BACKGROUND: Steroid injections into joints are frequently used to control symptomatic pain. Risks associated with intra-articular steroid injections are not well documented. METHODS: We report the case of a 29-year-old woman who was referred to a dental surgeon because of a suspected relationship between persisting chronic back pain and an arthrosis of the temporomandibular joint (TMJ). RESULTS: The dental surgeon diagnosed capsulitis of the right TMJ and injected 40 mg triamcinolone into the joint. Within 4 months the patient developed progressive pain and trismus of the right TMJ and the intra-articular injection was repeated. An occlusal splint slightly improved the patients' symptoms but induced crepitus. Magnetic resonance imaging revealed a disk dislocation in the right TMJ and severe necrosis of the condyle. The patient had persisting pain and ankylosis. Surgical restoration of the TMJ revealed a bony apposition in the fossa deformed with the socket of the joint, extensive medial erosion of the condyle and complete destruction of the disk. CONCLUSION: This case report supports earlier observations that intra-articular glucocorticoid injections, if used in a wrong way, may cause severe destruction of a joint.