Injection of corticosteroids is a common treatment for lateral elbow pain, de Quervain's tenosynovitis and CMC arthritis. Injections are delivered into the origin of the extensor carpi radialis brevis, into the first dorsal compartment of the wrist or into the trapeziometacarpal (TMC) joint, respectively. Several studies have tested the efficacy of steroid injections, including some prospective randomized trials. However, it is remarkable that only one of these have compared corticosteroid injection to placebo injection, especially in light of the fact that conditions like lateral elbow pain and de Quervain's tenosynovitis may be self-limiting. The psychological factors associated with receiving an injection may be important mediators of any treatment effects.