Research advances on atypical femoral fractures related to Bisphosphonates / 中华骨科杂志

ABSTRACT

Bisphosphonates have become the first-line drugs for the treatment of osteoporosis,which can reduce the risk of brittle fracture by inhibiting osteoclast activity and increasing bone density.Bisphosphonates bring benefits to osteoporosis patients,while some side effects can occur.In recent years,bisphosphonate related femoral atypical fractures (AFF) have been gradually recognized and become the focus of researches.AFF has typical clinical features and X-ray findings:Patients with long-term usage of bisphosphonate drug.AFF were defined as atraumatic or low-trauma fractures located in the subtrochanteric region or femoral shaft.X-ray showed transverse or short oblique fracture of the medial cortex which shaped like a "spike",and the bone cortex at the fracture area becomes thicker because of localized or diffuse periosteal reaction.AFF pathological mechanism is not clear,mainly with long-term use of bisphosphonates which seriously inhibit bone turnover,other theories including the theory of syndrome like collagen abnormal theory,mineral abnormal theory,hypophosphatasia,precise pathological mechanism still needs further study.Although the absolute incidence of AFF is very low,the number of AFF will inevitably increase with the increasing number of aging osteoporosis patients and the widespread application of bisphosphonates,which should be paid more attention to.AFF risk factors included long-term usage history of bisphosphonate,glucocorticoid treatment history,female patients,fracture prodromal symptoms including pain,discomfort or weakness in the thighs or groin and the bowing of the femoral shaft was associated with the location of AFF fracture.At present,the point of view of AFF treatment iscomplete fracture of femoral length,reamed intramedullary nail fixation.Even for incomplete fractures,preventive intramedullary nailing should also be considered.The healing time of AFF fracture increases obviously.The most common complications are delayed union and nonunion.The rate of delayed union can be as high as 26％.How to improve the curative effect of this kind of fracture needs further study.In this paper,the latest literature on the clinical features,diagnostic criteria,morbidity,risk factors,pathological mechanisms,treatment and complications of atypical fractures of the femur were reviewed.