Efficacy of a Low-Cost Tactile Incentiviser for Improving Partial Weight-Bearing Accuracy During Early Inpatient Rehabilitation After Lower-Limb Surgery: A Single-Centre Pilot Randomised Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 34
- 试验地点
- 1
- 主要终点
- Absolute deviation (kg) between prescribed 20 % body-weight load and actual load during gait
研究概览
简要总结
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.
详细描述
Background and Rationale Partial weight-bearing (PWB) restrictions (10-30% of body weight) are routinely prescribed for 2-6 weeks following hip or knee arthroplasty, fracture fixation, and pelvic or ankle reconstruction. Failure to adhere to these limits may overload internal fixation devices, delay bone healing, or impair implant osseointegration. While electronic smart-insole systems can enhance load accuracy, they often cost over €600, require batteries and smartphone connectivity, and are not readily available in low-resource settings. Therefore, a purely mechanical "tactile incentiviser" was developed to provide an immediate plantar cue when the load threshold is exceeded, aiming to offer a low-cost alternative.
Device Design and Calibration The incentiviser has a 3-mm rubber insole incorporating four spring-steel snap-buttons (15 mm diameter, 4 mm height) aligned along the heel-midfoot axis. Three interchangeable polyurethane-foam pads (35 / 45 / 60 Shore A, 6 mm thickness) allow adjustment according to participant body mass. Each insole is statically calibrated using a custom hydraulic press with a 0-500 N load cell (accuracy ± 0.5 N), increasing in 10 N increments until the buttons collapse at a target of 20% ± 1% of body weight. Calibration is performed in triplicate to ensure repeatability.
Study Design This is a single-centre, assessor-blinded, parallel-group pilot randomised controlled trial. Ethical approval was granted by the Institutional Review Board of the University of Insubria (protocol number 0026262).
Participants Eligible participants are adults aged 18-85 years undergoing hip or knee arthroplasty, femoral-shaft fracture intramedullary nailing, or pelvic fracture fixation who can ambulate ≥ 5 meters with assistive devices. Exclusion criteria include neurological gait disorders, pre-existing non-weight-bearing status, and foot sizes outside the 35-47 EU range.
Randomisation and Allocation Concealment All eligible admissions are listed chronologically each calendar week and assigned an incremental study ID. An independent researcher uses Random.org to randomly allocate three participants to the intervention arm and three to the control arm via simple random sampling without replacement. The allocation list is disclosed to ward staff only after baseline assessment to maintain allocation concealment. Outcome assessors and data analysts are blinded to group assignment. Due to the nature of the intervention, participants and therapists are not blinded.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 84 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •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
- •Sufficient cognitive capacity and language skills to follow instructions and provide written informed consent.
排除标准
- •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).
研究组 & 干预措施
Incentivator
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.
干预措施: mechanical feedback insole (Device)
Standard Physiotherapy
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.
干预措施: Standard physiotherapy without feedback device (Procedure)
结局指标
主要结局
Absolute deviation (kg) between prescribed 20 % body-weight load and actual load during gait
时间窗: Post-operative day 1 (baseline) and hospital discharge (~14 days post-op)
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.
次要结局
未报告次要终点
研究者
Piero Antonio Zecca
Researcher
Università degli Studi dell'Insubria