Unusual presentation of congenital radioulnar synostosis with osteoporosis,fragility fracture and nonunion:A case report and review of literature

BACKGROUND Congenital radioulnar synostosis(CRUS) is a rare deformity of the upper extremity. It is characterized by loss of rotation of the involved forearm and functional limitations in daily activities. No studies on CRUS with osteoporosis have been reported to date, and osteoporosis is usually recognized as an important dimension of genetic disorder in children. We discuss the possible relationship among this disorder, osteoporosis and fracture nonunion, investigate the strict surgical indications and recommended treatments.CASE SUMMARY A 14-year-old male patient with bilateral CRUS with osteoporosis, fragility fracture and nonunion of fractures in ulna and radius presented our institution for further treatment, complaining of limitation in rotation. The bone mineral density of the hip and lumbar spine was 0.687 g/cm2 and 0.705 g/cm2,respectively, and the Z-score for both was-2.1, which revealed osteoporosis and a high risk of fracture. Tow serum bone turnover markers indicated an imbalance of bone metabolism. Reoperation for ulna fracture with autogenous bone grafting and a postoperative physiotherapy program were adopted rather than the separation of pathological synostosis. Radiological examination, observational posture assessment and limb function scale were evaluated before and 1 year after surgery. At 1 year, the fracture nonunion had almost recovered, forearm movement function on the fracture side was restored, and function on the healthy side was significantly improved compared with that before rehabilitation.CONCLUSION Surgical indications for CRUS vary from person to person. Surgery should not be the first choice of treatment, and physiotherapy is not inferior to surgical treatment.