Comparison of postinjection protocols after intratendinous Achilles platelet-rich plasma injections: a cadaveric...

The purpose of the present investigation was to evaluate the distribution of intratendinous injected platelet-rich plasma (PRP) after 15 minutes of prone resting versus immediate manipulation simulating weightbearing. Ten cadaveric lower limbs were injected under ultrasound guidance with PRP dyed with India blue ink. The dyed PRP was injected into the mid-portion of the Achilles tendon, after which 5 specimens were placed in the prone position for 15 minutes (simulating rest) and the remaining 5 specimens were manipulated through 100 cycles of ankle dorsiflexion and plantarflexion (simulating walking). Thereafter, the specimens were dissected, and the distribution of the India blue dye was ascertained. In the simulated rest group, every specimen showed dyed PRP in the Achilles tendon and in the space between the paratenon and tendon. The median craniocaudal spread of the PRP was 140 (range 125 to 190) mm. In 4 of the simulated rest tendons (80%), the distribution of PRP extended across the entire transverse plane width of the tendon. In the simulated motion group, every specimen showed dyed PRP extending across the entire transverse plane width of the tendon and in the space between the paratenon and tendon. The median craniocaudal spread was 135 (range 115 to 117) mm. No statistically significant difference was found in the amount of craniocaudal spread between the simulated motion and rest groups. In conclusion, it does not appear to matter whether the ankle has been moved through its range of motion or maintained stationary during the first 15 minutes after PRP injection into the mid-portion of the Achilles tendon. The precise meaning of this information in the clinical realm remains to be discerned.