Coccydynia. Aetiology and treatment. A five-year prospective trial involving 120 patients was undertaken to investigate the aetiology and treatment of coccydynia. The cause lies in some localised musculoskeletal abnormality in the coccygeal region. Lumbosacral disc prolapse is not a significant factor. The condition is genuine and distressing and we found no evidence of neurosis in our patients. Physiotherapy was of little help in treatment but 60% of patients responded to local injections of corticosteroid and local anaesthesia. Manipulation and injection was even more successful and cured about 85%. Coccygectomy was required in almost 20% and had a success rate of over 90%. 