Achilles Tendon Injection

Chronic tendinitis

Causes and findings:
• Overuse
• Pain at posterior aspect of ankle
• Painful: resisted plantarflexion on one foot or from full dorsiflexion

Equipment:
Syringe - 2ml
Needle - 23G 1.25 inches (30mm) blue
Kenalog 40 - 20 mg
Lidocaine - 1.5 ml 2%
Total volume - 2 ml

Anatomy:
The achilles tendon lies at the end of the gastrocnemius as it inserts into the posterior surface of the calcaneus. It is absolutely contraindicated to infiltrate the body of the tendon because this is a large, weight-bearing, relatively avascular tendon with a known propensity to rupture.

Technique:
• Patient lies prone with foot held in dorsiflexion over end of bed. This keeps the tendon under tension and facilitates the procedure
• Identify and mark tender area of tendon - usually along the sides
• Insert needle on medial side and angle parallel to tendon. Slide needle along side of tendon, taking care not to enter into tendon itself
• Deposit half solution while slowly withdrawing needle
• Insert needle on lateral side and repeat procedure with remaining half of solution

Aftercare:
Absolute avoidance of any overuse is essential for about 10 days. Deep friction to the site should then be given a few times, even if the patient is asymptomatic, to prevent recurrence. When pain free, graded stretching and strengthening exercises are begun and should be continued indefinitely. Orthotics and retraining in the causal activity are often necessary.

Comments:
Although there are reports of tendon rupture after injection here, this has usually occurred as a result of repeated injections of large dose and volume into the body of a degenerate tendon and with excessive exercise postinjection. Because of this recognized risk therefore, we recommend scanning the tendon prior to injecting to ascertain the extent of the degeneration (Chapter 2). Clear degenerative changes within the substance, rather than just around the periphery, would indicate an absolute contraindication to injection. Depositing the solution along the sides is safe and effective but should not be repeated more than once in one attack. The committed athlete should preferably be offered deep friction and a graduated stretching/strengthening programme.

Alternative approaches:
No one method has been entirely successful in treating this condition. Recent novel approaches include the continuous application of topical glyceryl trinitrate and injection of a sclerosing local anaesthetic (Polidocanol; see Chapter 1).