Conservative Care For Mid-Portion Achilles Tendinopathy
Both short-term and long-term studies show good results when an experienced radiologist performs the injection under ultrasound and color Doppler guidance.31,39,40 Lind and co-workers advocate a medial approach (to avoid the sural nerve), depositing small amounts of polidocanol (0.1 to 0.2 mL, 1 to 2 mL total) around the neovessels predominantly outside the ventral part of the tendon.31
Patients should rest for one to three days after the injection and only undertake light tendon-loading activities for two weeks.4
How Prolotherapy Injections Work
Prolotherapy is a simpler injection treatment and does not require ultrasound. With prolotherapy, one injects a solution of hypertonic glucose and local anesthetic alongside the painful areas of the tendon with the aim of stimulating inflammation followed by collagen deposition. Prolotherapy also aims to reverse the neovascularization accompanying tendinosis but this effect is still speculative.41
A recent three-arm randomized clinical trial compared prolotherapy injections used alone and in combination with eccentric loading to an eccentric loading only group.41//OK as is?// The combination treatment group had a more rapid response in comparison to the exercise group. While all three treatment groups improved over time, the combination group was statistically and clinically better than the exercise group at 12 months in almost every outcome measure. Patients received a maximum of 12 weekly injections around the tendon using a solution of 20% glucose/ 0.1% lidocaine/ 0.1% ropivacaine (Naropin®, APP Pharmaceuticals). Importantly, patients can maintain normal activities without any rest period post-injection throughout treatment. Prolotherapy, when combined with eccentric loading exercises, provided good value for money in the study.
Two studies also showed favorable outcomes for ultrasound-guided prolotherapy injection for mid-portion Achilles tendinopathy over the short and long-term.42,43 Patients received intratendinous injections of a 25% dextrose-lidocaine solution every six weeks with a median of five treatments needed.
What You Should Know About Autologous Blood Injections And PRP Injections
Autologous blood injections have recently gained popularity. A technician would draw a small amount of autologous blood from the antecubital fossa and inject the blood under ultrasound guidance into the area of maximum tendon pathology.44 This often occurs after dry needling of the tendon and under local anesthesia.45,46 The rationale is that introducing growth factor beta and basic fibroblast growth factors will act as humoral mediators to induce the healing cascade.44
Two cohort studies in patients with tennis elbow and one study on patellar tendinopathy demonstrate improvement in pain but no randomized control studies have been published.44-46 Researchers advised participants in these studies to stop sporting activities to reproduce symptoms for three months.
The recent introduction of platelet-rich plasma (PRP) injections raised hopes for tendinopathy treatment. The thinking was that the injection of higher concentrations of growth factors in comparison to autologous blood would provide increased benefits. A larger amount of blood (about 54 mL) is required and this mixes with citrate to prevent clotting, spins down in a centrifuge for 15 minutes and is buffered to match the pH of tendon tissue.47
However, a recent randomized controlled trial showed that PRP injections in combination with eccentric loading exercises were no better than saline injections and eccentric loading exercises for Achilles tendinopathy.47