Do changes in foot and ankle structures relate to plantar fasciitis?

Rationale: Plantar fasciitis is the most common foot impairment and affects approximately 10% of all adults during their life. This disease is tedious and very painful due to degeneration or inflammation of the plantar enthesis of the plantar fascia at the calcaneus insertion site. Multiple hypotheses are formed about alterations in foot structures in order to describe the etiology of plantar fasciitis. Mostly, studies are performed on patients with a chronic form of plantar fasciitis. Therefore, up to this moment it is not clear what the role of these structural changes are in the formation of plantar fasciitis.

Objective: The goal of this study is gaining insight in the foot structures that may play a role in the formation of plantar fasciitis and the consequences on the gait pattern of patients with plantar fasciitis. In the future, such insights may result in more specific and more efficient conservative therapies.
Study design: This study has a cross-sectional design with one measurement session for assessing gait parameters and clinical scores.

Study population: 20 patients with acute or sub-acute plantar fasciitis participate in this study. The control group exists of 15 healthy persons without complaints to the lower extremities. The age, Body Mass Index and Foot Posture Index in the control group is comparable to that of the patient group. Patients are only included when foot complaints are present for less than four weeks and the thickness of the proximal plantar fascia is at least 4 mm and age must be within the range of 18 to 55 years old. Patients with a systemic disease, other conditions that have a negative influence on walking, or when patients already make use of walking aids are excluded from the study.

Main study parameters/endpoints: The main study parameters of this study are passive and active motion between different foot segments in different planes: motion of segments of the foot during walking, maximal dorsiflexion of the ankle, the height of the medial longitudinal arch of the foot in relation to weight loading and passive foot mobility in the frontal plane). In addition, the cross-sectional area of the intrinsic forefoot muscles will be studied.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Participation of a subject in this experiment has no direct benefit for him or her. However, insights from the measured parameters may indicate impairments and enable distinct and personalised therapy. The risk in participation is small because walking is a natural and familiar act and participation will not get in the way of recovery. Regarding the use of ultrasound, Merrit (Merritt, 1989) reports that ultrasound is a safe imaging modality. The World Health Organization supports that ultrasound is a safe and highly flexible imaging tool (World Health Organization, 1998). Therefore, no risks are associated with ultrasound when used once. Furthermore, during all the measurements a physiotherapist will accompany the subjects. Subjects can take rest between the measurements any time they like and may stop the experiment at any time desired.

Patients with plantar fasciitis will have impaired foot and ankle joint mobility and hypotrophy of the intrinsic foot muscles. These structural pathologies can be related to kinematic and kinetic gait parameters such as joint range of motion and ground reaction force.

One measurement time point for assessment of clinical and gait parameters.

Not applicable