Paraspinal NMES and Spinopelvic Alignment After Knee Arthroplasty

Official title

Effect of Paraspinal Neuromuscular Electrical Stimulation Added to Rehabilitation Program on Spinopelvic Alignment Parameters After Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

Overview

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.

Interventions

• Other Standard Postoperative Rehabilitation Program
  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
• Device Quadriceps Neuromuscular Electrical Stimulation
  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.
• Device Paraspinal Neuromuscular Electrical Stimulation
  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.

Primary outcome measures

• Change from Baseline in Pelvic Tilt (PT) [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) [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) [Time frame: Baseline (T0), before rehabilitation (T1), end of 4-week intervention (T2), and 6-month follow-up (T4)]

Secondary outcome measures (9)

• Change from Baseline in Knee Pain (Visual Analog 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 Low Back Pain (Visual Analog 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 WOMAC Osteoarthritis Index Score [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) [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) [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 [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 [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 [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 [Time frame: Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), and 6-month follow-up (T4)]

Eligibility criteria

Inclusion criteria

• Age between 40 and 80 years
• Diagnosis of primary knee osteoarthritis scheduled for total knee arthroplasty
• Radiographic evidence of Kellgren-Lawrence grade 3-4 knee osteoarthritis
• Preoperative knee flexion contracture ≥ 5°
• Measurable spinopelvic malalignment, defined as meeting at least one of the following criteria: pelvic tilt (PT) > 20°, sagittal vertical axis (SVA) > 50 mm, or lumbar lordosis (LL) < 40°
• IIntact cognitive function based on clinical judgment, sufficient to understand and follow verbal commands, cooperate with the rehabilitation program, and reliably comply with functional assessment procedures
• Provision of written informed consent
• Able to stand independently and undergo standing lateral radiography

Exclusion criteria

• Prior lumbar or thoracic spinal surgery
• History of hip arthroplasty
• Prior knee arthroplasty (revision arthroplasty patients)
• Active inflammatory arthritis (e.g., rheumatoid arthritis, psoriatic arthritis)
• Neurological disease, including stroke, Parkinson's disease, peripheral neuropathy, or spinal cord pathology
• Contraindications to NMES, including active cardiac pacemaker, implanted defibrillator, deep vein thrombosis, skin integrity impairment, malignancy, or epilepsy
• Severe hip osteoarthritis or other lower extremity pathology significantly affecting spinopelvic alignment (e.g., leg length discrepancy, developmental hip dysplasia, contracture)
• Inability to complete the standard rehabilitation protocol due to postoperative complications
• Osteoporotic vertebral fracture or significant osteoporosis (T-score < -2.5 at L1-L4)
• Active treatment for malignancy
• Psychiatric or medical condition that would prevent completion of the follow-up period
• General contraindications to exercise

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Turkey (Türkiye) · 1 center

• University of Health Sciences, Bursa Yuksek Ihtisas Training and Research Hospital — Bursa

Identifiers

NCT: NCT07741162 · 2026-9/11

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗