Acute Postoperative Bisphosphonate-Associated Atypical Periprosthetic Femoral Fracture: A Case Report

Is bisphosphonate use a risk factor for atypical periprosthetic/peri-implant fractures? - A metanalysis of retrospective cohort studies and systematic review of the current evidence

INTRODUCTION

Atypical periprosthetic/peri-implant fractures are not recognised in any widely used classification and therefore little focus is given to them. Multiple case reports and case series demonstrate these fractures exist and are related to bisphosphonate (BP) use.

HYPOTHESIS

Are patients taking long-term BPs at an increased risk of developing an atypical periprosthetic/peri-implant fracture? Is a particular BP drug causing an increased risk of fracture? Is there a correlation between the time of BP use and the incidence of fractures? Do vitamin D analogues or parathyroid hormones reduce the time to union?

MATERIAL AND METHODS

Systematic review of all available evidence on the existence of periprosthetic/peri-implant atypical fractures in patients taking long-term BPs and metanalysis of available retrospective cohort studies. Selected 1 systematic review, 7 retrospective cohort studies (5 used for metanalysis) and 32 case reports.

RESULTS

Metanalysis reported a risk ratio of 14.1, p=0.25, suggesting bisphosphonates are a risk factor in the development of periprosthetic/peri-implant atypical fractures. The secondary outcomes couldn't be reliably identified due to the small size of available studies and risk of significant bias.

DISCUSSION

Atypical periprosthetic/peri-implant fractures are an entity and seem to be associated with the use of bisphosphonates. The benefits of bisphosphonates use outweigh the risks, but clinicians should be aware of atypical fractures and actively search for them when patients on long-term bisphosphonates attend with non-specific pain close to the implant/prosthesis or reduced mobility.

LEVEL OF EVIDENCE

II, Systematic review and metanalysis.

Atypical Vancouver B1 Periprosthetic Fractures: The Unsolved Problem

Atypical femoral fractures (AFF) are stress or insufficiency fractures induced by low energy trauma or no trauma, frequently correlated with prolonged bisphosphonate therapy. The diagnosis follows major and minor criteria, originally described by the Task Force of the American Society for Bone and Mineral Research in 2010 and updated in 2014. However, the definition of AFFs in the report excluded periprosthetic fractures. When atypical fractures occur close to a prosthetic implant the situation become critical, the surgical treatment is often demolitive and supported by medical treatment. Moreover, acute ORIF as a first line treatment is frequently burdened by a high failure rate , and often a stem revision is required as second line treatment. The healing process is long and difficult with poor functional results and impairing outcomes. We present a case treated at our institution of a 78 year old woman with a history of a femoral atypical periprosthetic fracture, complicated by multiple surgical revisions. Its arduous management reflects all the difficulties that these type of fractures could present to the surgeon, while its good final result may teach us how to approach them in a correct way.

Incomplete Periprosthetic Atypical Femoral Fracture With Concomitant Hip and Knee Arthroplasties: A Case Report

CASE

We present a case of an incomplete periprosthetic femoral fracture at the mid-distal third of the femoral stem after 11 months of bisphosphonate use. It is 1 of 4 cases of mid-distal periprosthetic atypical femoral fractures (PAFFs) found in our literature review. She was treated with protected weight-bearing, cessation of bisphosphonates, and teriparatide. Eighteen months after diagnosis, follow-up radiographs showed a bridging callus and reduction of a transverse fracture line.

CONCLUSION

The incomplete PAFF was contributed by both decreased bone turnover from bisphosphonate use and increased mechanical stress at the lateral femoral cortex. Her previous left bipolar hemiarthroplasty and subsequent Total Knee Arthroplasty shifted the mechanical alignment medially, hence increasing tensile stress.

Surgical and Pharmacological Management of Periprosthetic Atypical Femoral Fractures: A Narrative Literature Review

Introduction

An increasing number of patients is annually undergoing total hip arthroplasty (THA), and a significant proportion of these patients are elderly and consequently at a higher risk of complications because of age, osteoporosis, and medical comorbidities. Periprosthetic femoral fractures (PFFs) are one of the worst complications of THA associated with high rates of unfavorable prognosis. Besides, in the last decade, a new independent disease entity called “atypical femoral fracture” (AFF) has been identified and defined by the American Society for Bone and Mineral Research (ASBMR) task force. Some PFFs present clinical history and radiographic aspect consistent with an AFF, meeting the ASBMR criteria for the diagnosis of AFF except that PFFs by themselves are an exclusion criterion for AFF. However, there is an increasing number of published studies suggesting that periprosthetic atypical femoral fractures (PAFFs) exist and should not be excluded by definition.

Significance

Nowadays, although there is an increasing interest in PAFFs, there are still very few studies published on the topic and a lack of consensus regarding their treatment. This narrative literature review aims to introduce this new emerging topic to a wider readership describing the characteristics of PAFFs and the state-of-the-art in their management.

Conclusions

Many authors agree that PAFFs should be considered as a subgroup of PFFs that have atypical characteristics; they also show a significant correlation with prolonged bisphosphonate use. A correct diagnosis is paramount for proper treatment of the disease that requires both surgical and medical actions to be taken.

Periprosthetic Atypical Femoral Fractures Exist: A Retrospective Study at a Single Institution. Prevalence on 115 Periprosthetic Femoral Fractures Around a Primary Hip Stem

BACKGROUND

Some periprosthetic femoral fractures (PFFs) present history and radiographic aspect consistent with an atypical femoral fracture (AFF), fulfilling the criteria for AFF except that PFFs by themselves are excluded from the diagnosis of AFFs. The aim of this study is to evaluate in a single institution series of PFFs if any of them could be considered a periprosthetic atypical femoral fracture (PAFF), and their prevalence.

METHODS

Surgical records were searched for PFFs around a primary hip stem from January 2013 to December 2019. Cases were classified according to Vancouver classification. Demographic and medical history was extracted. Fisher's exact test was used for statistical analysis.

RESULTS

One hundred fifteen PFFs were identified, 59 of them were type B1 and 16 were type C. Radiographs and medical records were available for all patients. Twenty-four patients (32%) have been treated with bisphosphonates (BPs) for longer than 4 years. Four patients presented a fracture with characteristics of PAFF. When enlarged to all PFFs of the series, no other PAFF was found: prevalence of PAFFs was 5.3% for type B1 and C cases and 3.5% for all surgically treated PFFs. Statistical significative difference between PAFFs and PFFs was found for prolonged BP assumption and for the level of fracture clear of the stem.

CONCLUSION

Fracture with characteristics of AFFs can also happen over a prosthetic stem, configuring themselves as PAFFs, and they are related to prolonged BP use. As a correct diagnosis is mandatory for proper treatment, a revision of criteria for AFFs should be considered, accepting that PAFFs exist.

A Periprosthetic Femoral Fracture with Characteristics of Atypical Femoral Fracture

Although the definition of atypical femoral fracture (AFF) excludes periprosthetic femoral fracture (PFF), the number of reports about PFF with characteristics of AFF is increasing. We present the case of such a fracture in this report. An 87-year-old woman who underwent bipolar hip arthroplasty for a femoral neck fracture 38 months prior reported left thigh pain with no history of trauma. Radiographs showed a simple transverse fracture at the level of the stem distal end with features of AFF: periosteal thickening of the lateral cortex, a medial spike, and a noncomminuted fracture. She presented other features resembling AFF: history of bisphosphonate use, prodromal symptoms, no associated trauma, and lateral bowing of the contralateral femur. The fracture showed nonunion after the initial osteosynthesis, and a revision surgery of the arthroplasty and osteosynthesis was performed. Nine months after the surgery, bony union was achieved and she regained the ability to walk. It is supposed that the fracture was influenced by a stress force related to implants and lateral bowing concentrating on the fracture site as a mechanical factor in addition to bisphosphonates as a biological factor. It would be important to recognize that AFF could occur at the peri-implant location, and early detection and treatment are essential.

Two Cases of Periprosthetic Atypical Femoral Fractures in Patients on Long-Term Bisphosphonate Treatment

The current definition of atypical femoral fractures (AFFs) excludes periprosthetic fractures. However, a few cases of bisphosphonates (BPs) -associated periprosthetic atypical femoral fractures (PAFFs) have been reported in the literature. Here, we report two rare cases of PAFFs that fulfilled the major criteria for AFFs in patients with prolonged use of BPs. Both cases progressed to a complete fracture with minor trauma from an incomplete fracture at the distal tip of the well-fixed femoral stem. The femoral stem effect on lateral femoral cortical bone, together with the decreased bone elastic resistance induced by BPs, was considered the cause of onset. In each case, we performed open reduction and internal fixation using a locking plate with cable grip and postoperatively prescribed teriparatide and low-intensity pulsed ultrasound (LIPUS). Both cases had a good clinical course. However, as conservative treatment was not effective in these cases, treatment such as non-weight-bearing exercises during hospitalization or prophylactic surgery may be necessary. Further studies are needed to determine the optimal treatment strategy.

Periprosthetic Femoral Stress Fracture After Bisphosphonate Treatment Resulting in Nonunion Successfully Treated with Teriparatide: A Case Report

CASE

We present the case of a postmenopausal osteoporotic woman, treated with bisphosphonates, who developed a stress fracture at the tip of a revision femoral component, resulting in nonunion after several operative treatment attempts. The nonunion healed after 7 months of subcutaneous injections of 20 μg/day of teriparatide.

CONCLUSION

Teriparatide treatment should be considered for use in recalcitrant stress fractures after total hip arthroplasty.

Progression of bisphosphonate-associated impending atypical femoral fracture despite prophylactic cephalomedullary nailing: A case report and review of literature

While bisphosphonates have been shown to be effective in reducing the incidence of typical osteoporotic fractures, long-term bisphosphonate may be associated with atypical femoral fractures. We report a case of a bisphosphonate-related impending atypical femoral fracture which progressed despite prophylactic cephalomedullary nailing. The fracture healed without further surgical intervention after correcting the patient's bone metabolic profile and stopping the possible offending factors. Although prophylactic fixation of these fractures is recommended, our case and relevant literature review demonstrate that a simple fixation without optimizing other possible predisposing factors may not prevent progression of these fractures.