osteoporosis - related fractures are a major public health problem mainly in postmenopausal women and the elderly .
osteoporosis affects an estimated of 75 million people in europe , united states of america , and japan .
there are several treatment options available including calcium , vitamin d , parathyroid hormone , strontium , and bisphosphonates .
alendronate ( fosamax , merck & company , inc . ) is one of the first bisphosphonates to be licensed and used .
recently , however , there is an emerging concern regarding long bone stress fractures secondary to long - term alendronate intake .
we present a case of bilateral femoral shaft insufficiency fractures secondary to long - term alendronate therapy .
a 74-year - old lady presented to orthopaedic clinic with a four - month history of bilateral thigh pain .
she had history of breast cancer treated with lumpectomy 10 years ago and has a history of well - controlled asthma , for which she did not require corticosteroid treatment .
radiographs revealed lateral cortical thickening of the mid - diaphysis of both femurs ( figure 1 ) .
the patient underwent a bone scan to rule out the possibility of metastases due to her previous history .
four days after consultation , she tripped and sustained a transverse fracture of the left femur and underwent uneventful femoral intramedullary nailing ( figures 3(a ) and 3(b ) ) .
bone mineral density scan was organized , and she was started on teriparatide treatment . because there was no progressive right thigh pain , no further surgical management was offered beyond close followup . at four months
postoperatively , the left femur fracture showed good radiological union ( figure 3(c ) ) .
there was still persistent pain in the right femur and a definite linear lucency in the lateral femoral cortex on plain radiographs .
she underwent prophylactic intramedullary nailing of the right femur and had eventual complete relief of her symptoms .
the lifelong risk of having a fracture related to osteoporosis is one in two for women and one in four for men .
bone formation coupled to resorption is also decreased resulting in an overall reduction of bone remodelling .
bisphosphonates also combine with calcium and become incorporated in the crystal structure of bone and retained within the skeleton for long periods of time .
therefore , they have the potential to exert efforts long after the treatment has been discontinued .
alendronate is the first bisphosphonate to be approved for the treatment and prevention of osteoporosis .
several previous studies have shown that alendronate reduces the risk of osteoporotic fractures and osseous resorption in high turnover bone disease .
it has an excellent benefit to risk ratio for women with osteoporosis when used for 3 - 5 years .
in addition to other well - known side effects of bisphosphonates , there is a recent concern regarding the association of cortical insufficiency fractures and low - energy femoral fractures with long - term alendronate use . several published case series and case reports suggest femoral shaft , and subtrochanteric femur fractures can be associated with long - term alendronate use [ 24 ] .
have shown a significant proportion of patients , in their study of low - energy sub - trochanteric and diaphyseal femur fractures , were on long - term bisphosphonates .
the characteristic features include prodromal pain in the thigh for several months prior to the fracture ( 76% of the reported cases ) , bilateral fractures either sequential or simultaneous , and fractures with trivial trauma .
the radiological features of these fractures are lateral cortical thickening , cortical spiking or beaking over the medial cortex , and transverse or short oblique fractures .  
neviaser et al . reported in their study that 19 of the 25 patients on alendronate demonstrate a simple transverse fracture with a unicortical beak in an area of cortical hypertrophy .
in contrast , this fracture pattern was seen in only one patient who was not being treated with alendronate , indicating that the fracture pattern is typical in alendronate users .
alendronate acts as a strong inhibitor of osteoclastic bone resorption which reduces the overall bone turnover .
this has a negative effect on bone healing and is likely one of the reasons why many of the insufficiency fractures have delayed healing .
since alendronate inhibits osteoclastic remodeling , endochondral fracture repair is the preferred method of fracture healing .
intramedullary reconstruction with full - length nails accomplishes this goal and protects the entire femur .
sayed - noor and sjdn reported a case series of delayed union even after internal fixation of a femoral insufficiency fracture in a patient who was on long - term alendronate .
capeci and tejwani and ha et al . reported union at an average of four and five months , respectively , after internal fixation [ 7 , 8 ] . in our case , the left femur fracture was treated with a reamed intramedullary nail with union at four months . because of the nonprogressive pain from the right femur stress fracture , close observation with protective weight - bearing was initially chosen but proved to be insufficient despite stopping alendronate .
we support the view of capeci and tejwani and ha et al . to treat even the incomplete insufficiency fractures with internal fixation .
as well , we feel clinicians should not be lured into conservative management by the radiographic features of focal cortical hypertrophy
. dietary calcium and vitamin d status should be assessed , and adequate supplementation should be prescribed .
although there is strong evidence supporting short - term alendronate therapy to reduce the risk of osteoporotic fractures , there is not enough evidence to suggest benefit in long - term use beyond five years .
the continuation of alendronate therapy after five years should be tailored to individual patients after appropriate followup and the need for ongoing therapy reassessed annually .
any patients with prodromal symptoms such as thigh pain should be investigated with routine bilateral radiographs of the femur looking for stress reaction , and if necessary , advanced imaging - like bone scan or magnetic resonance imaging .
this is not the first case report on insufficiency diaphyseal fractures related to long - term alendronate therapy .
however , this is a case report with characteristic features and bilateral involvement which highlights the importance of evaluating patients on long - term alendronate therapy and recommends early prophylactic internal fixation of these fractures .
patients on more than 5 years of alendronate therapy should be reevaluated annually regarding continuation of treatment and need close observation .
 osteoporosis - related fractures are a major public health problem and one in two women and one in four men are affected with osteoporosis - related fractures . 
 alendronate ( fosamax ) is one of the first bisphosphonates used to treat osteoporosis effectively . 
 recently , however , there is a concern regarding long bone insufficiency fractures related to long - term alendronate therapy . 
 we report a case of bilateral femoral insufficiency fractures likely related to long - term alendronate therapy , the classic symptoms , signs , and treatment of these fractures . 