Histological finding of atypical subtrochanteric fracture after long-term alendronate therapy

Bilateral lumbar pedicle fracture in a patient receiving long-term bisphosphonate therapy: a case report with pathological evaluation

BACKGROUND

Bilateral pedicle fractures of the lumbar spine are uncommon and are typically associated with strenuous activities, traumatic events, or previous spinal surgery. This study reported a case of bilateral pedicle fracture in a patient with a long history of osteoporosis treatment with bisphosphonate and included a histological evaluation of the bone.

CASE PRESENTATION

An 82-year-old woman with no history of trauma presented to our hospital with back pain that had worsened over the previous month. Computed tomography and magnetic resonance imaging revealed bilateral pedicle fractures of the third lumbar vertebra. She had osteoporosis and had been taking bisphosphonates for 9 years. The patient underwent posterior lumbar fusion, and her symptoms improved. Bone biopsy results from the spinous process revealed few osteoblasts and an absence of osteoclasts, indicating low bone turnover.

CONCLUSIONS

Long-term use of bisphosphonates may contribute to the development of atypical bilateral pedicle fractures in patients with osteoporosis.

Atypical fractures of the ulna: Effect of bowing of the ulna on fracture location and occurrence

INTRODUCTION

Ulnar fractures associated with long-term bisphosphonate (BPs) therapy are rare, and the nature and extent of this potential risk remains unknown. Although ulna is generally considered a "straight bone", it actually features a bow anatomically. For this reason, we speculated that ulnar bow may have a role in the development of atypical ulnar fractures (AUFs). Therefore, we compared the location and depth of ulnar bow between AUF patients and patients with atypical fractures other than the ulna. We aimed to answer: (1) whether a correlation exists between the location of the ulna bow and the location of AUFs, (2) whether the degree of ulnar bow affects the occurrence of AUFs.

HYPOTHESIS

Ulnar bowing could play a critical role in the location and occurrence of AUFs.

METHODS

We retrospectively reviewed the radiographs and medical records of 64 patients with atypical fractures admitted to our department between May 2010 to July 2020. The bow of the ulna was measured using anteroposterior (AP) and lateral radiographs. Bone angulation was described as apex of deformity, with apex lateral bow designated as AP plane bowing and apex posterior bow marked as lateral plane bowing.

RESULTS

In all patients with atypical fractures, bow locations were measured at the proximal third level to the index line in 68% of AP plane and 72% of lateral plane. In patients with AUFs, fracture sites occurred in the range of 20% to<40%, except in one patient. Fracture site versus apex lateral bow location and fracture site versus apex posterior bow location showed a statistically significant correlation coefficient of 0.81 (p<0.001) and 0.69 (p=0.003), respectively. In lateral plane, there was a significant difference between AUF patients and patients with atypical fractures other than the ulna in ulnar bow depth (p=0.014). However, no statistically significant differences were found in AP plane (p=0.110).

DISCUSSION

In AUFs, fracture site was highly correlated with ulnar bowing location, and, as the degree of apex posterior bow increased, occurrence of AUFs increased. These findings are helpful in understanding the role of bowing as the ulnar geometry in the development of AUF and early identification of the location of suspicious AUF.

LEVEL OF EVIDENCE

IV.

Treatment strategy for atypical ulnar fracture due to severely suppressed bone turnover caused by long-term bisphosphonate therapy: a case report and literature review

BACKGROUND

Atypical fractures may occur due to the combined effect of severely suppressed bone turnover (SSBT) caused by long-term bisphosphonate treatment and chronic repetitive bone microdamage. Atypical fracture of the ulna due to SSBT is a rare entity; there is no standardized treatment strategy for this condition. We successfully treated a patient with atypical fracture of the ulna. Herein, we present this patient, review the relevant literature, and discuss the treatment strategy.

CASE PRESENTATION

An 84-year-old woman presented with atypical fracture of the left ulnar shaft due to SSBT. She had a history of bisphosphonate therapy (ibandronate and alendronate) since more than 10 years; her bone turnover was severely suppressed. We performed open reduction and internal fixation (ORIF) using dual plate with some additional treatments. These included drilling and decortication, use of autogenous bone graft, low-intensity pulsed ultrasound (LIPUS) treatment, and administration of teriparatide. Finally, bone union was observed at 11 months after surgery.

CONCLUSIONS

Based on the literature review and our experience with this case, ORIF alone may not be adequate to achieve bone union; drilling, decortication, and use of cancellus bone graft is important to achieve favorable outcomes. Administration of teriparatide and LIPUS may facilitate early bone union, although further studies are required to provide more definitive evidence. Furthermore, ORIF using dual plate may help avoid implant failure owing to the long time required for bone union.

Atypical femoral neck fracture after prolonged bisphosphonate therapy

Of the drugs developed to prevent and treat osteoporosis, bisphosphonate has played a very important role in preventing osteoporotic fractures. However, case reports describing atypical femoral fractures in patients using long-term bisphosphonates have emerged. The majority of atypical femur fractures occurs in the lateral aspect of the subtrochanteric or femur diaphysis, which is explained by accumulation of tensile stress in these areas. Although the superior cortex of the femur neck withstands maximum tensile stress, to our knowledge, there have been only two reports (three cases) of atypical femoral neck fracture. In addition, none of those case reports revealed detailed pathology related to suppressed bone turnover rate. We encountered an incomplete femoral neck fracture and diagnosed it as "atypical" on the basis of the patient's lack of trauma and medication history and pathological findings. For patients with groin pain, minimal or no trauma, and a history of long-term bisphosphonate use, an atypical femoral neck fracture should be considered.

Unexpected iatrogenic fracture of the femoral neck during subtrochanteric fracture fixation in a patient on bisphosphonate treatment for osteoporosis: Case report

Osteoporotic patients being treated with bisphosphonates present an interesting dilemma when removing hardware such as dynamic hip screws “DHS”. In this paper, we describe the case of a 66-year-old osteoporotic patient who was placed on long term bisphosphonate therapy after sustaining an intertrochanteric hip fracture which was stabilized with a DHS. She presented with a subtrochantric fracture on the ipsilateral side. She was planned for DHS removal and intramedullary nailing. Removal of the dynamic hip screw proved to be difficult, likely due to possible cold welding of the DHS to the barrel of the side plate and sclerotic bone formation around the hardware secondary to the extended bisphosphonate use. The patient had an intra-operative femoral neck fracture while attempting the DHS removal. We had to convert to an unanticipated total hip replacement. Careful considerations should be taken when removing hardware from patients on long term bisphosphonate treatment.

Efficacy of bone-end intervention on fracture healing in bisphosphonate-related atypical femoral fractures

BACKGROUND

Delayed unions are quite common in the treatment of atypical femur fractures, which are thought to result from the long-term use of bisphosphonates. The effects of interventions for sclerotic tissue on the fracture line in atypical femoral fractures are not fully known. For this reason, we compared the results of patients with atypical femoral fractures treated by closed intramedullary nailing to patients treated by open surgery accompanied with interventions for their sclerotic bone ends, aiming to answer: (1) In the treatment of atypical femoral fractures, do bone-end interventions have a positive effect on the radiological union rate and radiological union time? (2) Do bone-end interventions influence complication rates in the treatment of atypical femoral fractures?

HYPOTHESIS

Bone-end interventions provide a faster and higher rate of union compared to closed intramedullary nailing and result in fewer complications in atypical femoral fractures.

PATIENTS AND METHODS

A total of 32 patients who met the inclusion criteria and had atypical femoral fractures treated by intramedullary nailing between 01/01/2012 and 12/31/2016 were reviewed. Of these, 15 fractures were treated with intramedullary nailing (Group 1), and 17 were treated with open surgery and drilling of the bone ends followed by intramedullary nailing (Group 2). Demographic data, laboratory values, radiological union times, and complications were compared between the groups. Nonunion was defined as fractures with a persistent fracture line 12 months after surgery without any sign of union.

RESULTS

A similar rate of primary union was obtained in both groups (Group 1, 13/15 [87%]; Group 2, 16/17 [94%]; p=0.471). The mean radiological consolidation period was shorter in Group 2 (Group 1, 6.8±1.8 months; Group 2, 5.1±1.3 months; p=0.004). Nonunion rates were similar between the groups (Group 1, 1/15 [7%]; Group 2, 1/17 [6%]; p=0.927). For 1 patient in Group 1, a femoral neck fracture occurred 10 months after surgery, and a revision was performed with a long femoral stem.

DISCUSSION

In the treatment of atypical femoral fractures with intramedullary nailing, we found that the patients who were treated with open intervention of the bone ends had similar union and complication rates to those treated with closed methods, but radiological union time was found to be shorter in the open-intervention group.

LEVEL OF EVIDENCE

III, retrospective case-control study.

A Case Series and Discussion on Surgical Treatment Strategy for Atypical Proximal Femoral Fractures Associated with Bisphosphonate Use

The aim of this study was to determine the incidence of atypical femoral fractures in our local population, study their current outcomes and present a novel surgical strategy based on these data. Patients who received surgical fixation of an atypical pattern proximal femoral fracture over a four-year period were identified and followed up in the clinic until union, revision surgery or death.

The local incidence of atypical femoral fractures is 1.1 per 1000 per annum amongst patients receiving bisphosphonates. Twelve fixation procedures were carried out in 10 patients. Intra-operative reduction and nailing led to an average deformity of 8.5° varus and 13° apex anterior. Five cases required revision surgery. Fifty percent of primary procedures resulted in radiographic union within two years. We suggest that the lateral side of the fracture should be considered a primary nonunion. We advocate undertaking a wedge excision to correct the bone to a valgus morphology and stabilising with an intramedullary nail and a lateral tension plate. Multicentre studies are needed to demonstrate the efficacy of any particular approach.

Bone Structure and Turnover Status in Postmenopausal Women with Atypical Femur Fracture After Prolonged Bisphosphonate Therapy

Atypical femur fracture (AFF), a serious complication of long-term bisphosphonate therapy, is usually preceded by an incomplete fracture appearing on the lateral femur. AFF is most likely the result of severely suppressed bone turnover (SSBT). However, the differences in bone structure and turnover between patients with incomplete and complete AFF remain unknown. We examined trans-iliac bone biopsies from 12 white postmenopausal women with AFF (incomplete = 5; complete = 7) on BP therapy of >5 years and 43 healthy white premenopausal women. Histomorphometric measurements were performed separately in cancellous, intracortical and endosteal envelopes. Of the 43 histomorphometric measurements on 3 difference bone surfaces (cancellous, intracortical and endosteal), only 2 bone resorption variables (Oc.S/BS and Oc.S/NOS) on the endosteal surface were significantly lower in patients with complete AFF than those with incomplete AFF. Compared to healthy premenopausal women, the trabecular bone volume, thickness and number were all significantly lower in patients with AFF. The dynamic bone formation variables in patients with AFF were significantly reduced on all bone surfaces. The likelihood of a biopsy with no tetracycline labeling was significantly higher in AFF patients than in healthy premenopausal women. Based on these results, we conclude that there are no significant differences in bone turnover between patients with incomplete and complete AFF, suggesting that the suppression of bone turnover had already existed in the femur with incomplete AFF. Compared to healthy premenopausal women, bone turnover is similarly suppressed in patients with either type of AFF.

Atraumatic intracapsular neck of femur fractures after prolonged bisphosphonate treatment: a new atypical variant?

We present 2 cases of elderly females presenting with atraumatic, near-vertical (Pauwells grade 3), intracapsular neck of femur fractures. Following diagnosis of osteoporosis on DEXA scans, they had received alendronic acid for 7 and 10 years respectively. Routine blood tests and serum estimations of calcium, vitamin-D and thyroid-stimulating hormone, done at admission, were within the normal ranges. These patients were managed with a hemiarthroplasty and a dynamic hip screw (DHS) respectively, following discontinuation of bisphosphonates. We present these 2 cases in light of emerging evidence that associates long-term bisphosphonate use with atypical low energy femoral fractures. Only subtrochanteric/diaphyseal fractures have been reported to date. We present a new variant of atypical femoral neck fractures in metaphyseal bone related to prolonged bisphosphonate therapy.

Histology of 8 atypical femoral fractures: remodeling but no healing

BACKGROUND AND PURPOSE

The pathophysiology behind bisphosphonate-associated atypical femoral fractures remains unclear. Histological findings at the fracture site itself may provide clues.

PATIENTS AND METHODS

Between 2008 and 2013, we collected bone biopsies including the fracture line from 4 complete and 4 incomplete atypical femoral fractures. 7 female patients reported continuous bisphosphonate use for 10 years on average. 1 patient was a man who was not using bisphosphonates. Dual-energy X-ray absorptiometry of the hip and spine showed no osteoporosis in 6 cases. The bone biopsies were evaluated by micro-computed tomography, infrared spectroscopy, and qualitative histology.

RESULTS

Incomplete fractures involved the whole cortical thickness and showed a continuous gap with a mean width of 180 µm. The gap contained amorphous material and was devoid of living cells. In contrast, the adjacent bone contained living cells, including active osteoclasts. The fracture surfaces sometimes consisted of woven bone, which may have formed in localized defects caused by surface fragmentation or resorption.

INTERPRETATION

Atypical femoral fractures show signs of attempted healing at the fracture site. The narrow width of the fracture gap and its necrotic contents are compatible with the idea that micromotion prevents healing because it leads to strains within the fracture gap that preclude cell survival.