Conservative Care For Mid-Portion Achilles Tendinopathy
The “4 out of 10 pain rule” also comes into play in the latter part of treatment. When patients are able to complete the eccentric loading exercise program pain-free, encourage them to add weight in a backpack. As a guide, I would normally start with 10 pounds, which will often be enough to return to a level of painful training. Most athletic patients should be able to perform the exercises with 50 pounds in the backpack before they return to full sport. There is no set time to add weight. This is entirely dependent on the progress of the patient.
Here are some other points to advise patients on when giving them eccentric loading exercises.
Knee bent exercises. Ensure the knee is in a bent position (about 120 degrees) throughout the exercise. Patients who have poor thigh strength will tend to straighten the knee as they eccentrically lower the calf. They are also more likely to start with the foot closer to horizontal as opposed to being close to vertical.
Go barefoot where possible. As long as patients can tolerate it, I will encourage them to do the exercises barefoot. Sometimes the tongue of the shoe may compress the anterior ankle, which will stop the ankle from getting into a fully dorsiflexed position.
Speed of the eccentric drop. Ensure patients are lowering the foot with a controlled contraction. It should be smooth, not bouncy or jerky. One complete repetition should take about three seconds.
In a relatively low number of cases (I would estimate 10 to 20 percent) in which a combination of eccentric loading exercises, activity modification and orthomechanical care is unsuccessful, other treatment options are available. These include topical glyceryl trinitrate patches, sclerosing injections, prolotherapy injections, autologous blood or platelet rich plasma injections, and extracorporeal shockwave therapy. These therapies do not replace the aforementioned initial treatment protocol but are normally used as adjuncts.
Can Topical Glyceryl Trinitrate Have An Impact?
Researchers have shown the NOS activity to be upregulated in rat Achilles tendinopathy while tendon healing increases when additional NO is present.23,24 Patients have used glyceryl trinitrate patches in combination with eccentric loading exercises with success. Patients apply one-quarter of the patch (1.25 mg/day) to the affected area daily. Randomized controlled trials have shown improved outcomes over three months, six months and three years in comparison to placebo patches.36,37 At three years, the mean estimated effect size for all outcome measures was small at 0.21 (on a scale of 0 to 1).37
However, another randomized controlled trial showed no benefit of using topical glyceryl trinitrate patches in combination with eccentric loading exercises in comparison to eccentric loading exercises alone.38 Furthermore, histological samples taken during surgery in those who did not improve did not show any difference between the two groups. The main side effect with glyceryl trinitrate patches is headache. These patches are a relatively straightforward adjunct to eccentric loading exercises, which are easy for patients to manage.
What About Sclerosing Injections?
Polidocanol (Asclera™, Merz Aesthetics) is an aliphatic, non-ionized nitrogen-free substance with a sclerosing and anesthetic effect.4 Traditionally used to treat varicose veins, it causes vessel thrombosis by selectively affecting the vascular intima, even when injected outside the vessel.31 Polidocanol may also affect the nerves adjacent to the neovessels.