The goal of this clinical trial is to learn whether personalized weight-bearing prescriptions using Smart Crutch Tips™ can improve recovery after surgery for tibial shaft fractures. The study will also assess how safe and practical this approach is in daily outpatient use. Can a personalized weight-bearing program based on CT and finite element analysis help the fracture heal faster? Can it help patients return to full weight-bearing sooner? Can it reduce the fear of movement during recovery? Does iterative walking in the early postoperative period support faster or better bone healing? Researchers will compare standard rehabilitation to different types of personalized weight-bearing programs to see which leads to faster healing, earlier mobility, and better outcomes. Participants will: Use Smart Crutch Tips™ during walking for up to 24 weeks; Follow a personalized weight-bearing prescription based on CT scans and biomechanical modeling; Follow a specific walking plan with real-time audio and visual feedback; Attend six follow-up visits over 36 weeks for clinical exams, x-rays, and CT scans; Complete online questionnaires about pain, activity, and fear of movement.
This is a pilot multicenter clinical trial designed to explore the impact of individual weight-bearing and iterative walking regimens on the healing of tibial shaft fractures. The study will enroll 30 adult participants (aged 18 to 60) with closed tibial shaft fractures (AO/OTA 42-A, 42-B, or 42-C) treated by intramedullary nailing. Participants will be allocated into three parallel groups (ten participants per group), two of whom will receive personalized weight-bearing protocols based on finite element analysis (FEA) performed using individual CT scan data. The goal of the study is to determine whether providing precise, data-driven weight-bearing recommendations-delivered through Smart Crutch Tips™ with real-time visual and auditory feedback-can enhance fracture healing by promoting safe interfragmentary motion. Group 1 (control - standard practice) will use Smart Crutch Tips™ for load data collection only, without feedback, and follow AO Foundation guidelines, progressing weight-bearing based on pain tolerance. Group 2 (controlled mechanical stimulation) will receive personalized FEA-based load prescriptions for optimal interfragmentary motion, with real-time audio/visual feedback from Smart Crutch Tips™. They will perform iterative walking sessions (minimum two-hour rest between), gradually increasing steps per their plan, plus prescribed lower limb strengthening exercises. Group 3 (optimized stimulation per Claes-Heigele theory) will receive FEA-based prescriptions targeting maximum fracture-zone voxel optimization, with real-time feedback. They will follow the same walking and exercise protocol as Group 2. Participants will use ComeBack Mobility Smart Crutch Tips™ all the time they use crutches in an outpatient setting for up to 24 weeks, depending on their healing progress. These devices provide real-time guidance to help users stay within their prescribed weight-bearing range and transmit data to a centralized monitoring platform. Participants will attend seven in-person follow-up visits: screening (Day 0-7), and then at 6, 12, 16, 20, 24, and 36 weeks after surgery. Аt each follow-up visit starting from Visit 1 (6 weeks) Radiographic assessments (X-ray) will be performed to monitor fracture healing, Computed tomography (CT) scans will be conducted only at specific time points: during the screening period (0-7 days post-surgery), and prior to Visit 1 (6 weeks), Visit 2 (12 weeks), and optional prior to Visit 3 (16 weeks) to adjust weight-bearing prescription and assess consolidation dynamics. Clinical data will be collected via the ComeBack Mobility app and electronic case report forms (eCRFs). Before each follow-up visit, participants will complete an online diary that includes validated questionnaires such as the Tampa Scale for Kinesiophobia (TSK-17) and the Lower Extremity Functional (LEFS). At Visit 1, participants will also complete the System Usability Scale (SUS) to assess their experience using the device. All study procedures will be conducted according to a standardized research protocol across multiple orthopedic hospitals and trauma centers in Ukraine, ensuring consistency in surgical technique, data collection, and follow-up.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
30
Smart Crutch Tips™ are sensor-equipped crutch attachments that measure real-time axial loading during ambulation. The devices connect via Bluetooth to a mobile application and deliver auditory and visual feedback to guide patients toward prescribed weight-bearing levels. The devices continuously record loading and step-count data for clinical monitoring and analysis.
Finite Element Analysis (FEA) is performed up to four times postoperatively to generate individualized weight-bearing prescriptions during rehabilitation. Simulations are based on CT scans and include segmentation and biomechanical modeling of the bone-fixator system. Assessments occur at: 7 days (baseline), 6 weeks, 12 weeks, and optionally at 16 weeks if healing isn't confirmed. Three regions are segmented: fixation system (screws and nail), bone fragments, and fracture gap. Materials: fixator (Titanium Grade 5), bone (mapped into cortical, trabecular, soft tissue, air), and fracture gap (early connective tissue). FEA calculates personalized safe loading based on: (1) Fixator safety (stress \< 290 MPa), (2) Interfragmentary motion (target: 0.5-2.0 mm), and (3) Strain in the fracture gap (octahedral: 0.001-0.05; hydrostatic: 0.001-0.02), supporting biological healing. Output informs weight-bearing prescriptions and step-count targets, delivered via Smart Crutch Tips™ with real-time fee
Participants will perform iterative walking sessions as part of their rehabilitation program. These sessions will be repeated throughout the day, with a minimum 2-hour rest interval between sessions. Step count will be progressively increased over time, according to the individualized rehabilitation plan. In the intervention arms, walking sessions will be guided by real-time auditory and visual feedback from Smart Crutch Tips™.
A structured exercise program prescribed postoperatively to promote functional recovery after tibial shaft fracture surgery. Exercises target quadriceps, hamstrings, gluteal muscles, and ankle/foot mobility to maintain muscle tone, prevent stiffness, and improve circulation. The program includes isometric and dynamic exercises such as: static quadriceps and hamstring contractions, straight leg raises, hip abduction, knee extension, hamstring curls, heel slides, ankle dorsiflexion/plantarflexion, ankle inversion/eversion, ankle circles, toe spreading, and passive ankle stretching using a strap or towel. Exercises are performed in pain-free ranges with gradual progression in repetitions and sets according to the rehabilitation plan. Certain ankle and foot mobility exercises (dorsiflexion/plantarflexion) are also performed hourly during the day to prevent swelling and thrombosis.
Kyiv City Clinical Hospital No. 1
Kyiv, Kyiv Oblast, Ukraine
RECRUITINGMunicipal Clinical Hospital No. 6 of the Dnipro City Counci
Dnipro, Ukraine
RECRUITINGMunicipal Clinical Hospital No. 4 of the Dnipro City Counci
Dnipro, Ukraine
RECRUITINGRailway Clinical Hospital No. 1 of Kyiv Station
Kyiv, Ukraine
NOT_YET_RECRUITINGKyiv City Clinical Hospital No. 17
Kyiv, Ukraine
NOT_YET_RECRUITINGInstitute of Traumatology and orthopedics of the national academy of medical sciences of Ukraine
Kyiv, Ukraine
NOT_YET_RECRUITINGKyiv City Clinical Hospital No. 12
Kyiv, Ukraine
NOT_YET_RECRUITINGKyiv City Clinical Hospital No. 6
Kyiv, Ukraine
RECRUITINGKyiv City Clinical Hospital No. 7
Kyiv, Ukraine
RECRUITINGKyiv Regional Council "Kyiv Regional Clinical Hospital"
Kyiv, Ukraine
NOT_YET_RECRUITING...and 2 more locations
Time to Radiographic Fracture Union
X-rays will be performed at Visit 1, Visit 2, Visit 3, Visit 4, Visit 5 and Visit 6 postoperatively. CT will be conducted at Visit 0, Visit 1, Visit 2, and optionally at Visit 3 to assess fracture union progression and load adaptation. Fracture Consolidation Assessment Procedure: CT and X-ray data will be evaluated separately. CT criteria include qualitative parameters (fracture line presence, edge clarity, cortical bridging) and quantitative parameters (Hounsfield units at the fracture site). Radiographic assessment will follow the modified RUST scale: Score 1 - no callus, visible line; Score 2 - callus without bridging, visible line; Score 3 - callus with bridging, visible line; Score 4 - callus with bridging, no visible line. The total score ranges from 4 to 16. Fracture is united if at least three cortices are bridged. Delayed union is defined as a visible fracture line and no callus after 3 months.
Time frame: 12 - 24 weeks post-surgery ± 7 days
mRUST Score
The modified Radiographic Union Scale for Tibial fractures (mRUST) is used to assess bone healing based on radiographs of the fracture site. Four cortices are evaluated, with scores assigned according to callus formation and visibility of the fracture line. The total score ranges from 4 to 16, with higher scores indicating more advanced bone healing. mRUST scores will be compared between intervention and control groups at each follow-up visit to determine the impact of the intervention on bone healing.
Time frame: at 6, 12, 16, 20, 24, and 36 weeks after surgery (+- 7 days)
Adherence to Prescribed Axial Loading
The percentage of steps taken within the prescribed range of axial loading. Higher percentages indicate better adherence to the prescribed loading regimen. This is measured through continuous monitoring using the Smart Crutch Tips™ device and analyzed at each follow-up visit (from 0 to 36 weeks).
Time frame: from 0 to 36 weeks post-surgery
Lower Extremity Functional Status (LEFS)
Assessed using the Lower Extremity Functional Scale (LEFS) - a validated instrument designed to measure a patient's ability to perform everyday physical activities involving the lower limbs. The questionnaire consists of 20 items, each scored from 0 (extreme difficulty or unable to perform) to 4 (no difficulty). The total score ranges from 0 to 80, with higher scores indicating better functional status.
Time frame: 0-7 days post-surgery and at 6, 12, 16, 20, 24, 36 weeks after surgery (+- 7 days)
Recording of AEs/SAEs AR/SAAR/SUSARs, including Postoperative Complications
The following types of postoperative complications will be recorded and analyzed: residual pain; delayed union; nonunion; malunion; implant failure; need for reoperation. Assessment will be performed clinically at each visit and supplemented with radiological evaluation (X-ray and CT), according to the visit schedule. All adverse events (AEs), serious adverse events (SAEs), adverse reactions (ARs), serious adverse reactions (SAARs), and suspected unexpected serious adverse reactions (SUSARs) identified during the study will also be recorded, described, and analyzed.
Time frame: 0-7 days post-surgery and at 6, 12, 16, 20, 24, 36 weeks after surgery (+- 7 days)
Pain Level
Assessed using the Visual Analogue Scale (VAS), presented electronically as a continuous line ranging from 0 (no pain) to 10 (worst possible pain). Higher scores indicate greater pain intensity. Assessment is conducted at each follow-up visit
Time frame: 0-7 days post-surgery and at 6, 12, 16, 20, 24, 36 weeks after surgery (+- 7 days)
Fear of Movement (TSK-17)
Assessed using the Tampa Scale for Kinesiophobia, 17-item version (TSK-17), which evaluates fear of physical activity due to pain or risk of re-injury. Scores range from 17 to 68, with higher scores indicating greater fear of movement. Administered electronically at each follow-up visit.
Time frame: 0-7 days post-surgery and at 6, 12, 16, 20, 24, 36 weeks after surgery (+- 7 days)
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