| The effect of peritenon injections of hydrocortisone acetate on the separation force required to completely avulse a posttraumatized Achilles tendon of the adult male rat was investigated. Although extensive research has been completed regarding the deleterious effects of cortisone on soft tissue, there has been almost a complete absence of histological research on the effects of cortisone on traumatized soft tissue. A two factorial crossed design was employed for this study. Adult male rats (x = 573 grams) were randomly assigned to three groups of 45. The first factor consisted of the physical condition of the tendons (traumatized and nontraumatized). The second factor was the number (1,3,5) of.10 cc (125 mg/ml) injections associated with the number of weeks (1, 4, or 7), respectively, following the initial injection until sacrifice. Fifteen animals were assigned to each of these 9 combinations. The experimental animals (anesthetized) acquiesced a direct weight drop to the right Achilles tendon producing a non-penetrating wound. At the time of sacrifice the functional unit of the tendo-os-calcis of the achilles tendon was dissected and tested in tension to failure employing a soft tissue linear disseminator maintaining a constant distraction force of 1.9 mm/second. A histological analysis utilizing light microscopy was performed to determine the collagen content, elastic tissue fiber content, and total cell and differential cell counts. To determine the immediate effects of hydrocortisone on tissue healing an additional group of animals were traumatized and injected four hours later. They followed the same protocol as above; however, they were sacrificed 24, 48, 72, and 96 hours after treatment. Histological analysis was performed with light and electron microscopy. From the statistical analyses of the data obtained, it was concluded that hydrocortisone acetate does not have a deleterious effect on the achilles tendon of the experimental animal. |
