Background: Recently, morphological signs of damage were reported in rabbit Achilles tendon following extracorporeal shock wave application (ESWA) with an energy flux density (EFD) of 0.6 mJ/mm(2). However, it is unknown whether or not the same can be found after ESWA to other tendons such as the quadriceps tendon.
Methods: We investigated the effects of ESWA in vivo on rabbit quadriceps tendon. Animals received 1,500 SW pulses each of different EFD ranging between 0.0 and 1.2 mJ/mm(2) on either the left or right quadriceps tendon. ESWA effects were investigated by histopathological examination.
Results: ESWA with EFD of 0.5 mJ/mm(2) upwards resulted in edema within the paratenon. ESWA with EFD of 1.2 mJ/mm(2) resulted in various morphological signs of damage within the tendon and paratenon.
Conclusions: We conclude that ESWA to the quadriceps tendon in clinical experimental use should be restricted to EFD less than 0.5 mJ/mm(2).