Tactile Incentiviser Improves Partial Weight Bearing After Lower-Limb Surgery

NCT06989554 | Completed

• 1 other identifier: 026262
• Study Type: interventional
• Target: 34
• Locations: 1 country
• Sites: 1

Brief Summary

Background: After lower-limb surgery, many patients are instructed to walk with only a fraction of their body weight on the operated leg (partial weight bearing). Traditional teaching methods-verbal instructions or brief practice with a bathroom scale-often fail to maintain the load within a safe range, potentially increasing the risk of delayed bone healing or implant failure. Purpose: This pilot study investigates whether a very low-cost, purely mechanical "tactile incentiviser" placed inside the shoe can assist participants in adhering to a 20% body-weight limit during the first two weeks of inpatient rehabilitation. Design: Single-centre, parallel-group, randomised controlled trial. Thirty-four adults undergoing hip or knee arthroplasty, or surgery for femoral-shaft or pelvic fracture, were enrolled. Randomisation was performed using a computer-generated list in sealed envelopes. Outcome assessors were blinded. Intervention: The device consists of four spring buttons embedded in a rubber insole that collapse and deliver a tactile cue when the 20% ± 1% load threshold is exceeded. Participants in the intervention group wore the insole during supervised walking sessions. Control participants received standard physiotherapy without feedback devices. Primary Outcome: Absolute deviation (kg) between prescribed and actual load, assessed with a pressure sensor at baseline and discharge. Secondary Outcomes: Pain intensity (NRS), Six-Minute Walk Test (6MWT) distance, and usability (System Usability Scale, SUS). Note: No results or conclusions are included here. Results will be reported in the appropriate Results Section after the study is completed.

Conditions

Femoral Fractures; Pelvic Fractures; Hip Fractures (ICD-10 72.01-72.2); Hip Arthroplasty; Knee Arthroplasty; Ankle Fractures

Keywords

partial weight bearing; tactile biofeedback insole; load-monitoring device; postoperative gait training; orthopaedic rehabilitation; lower-limb surgery; hip replacement rehab; femoral shaft fixation; pressure sensor calibration; System Usability Scale (SUS)

Outcome Measures

Primary Outcomes (1)

• Absolute deviation (kg) between prescribed 20 % body-weight load and actual load during gait

  The in-shoe pressure-sensor system (GeBioM MobilData) records vertical ground-reaction force for each step over a 10-m walkway. Load on the operated limb is averaged across 20 consecutive steps. Deviation is calculated as the absolute difference (kg) between this value and the target 20 % of the patient's body weight. Lower scores indicate better adherence.

  Post-operative day 1 (baseline) and hospital discharge (~14 days post-op)

Study Arms (2)

Incentivator

EXPERIMENTAL

Participants received a calibrated rubber insole containing four spring-loaded snap buttons that collapse and provide an immediate plantar tactile cue whenever the load on the operated limb exceeds 20 % ± 1 % of body weight. The insole was fitted on postoperative day 1 and worn inside the surgical-side shoe during every supervised ambulation session (walker or crutches) until hospital discharge (≈ 14 days, median 6 sessions per day). Patients were instructed to unload the limb instantly whenever the tactile "click" was felt. No batteries, electronics or external displays were used; calibration was performed once on a hydraulic press before first use.

Device: mechanical feedback insole

Standard Physiotherapy

ACTIVE COMPARATOR

Participants received routine ward physiotherapy only. Verbal instructions and a single bathroom-scale drill were used to teach 20 % body-weight partial loading, but no insole, sensor or tactile feedback device was provided thereafter. Treatment frequency, walking aids, pain management and discharge criteria were identical to the intervention arm.

Procedure: Standard physiotherapy without feedback device

Interventions

mechanical feedback insole DEVICE

A 3-mm rubber insole containing four 15-mm spring-steel snap buttons aligned along the heel-mid-foot axis. Each insole is statically calibrated on a hydraulic press so that the buttons collapse at 20 % ± 1 % of the individual's body weight, producing an unmistakable plantar cue when the load limit is exceeded. The device is purely mechanical, requires no batteries, and is fitted on postoperative day 1. Participants wear the insole during every supervised walking session until discharge (≈ 14 days).

Incentivator

Standard physiotherapy without feedback device PROCEDURE

Routine inpatient physiotherapy consisting of verbal instruction to limit loading to 20 % body weight, initial bathroom-scale training, and assisted ambulation with walker or crutches. No tactile, visual, or electronic feedback device is provided. Session frequency, walking aids, analgesia, and discharge criteria are identical to the intervention arm; duration ≈ 14 days.

Standard Physiotherapy

Eligibility Criteria

• Age: 18 Years - 84 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Recent lower-limb orthopaedic surgery with a prescription of 20 % body-weight partial weight bearing: femoral-shaft fracture fixation, pelvic fracture fixation, total hip arthroplasty, hip hemi-arthroplasty, total knee arthroplasty, or trimalleolar ankle fracture fixation.
• Able to stand and walk ≥ 5 m with a walking aid on postoperative day 1.
• Sufficient cognitive capacity and language skills to follow instructions and provide written informed consent.

You may not qualify if:

• Pre-existing gait disorder or neurological condition affecting load perception (e.g., stroke, Parkinson's disease, peripheral neuropathy, spinal cord injury).
• Surgeon-ordered non-weight-bearing restriction.
• Foot size \< EU 35 or \> EU 47, which cannot be accommodated by the insole.
• Active foot ulcer, severe peripheral vascular disease, or local infection on the operated limb.
• Clinically significant cognitive impairment (MMSE \< 24) or language barrier precluding comprehension of study procedures.
• Participation in another interventional study that could influence gait within the past 30 days.
• Any medical condition that, in the investigator's judgement, contraindicates participation (e.g., unstable cardiopulmonary status, uncontrolled pain ≥ 7/10 NRS).

Sponsors & Collaborators

• Università degli Studi dell'Insubria: lead

Study Sites (1)

University of Insubria

Varese, Varese, 21100, Italy

Location

Related Publications (4)

• Amoruso E, Dowdall L, Kollamkulam MT, Ukaegbu O, Kieliba P, Ng T, Dempsey-Jones H, Clode D, Makin TR. Intrinsic somatosensory feedback supports motor control and learning to operate artificial body parts. J Neural Eng. 2022 Jan 24;19(1):016006. doi: 10.1088/1741-2552/ac47d9.

  PMID: 34983040 BACKGROUND

• Tamburella F, Lorusso M, Tagliamonte NL, Bentivoglio F, Bigioni A, Pisotta I, Lancini M, Pasinetti S, Ghidelli M, Masciullo M, Saraceni VM, Molinari M. Load Auditory Feedback Boosts Crutch Usage in Subjects With Central Nervous System Lesions: A Pilot Study. Front Neurol. 2021 Jul 6;12:700472. doi: 10.3389/fneur.2021.700472. eCollection 2021.

  PMID: 34295303 BACKGROUND

• van Lieshout R, Pisters MF, Vanwanseele B, de Bie RA, Wouters EJ, Stukstette MJ. Biofeedback in Partial Weight Bearing: Usability of Two Different Devices from a Patient's and Physical Therapist's Perspective. PLoS One. 2016 Oct 31;11(10):e0165199. doi: 10.1371/journal.pone.0165199. eCollection 2016.

  PMID: 27798674 BACKGROUND

• Hustedt JW, Blizzard DJ, Baumgaertner MR, Leslie MP, Grauer JN. Current advances in training orthopaedic patients to comply with partial weight-bearing instructions. Yale J Biol Med. 2012 Mar;85(1):119-25. Epub 2012 Mar 29.

  PMID: 22461750 BACKGROUND

MeSH Terms

Conditions

Femoral Fractures; Hip Fractures; Ankle Fractures

Condition Hierarchy (Ancestors)

Fractures, Bone; Wounds and Injuries; Leg Injuries; Hip Injuries; Ankle Injuries

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Researcher

Study Record Dates

• First Submitted: May 7, 2025
• First Posted: May 25, 2025
• Study Start: January 1, 2024
• Primary Completion: April 1, 2025
• Study Completion: April 25, 2025
• Last Updated: May 25, 2025

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)