I've received a cortisone injection in the past but now my pain is worsening again. Why does my doctor want additional diagnostic testing before I receive another injection?

For specific conditions, your doctor may want to rule out any possibility of a ligament or tendon tear or rupture as cortisone injections can worsen these injuries.  New or worsening pain needs to be fully assessed before pursuing additional treatment.  If a tear or rupture is present, cortisone can weaken tissue and prolong healing.  Once your doctor determines no rupture or tear is present, additional corticosteroid can be considered.