Solitary unicameral bone cyst

This study discusses the results of the 24 patients who had unicameral bone cyst treated by the author surgically and conservatively between 1982 and 1992. The patients were sixteen males and eight females giving a male to female ratio of 2:1. Their ages ranged from two to 34 years with a mean age of 18 years. The long bones were commonly affected as follows: humerus in eight patients; femur in six patients; tibia in two patients. All were affected on the proximimal part of the bones, and there were three cysts found in the calcaneus. The main complaint was mild dull pain on the affected site. In some cases the pain was severe and associated with inability to use the affected limb. X-ray findings showed medullary cavity and adjacent inner cortical destruction with mild subperiosteal new bone formation causing an expansile appearance and multiloculation. At surgery, an area of bone expansion was found with weakened periosteum and underlying thin cortex which easily collapsed on pressure leading to a cavity containing yellowish fluid. The wall consisted of a thin membrane with ridges which was histologically reported as connective tissue with a few bone spicules. Surgical results were graded as "good" in 73% and "poor" in 27% due to recurrent, shortening or occurrence of sepsis. The bone metabolism studies and total blood count were normal.