Paraspinal NMES and Spinopelvic Alignment After Knee Arthroplasty

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

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 Overview

• Status: Not yet recruiting
• Conditions: Knee Osteoarthritis; Postoperative Rehabilitation
• Intervention / Treatment: Other: Standard Postoperative Rehabilitation Program; Device: Quadriceps Neuromuscular Electrical Stimulation; Device: Paraspinal Neuromuscular Electrical Stimulation

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Sinem Akselim; Phone Number: +905336391332; Email: sinemakselim@gmail.com

Study Locations

• Turkey (Türkiye)
  • Bursa, Turkey (Türkiye)
    • University of Health Sciences, Bursa Yuksek Ihtisas Training and Research Hospital
    • Contact: Sinem Akselim; Phone Number: +905336391332; Email: sinemakselim@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental: Intervention Group; Standard Rehabilitasyon + Quadriceps NMES + Paraspinal NMES Description: Participants in this arm will receive the standard postoperative rehabilitation program combined with quadriceps NMES, plus additional paraspinal (erector spinae and multifidus) NMES applied bilaterally over the L4-L5 region for 20 minutes/day, 5 days/week, for 4 weeks.	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 and edema control throughout.; 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.; Other Names: Chattanooga Physio NMES device; 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.; Other Names: Chattanooga Physio NMES device
Active Comparator: Active Comparator: Control Group; Standard Rehabilitasyon + Quadriceps NMES Description: Participants in this arm will receive the same standard postoperative rehabilitation program combined with quadriceps NMES (bilateral VMO and rectus femoris electrode placement) for 20 minutes/day, 5 days/week, for 4 weeks, without paraspinal NMES.	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 and edema control throughout.; 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.; Other Names: Chattanooga Physio NMES device

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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	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	Baseline (T0), before rehabilitation (T1), end of 4-week intervention (T2), and 6-month follow-up (T4)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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)	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)	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	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	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)	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	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	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	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	Baseline (preoperative, T0), end of 4-week intervention (postoperative week 6, T2), and 6-month follow-up (T4)

Collaborators and Investigators

• Sponsor: Bursa Yuksek Ihtisas Training and Research Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): July 30, 2026
• Primary Completion (Estimated): July 30, 2027
• Study Completion (Estimated): July 30, 2027

Study Registration Dates

• First Submitted: July 23, 2026
• First Submitted That Met QC Criteria: July 27, 2026
• First Posted (Actual): August 3, 2026

Study Record Updates

• Last Update Posted (Actual): August 3, 2026
• Last Update Submitted That Met QC Criteria: July 27, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Total knee arthroplasty; Neuromuscular electrical stimulation; Postoperative rehabilitation; Spinopelvic alignment; Paraspinal muscles
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Knee
• Other Study ID Numbers: 2026-9/11

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No