The cause is not fully understood but it is thought small tears in the fascia cause inflammation and swelling. The normal fascia is approximately 3mm thick but in severe plantar fasciitis the swelling can increase this to 15mm. These tears can be caused by repetitive traction on the fascia during activities such as walking or running.
There are many factors that will increase the risk of getting these tears. These include being overweight, inappropriate footwear that does not support the foot adequately, jobs where most of the day is spent standing, tight calf muscles or achilles tendon, structural abnormalities of the foot.
Other diagnoses that can cause similar symptoms include, lateral plantar nerve compression (tarsal tunnel syndrome), tibialis posterior inflammation or dysfunction, subcalcaneal bursa or fat pad pain, calcaneal stress fracture.
An X-ray may be requested especially if a stress fracture of the calcaneum is suspected. Often a spur of bone is found that projects forwards from the calcaneum. This has in the past been thought to be a cause of plantar fasciitis but we now know that this is not the case and if there is a spur present it is not associated with a diagnosis of plantar fasciitis.
Isotope bone scan may be used if a stress fracture is suspected if the X-rays are normal but a MRI scan is probably a better investigation in this scenario.
Nerve conduction studies may be used if there is a suspicion of nerve compression.
Night splints are aimed at reducing the pain in the morning when first getting out of bed. Plastic splints are not always tolerated. An alternative is a Strasburg sock and these are available from many pharmacists and online retailers.
Steroid injection may be offered if symptoms don’t respond to the other treatments.
Surgery is a last resort and is only used if the symptoms have not responded to twelve months of proper conservative treatments. Surgery is only successful in 50 – 60% of cases.
A new non operative treatment is now available called shockwave therapy and further details can be found in the shockwave section