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.
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.