Plantar fasciitis (Heel Pain)

Plantar fasciitis (Heel Pain)

Is the inflammation of the plantar fascia caused due to repetitive stress applied to it.

It is usually common in active individual, obese, runners or athletes, people who spend most of their day on foot.

The pain is usually characterized by piercing or searing type of heel pain that appears in the first few steps in the morning or after a period of inactivity.

Patient may present with tenderness around the medial calcaneal tuberosity at the plantar aponeurosis.

Pain increases when walking barefoot on toes or while climbing stairs.

Patho-physiology

As the term implies plantar fasciitis is the inflammation of the plantar fascia however in all the samples reviewed there is no evidence of inflammation histologically.

However research shows that plantar fascia is a degenerative condition, hence it is better to be  called “fasciosis” than fasciitis.¹

Biomechanics of the foot during gait

There are 6 phases of gait cycle : heel contact, weight acceptance, mid stance, push off , propulsion and toe off phase. Foot goes for supination during heel contact phase followed by pronation in weight acceptance phase, in order to maintain contact with the surface. From the mid stance to the toe off phase the foot goes for supination thus making the foot as a rigid lever which is necessary for the propulsion of the foot.

Plantar fascia plays a very important role in maintaining this arch during the gait cycle of the foot. Because if plantar fascia fails to work effectively the medial arch arch would disrupt and the force required to control supination and pronation would be altered. Hence plantar fascia plays a very important role in control of supination and pronation of the foot during gait cycle.

Evidence based therapy for plantar fasciitis

• Cryotherapy or NSAIDS – Not much effective in the treatment of plantar fascia, however it provides only temporary pain relief.
•  Taping – No studies have proved the effectiveness of taping.
•  Shoe inserts-  a study was done to compare the effectiveness of the custom made orthotics and prefabricated shoe inserts with stretching. It was found that prefabricated shoe inserts with stretching showed more effect than custom made orthotics.
•  Stretching – A study shows plantar fascia stretch alone more effective than combined stretch of calf muscle and Achilles tendon.
•  Night splints – limited evidence suggesting the effectiveness of night splints.
•  Extra-corporeal shock-wave therapy – No evidence supporting the effectiveness of Extra-corporeal shock wave therapy for reducing night pain and resting pain in short term.
• Corticosteroid injection – According to Cochraine review Steroid iontophersis injecton improved only short term outcomes.²

As mentioned earlier the arch of the foot is very important to maintain stability on the surface when walking or standing. Overpronation or underpronation can have direct influence on the effective working of plantar fascia.

Overpronated foot

Overpronation of the foot is caused due to muscle weakness, tightness in the heel cord and abnormal structure of the foot. Proximal muscles such as gluteus medius, gluteus minimus, tensor fascia latae or quadriceps can contribute to the pronation of the foot. These proximal muscles help in assisting lower extremity response during gait, hence weakness of these muscles will transmit greater shock to the supporting foot structures and decreased pronation control.

Heel cord assist in dorsiflexion of the foot during gait, hence tightness in the heel cord limits the ability to dorsiflex the ankle at heel strike phase of the gait thus making the foot to over pronate more at the midtarsal joints in order to make contact with the surface of the ground.

Structural deformities include excessive sub-talar or forefoot varus.

Treatments for overpronated foot include strengthening of the weak muscles, stretching of the calf muscles, and using appropriate shoes with sufficient toe box and firm ankle grip to control the movement of the ankle within the shoes. Insoles made of polyurethane and ethyl vinyl acetate also enhances shoe support.³

Underpronated foot (Supination)

Supinated foot which is caused due to factors such as increased muscle tightness, decreased mobility within the joints and decreased plantar fascia extensibility.

Highy arched or cavus foot will have limited joint mobility to distribute the force during weight acceptance phase. Hence when foot does not pronate during weight acceptance phase, it indirectly applies a lot of tension force to  the insertion of plantar fascia at the medial tubercle of calcaneum.

Treatment for supinated foot include Stretching of calf muscles, mobilization of joints and increase plantar fascia extensibility. Appropriate shoe wear with ethyl vinyl acetate midsole provides appropriate space for the rearfoot and forefoot to move , offers much shock absorption.

Silicone heel pad can further enhance shock absorption.³

By Dr. Liana Thomas (PT)

Reference –

1. Plantar fasciitis  A degenerative process without Inflammation (Harvey Lemont et al.)
2. Plantar fasciitis (Charles Cole, Craig Seto et al.)
3. Plantar faciitis and the Windlass mechanism : A Biomechanical Link to clinical practice (Lori   A. Bolgia et al. )