Can a cortisone injection be used for tendinitis? From a clinical perspective, for tendinitis, other conservative treatments such as physical therapy, massage, and oral medications can be used. When treatments like phototherapy are ineffective or not yielding results, a cortisone injection is certainly an option. As long as it is accurately targeted, the results of a cortisone injection are very satisfactory. In some cases of tendinitis, a cortisone injection can even achieve a curative effect. Thus, after tendinitis, a cortisone injection can definitely be used for treatment.