Background

Tendon injuries in athletes are often treated by administration of corticosteroid locally into the affected area of the tendon—however, the possible detrimental effects of this treatment on tendon are not known.

Research question/s

Does intratendinous injection of corticosteroids have any detrimental effect on the biomechanical properties of collagen fascicles in a tendon (animal model)?

Methodology

Animal material: Twenty-four Wistar male rats (∼250 g).

Experimental procedure: The animals were randomly divided into a control group (CON=12, injected in the rat tail with 9% saline) and a corticosteroid group (CST=12, injected into four sites in the tail tendon with 50 mg (1 ml) methylprednisolone acetate). Rats were killed 3 days after injection, and single individual collagen fascicles were collected. Fascicles were assessed (diameter) and also underwent biomechanical testing to failure—yield strength, Young modulus, peak stress).

Measures of outcome: Fascicle diameter, biomechanical variables.

Main finding/s

Fascicle diameter: There was no significant difference in fascicle diameter between the CON and CST groups.

Conclusion/s

In an animal study, corticosteroid infiltration resulted in significant detrimental biomechanical effects 3 days after intratendinous injection.