The Achilles tendon is the strongest, thickest tendon in the body. It is the tendon for the gastrocnemius and soleus muscles whose primary motor function is plantar flexion of the ankle.
Achilles tendonitis, which is seen in athletes, runners and hikers, is caused by local irritation of the paratenon or degeneration within the tendon.
The pain may be felt at site where the tendon inserts into the calcaneus (Insertional Achilles Tendinosis) or in the watershed area about 3cm from the insertion (Non-insertional Achilles Tendinosis). The latter is often associated with a fusiform or spindle like swelling at this point. The pain is typically exacerbated by activity and sometimes precipitated by a change in training pattern or shoe wear.
The exact cause is not known but there are several factors that contribute. One simpler explanation is that part of the strength of the achilles tendon comes from the fact that the tendon fibers are twisted. As we push off with our heel the tendon untwists and this elastic recoil improves the “bounce” generated by the tendon. The epicentre of the twist is about 3cm from where the tendon attaches to the bone so here we are wringing the tendon of its blood supply- just like when we dry a wet sock! Small tears in the tendon at this sit don’t heal as well and as they heal with scar, the tendon gets fatter.
Most cases settle with medical treatment with NSAIDS, eccentric loading exercises following the Alfredson regime, hell lifts and a reduction in activity. It can take some months to settle.
Injection of a high volume of fluid around the tendon by the x-ray doctor under ultrasound guidance may help. The fluid and steroid can free the sheath off the underlying tendon. The small nerve endings that cause pain can be chemically destroyed with concentrated glucose.
Only when symptoms fail to settle with the above simpler measures do I consider
Surgeries to tidy up the tendon. If the pain is where the tendon inserts into the heel then often a bony prominence (Haglund bump) will need to be removed. If the tendon is very damaged with lots of extra calcium in the tendon itself then part of the tendon will have to be lifted off the bone and the muck scooped out. The tendon is then reattached with very strong sutures.
When the pain or disease in the tendon is away from where the tendon inserts into the bone then the bad tissue is scooped out of the tendon, any splits in the tendon are repaired. If the sheath around the tendon is tight it is released.
Post-operative rehabilitation varies with each case and is something I will go over with you.