Focused Registry SmartFix (FRSmartFix)

Clinical Data Collection With a Novel Biofeedback Technology for Continuous Monitoring of Bone Healing

20 patients having received an AO large external fixator at the tibia will be equipped with a data logger device (AO Fracture Monitor) attached post-operation to a connection rod of the external fixator. The device continuously measures deformation of the fixator frame due to weight bearing for up to 6 months by means of a strain gauge. Several parameters are calculated from the recorded change in the strain signal and are stored at a regular interval.

Study Overview

• Status: Completed
• Conditions: Fracture of Shaft of Tibia
• Intervention / Treatment: Device: SmartFix

Detailed Description

Maturation of fracture callus leads to unloading of the fracture fixation hardware due to an increased load-share of the repair tissue. A novel data logger device (AO Fracture Monitor) continuously measures the decline in fixation hardware deflection under physiological loading as indirect indicator for the healing progress. Parameters obtained from the data logger device carry potential to significantly improve the assessment of fracture healing in the future. Meaningful interpretation of measurements requires a set of clinical reference data.

20 patients having received an AO large external fixator at the tibia will be equipped with a data logger device (AO Fracture Monitor) attached post-operation to a connection rod of the external fixator. The device continuously measures deformation of the fixator frame due to weight bearing for up to 4 months by means of a strain gauge. Several parameters are calculated from the recorded change in the strain signal and are stored at a regular interval. Data is collected from the AO Fracture Monitor at follow-up visits of the patient by wireless data transfer. Together with additional variables such as treatment details, fracture healing and pain reported by the patient, the collected data is used to build up a database. Data from the AO Fracture Monitor will be correlated with patient data to investigate the relevance and reliability of the data derived from the AO Fracture Monitor.

In this phase, the study does not imply changes on the operational treatment, nor does it allow for therapeutic consequences based on the derived data.

• Study Type: Observational
• Enrollment (Actual): 10

Contacts and Locations

Study Locations

• Germany
  • Baden Württemberg
    • Tübingen, Baden Württemberg, Germany, 72076
      • Berufsgenossenschaftliche Unfallklinik

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients with Tibia shaft fracture and external fracture fixation (AO large external fixator).

Patients capable of at least partial weight-bearing (or expected to do so in the course of healing).

Description

Inclusion Criteria:

• Age 18 years and older
• Diagnosis of Femoral or tibial fracture (AO 41-43)
• External fracture fixation with AO large external fixator
• Capable of at least partial weight-bearing

• Informed consent obtained, i.e.:

  • Ability to understand the content of the patient information/Informed Consent Form (ICF)
  • Willingness and ability to participate in the Focused Registry according to the Registry Plan (RP)
  • Signed and dated Ethics Committee (EC) approved written informed consent

Exclusion Criteria:

Preoperative exclusion criteria:

• External fixation as temporary stabilization
• Joint-bridging external fixation
• Any not medically managed severe systemic disease
• Recent history of substance abuse (i.e. recreational drugs, alcohol) that would preclude reliable assessment
• Pregnancy or nursing mother
• Emergency patient
• Prisoner
• Participation in any other medical device or medicinal product study within the previous month that could influence the results of the present study

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Only
• Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Parameters derived from the AO Fracture Monitor during bone healing	AO Fracture Monitor: Mean deformation amplitude per 6 hours; Mean deformation rate; Number of load-cycles; Histogram of patient activity (load intensity distribution)	Discharge, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Pain during bone healing	Pain measured with visual analog scale (VAS)	Preoperative, Discharge, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months (after surgery)
Change in weight-bearing during bone healing	Documentation of allowed weight-bearing	Discharge, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months (after surgery)
Repeated reference deformation at a load of 20 / 30 kg	Two reference deformation values are measured under a load 20 kg and 30 kg respectively. The patient steps with his injured leg on a bathroom scale and loads it first with the reference load of 20 kg. The investigator then starts the measurement of the corresponding deformation value. After an acoustic signal indicates the end of the measurement, the procedure is repeated with a reference load of 30 kg. If the patient is not able to put the required load on his leg (e.g. due to pain), the reference value should be measured at a lower load with a note of the actually applied load in the patient record.	Discharge, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months (after surgery)
Patient information	Patient demographics; Comorbidities	Up to 4 weeks before surgery
Treatment information	Fracture classification according to AO and Gustilo; Reason for external fixator treatment; Previous treatment related to current injury, if any; Fixator configuration	Discharge
Development of the radiological healing assessment: RUST system	The Radiographic Union Score for Tibial fractures (RUST score) is a reliable score to assess the healing of tibial fractures. Each of the four cortices (anterior, posterior, medial and lateral) is given a value from 1 to 3, depending on the presence of a callus and the visibility of the fracture line. The sum of the individual cortical scores results in a RUST value between 4 (definitely not healed) to 12 (definitely healed). To investigate, whether patient activity as measured by the AO Fracture Monitor correlate with the radiological assessed course of healing.	Discharge, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months (after surgery)

Collaborators and Investigators

• Sponsor: AO Clinical Investigation and Publishing Documentation
• Investigators: Principal Investigator: Dankward Höntzsch, Professor, Berufsgenossenschaftliche Unfallklinik Tübingen

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2015
• Primary Completion (Actual): February 1, 2017
• Study Completion (Actual): July 1, 2017

Study Registration Dates

• First Submitted: March 18, 2014
• First Submitted That Met QC Criteria: March 19, 2014
• First Posted (Estimate): March 21, 2014

Study Record Updates

• Last Update Posted (Actual): August 12, 2020
• Last Update Submitted That Met QC Criteria: August 11, 2020
• Last Verified: January 1, 2018

More Information

Terms related to this study

• Keywords: External Fixation; Tibial fracture; Fracture healing
• Additional Relevant MeSH Terms: Wounds and Injuries; Fractures, Bone
• Other Study ID Numbers: FRSmartFix