Evidence Behind Corticosteroid Injections of the Foot and Ankle
In this post, we review corticosteroid injections to the foot and ankle. As with other posts, we will cover randomized controlled trials and systematic reviews on corticosteroid injections for issues common to orthopedics such as ankle osteoarthritis, plantar fasciitis and Morton’s neuroma.
Between 6% and 13% of individuals suffer from ankle osteoarthritis which can be a chronic source of ankle pain (Thomas, 2003). Nearly 70% of ankle osteoarthritis is post-traumatic (Thomas, 2003). Patients will typically present with anterior ankle pain with weight bearing or while pushing off with their foot. The patient may have limited or painful range of motion. First line treatment usually includes NSAIDs, activity modification, rocker sole shoes and possibly bracing.
Plantar fasciitis is a source of foot pain that typically affects adults over 40, with an incidence of around 7% (Clement, 1981). It also accounts for around 25% of all foot disorders in athletes (Cole, 2005). It is also a common diagnosis among running athletes with an incidence from 8% to 12 % (Knobloch, 2008). Patients usually complain of pain under the heel and medial sole of the foot that is worst with the first steps in the morning or after prolonged sitting or rest. It can also bother patients with prolonged walking or weight bearing. Tenderness along the origin of the plantar fascia is common and can be exacerbated by toes and ankles in dorsiflexion and diagnosis can usually be made clinically.
Morton’s neuroma, an interdigital neuroma with unclear etiology, causes paroxysmal neuralgia and a common cause of forefoot pain. It presents in most cases with sharp burning pain in the web space and involves the third and fourth toes around 80% of the time (Singh, 2005). Physical exam may reveal a clicking sensation (Mulder’s sign) when palpating the involved interspace while simultaneously squeezing the metatarsal joints. There may also be tenderness to palpation between the wb spaces. Ultrasound and MRI have been used to confirm the diagnosis, although diagnosis can be made clinically in most cases. Nonoperative and noninvasive management is first line treatment including treatment with orthotics and adequate footwear modifications.
Tarsal tunnel syndrome
Tarsal tunnel syndrome is another cause of foot pain and is caused by tibial nerve compression in the medial ankle as the nerve passes under the transverse tarsal ligament. It is most commonly caused by a fracture of the talus, calcaneus or medial malleolus, but can also be caused by a mass. Common complaints include pain behind the medial malleolus along with burning, aching and numbness in the sole of the foot, the distal foot or toes. Symptoms seem to be exacerbated during the night and while driving. A Tinel’s test of the tibial nerve can reproduce numbness into the plantar aspect of the foot. EMG studies are commonly done to aid in diagnosis.
In summary, there is limited data on corticosteroid injection as treatment for ankle osteoarthritis and relief was shown to be up to 6 months. Plantar fascia corticosteroid injections do carry a small risk of plantar fascia rupture, but studies have consistently shown at least short term relief. More recent studies have shown about two-thirds of patients undergoing injections for Morton’s neuroma report relief or satisfaction and there have been reports of cure of symptoms following localized corticosteroid injection. There is paucity of data regarding tarsal tunnel syndrome and corticosteroid injections and cannot be recommended with confidence.