Treatment for subtrochanteric fracture and subsequent nonunion in an adult patient with osteopetrosis:A case report and review of the literature

BACKGROUND As a congenital metabolic bone disease caused by defective osteoclastic resorption of immature bone,osteopetrosis is characterized by diffused sclerosis of bones,brittle bones,easy fracturing,narrow medullary canals,and a weak fracture healing ability.At present,clear standards and principles for the treatment of fractures in patients with osteopetrosis are lacking.Non-operative treatment can prevent fracture hematoma and preserve the blood supply to the bone fragments,while being associated with frequent failures and higher mortality rates.Meanwhile,closed reduction and internal fixation with intramedullary nail(CRIF+IMN)approaches can also protect blood supply to the fracture site.However,IMN cannot be used for the vast majority of patients with osteopetrosis due to the narrowing of medullary canals.Thus,open reduction and internal fixation with plate remains the most appropriate surgical method for treating fractures in patients with osteopetrosis,but this approach is complicated by the lack of intramedullary hematopoiesis in such patients.Fracture healing primarily depends on the blood supply to the external periosteum.Open reduction can also easily destroy the periosteum and cause delayed fracture healing or even nonunion;however,CRIF may be the most practical approach.As a result,it would be prudent to solve the difficulty of drilling during the operation and the problem of postoperative nonunion.CASE SUMMARY In 2018,we treated an adult patient with osteopetrosis presenting with a subtrochanteric fracture.The fracture was fixed using a femoral locking compression plate.Because of delayed consolidation,at 12 mo postoperatively the patient was further treated with platelet-rich plasma(PRP)combined with radial extracorporeal shock wave therapy(rESWT).Antero-posterior and lateral radiographs obtained at the latest follow-up(10 mo)showed that the callus had grown at the original fracture site,and the medial fracture line almost disappeared.CONCLUSION Osteosynthesis remains the first choice of treatment approach for fractures in patients with osteopetrosis,especially peritrochanteric fractures.Preoperative preparation is necessary to avoid risks such as drill bit breakage and iatrogenic fracture during the operation.Moreover,fractures in a patient with osteopetrosis present with a high risk of delayed union and nonunion,which can be potentially cured with PRP+rESWT.