Total knee arthroplasty (TKA) is a widely performed surgical procedure for patients with severe knee osteoarthritis. Following TKA, changes in lower extremity alignment and gait mechanics may influence the spinopelvic sagittal alignment, and postoperative rehabilitation programs traditionally focus on the knee joint without addressing the lumbopelvic chain. This study aims to investigate whether adding paraspinal neuromuscular electrical stimulation (NMES) to a standard postoperative rehabilitation program (which includes quadriceps NMES) affects spinopelvic sagittal alignment parameters in patients undergoing TKA for primary knee osteoarthritis, compared with standard rehabilitation and quadriceps NMES alone. In this single-center, prospective, randomized, single-blind (outcome assessor-blinded) controlled trial, eligible participants aged 40-80 years with primary knee osteoarthritis scheduled for TKA and with measurable spinopelvic malalignment will be randomly assigned in a 1:1 ratio to receive either standard rehabilitation with quadriceps NMES plus paraspinal NMES (intervention group) or standard rehabilitation with quadriceps NMES alone (control group) for 4 weeks (20 sessions). The primary outcome is the change in radiographic spinopelvic parameters - including pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, sagittal vertical axis, and spinosacral angle - measured on standing lateral whole-spine radiographs at baseline (preoperative), before rehabilitation, after the 4-week intervention, and at 6-month follow-up. Secondary outcomes include knee and back pain (VAS), functional and quality-of-life measures (WOMAC, Knee Society Score, Forgotten Joint Score, Oswestry Disability Index, Nottingham Health Profile), performance-based tests (Timed Up and Go, 6-Minute Walk Test), and knee range of motion. The investigators hypothesize that adding paraspinal NMES to standard rehabilitation will result in greater improvement in spinopelvic alignment parameters, and potentially in clinical/functional outcomes, compared with standard rehabilitation alone.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
80
A structured rehabilitation program including early postoperative mobilization (days 1-3: standing, short-distance ambulation, quadriceps isometric exercises, ankle pumping, breathing exercises, cold application), pre-rehabilitation phase (days 4-15: assisted ambulation, straight leg raise, passive range-of-motion exercises), and active rehabilitation phase (weeks 2-3: active-assisted knee ROM exercises, closed kinetic chain exercises, balance training, stair and gait training), along with pain and edema control throughout.
Surface NMES applied bilaterally over the vastus medialis obliquus and rectus femoris muscles (long-sitting position, knee at 30° flexion). Parameters: 50 Hz frequency, 300-400 µs pulse width, duty cycle 1:3 (10 sec on-30 sec off), intensity titrated to patient tolerance to produce visible muscle contraction, 20 minutes/session, once daily, 5 days/week, for 4 weeks.
Surface NMES applied bilaterally to the lumbar paraspinal muscles (erector spinae and multifidus) via 4 hydrogel electrodes placed bilaterally around the L4-L5 spinous processes, in prone position. Parameters: 50 Hz frequency, 250-350 µs pulse width, duty cycle 1:3 (10 sec on-30 sec off), intensity titrated to patient tolerance to produce visible muscle contraction, 20 minutes/session, once daily, 5 days/week, for 4 weeks.
University of Health Sciences, Bursa Yuksek Ihtisas Training and Research Hospital
Bursa, Turkey (Türkiye)
Change from Baseline in Pelvic Tilt (PT)
Pelvic tilt will be measured as the angle between the line connecting the midpoint of the sacral plate to the center of the femoral head axis and the vertical line, assessed on standing lateral whole-spine radiographs (36-inch cassette) by two independent physicians blinded to group allocation. Measurements will be performed using PACS-integrated measurement software. Interobserver reliability (ICC ≥ 0.85) and intraobserver reliability (repeat measurement at 2-week interval) will be assessed. Unit of Measure: degrees
Time frame: Baseline (preoperative, T0), before rehabilitation (postoperative, T1), end of 4-week intervention (postoperative week 6, T2), and 6-month follow-up (T4)
Change from Baseline in Sagittal Vertical Axis (SVA)
The horizontal distance between the C7 plumb line and the posterosuperior corner of S1 will be measured on standing lateral whole-spine radiographs. Unit of Measure: millimeters
Time frame: Baseline (T0), before rehabilitation (T1), end of 4-week intervention (T2), and 6-month follow-up (T4)
Change from Baseline in Radiographic Spinopelvic Angular Parameters (Sacral Slope, Lumbar Lordosis, Spinosacral Angle)
Sacral slope (angle between the S1 superior endplate and horizontal), lumbar lordosis (Cobb angle between L1 and S1), and spinosacral angle (angle between the line connecting the C7 center to the sacral plate midpoint and the sacral plate) will be measured on the same standing lateral whole-spine radiographs described above. Unit of Measure: degrees
Time frame: Baseline (T0), before rehabilitation (T1), end of 4-week intervention (T2), and 6-month follow-up (T4)
Change from Baseline in Knee Pain (Visual Analog Scale)
Knee pain will be assessed using a 0-10 cm Visual Analog Scale, with scores ranging from 0 (no pain) to 10 (worst imaginable pain); higher scores indicate greater pain intensity. Unit of Measure: score on a scale (0-10)
Time frame: Baseline (preoperative, T0), before rehabilitation (postoperative, T1), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in Low Back Pain (Visual Analog Scale)
Low back pain will be assessed using a 0-10 cm Visual Analog Scale, with scores ranging from 0 (no pain) to 10 (worst imaginable pain); higher scores indicate greater pain intensity. Unit of Measure: score on a scale (0-10)
Time frame: Baseline (preoperative, T0), before rehabilitation (postoperative, T1), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in WOMAC Osteoarthritis Index Score
Knee-related pain, stiffness, and physical function will be assessed using the Turkish-validated WOMAC index, with a total score ranging from 0 to 96; higher scores indicate greater symptom severity and worse function. Unit of Measure: score on a scale
Time frame: Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in Knee Society Score (KSS)
Knee pain, range of motion, and functional status will be assessed using the Knee Society Score, comprising a knee score and a function score, each ranging from 0 to 100; higher scores indicate better knee status and function. Unit of Measure: score on a scale
Time frame: Baseline (preoperative, T0), before rehabilitation (postoperative, T1), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in Forgotten Joint Score (FJS)
Awareness of the artificial joint during daily activities will be assessed using the FJS, with scores ranging from 0 to 100; higher scores indicate lower joint awareness, reflecting a better outcome. Unit of Measure: score on a scale (0-100)
Time frame: Baseline (preoperative, T0), before rehabilitation (postoperative, T1), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in Timed Up and Go (TUG) Test
Functional mobility will be assessed using the TUG test, measuring the time required to stand up from a chair, walk 3 meters, turn, return, and sit down. Higher times indicate poorer mobility. Unit of Measure: seconds
Time frame: Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in 6-Minute Walk Test Distance
Aerobic capacity and functional endurance will be assessed using the distance walked in 6 minutes. Greater distance indicates better functional capacity. Unit of Measure: meters
Time frame: Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in Oswestry Disability Index
Low back function-related disability will be assessed using the Turkish-validated Oswestry Disability Index, with scores ranging from 0% to 100%; higher scores indicate greater disability. Unit of Measure: percentage
Time frame: Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), postoperative month 3 (T3), and 6-month follow-up (T4)
Change from Baseline in Nottingham Health Profile
General health-related quality of life will be assessed using the Turkish-validated Nottingham Health Profile. Unit of Measure: score on a scale
Time frame: Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), and 6-month follow-up (T4)
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