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

The definition of atypical femoral fractures should include periprosthetic femoral fractures (PAFFs)

Periprosthetic hip fractures may have features of atypical femoral fractures.

PURPOSE

Atypical femoral fracture (AFF) is a rare complication of treatment with bisphosphonates (BPs) or denosumab. The American Society for Bone and Mineral Research (ASBMR) Task Force definition for AFFs excludes periprosthetic fractures. The purpose of this study was to determine prodromal symptoms, frequency, treatment, and outcomes of periprosthetic AFFs (PAFFs) in persons prescribed a BP or denosumab for osteoporosis and later diagnosed with a periprosthetic hip fracture.

METHODS

Participants were all veterans (age ≥ 50) from the VA Corporate Data Warehouse with at least one filled prescription for an oral or intravenous BP or denosumab from October 1999 through December 2022, prior to an ICD code for a periprosthetic fracture around a hip joint. Radiographs were reviewed for features of AFF. In those with a PAFF, the presence of a contralateral AFF was sought. Medical records of those with a PAFF were reviewed to identify prodromal symptoms, treatments, and outcomes.

RESULTS

Among approximately 400,000 veterans who received a BP or denosumab, there were 76 ICD-coded periprosthetic hip fractures, including one AFF. This fracture met all five ASMBR-defined AFF criteria. The PAFF, a Vancouver C cemented periprosthetic femur fracture, occurred in a man with > 7 years of BP therapy. There was no contralateral AFF. The BP was discontinued and the fracture was treated with an interlocking plate with cerclage wires. In the 12 months following PAFF, there were no infectious complications, but the fracture had a chronic nonunion.

CONCLUSION

Periprosthetic hip fractures may rarely have features of AFFs. Fracture nonunion may complicate PAFFs.

Atypical Periprosthetic Femoral Fracture Might be Considered a Distinct Subtype of Atypical Femoral Fracture: A Retrospective Study

OBJECTIVE

The exact relationship among atypical periprosthetic femoral fractures (APFFs), typical periprosthetic femoral fractures (PFFs), and atypical femur fractures (AFFs) remains unclear. This study aimed to investigate the prevalence of APFFs among PFFs and to identify the clinical characteristics, management, and prognosis that distinguish APFFs from typical PFFs and AFFs to further determine the relationship among these three fracture types.

METHODS

In this retrospective study, we reviewed the clinical data of 117 consecutive patients who had PFFs after hip arthroplasty between January 2012 and December 2022 and further classified them into an APFF group and a typical PFF group according to the revised ASBMR diagnostic criteria for AFF. Moreover, patients who had subtrochanteric or femoral shaft fractures in the same period and met the diagnostic criteria for AFF were recruited and classified into the AFF group. Demographic information, minor features of AFF, comorbidities, history of medication usage, management, and complications were collected and compared among patients with typical PFFs, APFFs, and AFFs.

RESULTS

Eleven PFFs were identified as APFFs, and the prevalence of APFFs among PFFs was 9.4%. Significant differences were found in generalized increase in cortical thickness (p = 0.019), prodromal symptoms (p < 0.001), and the incidence of bilateral fractures (p = 0.010) among the groups, where the incidences of these minor features in the APFF group and the AFF group were higher than those in the typical PFF group. Of note, the duration of fracture healing of APFFs was significantly longer than that of typical PFFs and AFFs (p < 0.001 and p = 0.004, respectively). In addition, the APFF group and the AFF group had higher proportions of patients with rheumatoid arthritis (p = 0.004 and p = 0.027, respectively), bisphosphonate (BP) usage (p = 0.026 and p < 0.001, respectively), and longer duration of BP usage (p = 0.003 and p = 0.007, respectively) than the typical PFF group. Furthermore, significant differences were found in management (p < 0.001) and complication rate (p = 0.020) among the groups, and the rate of complications in the APFF group and the AFF group was higher than that in the typical PFF group.

CONCLUSIONS

APFFs not only fulfilled the mandatory and major diagnostic criteria for AFF but also had many clinical characteristics, management and prognosis distinguishing them from typical PFFs but resembling AFFs; hence, the diagnostic criteria for AFF might be revised to incorporate APFF as a distinct subtype of the condition.

Frequency and pathogenesis of periprosthetic atypical femoral fractures associated with total knee arthroplasty: A multicenter prospective study with complementary histopathological and biomechanical analysis

INTRODUCTION

Although the diagnostic criteria for atypical femoral fracture (AFF) exclude periprosthetic fractures, reports of periprosthetic femoral fractures with characteristics of AFF are rapidly increasing. In this study, we investigated the frequency and pathogenesis of periprosthetic AFF associated with total knee arthroplasty (TKA) based on a theory of AFF subtypes that divides AFFs into two main types: fragility stress fractures of the bowed femoral shaft in the mid-shaft and "typical" subtrochanteric AFFs due to suppression of bone turnover (e.g., by bisphosphonates).

PATIENTS AND METHODS

This multicenter prospective study of AFFs was conducted from 2015 through 2022. Clinical, pathological, and morphological characteristics were investigated in patients with periprosthetic AFFs associated only with non-stem TKA. Then, biomechanical investigation of the periprosthetic AFF was performed by computer tomography-based finite element analysis (CT/FEA) using two models with different load axes to examine how the correction of lower limb alignment by TKA influences the tensile stress distribution of the femur and the location of the AFF.

RESULTS

Four of 61 AFFs (6.6%) were identified to be periprosthetic AFF (1 mid-shaft; 3 subtrochanteric). Periprosthetic AFFs had characteristics including mechanical stress due to bowing deformity and potentially suppressed bone turnover due to long-term exposure to specific drugs (e.g., bisphosphonates and glucocorticoids). Although 2 periprosthetic AFFs appeared to involve a bowed femur, one with both of the aforementioned characteristics occurred in the subtrochanteric region, which would be an unusual site for a bowed AFF, and it was demonstrated histologically to have biological activity at the fracture site, suggesting a stress fracture. Furthermore, CT/FEA revealed that tensile stress distribution changed proximally as load axis was shifted laterally according to correction of lower limb alignment by TKA.

CONCLUSION

Orthopedic surgeons should recognize the presence of TKA-associated periprosthetic AFF caused by various factors including specific drugs, bowing deformity, and lower limb alignment. X-rays of the full-length femurs should be checked regularly after TKA, especially in patients with bowed femurs or long-term exposure to specific drugs.

Low Risk of Fracture Using a Cementless Triple-tapered Collared Femoral Stem with Automated Impaction in Direct Anterior Approach Total Hip Arthroplasty

INTRODUCTION

Direct anterior approach (DAA) total hip arthroplasty (THA) has been associated with increased periprosthetic femoral fracture (PFF) risk. The aim of our study was to evaluate the fracture risk utilizing a triple tapered, collared stem with automated impaction through the anterior approach.

METHODS

We retrospectively reviewed consecutive DAA THA procedures at a single institution performed by four experienced DAA THA surgeons between 2019 and 2021. We collected data on age, sex, body mass index, preoperative diagnosis, and intraoperative and early postoperative PFF within 6 weeks postoperatively. Preoperative radiographs were evaluated to determine femoral neck-shaft angle and Dorr classification. We used Wilcoxon Rank sum or Chi-square tests to assess differences between patients who did and did not have PFF. We also evaluated potential risk factors for PFF in unadjusted and adjusted regression analyses. In all, 24 PFFs (1.6%) occurred. There were eighteen fractures (1.2%) recognized and managed intraoperatively (15 calcar, 2 greater trochanter, 1 posterior cortical). There were six PFFs (0.4%) identified postoperatively (5 greater trochanter, 1 diaphyseal), of which 1 required a revision surgery.

RESULTS

Identified risk factors for fracture in adjusted regression models included women (Odds Ratio (OR)=2.76, P=0.047), preoperative coxa valga (OR= 4.54, P=0.005), and coxa vara (OR=2.85, P=0.03).

CONCLUSION

The incidence of periprosthetic femoral fractures is low using a triple tapered, collared cementless femoral stem with automated impaction through the DAA. Our findings agree with previous reports that have demonstrated women and preoperative valgus neck angle are risk factors for PFF.

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.

Treatment Algorithm of Periprosthetic Femoral Fracturens

Introduction. The ever-expanding indications for total hip arthroplasty are leading to more implants being placed in younger as well as in older patients with high functional demand. Also, prolonged life expectancy is contributing to an overall increment of periprosthetic femoral fractures. The Vancouver classification has been the most used for guiding the surgeon choice since its proposal in 1995. Fractures occurring over a hip femoral implant can be divided into intra-operative and post-operative PFFs, and their treatment depends on factors that may severely affect the outcome: level of fracture, implant stability, quality of bone stock, patients' functional demand, age and comorbidities, and surgeon expertise. There are many different treatment techniques available which include osteosynthesis and revision surgery or a combination of both. The goals of surgical treatment are patients' early mobilization, restoration of anatomical alignment and length with a stable prosthesis and maintenance of bone stock. Significance. The aim of this review is to describe the state-of-the-art treatment and outcomes in the management of PFFs. We performed a systematic literature review of studies reporting on the management of PFFs around hip stems and inter-prosthetic fractures identifying 45 manuscripts eligible for the analysis. Conclusions. PFFs present peculiar characteristic that must be considered and special features that must be addressed. Their management is complex due to the extreme variability of stem designs, the possibility of having cemented or uncemented stems, the difficulty in identifying the "real" level of the fracture and the actual stability of the stem. As a result, the definition of a standardized treatment is unlikely, thereby high expertise is fundamental for the surgical management of PPFs, so this kind of fractures should be treated only in specialized centres with both high volume of revision joint arthroplasty and trauma surgery.

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.

Combined Surgical and Medical Treatment for Vancouver B1 and C Periprosthetic Femoral Fractures: A Proposal of a Therapeutic Algorithm While Retaining the Original Stable Stem

INTRODUCTION

There is lack of consensus regarding best operative fixation strategy for periprosthetic femoral fractures (PFFs) around a stable stem. Evidence exists that some patterns of fracture around a stable stem are better treated with revision surgery than with standard fixation. Anyway, a more aggressive surgical procedure together with medical treatment could allow for stem retention, and reduced risk of nonunion/hardware failure, even in these cases.

SIGNIFICANCE

This paper is placed in a broader context of lack of studies on the matter, and its aim is to shed some light on the management of PFFs around a stable stem, when peculiar mechanical and biological aspects are present.

RESULTS

Based on our casuistry in the treatment of nonunions after PFF successfully treated with original stem retention, and on review of Literature about risk factors for fixation failure, an algorithm is proposed that can guide in choosing the ideal surgical technique even for first-time PFFs with a stable stem, without resorting to revision. Mechanical (major and minor) and biological (local and systemic) factors that may influence fracture healing, leading to nonunion and hardware failure, and subsequent need for re-operation, are considered. The proposed surgical technique consists of rigid fixation with absolute stability (using a plate and structural allograft) plus local biological support (structural allograft and autologous bone marrow concentrate over a platelet-rich plasma-based scaffold) at fracture site. Systemic anabolic treatment (Teriparatide) is also administered in the post-operative period.

CONCLUSION

Mechanical factors are not the only issues to be considered when choosing the surgical approach to PFFs over a stable stem. Systemic and local biological conditions should be taken into account, as well. A therapeutic algorithm is proposed, given the prosthetic stem to be stable, considering mechanical and biological criteria.

Revision rate is higher in patients with periprosthetic femur fractures following revision arthroplasty in comparison with ORIF following our algorithm: a two-center 1 analysis of 129 patients

Purpose

Effective therapy of periprosthetic femur fractures of the hip (PPF) are challenging due to patients’ frailty and complexity of fracture patterns. The aim of this cohort study was to analyze the radiological and functional outcome following PPF.

Methods

A retrospective, multicenter study in the period 2009–2019 of patients with PPF at two level I trauma centers in Germany was performed. PPF were classified according to the Vancouver classification system. Demographic data, American Society of Anesthesiologists (ASA) classification, type of surgery, complications, and reoperation rate were obtained from patient records. The functional outcome was assessed by the modified Harris-Hip Score (mHHS), general health using the EQ-5D, and radiological outcome by Beals & Tower (B&T) criteria.

Results

A total of 129 patients with a mean age of 79 years (range 43–102) were included. 70% of all patients were female and 68% of the patients had an ASA score ≥ 3. 20 patients suffered from a Vancouver A, 90 from a Vancouver B and 19 from a Vancouver C fracture. 14% of the patients died within the first 2 years after surgery. The reoperation rate after open reduction and internal fixation (ORIF) (n = 60) was 8% and after revision arthroplasty (RA) (n = 47) 30% (OR 3.4, 95% CI [1.21–10.2]). Mean mHHS (n = 32) was 53 ± 19.4 and EQ-VAS was 50 ± 24.6. According to B&T criteria, 82% of patients treated with ORIF (n = 17) and 62% after RA (n = 13) showed an excellent outcome.

Conclusion

Patients with a PPF of the hip are elderly and at increased operative risk. In cases with a stable prosthesis, ORIF provides good radiological outcome with low reoperation rates. In case of RA, the risk for revision surgery is higher.