A Closer Look At Platelet-Rich Plasma For Achilles Tendon Pathology
Sarrafian and colleagues performed a study to compare a cross-linked acellular porcine dermal patch (APD) against a platelet-rich plasma fibrin matrix (PRPFM) for repair of acute Achilles tendon rupture in a sheep model.22 They reapproximated two surgically transected tendon ends in groups one and two, and left a gap between the tendon ends in group three. Sarrafian and co-workers used the acellular porcine dermal patch to reinforce the repair in group two. They employed autologous platelet-rich plasma fibrin matrix to fill the gap and reinforced this with the acellular porcine dermal patch in group three.
Tensile strength testing showed a statistically significant difference in elongation between the operated limb and the unoperated contralateral limb in groups one and three, but not in group two.22 In group one, all surgical separation sites were identifiable and healing occurred via increasing tendon thickness. In group two, healing occurred with new tendon fibers across the separation without increasing tendon thickness in two out of six animals. Group three showed complete bridging of the gap with no change in tendon thickness in two out of six animals. In groups two and three, researchers observed peripheral integration of the acellular porcine dermal patch to tendon fibers. The study authors concluded that use of the acellular porcine dermal patch, alone or with a platelet-rich plasma fibrin matrix, to augment Achilles tendon repair in a sheep model is a viable and strong repair.
De Jonge and colleagues performed a double-blinded, randomized, placebo-controlled trial with PRP treatment in chronic Achilles tendinopathy with a one-year follow-up.12 The study involved 54 patients, ranging between 18 to 70 years of age, with chronic tendinopathy 2 to 7 cm above the Achilles insertion who were randomized to receive either a blinded, ultrasound-guided injection of PRP (27 patients) or saline (27 patients) in addition to an eccentric training program.
After the injection, patients had to avoid sports activities for four weeks and start a stretching program at two weeks. At 12 weeks, they started an eccentric exercise program. Patient follow-up visits occurred at six, 12 and 24 weeks and one year with both clinical and ultrasound assessments. In using ultrasound assessments, researchers were able to measure both the structure of the tendon and neovascularization by color Doppler. Although they noted a significant improvement in the PRP treatment group, they found no clinical or sonographic benefit of a PRP injection at the six-month and one-year follow-up visits.12 They hypothesized that needle trauma may initiate a healing response and that an increase in peritendinous volume may help decrease pain by destroying vascular and neural growth.
Pertinent Insights From Our Clinical Experience With PRP
We have used PRP for the treatment of chronic Achilles tendinopathy and rupture repair in many cases. The treatment protocol is very similar to that of plantar fasciitis. We choose patients for this procedure based on the chronicity of their symptoms and the quality of the tendon. Those patients who have failed conservative therapies after three to six months are good candidates. In addition to pain, decreased activity and loss of function, most patients present with nodular thickening within the substance of the tendon. Some may even have multiple fibrotic nodules.
When it comes to patients who have an associated retrocalcaneal exostosis, we have also used PRP for these patients with varying results. One would confirm the diagnosis with ultrasound and/or MRI. Place a local anesthetic block well above the site of injection. Prepare the PRP at the desired concentration from the whole blood collection and activate it with calcium citrate. Proceed to inject between 6 and 10 cc of PRP within the substance of the tendon beginning at the site of pathology (pain and any bulbous mass).