Steroid Ankle Injections

The ankle is essentially the articulation of the talus with the tibia and fibula. It contains three joints:

• The talocrural (ankle) joint: A hinge joint between the inferior surface of the tibia and the superior surface of the talus. The medial and lateral malleoli have additional articulations and add stability. This joint allows plantar and dorsiflexion.
• The inferior tibiofibular joint: The articulation of the distal parts of the tibia and fibula. This joint allows some rotation.
• The subtalar joint: Between the talus and the calcaneus. This joint allows shock absorption, inversion and eversion and adjustment so that the foot can remain flat when on uneven ground.¹

There are medial, lateral, anterior and posterior ankle ligaments and tendons. The Achilles tendon is an important tendon in the ankle region.

Pain in the ankle usually arises from:

• Synovitis or arthritis of the joints.
• Ligament sprains.
• Tenosynovitis of the sheaths of adjacent tendons:
  • The peroneal tendons behind the lateral malleolus.
  • The extensor tendons in front of the ankle.
  • The posterior tibial tendon behind the medial malleolus.
  • The Achilles tendon at the back of the ankle.^2,3,4

Joint injection of the ankle can provide a useful diagnostic and therapeutic tool. Indications for injection are pain and disability in the ankle region due to:

• Advanced osteoarthritis, rheumatoid arthritis, crystalloid deposition disorders or other inflammatory arthritides.
• Synovitis.
• Ankle sprains: These are best treated with RICE (rest, ice, compression, elevation) plus physiotherapy as required. Sports doctors sometimes inject local anaesthetic ± steroid into the site of maximal tenderness in the ankle.
• Achilles bursitis.
• Achilles tendinitis: Use is controversial and evidence clarifying the risk/benefit ratio is lacking.⁶Injections in close proximity to the Achilles tendon should be undertaken by a specialist since relief tends to be temporary and there is a risk of tendon rupture and subsequent litigation. Such injections are not discussed further in this article.

• Suspected joint infection is an absolute contraindication.
• Broken skin over injection site or evidence of cellulitis.
• Significant bleeding disorder or anticoagulant therapy.

• Fully consent the patient and explain possible complications.
• Equipment required:
  • 2 x 5 ml syringes
  • 2 x 25 gauge needle
  • 3-5 mls of 1% lidocaine
  • 1 ml of methylprednisolone acetate 40 mg/ml
  • Method of sterilisation for the skin
  • Dressing

• Sit patient either in a supine position with the ankle relaxed, or seated with shin vertical and foot horizontal.
• Use an aseptic technique.
• Sterilise the skin.
• The ankle joint is injected using an anterior approach.
• Landmarks: Identify the space between the anterior border of the medial malleolus and the medial border of the tibialis anterior tendon. Palpate for the articulation of the talus and tibia. See reference 3³ or reference 4⁴ for illustrations.
• Inject local anaesthetic to area.
• Insert needle containing steroid.
• Reduced resistance should be felt on entering joint space. Confirm position by aspirating fluid.
• Inject 1 ml methylprednisolone acetate (40 mg/ml).
• Remove needle and syringe and apply sterile dressing.
• Passive foot movement helps to distribute the injection.
• The patient should remain lying or sitting for several minutes after injection and should be monitored for a further 30 minutes to ensure no adverse reactions.
• Access to ultrasound or fluoroscopic guidance to enable better targeting of steroid injections may improve efficacy^7,8

• Avoid any strenuous activity for 48 hours.
• Avoid stress to foot for 2 weeks after injection.
• Advise may experience a 'steroid flare' with worsening symptoms over next 24-48 hours which should be treated with ice and NSAIDs.
• Arrange appropriate follow-up.

• Due to injection:
  • Bleeding (rare)
  • Infection (1/10,000)
  • Joint injury (do not move the needle from side to side within the joint)
• Due to corticosteroid:
  • Tendon rupture (<1%): avoid direct tendon injection
  • Acceleration of septic joint
  • Subcutaneous fat atrophy (<1%)
  • Fistula formation
  • Steroid flare and worsening of symptoms (2-5%)
  • Cartilage damage and osteoporosis: avoid repeated injections (no more than 3 injections in each location per year)
  • Allergy or hypersensitivity reaction
  • Pericapsular calcification(>40%)