An expanding suture anchor in which a distal end of the rigid anchor body includes at least one annular protrusion. A mating deformable cap includes at least one annular slot or ridge that engages the annular protrusion such that the annular slot and annular protrusion are coupled when the deformable cap is pushed or pulled onto the rigid anchor body. The engagement of the annular slot and the annular protrusion may lock the deformable cap and rigid anchor body into a mated position and inhibits distal retraction of the deformable cap from the anchor body.
