Undisturbed local bone formation capacity in patients with atypical femoral fractures: a case series

Intramedullary Nail Fixation with Autologous Bone Marrow Transplantation in an Incomplete Atypical Femoral Fracture Patient: Use of Bone Marrow Extracted from the Hollow Reamer

The present report describes an incomplete atypical femoral fracture (AFF) patient who underwent simultaneous autogenous bone transplantation to the resected fracture region during intramedullary nail fixation. A 73-year-old female with a history of multiple myeloma had been undergoing treatment with intravenous drip injections of Zoledronic Acid. She was introduced to our department due to the left lateral thigh pain, with no trauma incidence. An anteroposterior radiograph showed a transverse thin fracture line with localized periosteal and endosteal thickening, which is compatible with subtrochanteric incomplete AFF. A biochemical investigation revealed the existence of severely suppressed bone turnover. She underwent intramedullary nail fixation for fear of a complete fracture. After the fixation, the cortical bone at the fracture region was excised as a wedge-shaped block, and bone marrow extracted from the hollow reamer was simultaneously transplanted to the resected fracture region. Histological examination showed few bone formation features at the fracture line in the excised lateral cortical bone. At 7 months after surgery, radiographs demonstrated complete bone repair, and no clinical problems were observed two years postoperatively. To the best of our knowledge, this is the first report in which autogenous bone marrow transplantation, noninvasive to the iliac crest, was performed in an incomplete AFF patient. We believe that this low invasive procedure can be a useful technique for AFF treatment.

Management Challenges in Atypical Femoral Fractures: A Case Report

A 78-year-old woman presented with an atypical femoral fracture of her right femur associated with a left thigh stress fracture following 9 years of bisphosphonate therapy. The fracture was managed with femoral nailing. However, she represented 3 years later with peri-prosthetic infection, worsening of the left-side stress fracture, and low bone turnover in a bone metabolic study, consistent with an ongoing bisphosphonate effect. This case highlights the increased rate of postoperative complications in atypical femoral fractures even years after surgery as well as the challenging management issues for contralateral fracture and the risk of missing bilateral fractures.

Increased rate of reoperation in atypical femoral fractures is related to patient characteristics and not fracture type. A nationwide cohort study

Atypical femoral fractures are burdened with a high rate of reoperation. In our nationwide analysis, the increased rate of reoperation was related to patient background characteristics, such as age and health status, rather than fracture type.

INTRODUCTION

Patients with atypical fractures are complex to treat and burdened with a high risk of reoperation. We hypothesized that patients with surgically treated, complete atypical fractures have a higher risk of any reoperation and reoperation related to healing complications than patients with common femoral shaft fractures but that this increase would become insignificant when adjusted for predefined characteristics.

METHODS

A cohort of 163 patients with atypical fractures and 862 patients with common femoral shaft or subtrochanteric fractures treated from 2008 to 2010 and who had follow-up radiographs and register data available until 31 December 2014 was included. Reoperations were identified by a complementary review of radiographs and register data and were used to calculate risks for any reoperation and reoperations related to healing complications.

RESULTS

Patients with atypical fractures were more likely to be reoperated for any reason, age-adjusted OR 1.76 (95% CI, 1.08 to 2.86). However, patients with common fractures had a shorter follow-up due to a threefold higher death rate. Accordingly, in a multivariable-adjusted time-to-event model, the increased risk lost statistical significance for any reoperations, cause-specific HR 1.34 (95% CI, 0.85 to 2.13), and for reoperations related to healing complications, HR 1.32 (95% CI, 0.58 to 3.0). Continued use of bisphosphonate in the first year after the fracture did not affect the reoperation rate.

CONCLUSIONS

Our findings suggest that the increased risk of reoperation after an atypical femur fracture is largely explained by patient characteristics and not fracture type.

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.

Current Understanding of Epidemiology, Pathophysiology, and Management of Atypical Femur Fractures

PURPOSE OF REVIEW

To summarize reports published since the 2013 American Society of Bone and Mineral Research Task Force Report on atypical femoral fractures (AFF).

RECENT FINDINGS

The absolute incidence of AFFs remains low. AFFs are primarily associated with prolonged bisphosphonate (BP) exposure, but have also been reported in unexposed patients and those receiving denosumab for osteoporosis and metastatic bone disease. Asians may be more susceptible to AFFs. Lateral femoral bowing and varus hip geometry, which increase loading forces on the lateral femoral cortex, may increase AFF risk. Altered bone material properties associated with BP therapy may predispose to AFFs by permitting initiation and increasing propagation of micro-cracks. Relevant genetic mutations have been reported in patients with AFFs. Single X-ray absorptiometry femur scans permit early detection of incomplete and/or asymptomatic AFFs. Orthopedists recommend intramedullary rods for complete AFFs and for incomplete, radiologically advanced AFFs associated with pain and/or marrow edema on MRI. Teriparatide may advance AFF healing but few data support its efficacy. Greater understanding of biological and genetic predisposition to AFF may allow characterization of individual risk prior to initiating osteoporosis therapy and help allay fear in those at low risk for this complication, which remains rare in comparison to the osteoporotic fractures prevented by antiresorptive therapy.