint rehabilitation robot rars-ii was applied in the rehabilitation treatment of hemiplegia patients in this study, which was compared with the conventional rehabilitation treatment scheme, to preliminarily explore its clinical effect and feasibility. The results are reported below.

2. Materials and methods

2.1 General information

Ninety patients with lower limb dysfunction and hemiplegia who were treated in our hospital between April 2017 and March 2019 were selected as subjects. Two groups were divided into control group and observation group by random number table method, with 45 cases in each group. Both groups of patients received comprehensive rehabilitation treatment including language training, physical therapy, sports therapy, spa, occupational therapy and massage, and the observation group received assisted intervention by ankle joint rehabilitation robot on this basis. Inclusion criteria: (1) in line with the diagnostic criteria in "diagnosis of various cerebrovascular diseases" [8], diagnosed as hemiplegia; (2) secondary lower limb muscle tension is too high, adductor gait, ankle joint excessive metatarsal flexion and other clinical manifestations; (3) no other serious systemic diseases; Informed consent signed by patients and their families. Exclusion criteria: (1) complicated with skin damage, infectious skin disease or acute inflammation; Cannot insist on receiving treatment; (3) with epilepsy or other seizures; (4) age < 70. The patients in the control group were 45～69 years old, with an average age of (58.21±9.74). Body mass index was 19.82～25.39kg, with an average (22.12±2.72) kg. The patients in the observation group were 43～70 years old, with an average age of 57.35±9.81 years. Body mass index was 19.17～25.22kg, with an average (23.02±2.19) kg. There was no significant difference in age, body mass index and other general data between the two groups (P >.05), indicating comparability.

2.2 Methods

Both the observation group and the control group received comprehensive rehabilitation treatment such as language training, physical therapy, sports therapy, spa, occupational therapy and massage, etc. On this basis, the observation group received assisted intervention of ankle joint rehabilitation robot, and the course of treatment was 14d.

Assisted intervention training of ankle joint rehabilitation robot: a combination of static drafting and passive training. Prior to the start of the training, the Angle of the passive training was set by manually measuring the ankle range of motion of the patient beforehand. With 10 exercise cycles as a group, the mechanical pedal drives the soles of the feet to move from the middle position of the ankle to the dorsalflexion direction, and then stops for 10 s at the maximum motion Angle, and then drives the solar metatarsal flexion in the opposite direction. When the soles reach the set Angle, they rest for 10 s, and then return to the neutral position to continue the next cycle. In the process of passive pulling, the robot adopts intelligent speed control. At the end of the joint movement, the motion speed of the foot plate of the robot will gradually decrease to adapt to the gradually increasing antagonistic torque, improve the safety of drafting and avoid secondary damage; In the middle of the movement, the foot speed of the robot will be increased to improve the efficiency of the training in one cycle. The training frequency was 5 groups/time, and each group had a rest interval of 2 min, 2 times/day, and 6 days/week, with a course of 14 days.

2.3 Observation indicators

Metatarsal moment of the ankle before and after treatment; The modified Tardieu scale Angle before and after treatment in the two groups; The total effective rate of the two groups of patients receiving treatment.

2.4 Evaluation criteria

2.4.1 Metatarsal flexion moment of ankle joint [9]

The patient was placed in the supine position and relaxed, and the resistance of the ankle joint under slow passive draft to different dorsi angles (0 , 10 , 20 , 30 ) was measured, namely the metatarsal flexion impedance torque value.

2.4.2 Modified Tardieu scale [10]

The patient was placed in a supine position and relaxed. The tester, who had nothing to do with grouping or treatment, held the patient's foot with one hand and the distal leg with the other. Then slowly dorsiflexion the ankle to a stop where movement is limited, at an Angle of R2.

2.4.3 Active ankle back extension Angle [11]

An increase of < 5 in the active ankleback extension Angle is invalid, an increase of 5～10 is effective, and an increase of > 10 is obvious.

2.5 Statistical methods

Processing data using SPSS19.0. The metatarsal flexion moment of the ankle joint and the modified Tardieu scale were determined to be normal distribution by shapiro-wilk test. The data were expressed as (x±s) and t test was used. The total response rate of the treatment was calculated as %, using the 2 test. When P<0.05, the difference was statistically significant.

3. Results

3.1 Comparison of metatarsal flexion moment of the ankle joint between the two groups of patients

After treatment, the antagonistic torque of plantar flexors at each dorsalflexion Angle of the ankle significantly decreased in the two groups (P < 0.05), and was significantly lower in the observation group than in the control group (P < 0.05). See table 1.

3.2 Comparison of two groups of patients with modified Tardieu scale

After treatment, the R1 and R2 angles measured by the modified Tardieu scale of ankle plantar flexors in the two groups increased significantly, and the r2-r1 difference decreased significantly (P < 0.05), and the improvement degree of the observation group was significantly better than that of the control group (P < 0.05). See table 2.

3.3 Comparison of active dorsal extension of the ankle and effective rate of treatment between the two groups

After treatment, the active malleolus dorsalis of the two groups increased significantly (P < 0.05), and the effective rate of treatment in the observation group was significantly higher than that in the observation group (P < 0.05), as shown in table 3.

4. Discussion

Spastic cerebral palsy is the most common sequela after stroke, mainly manifested as postural abnormalities and increased muscle tone. The influencing factors of dysfunction include muscular soft tissue factors (contracture) and neurological factors (spasm) [12]. The more widely used intervention means in clinic is to use passive draft training, gradually increase the range of joint motion, improve soft tissue compliance and ductility, and improve motor dysfunction. In the traditional rehabilitation training for patients with hemiplegia, therapists mainly carry out manual drafting exercise on the limbs and joints of patients, but it is difficult to achieve the ideal training effect due to the long duration of treatment, poor human control and other reasons [13]. In addition, due to the inadaptability of patients to treatment operations, they often fail to cooperate with each other, and their families often misunderstand that the operation of therapists is not standard, thus generating negative emotions and refusing to insist on long-term rehabilitation training, which causes great obstacles to the recovery of the condition [14]. Therefore, in view of the above problems, joint robot rehabilitation system has been clinically introduced in recent years as an implementation unit of intelligent and standardized rehabilitation training.

But in the current most of the reported robot study, mainly concentrated in the design and control the ankle drive, but dueto ankle passive drawing requirements according to the standard position, in the process of the proximal limb fixed properly, to avoid compensatory action, so you also need to consider the practical application in the process of the adjustment of the patients posture position [15], at the same time in the process of movement, because of the need to implement the human body and the mutual coupling of robot movement, members need to be fixed with robots, where you need to consider to avoid inappropriate or excessive exercise, guarantee the safety of the human-computer interaction [16], avoid to bring the secondary damage to the patients. The ankle rehabilitation robot rars-ii system introduced in this study was designed and developed to adapt to the physiological and psychological characteristics of patients after stress. The interactive process was presented on the screen in the form of visual feedback, which not only attracted patients' interest but also diverted their attention, so as to reduce pain or discomfort during training. On the other hand, from the sensing system, mechanical design and intelligent control and other levels to coordinate the simplicity and safety of the robot system, not only to meet the calf position and rehabilitation sitting posture automatic adjustment, but also to ensure the safety of mechanical parts fixed, to avoid the patient due to curiosity caused by the wrong operation. In this study, 90 patients were selected as subjects, of which 45 received ankle rehabilitation robot training. Throughout the treatment in patients with treatment compliance and compliance are high, does not happen the situation of the training, focus on the feedback on the screen, compared with the traditional artificial passive drawing, and ankle rehabilitation robot more fun and comfort, therefore more easily accepted by patients, at the same time, to a great extent, save the therapist and the family member energy and physical strength, improve the satisfaction of users. In addition, the robot system can also adjust the drafting force in the field through the embedded programmable gate array (FPGA) system to adapt it to the functional status of the ankle joint of different patients, effectively reducing the risk of secondary injury caused by improper drafting force.

Table 1 comparison of metatarsal flexion moment of ankle before and after treatment (x±s, /N•m)

Table 2 comparison of results of modified Tardieu scale before and after treatment (x±s, °)

Table 3 comparison of activity and efficacy of active dorsal extension of the ankle

In terms of the evaluation of the draft effect, this study adopted the quantitative evaluation method, and selected three indexes of ankle plantar flexion moment, modified Tardieu scale and active ankle dorsalis extension, which fully met the requirements of objectivity and measurability. The metatarsal flexor moment of ankle joint is inversely proportional to the compliance and ductility of metatarsal flexor muscle group. The modified Tardieu scale is often used to determine the degree of lower limb spasm in clinical practice, with high validity and reliability. The stretch reflex Angle (R1) produced by rapid passive draft reflects the strength of the influence of the neurogenic factor (spasm) causing the increased muscle tone, while the Angle with slow passive draft reaching the upper limit of the range of motion (R2) reflects the strength of the influence of the muscle-soft tissue factor (contracture) causing the increased muscle tone. The greater the absolute value of r2-r1, the more severe the limb spasm was [17]. Active ankleback extension is the most direct index of rehabilitation training, which is inversely proportional to the degree of ankle dysfunction. Results show that the observation group of patients with ankle dorsiflexion Angle under each plantar flexors against torque, improved Tardieu scale of R1, R2, R1 and R2 and the improvement of the difference were significantly better than that of control group (P < 0.05), suggesting the institute the ankle rehabilitation robot RARS - II system in clinical has positive significance for the treatment of patients with hemiplegia.

Due to limited conditions, this study only verified the feasibility and effectiveness of one robotic rehabilitation system, and failed to compare the clinical effects of different rehabilitation robot systems. In the future, a multicenter randomized controlled study is needed to further improve the relevant data and provide a reliable basis for clinical practice. To sum up, the ankle rehabilitation robot system auxiliary intervention treatment, can effectively improve spasm type in a short time children's ankle soft tissue compliance, reduce plantar flexion contracture state, improve the joint movement disorders, patients and their families at the same time cooperate and receive degrees higher, is an effective means to improve treatment effect.