Clinical trial NCT01844479: Multi-layer Insoles for a Patient-specific Approach to Shear and Pressure Reduction in Diabetes-related Foot Ulcer
Official title: Multi-material, Layer, and Density Insoles for a Patient-specific Approach to Shear and Pressure Reduction in the Treatment and Prevention of Diabetes-related Foot Ulcer
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Diabetic Foot Ulcer
Diabetic Foot
Keywords: diabetic foot ulcer
diabetic foot
Lead sponsor: University of Michigan
Sponsor class: OTHER
First posted: 2013-05-01
Enrollment: 27
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: PREVENTION

Brief summary: In this pilot study, the first objective is to bench test a novel shear reducing insole and compare it to current standard insoles and shoes. The second objective is to study twenty-seven insensate diabetes patients with pre-ulcerative foot callus to examine for changes in spatial temporal gait including gait initiation, risk of falling, static and dynamic balance, and plantar temperature response to walking and consecutive plantar stress in both footwear conditions.

Detailed description: Device Description: The Dynamic Foot Orthosis (DFO) is designed with a rolling link mechanism at the distal 3rd. It is designed to reduce sliding friction and torque at the metatarsal heads in addition to decreasing compressive forces that is accomplished by the conventional multi-durometer FOs. The relative sliding motion of two compliant surfaces over each other allows some deformation horizontally and lowers frictional resistance. The DFO addresses the friction element by accommodating the normal sliding and rolling motion at the distal 3rd of the foot during gait. Additionally, the DFO has a silicone layer at the metatarsal head and the remainder of the anterior section made of 2 separated orthotic layers that slide over each other. This provides an articulating surface to provide a relative motion between the orthotic segments while transmitting load.

Study Objectives: In this pilot study, the first objective is to bench test a novel shear reducing insole and compare it to current standard insoles and shoes. The second objective is to study twenty-seven insensate diabetes patients with pre-ulcerative foot callus to examine for changes in spatial temporal gait including gait initiation, risk of falling, static and dynamic balance, and plantar temperature response to walking and consecutive plantar stress in both footwear conditions.

Study Design: This is an interventional study. For objective one, changes in compression stiffness and static coefficients of friction will be measured using a force dynamometer in the lab of Professor Albert Shih. A test platform will be built to evaluate the performance of the shear reduction shoe sole design and characteristic of the force, in two directions parallel (shear) and perpendicular to the ground, and the associated deformation under the steady-state and impulse conditions.

For objective two, diabetes patients presenting to the Michigan Orthotics and Prosthetics Center for fabrication and dispensing of diabetic shoes and innersoles will be invited to participate. Twenty-seven insensate diabetes patients with pre-ulcerative foot callus will be enrolled. Patients will wear body worn sensors (LegSys) to measure changes in spatial-temporal gait and static and dynamic balance parameters prior and post usage of the insoles. To reduce the effects of learning from naïve use of novel footwear, the testing sequence between the experimental and standard footwear will be randomized. We will examine increase on foot temperature over 200 steps of continuous walking using the DFO and using standard insoles. We will also examine if the thermal changes are mediated by autonomic neuropathy as measured by sudomotor function. The footwear testing sequence will be randomized and an acclimatization procedure will be followed in an effort to minimize the potential effects of cumulative plantar temperature responses to walking and footwear conditions. We will also examine static balance by measuring center of mass with eyes open and eyes closed condition.

Outcome Measures: For objective one, the primary endpoints will be the compression stiffness and static coefficients of friction. For objective two, plantar foot temperature changes in regions-of-interest in response to walking 200 steps will be measured in each footwear condition and compared to baseline. Other outcome measures include gait analysis, including gait initiation, gait speed, double support time, medial and lateral center of mass displacement, and inter-cycle variability under single and dual task conditions. This will be measured during each footwear condition. Static balance will also be measured in each footwear condition. Using the Romberg's test, we will also assess center of mass displacement and reciprocal hip and ankle motion under eyes open and closed conditions. Sudomotor function will be measured by electrical sweat conductance (ESC), as expressed in microSiemens (µS).

Safety Evaluation: All subjects who sign the informed consent form and are determined to be eligible for treatment will be included in the analysis of safety. Collection, classification and summary analysis of adverse events will be performed.

Duration of Participation: One visit lasting approximately 1 hour.

Duration of Study: One year

Inclusion Criteria: Patients will be included if they have diabetes and have been referred for diabetic shoes. They will also be insensate with pre-ulcerative plantar callus or previous plantar foot ulcer.

Exclusion Criteria: Patients will be excluded if they are unable to independently walk 100 feet, lower extremity prosthesis user, have active cellulitis, foot ulcer, or Charcot foot.

Eligibility criteria: Inclusion Criteria:

* Patients will be included if they have diabetes and have been referred for diabetic shoes. They will also be insensate with pre-ulcerative plantar callus or previous plantar foot ulcer.

Exclusion Criteria:

* Patients will be excluded if they are unable to independently walk 100 feet, lower extremity prosthesis user, have active cellulitis, foot ulcer, or Charcot foot.

Primary outcomes:
measure: Plantar Foot Temperature Changes in Regions-of-interest in Response to Walking
timeFrame: baseline and after 200 steps in each condition, this is a single visit study expected to last one hour
Secondary outcomes:
measure: Gait Initation - Single Task
timeFrame: during each foot wear condition up to 30 minutes
measure: Gait Initiation - Dual Task
timeFrame: during each foot wear condition up to 30 minutes
measure: Stride Velocity - Dual Task
timeFrame: during each foot wear condition up to 30 minutes
measure: Double Support Time Single Task
timeFrame: during each foot where condition up to 30 minutes
measure: Double Support Time Dual Task Gait Initiation
timeFrame: during each foot where condition up to 30 minutes
measure: Medial and Lateral Center of Mass Displacement Single Task
timeFrame: under each foot where condition up to 30 minutes
measure: Medial and Lateral Center of Mass Displacement Dual Task
timeFrame: both footwear conditions up to 30 minutes
measure: Gait Speed Variability Single Task
timeFrame: both footwear conditions up to 30 minutes
measure: Gait Speed Variability Dual Task
timeFrame: Both footwear conditions up to thirty minutes
Other outcomes:
measure: Stride Velocity - Single Task
timeFrame: during each foot wear condition up to 30 minutes
measure: Sudomotor Function
timeFrame: at baseline, this is a single visit study expected to last one hour
Locations:
city: Ann Arbor
country: United States
facility: Michigan Orthotics and Prosthetics
state: Michigan
Study officials:
affiliation: UMHS
name: James Wrobel, DPM, MS
role: PRINCIPAL_INVESTIGATOR
References:
citation: Belmont B, Wang Y, Ammanath P, Wrobel JS, Shih A. An apparatus to quantify anteroposterior and mediolateral shear reduction in shoe insoles. J Diabetes Sci Technol. 2013 Mar 1;7(2):410-9. doi: 10.1177/193229681300700218.
citation: Wrobel JS, Ammanath P, Le T, Luring C, Wensman J, Grewal GS, Najafi B, Pop-Busui R. A novel shear reduction insole effect on the thermal response to walking stress, balance, and gait. J Diabetes Sci Technol. 2014 Nov;8(6):1151-6. doi: 10.1177/1932296814546528. Epub 2014 Aug 7.