Individually optimised rocker profiles to reduce mechanical load in patients with Achilles Tendinopathy and Plantar Fasciitis.

Running is an easy way to get necessary physical activity. However, running
does not come without risk1. Unfortunately, from this group of runners about 8%
suffer from an Achilles tendon inflammation or plantar faciitis (an
inflammation of the tendon plate in the sole of the foot)2. Complaints arising
from these disorders can in many cases be treated by so-called rocker shoes
with 'roll-over corrections' for human gait: modifications to the outsole of
the shoe that reduces the mechanical load on the Achilles tendon and plantar
fascia (tendon plate of the foot sole)3. However, the way these roll-over
corrections are made can be optimized. These sole adjustments are currently
made by applying extra sole material under a shoe and is reshaped (by sanding)
for an optimal curvature4. The knowledge and technical abilities of the
orthopaedic shoe technician, who performs the sanding process, and the quality
of the doctor's design determines the effectiveness of the treatment5. The
design of rocker soles has historically been based on theoretical
considerations and empirical observations with minimal scientific study and
validation. Consequently, at this moment, patients are depending on the
clinical experience of the doctor and the craftsmanship of the orthopaedic shoe
technician. Therefore, the treatment might not be of constant quality. In
addition, the craftsmanship in this sector is under pressure. Companies in this
sector experiences that there is an outflow of skilled people. Currently,
biomechanical measurements are used to evaluate orthopaedic interventions. In
this study, input from person-related biomechanical, anamnestic and body
measurements will be used to develop an individual rocker sole. This input will
be used in a custom-made algorithm that renders an optimal shape of the shoe
sole for each individual patient. This might lead to a more constant quality of
rocker soles. The algorithm is the result of two years of research by the
department of Rehabilitation Medicine of the University Medical Centre
Groningen (UMCG). The biomechanical effect will be evaluated by measurements in
the clinical gait labs of the UMCG.

The objective of this study is to evaluate the biomechanical effect of the
newly developed rocker soles aiming to reduce the mechanical load in patients
suffering with Achilles tendinopathy and plantar fasciitis. A secondary
objective is to evaluate use of the product and the effect of use (4 weeks) on
pain and comfort.

This study has a pre-posttest design. Subjects will recruited from September
2019 until April 2020. The study will be performed at the University Medical
Center Groningen, Center for Rehabilitation. After inclusion, participants will
visit the Motion Lab, UMCG (M1). Here, participants will undergo a 3D gait
analysis (a non-invasive measurement) while walking on neutral shoes. Also
specific body parameters like (weight, height, foot size, maximal ankle
dorsiflexion, location of the metatarsal phalangeal joints) and pain score and
pain regions will be collected. After the first session, a rocker shoe will be
individually designed and made based on M1 outcomes. After approximately 2
weeks, participants will visit the Motion Lab again and will receive their
individually made rocker shoes. Wearing these rocker shoes, participants
undergo another 3D gait analysis (M2) and thereafter the participants keep the
shoes for use at home. During four weeks comfort and pain level will be
assessed on a weekly basis according a self-developed questionnaire about the
the rocker shoes.

Participants will be fitted with individual orthopaedic shoes which are a
standard shoes with a 3D-printed outsole by a certified orthotist. Shoe
characteristics are calculated by a self-made algorithm based on gait
parameters (measured during M1) of the participant. The non CE-marked medical
device will be used as intended.

Risks for the subjects are very low. Subjects will get familiar with an
individual medical device that aims to reduce the subjects* tendon load during
gait. This study is needed to validate the benefits of this device.