Unknown
NA
INTERVENTIONAL
NCT03086512
A Study Comparing Computerized Tomographic Progression of Bone Bridging After Subtalar Fusion Using Fully and Partially Threaded Screws
View on ClinicalTrials.gov
Updated Dec 15, 2025
Brief Summary
The study was designed by the principal investigator, Dr. Alastair Younger, and the St. Paul's Hospital Foot and Ankle Research Group, who will conduct the study. The study is being funded by Acumed LLC, the manufacturer of the Health Canada approved Acutrak 2® - 7.5 fully threaded screw. The purpose of this study is to assess and compare the effectiveness of fully threaded screws versus partially threaded screws in subtalar fusion, in order to determine the effect of the thread configuration on the success of the fusion procedure. Efficacy will be assessed primarily by computed tomography (CT) analysis of percent bone bridging across the subtalar joint at both 12 and 24 weeks post-op. Outcome scores will also be administered to compare general health and foot function between the two groups at baseline and at multiple post-op follow-up visits. Additional resource utilization (i.e. additional clinic and/or hospital admissions) will also be compared between the two groups post-op.
Interventions
Name:
Acutrak 2® - 7.5 Screw
Type:
DEVICE
Description:
The Acumed Acutrak 2® - 7.5 is a fully-threaded headless screw fixation, composed of 17 unique screw size options. The Acutrak 2® - 7.5 is available in sizes from 40 mm to 120 mm and is inserted using a 4.0 mm hex driver over a .094" guide wire. The Acutrak 2 Part Number is 30-0XXX and 30-0XXX-S.
Name:
Synthes® 7.3 Cannulated Screw
Type:
DEVICE
Description:
The Synthes® 7.3 mm Cannulated screws are available in three thread options: 16 mm, 32 mm or fully threaded. This study will use the partially threaded options. The screws can be placed by small diameter guide wires. They are composed of 316L stainless steel or titanium alloy (Ti-6Al-7Nb).
Primary Outcomes
Measure:
Post-operative CT Scans: 12 Week Width of Joint
TimeFrame:
Measurements will be assessed at 12 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* For each observer at the time-point, each slice of the CT scan will be reviewed and the width of the joint will be measured.
Measure:
Post-operative CT Scans: 12 Week Width of Bone Bridging
TimeFrame:
Measurements will be assessed at 12 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* For each observer at the time-point, each slice of the CT scan will be reviewed and the width of bone bridging will be measured.
Measure:
Post-operative CT Scans: 12 Week Width of Any Fixation Hardware
TimeFrame:
Measurements will be assessed at 12 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* For each observer at the time-point, each slice of the CT scan will be reviewed and the width of any fixation hardware will be measured.
Measure:
Post-operative CT Scans: 24 Week Width of Joint
TimeFrame:
Measurements will be assessed at 24 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* For each observer at the time-point, each slice of the CT scan will be reviewed and the width of the joint will be measured.
Measure:
Post-operative CT Scans: 24 Week Width of Bone Bridging
TimeFrame:
Measurements will be assessed at 24 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* For each observer at the time-point, each slice of the CT scan will be reviewed and the width of bone bridging will be measured.
Measure:
Post-operative CT Scans: 24 Week Width of Any Fixation Hardware
TimeFrame:
Measurements will be assessed at 24 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* For each observer at the time-point, each slice of the CT scan will be reviewed and the width of any fixation hardware will be measured.
Measure:
Post-operative CT Scans: 12 Week Bone Bridging
TimeFrame:
Measurements will be assessed at 12 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* The percent of bone bridging will be calculated for each slice.
Measure:
Post-operative CT Scans: 24 Week Bone Bridging
TimeFrame:
Measurements will be assessed at 24 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* The percent of bone bridging will be calculated for each slice.
Measure:
Post-operative CT Scans: 12 Week Group Average Comparisons
TimeFrame:
Measurements will be assessed at 12 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* The averages of all coronal slices for the three observers (6 readings per 12 week post-operative CT scan) will be compared between the two study groups.
Measure:
Post-operative CT Scans: 24 Week Group Average Comparisons
TimeFrame:
Measurements will be assessed at 24 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* The averages of all coronal slices for the three observers (6 readings per 24 week post-operative CT scan) will be compared between the two study groups.
Measure:
Post-operative CT Scans: 12 Week Inter- and Intra Observer Reliability
TimeFrame:
Measurements will be assessed at 12 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* The averages of all slices in the coronal plane will be compared between the three observers at 12 weeks to determine the inter- and intra- observer reliability of the measurements.
Measure:
Post-operative CT Scans: 24 Week Inter- and Intra Observer Reliability
TimeFrame:
Measurements will be assessed at 24 weeks post-operation.
Description:
This outcome measure is to compare bone bridging between full thread versus partial thread screw.
* The coronal images will have the area of the screw masked and will be reviewed by three independent, trained, and blinded observers.
* The averages of all slices in the coronal plane will be compared between the three observers at 24 weeks to determine the inter- and intra- observer reliability of the measurements.
Trial Information
NCT ID
NCT03086512
Status
Unknown
Study Type
INTERVENTIONAL
Phases
NA
Sponsor
St. Paul's Hospital, Canada
Last Updated
December 15, 2025