Network Magazine Winter 2019 | Page 49

Fibula Tibia INJURY & REHAB PLANTAR FASCIITIS Plantar fasciitis is one of the most common causes of plantar heel pain. Clinical lead podiatrist, Jai Saxelby, provides a technical insight into the condition, and details treatment therapies. he plantar fascia, also known as the plantar aponeurosis, is a visco-elastic structure that spans the underside of the foot (from the heel to the toes) and plays a significant role in the weight-bearing foot, both statically and dynamically. Its design is equipped to resist elongation under tensile load, resulting in the storage of elastic energy. Working synergistically with the Achilles tendon, it absorbs energy during initial weight-bearing, then returns the energy during propulsion, acting like a spring. Measurement of oxygen consumption during running suggests the storage of elastic energy in muscle and tendons saves about 50% of the metabolic energy that would otherwise be needed. Box 1 explains the foot model known as the ‘windlass mechanism’, which illustrates the relationship between the foot joints and the plantar fascia, and how to test it yourself. T Windlass mechanism and test The anatomy involved is the medial slip of the plantar fascia and the medial (inside of the foot) arch. The plantar fascia originates from the medial tubercle of the heel and inserts into the base of the proximal phalanx of the first metatarsophalangeal joint (MTPJ). The windlass test requires the big toe to be dorsiflexed (upward movement); this tightens the plantar fascia due to it being wound around the first metatarsal head, effectively drawing the first MTPJ and heel together, thereby ‘shortening’ the arch (see Box 1). How to use the windlass test Stand the client on a step, allowing the toes to overhang. Apply an upward force to the big toe and feel the tension in the plantar fascia; Achilles tendon Talus Navicular Cuneiforms Calcaneus Irritated and inflamed plantar fascia approximately 65 degrees is regarded as a normal range of movement (Box 1a). The more restricted the movement, the greater the tension in the plantar fascia – in some cases it may even provoke symptoms. There are various causes that result in this restriction, including: bony deformity (hallux rigidus); excessive foot pronation; and restricted ankle joint movement, e.g., tight calves. Function of the windlass in the gait cycle During initial contact, the windlass unwinds, the arch elongates, and the fascia goes taut (Box 1b). Synchronous with this, the foot pronates (heel everts, midfoot pronates and the forefoot inverts). During propulsion, the windlass tightens and the arch shortens. Synchronous with this, the foot supinates (heel inverts, midfoot supinates and the forefoot everts) (Box 1c). What is plantar fasciitis? Plantar fasciitis is one of the most common musculoskeletal foot injuries, but is often used as a cover term for all plantar heel pain. The evidence suggests that the condition is a chronic degenerative/ reparative process caused by repetitive micro-trauma to the fascia over time. Due to this, the term plantar fasciopathy is now commonly used. Box 2 details the anatomy, the location of the pain, and the clinical signs and symptoms used to make a clinical diagnosis of plantar fasciitis. Diagnostic imaging, such as an ultrasound or MRI, has been shown to be useful for confirming diagnosis. Plantar fasciitis is prevalent in athletic, military and non-athletic populations and is Metatarsals Phalanges Box 1. Windlass test and function a b c Box 2: Anatomy of the plantar foot and plantar fascia Plantar fascia Lateral plantar fascia Medial plantar fascia Tearing and inflammation at the heel bone Heel bone NETWORK WINTER 2019 | 49