Operative fixation of 22 nonunited fractures was undertaken in 21 obese patients. Eleven patients were women and 10 were men, with an average age of 46.3 years (range 25-74). The average body mass index in this group of patients was 37.9 kg/m2 (range 33.2-57.1). Two patients were classified as morbidly obese and 19 as severely obese. The management of these patients proved to be fraught with difficulties related to their obesity. There were a number of occurrences believed to be related to poorly protective positioning and prolonged ischemic pressure under the patient's body weight during the administration of anesthetic, including a peroneal compartment syndrome, a gluteal compartment syndrome with sciatic nerve palsy, bilateral brachial plexus stretch injuries, an anterior interosseous nerve palsy, and the postoperative development of a patch of scalp alopecia. There were two wound separations and no episodes of thromboembolic disease. Sixteen nonunited fractures healed after the index procedure at an average time to healing of 5.6 months (range 2-14). Five nonunited fractures required a second procedure to gain union [average total time to healing 17 months (range 10-31)]. A single fracture remains ununited. Awareness of the unique technical demands and operative and anesthetic risks encountered when undertaking an operative procedure in a severely obese patient is imperative for the safe and successful treatment of orthopaedic surgical problems in these patients.