A Closer Look At Platelet-Rich Plasma For Achilles Tendon Pathology
- Volume 24 - Issue 11 - November 2011
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When using a simple centrifugation process, the blood collected spins down between 5 and 20 minutes depending on the speed of the centrifuge and the concentration desired. There will be three relative layers of product in the tube: the plasma layer (platelets), the buffy coat layer (white blood cells) and remaining blood products (red blood cells). The platelets are at the top of the tube. There has been debate on the true concentrations obtained through simple centrifugation and the true output of platelet rich versus platelet poor product. One would then collect the platelet rich plasma using a syringe and 18-gauge needle, being careful not to collect any platelet poor or red cells.
A similar method of collection uses an automated centrifugation process, which separates the platelets from the whole blood and then automatically sends the product to a separate syringe using an infrared microprocessing sensor to differentiate between red blood cells and platelet rich plasma. This type of system seems to lead to more accuracy and allows for more reproducible concentrations. There is presumably less error with less manual manipulation of the blood product through automated separation. One such device is the Magellan Autologous Platelet Separator System (Arteriocyte Medical Systems). With either method, the tube that initially collected the blood must have an anticoagulant. The kits that come with the products usually have tubes already with anticoagulant or come with a separate anticoagulant.
A Review Of The Anatomy And Pathomechanics With Achilles Tendon Injuries
The Achilles tendon is the distal insertion of the triceps surae, which consists of two heads of the gastrocnemius muscle and the soleus muscle. The two heads of the gastrocnemius muscle (medial and lateral) originate from the posterior aspect of the femoral condyles and coalesce as they descend down the leg until they form the Achilles tendon approximately 12 to 15 cm from its insertion on the calcaneus. The soleus muscle arises deep to the gastrocnemius muscle and originates from the posterior aspect of the proximal tibia and fibula. The soleus tendon is independent from the gastrocnemius tendon until approximately 5 to 6 cm above its insertion into the calcaneus, where it coalesces with the overlying gastrocnemius tendon. The tendon rotates as it descends to its insertion at into the posterior surface of the calcaneus.2,3
The Achilles tendon is encased by a paratenon, which is rich in vascularized tissue. The paratendon supplies a significant portion of blood to the tendon. The musculotendinous junction and the osseous insertion also supply blood to the tendon. Approximately 2 to 6 cm proximal to the insertion is a region of poor blood supply to the tendon, making it susceptible to degeneration and injury.2,3
Although the Achilles tendon is the largest and the strongest tendon in the body, it is one of the most frequently injured tendons in the body. This is due to higher participation in sport-related activities.2,3 Approximately seven in every 100,000 people will suffer from an Achilles tendon injury every year.3 The Achilles tendon can be injured either in the main body of the tendon, the osseotendinous junction or, more rarely, the myotendinous junction.4