General Information of Participants
A total of 60 patients who were hospitalized for total hip arthroplasty for various reasons from January 2021 to June 2021 at the Affiliated Hospital of Chengdu University were included in this study(Sample estimation is based on pre-tested data, and the sample size of the study is calculated according to the sample calculation formula for comparing two means. The experimental level α was 0.05, the experimental efficiency of 1 -β was 0.8, the ratio of experimental group to control group was 1:1, and the subsequent loss rate was 0.1 according to the bilateral test. The estimated sample size was 25 cases, and the experimental group and control group were 25 cases. The sample size of this experiment is designed to be 30 cases, which is larger than the estimated sample size.), and were randomly divided into a conventional rehabilitation treatment group (Group A) and a lower limb rehabilitation system group (Group B) using the number table method, with 30 cases each. Both groups underwent conventional rehabilitation treatment, while the lower limb rehabilitation system group (Group B) added lower limb rehabilitation system exercises to the conventional rehabilitation treatment. All patients were operated on by the same group of surgeons using the same surgical procedure and the rehabilitation treatment was carried out by the same group of experienced rehabilitation therapists. All patients were fully informed of the rehabilitation protocol and signed a subject information registration form and an informed consent form prior to the rehabilitation treatment.This trial has been approved by the ethics committee of the Affiliated Hospital of Chengdu University. The ethics number is pj2022-048-02, and the clinical trial number is chictr220060063.
Inclusion criteria: 1) Patients aged 50–75 years; 2) Patients with good healing of the incision after total hip replacement; 3) Patients without neurological or osteoarthritic diseases; 4) Patients without loose displacement of the hip prosthesis; 5) Patients without cognitive impairment.
Exclusion criteria: 1)Patients with cognitive dysfunction who are unable to cooperate; 2) Patients with depression, anxiety and other psychiatric disorders; 3) Patients with neurological dysfunction or behavioural disorders; 4) Patients with severe cardiopulmonary insufficiency.
Lower limb rehabilitation system device
The lower limb rehabilitation system used in this study is a rehabilitation system developed by Beijing University of Aeronautics and Astronautics together with the General Hospital of the Chinese People's Liberation Army.The system's training scenarios are designed using Unity3D software to build virtual reality scenarios: 3D models of the human body, bicycles, aircraft, cars and other 3D models are built using software such as 3DMax.When the patient undergoes rehabilitation training, the system can select the training scenario and mode (e.g. walking, racing, running), while collecting movement information. Through the designed communication protocol, the Unity3D rendering software recognises the transmitted data for real-time rendering, with good human-machine interaction function.
Biomotion information acquisition device
The joint movements of the character in the virtual scene drive the biomotor information acquisition device, which predicts the patient's next active movement intention by analysing the changes in the position of the patient's movement device and the dynamics model established.The motion recognition software of the rehabilitation system, based on the principles of human kinematics, analyses the joint change values for superimposing the rendering of the movement state of the character in the virtual scene at the next moment.As there are obstacles such as pedestrians, flowers, trees and steps in the virtual scene, when the patient's movements collide they generate a corresponding interaction force in the virtual scene.The lower limb rehabilitation system reacts this interaction force to the patient, enhancing the patient's presence in the scene, enabling the patient to receive timely feedback on the movement state, correcting the movement state in a timely manner, and enabling the patient to adjust and rehabilitate according to the correct movement state information of the living scene(Figure 1).
Preparation for rehabilitation treatment
In conjunction with post-operative supportive therapy, the patient has a positive and lateral hip radiograph and, if necessary, a CT to clarify any loosening or displacement of the joint prosthesis.The rehabilitation therapist will provide education before the rehabilitation treatment.
Conventional rehabilitation treatment group (Group A): Patients in both groups were given conventional rehabilitation treatment starting from the day after surgery, and the specific rehabilitation items are shown in Table 1(Figure 2).
Table 1
Post-operative rehabilitation items and rehabilitation contents of the hip joint
Rehabilitation items
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Content of rehabilitation
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Cold therapy
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An ice pack was placed on the surgical site for 30 minutes/time on the first day after surgery, twice a day, until the swelling and pain in the joint had subsided.
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Light therapy
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Red light will be applied on the first day after surgery for 30 minutes twice a day until the swelling and pain in the joint area is reduced.
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Muscle training
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Isometric contractions of the gluteus medius, gluteus minimus, pear-shaped muscles and quadriceps, as well as impedance training of the ankle, knee, healthy side and upper limb of the operated side, will be started on the 1st postoperative day. Impedance training will be performed on the operated side 1 week after surgery.
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mobility training
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Hip mobility training (avoiding dangerous positions) should be started on the first postoperative day, once every hour, twice a day.
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Tension training
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Start hip tension training (taking care to avoid dangerous positions) 1 day after surgery, once every hour, twice a day.
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Lower Extremity Rehabilitation System Group (Group B):Multi-scene rehabilitation training is carried out on the basis of conventional rehabilitation treatment. The patient's body is first fixed to the Lower Limb Rehabilitation System by means of a suspension device with the help of a rehabilitation practitioner, then the sling is tightened to reduce the patient's weight and the patient is instructed to walk with both feet in the direction of the Lower Limb Rehabilitation System. During the walking process, the patient is instructed by the rehabilitation practitioner to perform multi-scene rehabilitation mode training with the aid of the lower limb rehabilitation system. Training begins in week 1 with two 30-minute sessions per day for 16 weeks. If the patient does not adapt during training or if the rehabilitation robot malfunctions, the rehabilitation physician will immediately switch on the termination device and stop the training(Figure 3).
After 4 weeks of rehabilitation treatment, patients in Group A went home on their own to carry out rehabilitation training, which was uniformly taught by the rehabilitation therapist, emphasizing precautions and follow-up time; patients in Group B, on the basis of their own rehabilitation training, carried out multi-scene rehabilitation mode training of the lower limb rehabilitation system in the hospital at a fixed place and scheduled time every day.
Evaluation indicators
Basic information about the subject was recorded, including name, age, gender, case number, side of surgery and length of stay.the percentage of unipedal support time, standardised stride length, stride frequency and maximum walking speed were collected using the lower limb rehabilitation system
The Fugl-Meyer score, which is an internationally accepted assessment standard, was collected at the end of the 8th, 12th and 16th week after rehabilitation.The Fugl-Meyer score is an internationally accepted standard for assessing the functional capacity of the lower limb and consists of 17 items, each with a score of 0–2, for a total score of 34.
The Holden Functional Ambulation Classification (FAC) assesses the patient's ability to walk with the lower limb on a scale of 0 to 5, with the higher the scale, the better the walking ability and the less assistance required.
Statistical methods
SPSS 20.0 software(International Business Machines Corporation, Armonk, New York, USA)was used to statistically analyse the data obtained. The measurement data were expressed as x ± s and t-tests were performed to compare the data between groups; the count data were expressed as rates (%) and chi-square tests were performed to compare the data between groups.Functional scores collected at different time points for the two training modalities were assessed by repeated measures ANOVA, with P < 0.05 being considered significant.