Key Insights On Platelet-Rich Plasma For Soft Tissue Repair
While basic science does show early enhanced healing in acute injuries with PRP application, randomized controlled studies involving humans have failed to show an improvement over conventional methods.
In my experience, I have used PRP to treat acute tibiofibular ligament high ankle sprains in college level athletes and performed the injection within 48 hours after the injury. These athletes were able to return to competition seven to 10 days after the injury using a protective ankle support.
Animal studies by Kajikawa and colleagues show that macrophages and fibroblasts are present in the early stages in tendon healing but decrease over time.9 Platelet-rich plasma enhanced the number of fibroblasts in tendon and the amount of collagen synthesis in the initial stage after tendon injury, according to another study by Kajikawa and co-workers.10
Research has shown that single PRP injections increase tendon strength to failure, stiffness and ultimately the amount of stress that the tendon can withstand in the early stages of healing.11-13
Aspenberg and Virchenko transected the Achilles tendon in rats and removed a 3 mm segment of tendon.11 The percutaneous injection of a platelet concentrate into the hematoma increased tendon callus strength and stiffness by about 30 percent after one week, an effect the authors say persisted for as long as three weeks after the injection.
In a study of 48 rabbits, Lyras and colleagues noted the presence of significantly more angiogenesis in those injected with PRP in comparison to the control group during the first two weeks of the healing process.12 In another study of rabbits, Lyras and colleagues showed that PRP may affect the tendon healing process by altering the expression of TGF-b 1.13
Sanchez and colleagues performed a case-control study looking at the use of a preparation rich in growth factors (PRGF) in the repair of acute Achilles tendon ruptures.14 Six athletes who had a complete Achilles tendon tear had open suture repair and also received PRGF injections in comparison to six athletes who received surgical treatment without PRGF. The adjunctive PRGF group demonstrated an earlier return to range of motion, an earlier return to gentle running and earlier resumption of sports training activities. The study’s main disadvantage is a low number of patients.
In contrast to this study, another randomized controlled trial by Schepull and colleagues compared 30 patients who had repair of an acute Achilles rupture.15 Sixteen patients received an injection with PRP prior to skin closure and 14 patients received no injection. The Achilles Tendon Total Rupture Score showed no significant difference at one-year follow-up in the heel raise index between the groups. In fact, the Achilles Tendon Total Rupture Score was significantly lower in the PRP group.
There is a lack of high quality studies that prove or disprove the use of PRP in the treatment of acute tendon injuries.
I have used PRP with repair of acute Achilles tendon ruptures or tears successfully over the last three years. The preferred method is the use of a platelet-rich fibrin clot in order to suture the clot directly into the substance of the tendon.
Exploring The Potential Of PRP For Chronic Tendinopathy
Chronic tendinopathy typically has a histological appearance of collagen fiber disruption, mucoid degeneration, neovascularization and a lack of inflammation.6 Researchers have suggested the use of PRP for chronic tendinopathy improves angiogenesis and collagen synthesis.16,17