Evaluation of Heel Offloading Devices for Reducing Heel Contact Pressures in Healthy Volunteers

Prevention of heel pressure ulceration is a major clinical concern. Clinical research has shown that heel-offloading devices are effective at preventing heel ulceration when compared to no offloading or sub-optimal offloading methods (i.e. use of a hospital pillow to offload the heel). As a result, a plethora of heel-offloading devices have been developed that utilize different designs and materials to offload the heel. Despite the availability of these devices, some healthcare facilities still employ no heel offloading or utilize sub-optimal heel offloading strategies. It is also difficult for clinicians to compare the effectiveness of different heel offloading device without conducting extensive clinical evaluations. Pressure mapping of the pressure experienced by the heel while offloaded offers a potential method to assess the effectiveness of different heel offloading strategies. The primary hypothesis of this study is that the three tested heel offloading devices will significantly decrease the heel contact forces compared to no offloading and sub-optimal heel offloading conditions. The secondary objective is to quantify differences in heel contact forces experienced by the heel when placed in each heel offloading device to demonstrate the utility of pressure mapping as a tool to evaluate the effectiveness of different heel offloading devices. The study will recruit 21 healthy volunteers as research subjects with 7 having a normal BMI, 7 having an overweight BMI, and 7 having an obese BMI. Pressure mapping will be conducted on each research subject for seven randomly applied conditions while the patient lies comfortably in a hospital bed. The seven conditions include no heel offloading, 3 sub-optimal offloading conditions, and offloading in 3 different heel-offloading devices. Pressure measurements corresponding to the heel will be used to determine the average peak pressure contact force for each research subject in each condition.

Each research subject will have pressure mapping performed on his or her right foot in the 7 conditions described for each study arm to determine the contact forces experienced by the heel in each off-loading condition. Each intervention will be randomly applied.

The heel is offloaded by placing a standard hospital pillow under the calf suspending the heel above the hospital bed mattress.

Heel offloading device that utilizes open cell foam to offload the heel. Device has a published clinical study demonstrating effectiveness at reducing heel ulceration rate.

Heel offloading device that utilizes pressure absorbing filling to offload the heel. Device has a published clinical study demonstrating effectiveness at reducing heel ulceration rate

Heel offloading device that utilizes a similar pressure absorbing filling to Offloading Device B; however this device does not have published clinical literature demonstrating effectiveness at reducing heel ulceration in the clinic.

Average contact force calculated from an area of 40.32 cm^2 that encompassed the entire posterior heel. Pressure readings obtained by pressure mapping

Peak pressure index calculated by centering a 3 X 3 region of interest (14.52 cm^2) over maximum pressure sensor reading within the region of interest encompassing the heel.

Inclusion Criteria: 18 years old or older No musculoskeletal injury in the past month Body Mass Index (BMI) between 18.5 and 39.9 Exclusion Criteria: 17 years old or younger Musculoskeletal injury in the past month Pregnant or lactating female History of heel pressure ulceration BMI below 18.5 or above 39.9