Iterative Design of Custom Dynamic Orthoses to Reduce Articular Contact Stress
Condition: Ankle Fractures; Post-traumatic Osteoarthritis; Osteoarthritis Ankle
MeSH terms: Osteoarthritis; Ankle Fractures
Study type: Interventional

Summary: 
      The proposed study evaluates the effect of carbon fiber brace design on forces across the
      ankle joint. Research suggests that ankle arthritis develops after ankle fracture, in part,
      due to elevated forces on the cartilage. It is expected that carbon fiber braces can be
      designed to reduce forces in the ankle joint and thereby reduce the risk of developing
      arthritis following traumatic injury. In this study, brace geometry will be varied to
      determine how these changes influence the forces experienced by ankle cartilage. The proposed
      study will provide evidence that can be used by clinicians and researchers to design braces
      that most effectively reduce forces on ankle cartilage.
    

Detailed description: 
      The primary purpose of this line of research is to investigate the effects of carbon fiber
      custom dynamic orthosis (CDO) design on the forces and contact stress at the ankle, with the
      goal of reducing the development of post traumatic osteoarthritis (PTOA) in the ankle.
      Research suggests that ankle arthritis develops, in part, due to increased contact stresses
      within the ankle joint following fracture. It is expected that reducing articular contact
      stress at the ankle has the potential to delay or prevent the development of PTOA. CDOs have
      been shown to significantly improve function following extremity injury, and show promise for
      offloading the injured limb after severe lower extremity injuries. Therefore, the proposed
      effort is designed to evaluate how different CDO design factors influence offloading and
      therefore the reduction of forces and articular contact stress at the ankle.

      Adult participants will be evaluated while wearing carbon fiber braces of varied geometry.
      The primary dependent measure is ankle joint contact stress. Following consent and enrollment
      computerized tomography (CT) images will be used to determine the geometry of the joint
      articular surfaces. Ankle contact stress will be calculated using discrete element analysis
      and biomechanical data collected in subsequent data collection.

      Participants will be cast and fit for three CDOs with varied geometry. Participants will be
      blinded to the design variation of each device and will only know them as CDO-A, CDO-B, or
      CDO-C. Testing will be completed under 4 conditions: No-CDO, CDO-A, CDO-B, CDO-C, with each
      bracing condition (A/B/C) representing a CDO design variant. Physical performance measures
      will incorporate tests of agility, speed, and lower limb power to ensure that changes to
      device design do not negatively affect physical function. Questionnaires will be used to
      evaluate participants' current and desired activity level, pain with and without CDO use,
      satisfaction with the devices, perception of comfort and smoothness between devices, and
      preference between CDOs. Semi-structured interviews will be completed to fully capture the
      participant's perspective. Lower limb forces and motion will be assessed using a computerized
      motion capture system and force plates in the floor. Forces between the foot and CDO will be
      measured using force sensing insoles, and muscle activity data will be collected using
      surface electromyography. Devices will be mechanically tested, and participant demographic
      and anthropometric data will be recorded.
    

Intervention name(s): Custom Carbon Fiber Dynamic Orthosis (CDO)
Intervention type(s): Device
Intervention description(s): The custom carbon fiber dynamic orthoses will consist of a semi-rigid foot plate, a posterior carbon fiber strut, and a proximal cuff below the knee.
Other intervention name(s): Ankle Foot Orthosis
Intervention MeSH terms: Carbon Fiber
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: All participants will be cast and fit with three carbon fiber custom dynamic orthoses (CDOs). Each CDO will differ from the others in design and will be labeled as CDO-A, CDO-B and CDO-C. Participants will be randomly assigned to one of six CDO testing sequences (ABC, ACB, BCA, BAC, CAB, CBA) to prevent testing order from influencing study results. Multiple rounds of evaluation (~5 rounds) with small groups of participants in each round (n=~6) will be used.
Masking: Single (Participant)
Primary purpose: Other
Keywords: Carbon Fiber; Gait Analysis; Ankle Foot Orthosis; Arthritis; Biomechanics; Ankle; Adult