Conditions which cause pain and inflammation are treatable with the use of diagnostic and therapeutic injections. The purpose of this article is to shed some light on common ankle and foot conditions that may require injections and where the proper sites to perform these injections are located.
The ankle joint is formed by articulation of the tibia and talus. Injections are performed here to alleviate pain occurring from trauma, arthritis, gout, or other inflammatory conditions. Anterolateral Ankle Impingement can occur due to the build-up of scar tissue in the ankle joint or from the presence of bony spurs. When executing an injection here, the ankle will need to be in a neutral position. The physician will mark the injection site just above the talus and medial to the tibialis anterior tendon. The injection site should be disinfected with betadine. Then, the needle is inserted into the identified site and directed posterolaterally. The solution is injected into the joint space and should flow smoothly without resistance. It may be helpful to pull on the foot in order to distract the ankle joint.
First Metatarsophalangeal Joint
The MTP joint is a common injection site frequently affected by gout and osteoarthritis. The injection site is first disinfected with betadine and then the needle is inserted on the dorsomedial or dorsolateral surface. The needle is angled at 60-70° of the plane to match the slope of the joint. The solution is injected into the joint space and should flow smoothly without resistance. Pulling on the big toe is sometimes helpful in distracting the joint.
Peroneal Tendonitis is an irritation to the tendons that run on the outside area of the ankle, the peroneus longus and peroneus brevis. First, the injection site is disinfected with betadine. Then, the needle should be carefully inserted in a proximal direction when injecting the peroneus brevis and longus tendon sheath. The needle will need to advance distally to inject the peroneus brevis alone at its bony insertion.
Achilles Tendonitis is an irritation and inflammation of the large tendon in the back of the ankle. Achilles tendonitis is a common overuse injury that occurs in athletes. Injections of steroids should be given around the tendon, not through the tendon. The injections inserted directly into the tendon is not recommended due to the increased risk of tendon rupture. A platelet injection can be done through the tendon with needling and fenestration.
Tarsal Tunnel Syndrome
Tarsal Tunnel Syndrome is a condition of pain and paresthesia caused by irritation to the posterior tibial nerve. When performing an injection for this condition, the physician will want to feel the pulse of the posterior tibial artery. The nerve is posterior and the physician will want to find the area of maximum tenderness. The injection site should be 1-2cm above the tender area, which is marked on the medial side of the foot and disinfected with betadine. The solution is injected at a 30° angle and directed distally. It is important to inform the patient that the foot may become numb and that care should be taken when walking and driving. Injections for Tarsal Tunnel Syndrome are usually performed after a treatment program which can include rest stretching and the use of shoe inserts.
The plantar fascia is a band of connective tissue deep to the fat pad on the plantar aspect of the foot. Patients with plantar fasciitis complain of chronic pain symptoms that are often worse in the morning with walking. The injection site is identified and marked on the medial side of the foot and betadine is used as a disinfectant. The physician will need to avoid injecting through the fat pad at the bottom of the foot to avoid fat atrophy. The needle is inserted in a medial to lateral direction one finger breath above the sole of the foot, in a line that corresponds to the posterior aspect of the tibia. The solution is injected past the midline of the width of the foot.