The goal of this observational study is to compare the functional outcome of patients with end-stage knee osteoarthritis (OA) before and after total knee arthroplasty based on the phase angle level. The main questions it aims to answer are: * Do patients with low phase angle show worse functional recovery after total knee arthroplasty compared to those with high phase angle? * Is postoperative physical function associated with preoperative phase angle level? Researchers will compare postoperative physical function and muscle strength between the low and high phase angle groups to determine whether a low phase angle is associated with poorer functional recovery. Participants will: Perform physical function tests, isokinetic strength assessments, and bioelectrical impedance analysis before and three months after surgery.
After obtaining informed consent, a pre-surgical screening is conducted. Participants complete a history survey, a sarcopenia questionnaire, and the International Physical Activity Questionnaire (IPAQ). The screening includes a comprehensive evaluation of baseline symptoms, followed by functional assessments that incorporate bioelectrical impedance analysis, muscle strength testing, and performance-based tests: * A modified Charlson Comorbidity Index (CCI) is used to assess comorbidity burden, and a Numeric Pain Rating Scale (NPRS) records participants' initial pain levels. * Radiographic assessments are performed to evaluate the frontal alignment of the lower extremities and the radiographic severity of knee osteoarthritis (OA) using the Kellgren-Lawrence (K-L) grading system. * Multifrequency bioelectrical impedance analysis (BIA) is used to measure phase angle and body composition. * Handgrip strength is measured through three trials on each side, with the average recorded. * Knee strength is measured using an isokinetic dynamometer. * Performance-based tests include the 10-meter walk test, the Timed Up and Go (TUG) test, and the Berg Balance Scale (BBS). Follow-up assessments are conducted three months after total knee arthroplasty, with participants undergoing the same protocol for performance-based tests, isokinetic knee strength evaluation, and bioelectrical impedance analysis.
Study Type
OBSERVATIONAL
Enrollment
200
Yongin Severance Hospital
Yongin-si, Gyeonggi-do, South Korea
RECRUITINGTimed up and go test (TUG)
Researchers ask patients to rise from a seated position, walk a distance of 3 m, turn around, return to the chair, and sit back. The average time of three trials was recorded as a result
Time frame: Baseline and 3 months after surgery
10 meter walk test (10MWT)
Patients are instructed to walk 14 m, including 2 m at both ends for acceleration and deceleration, at their comfortable speed. Gait speed was calculated by dividing the 10m distance by the time taken.
Time frame: Baseline and 3 months after surgery
Berg balance scale (BBS)
Patients are asked to perform 14 tasks regarding the static and dynamic balance of patients. Each task was rated on a five-point scale from 0 to 4, with a total score of 56.
Time frame: Baseline and 3 months after surgery
Isokinetic peak torque of knee flexion at 60°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the peak flexion torque is performed at preset constant angular velocities, 60°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic peak torque of knee flexion at 150°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the peak flexion torque is performed at preset constant angular velocities, 150°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic peak torque of knee extension at 60°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the peak extension torque is performed at preset constant angular velocities, 60°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic peak torque of knee extension at 150°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the peak extension torque is performed at preset constant angular velocities, 150°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic total work of knee flexion at 60°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the total knee flexion effort is performed at preset constant angular velocities, 60°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic total work of knee flexion at 150°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the total knee flexion effort is performed at preset constant angular velocities, 150°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic total work of knee extension at 60°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the total knee extension effort is performed at preset constant angular velocities, 60°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Isokinetic total work of knee extension at 150°/s
* Isokinetic knee assessment is assessed using an isokinetic dynamometer (Cybex NORM®, Humac, CA, USA). * Each participant is positioned on an adjustable chair and secured to the equipment with straps across the trunk, hip, and thigh. * Gravity correction measurements are made according to the manufacturer's instructions. * Participants are instructed on standardized procedures before and during the test. * Concentric measurement of the total knee extension effort is performed at preset constant angular velocities, 150°/s, with a rest period between each trial to prevent fatigue and ensure consistent effort levels. * Participants warm up with five to six submaximal practice repetitions before each test series. After repeating three times, the examiner records the average value.
Time frame: Baseline and 3 months after surgery
Whole body phase angle at 50kHz
* Whole body phase angle is calculated using the multifrequency Bioelectrical impedance analysis (BIA) with the InBody S10 (BioSpace, Seoul, Korea). * Before measurement, all patients are asked to fast for a minimum of 3 hours with the bladder emptied and avoid alcohol or vigorous activity. * Tetrapolar 8-point electrodes are placed on the dorsal surfaces of both wrist and foot according to the manufacturer's instruction. * After resting for 15 minutes, a weak current under 100uA is applied to measure the reactance (Xc) and impedance (R) of 6 Different Frequencies (1kHz, 5kHz, 50kHz, 250kHz, 500kHz, 1000kHz). * A whole body Phase angle is calculated as an arctangent of the Xc to R ratio at 50kHz. \[Phase angle (degrees) arctan(Xc/R) (180/π)\]
Time frame: Baseline and 3 months after surgery
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