Ankle osteoarthritis (OA) is a painful, progressive condition that can severely limit physical activity and reduce quality of life. Foot and ankle conditions are the fourth most frequent cause for medical separation from the military and veterans are more likely to have to ankle OA than non-veterans. Rocker bottom (RB) shoes and ankle-foot orthoses (AFOs), e.g., the Toeoff, are commonly used to conservatively treat ankle OA. RB shoes have a curved sole in the anterior-posterior direction that may alleviate joint pain by reducing ankle [sagittal plane] range of motion (ROM). Similarly, AFOs may reduce joint motion by securing the foot and ankle within the ankle-foot orthosis (AFO) superstructure. However, the ability of RB shoes and AFOs to improve mobility, by alleviating pain and reducing joint motion, has not yet been fully determined, clinical evidence is lacking. We propose to compare the RB shoe to the Toeoff AFO in OA subjects by measuring their mobility and pain during and after a three-week trial period. We will use a biplane fluoroscopy system to measure hindfoot and midfoot joint motion between and at the end of the trial periods. We will include a control subject group to contrast to the clinical and biomechanics outcomes of OA subjects.
Specific Aim 1 : Compare the daily step count, self-selected walking speed, Patient Reported Outcomes Measurement Information System (PROMIS) pain interference, PROMIS physical function, AAOS Foot and Ankle Module, Foot and Ankle Outcome Score and numeric pain rating of a control shoe, RB shoe and the Toeoff AFO worn over three-week trial periods. We will recruit 30 OA subjects and 10 control subjects, obtain baseline measures, and then assign them a randomly selected order of RB shoe, control shoe or Toeoff to wear for a three-week trial period. Subjects will have their clinical and laboratory measures repeated after each condition until all three footwear conditions have been worn. This will indicate how subjects respond to these treatment conditions ? what their pain levels are compared to baseline, how they self-report functional change, and from their step count, a quantitative measure of their mobility in the treatment footwear.
Specific Aim 2 : Evaluate the effect of a control shoe, a RB shoe and the Toeoff AFO on the [sagittalplane] ROM of the talocalcaneal, talocrural, talonavicular, naviculocuneiform, and first cuneometatarsal joints. Using biplane fluoroscopy, we will measure afflicted and adjacent joint ranges of motion between the three-week trial periods, and at the end of the study. This will allow us to determine how these devices shield the ankle from motion ? potentially protecting it, and if they impose abnormal motion on adjacent foot joints ? potentially exposing them to additional wear and increasing their risk for long term OA development.
Specific Aim 3 : Compare the ankle OA clinical and biomechanical outcome measures for the control shoe, RB shoe, and AFO to a healthy control group wearing control shoes. This will allow us to determine the difference in clinical and biomechanical outcomes related to the presence of OA. This will also yield valuable data about the function of healthy, shod foot and ankle joints. Active duty military personnel and veterans are burdened by ankle OA. The efficacy of conservative treatments such as RB shoes and AFOs for managing OA pain and discomfort is not well supported by clinical evidence. By using biplane fluoroscopy along with validated clinical measures of pain and mobility, this study will elucidate the mechanism by which RB shoes and AFOs alter foot and ankle function ? and provide baseline control data to contrast against. Identifying beneficial treatment strategies will help veterans with ankle OA regain their mobility and improve their quality of life.

Public Health Relevance

The rigors of military service can lead to a condition known as osteoarthritis (OA) ? a degradation of the cartilage covering the bone. OA is a painful condition that can reduce quality of life. For this study, we are investigating two types of devices (a modified shoe, and an ankle brace) which may relieve pain and increase mobility in veteran patients with OA. We plan to collect data from 25 subjects with ankle OA and 10 healthy control subjects without OA, while they walk wearing these devices. By measuring motion, pain and step count, we can determine how these devices improve function and reduce pain in patients with ankle OA. This research has the potential to improve the treatment of ankle OA by providing evidence about treatment effectiveness. Treating patients conservatively (as opposed to surgically), reduces medical cost, recovery time and the risk to the patient. Overall, these benefits should improve the quality of life of service members and veterans with ankle OA.

National Institute of Health (NIH)
Veterans Affairs (VA)
Non-HHS Research Projects (I01)
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Musculoskeletal Health & Function (RRD2)
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VA Puget Sound Healthcare System
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