Interprosthetic femoral fractures: proposed new classification system and treatment algorithm

The History of Classification Systems for Periprosthetic Femoral Fractures: A Literature Review

Periprosthetic femoral fractures (PPFFs) following total hip arthroplasty (THA) present a significant clinical challenge due to their increasing incidence with an aging population and evolving surgical practices. Historically, classifications were primarily based on anatomical fracture location, the stability of the implant, and bone quality surrounding the implant. We critically analyzed 25 classification systems, highlighting the emergence and adaptations of key systems such as the Vancouver classification system (VCS) and the Unified classification system (UCS), which are lauded for their simplicity and effectiveness yet require further refinement. VCS, developed in 1995, categorizes fractures based on the site, implant stability, and bone quality, and remains widely used due to its robust applicability across different clinical settings. Introduced in 2014, UCS expands the VCS to encompass all periprosthetic fractures with additional fracture types, aiming for a universal application. Despite their widespread adoption, these systems exhibit shortcomings, including the incomplete inclusion of all PPFF types and the imprecise assessment of implant stability and surrounding bone loss. These gaps can result in misclassification and suboptimal treatment outcomes. This paper suggests the necessity for ongoing improvements in classification systems to include emerging fracture types and refined diagnostic criteria, ensuring that they remain relevant to contemporary orthopedic practices and continue to facilitate the precise tailoring of treatment to patient-specific circumstances. This comprehensive historical review serves as a foundation for future innovations in classification systems, ultimately aiming to standardize PPFF treatment and improve patient prognosis.

[Treatment aspects of interprosthetic femur fractures-retrospective analysis of 70 patients]

BACKGROUND

Interprosthetic femur fractures (IFF) are rare injuries, whose surgical treatment is basically with osteosynthesis or revision arthroplasty. Various therapy algorithms have been proposed based on very small study collectives. Factors influencing the outcome are not known.

OBJECTIVES

The aim of the retrospective monocentric study is to derive a treatment algorithm based on a large number of cases and to identify factors influencing the outcome.

MATERIALS AND METHODS

Between 2006 and 2020, 70 IFF were identified. The surgical treatment comprised 38 osteosyntheses, 30 revision arthroplasties and 2 amputations. With classification and time to surgery, 69 perioperative variables were recorded. General and operative complications, as well as mortality, were determined in the follow-up period of 1 year.

RESULTS

ASA and Charlson score correlated with 1‑year-mortality. In addition, preoperatively increased CRP levels, reduced hemoglobin and the CHA2DS2-VASc score were identified as factors influencing mortality. Surgery within 24 h showed a trend towards fewer general complications. Transferred patients indicated an increased mortality. Based on classification according to Pires et al. or Füchtmeier et al. no clear treatment decision could be made. Relevant criteria for the surgical treatment were fracture localization, implant stability, bone vitality, anchoring possibility of the revision stem, as well as general condition of the patient.

CONCLUSIONS

The identified factors influencing the outcome correspond to those of patients with hip fractures. IFF should be treated timely. A treatment path was developed on the basis of the largest patient group to date.

Interprosthetic and interimplant femoral fractures: is bone strut allograft augmentation with ORIF a validity alternative solution in elderly?

BACKGROUND

Nowadays orthopedic surgeons have a new challenge to treat the interimplants fractures. Although fixation strategies exist for periprosthetic hip and knee fractures, there is no standard of care regarding the more complex interprosthetic and interimplants fractures.

OBJECTIVE

The aim of our study is targeting the focus on the bone strut grafting to avoid the metal hardware failure and to achieve the bone healing in these injuries.

METHODS

A prospective case note review of all interprosthetic or interimplants femoral fractures admitted to our trauma center. There were 11 patients (2 males and 9 females) with a mean age over 85 years old. We treated all the patients by ORIF and medial graft strut allograft to reduce the main complication leading to re-operations and morbidity or mortality is the nonunion or delayed union. The criteria to evaluate the patients during the follow-up were: the survival and complication after the surgery; the objective quality of life measured by Activities of Daily Living Score (ADL). The bone healing was measured by X-rays control as the alignment was measured by radiographic UNION SCORE, and postoperative complications.

RESULTS

All the patients reduced their ADL. In the most of cases we had a good x-rays reduction. We had not: No nonunion or Not delayed union. All patients died within 2 years from the surgery but not due by surgical complications.

CONCLUSIONS

According us, the purpose of this surgery is to limit comorbidities and early mortality not to improve optimal restoration of lower limb function.

A systematic review of the surgical outcomes of interprosthetic femur fractures

Background

Interprosthetic femur fractures (IFFs) are rare, but the treatment is challenging. Currently, there are many treatment methods used in practice, but an updated systematic review of comparison of common different surgical outcomes has not been thoroughly inspected.

Methods

A systematic review of retrospective studies was conducted. The resource databases of PubMed, Cochrane, and Embase were searched using a combination of the keywords involving IFFs and surgical outcomes from inception through June 2021. Data collected included patient demographics, intraoperative data, and postoperative outcomes. Outcomes were measured based on healing time, revision rate, complication rate, and functional scores.

Results

Forty studies were included for review with a total of 508 patients. Average reported age of patients was 78.7 years old and 403 (79.3%) were females. Overall union rate was 74.0% with 376 of 508 patients achieving fracture union after primary treatment of IFF. Only 271 patients had reported healing times of fractures with a mean of 5.15 months. The plate, prosthetic revision, nail/rod, and external fixator groups had mean healing times of 4.69, 8.73, 6.5, and 5.1 months, respectively. Revision rates were highest in the femur replacement treatment group with 9 (32.1%) patients needing at least one reoperation surgery for any reason. Overall, hardware failure and non-unions were the most reported complications in treatment of IFFs. Postoperative functional outcome scores were available for 242 patients. Harris Hip Scores for the plate, revision, replacement, nail/rod, and plate + revision groups were 76.84, 77.14, 69.9, 77, and 78.4, respectively.

Conclusion

Each treatment method should be carefully considered by the surgeon depending on the patient. Locking plate was the most common method for the treatment of the patients with IFFs. Half of them combined with cerclage wires/cables. Around two thirds' patients could achieve union with the fastest mean healing time around 4.69 months. Other less common methods included prosthetic revision, femur replacement, nail/rod, external fixator, etc. A small number of patients treated with Ilizarov external fixator, and it has proven to be a viable option with few complications and high union rates.

Interprosthetic Femur Fractures: A Review Article

➢

The prevalence of interprosthetic femur fractures (IFFs) is rising with the aging population and increased prevalence of total joint arthroplasty.

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IFFs have high rates of complications and high associated morbidity and mortality.

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The main treatment methods available for IFFs include plate fixation, intramedullary nailing, combined plate fixation and intramedullary nailing, and revision arthroplasty including partial and total femur replacement.

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There have been several proposed classification systems and at least 1 proposed treatment algorithm for IFFs; however, there is no consensus.

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Whichever treatment option is chosen, goals of surgery should include preservation of blood supply, restoration of length, alignment, rotation, and sufficient stabilization to allow for early mobilization.

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.

Periprosthetic femoral fracture type and location are influenced by the presence of an ipsilateral knee arthroplasty implant: A case-control study of 84 interprosthetic femoral fractures

BACKGROUND

This multicentre case-control study compares Vancouver Classification System (VCS) grade and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) fracture type in interprosthetic femoral fractures (IPFFs) between primary total hip arthroplasty (THA) and ipsilateral total knee arthroplasty (TKA) to periprosthetic femoral fracture (PFF) without ipsilateral TKA.

METHODS

Data were collected following institutional approval. Eighty-four IPFFs were assessed for VCS grade and AO/OTA type. Each IPFF case (84) was matched to five PFF controls (360) by age, gender and stem fixation philosophy (SMD<0.1). VCS grade and AO/OTA type were compared between the IPFF and PFF groups using weighted proportions and medians.

RESULTS

Median (IQR) age of IPFF patients was 81.75 (76.57-85.33) years and 61 (72.6%) were female. The commonest VCS grade was B1 (34, 40.5%). The commonest AO/OTA type was spiral (51.8% of VCS B fractures; 50.0% of VCS C fractures). A greater proportion of fractures occurred distal to the stem in IPFF patients versus PFF patients (33.3% versus 18.2%, p = 0.003). VCS grade was significantly different between groups (p = 0.015). For VCS C fractures, twice as many AO/OTA transverse and wedge fractures occurred in the IPFF group compared to the PFF group (25.0% versus 12.6% and 7.1% versus 3.3%, respectively) although the overall difference was not statistically significant (p = 0.407).

CONCLUSION

The presence of an ipsilateral TKA affects the location of PFF with more fractures occurring distal to the stem. A greater proportion of bending type fractures occurred when an ipsilateral TKA was present. These unstable fractures often require more complex surgery.

Direct medical costs of interprosthetic femoral fracture treatment: A cohort analysis

INTRODUCTION

Periprosthetic femoral fractures (PPFs) represent a challenging clinical problem with a fast-rising incidence. Interprosthetic fractures (IPFs) represent one of its most difficult variants. There is a paucity of data regarding the financial burden of PPFs, and none for IPFs. This study aims to estimate the direct medical cost of the surgical treatment of IPFs in NHS, and analyse the factors influencing this when using different methods of surgical treatment.

METHODS

A cohort of patients with IPFs treated in a single academic unit over a period of 8-years with different surgical methods was studied. In-hospital details, as well as outpatient follow-up data, were gathered relevant to their clinical and radiological outcome until discharge. Local and national NHS data were acquired from the financial department, as well as industry-related resources. The economic analysis was structured as a cost identification analysis (CIA) of the overall cohort, but also as a comparative best-case scenario (uncomplicated course till discharge) comparison between the 3 main different management strategies (a) revision arthroplasty (RTHA), b) plate fixation (ORIF), c) combination of implants (COMBO).

RESULTS

Data from 28 patients (22 females) with IPFs were analysed with a median age of 78.4 years. The overall direct medical cost of treating this cohort of patients was £468,330, with a median of £15.625 (range £10,128 to 33,060). Comparing the three different surgical modalities, the median cost in groups a, b, and c was £20,793 (range £12,110 to £24,116), £12,979 (range £10,128 to £20,555), and £22,316 (range £10,938 to £23,081) respectively. In all groups, the 2/3 of the identified costs were relevant to the inpatient stay. Transfusions were the highest (3 units of cRBC on average) to the patients that received a revision THA vs the other two groups (p=0.022). There was statistically significant higher mean overall cost between the RTHA and the ORIF groups (£19,453 vs. £14,201, p=0.0242), but not when compared with the COMBO cases (£19,453 vs. £18,788, p=0.86).

CONCLUSION

The first cost identification study and "best case scenario" comparative analysis for IPFs demonstrated a significant overall direct medical cost, when managing these complex fractures with variable contemporary techniques. Evidence based reimbursement strategies should be developed to allow the sustainability of the clinical service we offer in this challenging patient population.

Interprosthetic femoral fractures managed with modern distal femoral locking plates: 10 years' experience at a UK major trauma centre

INTRODUCTION

Interprosthetic femoral fractures (IFF) are rare but increasing with an ageing population. Operative management is challenging and there is currently a paucity of outcome data in literature. The purpose of this study was to evaluate outcomes of IFFs managed with modern distal femoral locking plates, in a larger sample size than previously published.

METHOD

This retrospective study reviewed 49 closed IFFs in 48 patients at a major trauma center from 2009 to 2019 occurring between previous total hip arthroplasty (n=38), hemi hip arthroplasty (n=3), dynamic hip screw (n=6) or cephalomedullary nail (n=2) and total knee arthroplasty. They were managed with Minimally Invasive Plate Osteosynthesis (MIPO) employing modern biological fixation techniques and stabilised with VA-LCP Condylar (Synthes; n=28) or Peri-Loc (S&N; n=21) plate. Clinical and radiographic outcomes were measured.

RESULTS

The majority of fractures were in female patients (80%), who were elderly (average 83 years), and comorbid (55% ASA grade 3 or 4). Most fractures were Pires type IIA and OTA/AO type 33A. Average plate spanning femur was 16 holes, with average working length of 6 holes. 86% had unrestricted weight bearing immediately post operatively. 31 fractures reached radiological (n=25) or clinical (n=6) union. 13 patients died with 2 lost to follow up. There were 3 non-unions, with implant failure occurring before 4 months in all 3. We present a union rate of 91% (n=31/34).

CONCLUSION

IFFs are occurring with increasing frequency in a frail elderly population. In patients with IFFs, MIPO and biological fixation techniques using modern distal femoral locking plates can achieve high rate of union when combined with immediate unrestricted weight bearing postoperatively.

[Complex periprosthetic combination injury : Periprosthetic, interprosthetic and patellar fractures in an aged person]

Due to the demographic trend and the rising number of implanted joint prostheses, the incidence of periprosthetic fractures is going to increase in the future.This article describes the case of an aged person with a very unusual combination of periprosthetic and interprosthetic fractures with an inlying cementless total hip replacement and total knee replacement.By complying with the treatment strategies recommended for the respective individual injuries and the use of a geriatric trauma algorithm, it is even possible to successfully treat such a case.In addition to the unusual injury constellation, especially the surgical and geriatric traumatological treatment strategy are presented.

Periprosthetic hip fractures: an update into their management and clinical outcomes

The Vancouver classification is still a useful tool of communication and stratification of periprosthetic fractures, but besides the three parameters it considers, clinicians should also assess additional factors.

Combined advanced trauma and arthroplasty skills must be available in departments managing these complex injuries.

Preoperative confirmation of the THA (total hip arthroplasty) stability is sometimes challenging. The most reliable method remains intraoperative assessment during surgical exploration of the hip joint.

Certain B1 fractures will benefit from revision surgery, whilst some B2 fractures can be effectively managed with osteosynthesis, especially in frail patients.

Less invasive osteosynthesis, balanced plate–bone constructs, composite implant solutions, together with an appropriate reduction of the limb axis, rotation and length are critical for a successful fixation and uneventful fracture healing.

Cite this article: EFORT Open Rev 2021;6:75-92. DOI: 10.1302/2058-5241.6.200050

Postoperative periprosthetic femoral fracture around total hip replacements: current concepts and clinical outcomes

The rising incidence of postoperative periprosthetic femoral fracture (PFF) presents a significant clinical and economic burden.

A detailed understanding of risk factors is required in order to guide preventative strategies.

Different femoral stems have unique characteristics and management strategies must be tailored appropriately.

Consensus regarding treatment of PFFs around well-fixed stems is lacking, but revision surgery may provide more predictable outcomes for unstable fracture patterns and fractures around polished taper-slip stems.

Future research should focus on implant-related risk factors, treatment of concurrent metabolic bone disease and the use of large endoprostheses.

Cite this article: EFORT Open Rev 2020;5:558-567. DOI: 10.1302/2058-5241.5.200003

[Periprosthetic fractures: basics, classification and treatment principles]

Periprosthetic fractures (PPFx) are becoming an increasingly important topic in orthopedics and trauma surgery due to the rising number of endoprosthetic joint replacements. The recently published unified classification system (UCS) has replaced numerous historical classification systems and can be applied to all PPFx regardless of the bone or joint involved. The treatment of PPFx requires individual therapeutic concepts taking patient-dependent and patient-independent factors into consideration. The conservative treatment of PPFx is only justified in exceptional situations. In contrast, the choice between operative treatment and deciding between osteosynthesis or revision arthroplasty is particularly based on the assessment of the implant stability. In order to achieve fracture consolidation and also a good functional outcome, knowledge of the basic biomechanical principles of operative (osteosynthesis or endoprosthesis) treatment of periprosthetic fractures is necessary.

Interprosthetic femoral fractures: management challenges

Interprosthetic femur fractures are a rare but serious complication following total hip and knee arthroplasty. Classification systems have focused not only on diagnosis but also on treatment algorithm. Critical to the evaluation of patients with these fractures are an assessment of fracture location, bone quality, and the presence of stemmed implants. The gold standard for fracture fixation is locked plating with bicortical and unicortical screws, supplemented with wires or cables as needed. For patients with compromised bone stock or insufficient bony area for fixation, allograft augmentation with struts or interprosthetic sleeves may be used. For fractures with severe bone loss, conversion to a megaprosthesis or total femur replacement may be warranted.

Outcome of surgical treatment of inter prosthetic fractures: A case series

INTRODUCTION

Interprosthetic fractures occur between a total knee replacement and a femoral stem of either a hemiarthroplasty or total hip replacement. The number of interprosthetic fractures will increase as the number of joint replacements rises. There is currently a paucity of literature looking at the outcomes of interprosthetic fractures. Therefore, we performed a retrospective study to: (1) determine fracture union in patients following surgical treatment of a femoral interprosthetic fracture, (2) measure outcomes included mortality and complications.

HYPOTHESIS

Favoring bone fixation instead of prosthetic revision gives an acceptable rate of reoperation.

MATERIALS AND METHODS

A retrospective case note review of all interprosthetic femoral fractures admitted to a tertiary trauma centre over a 7-year period. There were 24 patients (4 males and 20 females) with a mean age of 82.3 (65-98). The initial operative procedure was a total hip replacement (THR) and a total knee replacement (TKR) in 19 patients, one THR and revision TKR, four hip hemiarthroplasty and TKR. There were 23 cemented femoral stems, and 1 uncemented femoral stem. The median time to surgery was 84hours. The median length of hospital stay was 16 days. Nineteen patients underwent open reduction internal fixation and 1 of these used a strut graft. Two patients underwent revision knee replacements and 3 underwent a revision hip replacement. All patients had at least 2 years clinical follow-up.

RESULTS

One patient died within 30 days of fracture, leaving 23 patients to assess bone union. Another patient died within 1 year of fracture. Three out of 24 patients (12.5%) suffered a complication that required further surgery. The fracture united in 19/23 (82.6%) of patients and the 2-year mortality rate was 5/24 (20.8%).

DISCUSSION

Interprosthetic fractures are complex fractures occurring in elderly patients with multiple medical comorbidities. Whenever possible bone fixation instead of prostehtic revision give a low rate of complication and reoperation. The surgical treatments are complex, but with a well-performed surgical technique and an adequate rehabilitation program can result in satisfactory outcomes.

LEVEL OF EVIDENCE

IV, retrospective case series.

Interprosthetic femoral fractures: Morbidity and mortality in a retrospective, multicenter study

INTRODUCTION

Interprosthetic femoral fractures (IFF) are becoming more frequent; however they have not been the subject of many publications and the largest study on this topic includes only 30 cases. The complication rate and clinical outcomes have only been evaluated in small case series. This led us to conduct a retrospective, multicenter, observational study in IFF patients with at least 12 months' follow-up to (1) determine the mortality and morbidity (2) determine the clinical and radiological outcomes and (3) identify elements of the treatment indications.

HYPOTHESIS

The morbidity and mortality rates will be comparable to those in recent studies on this topic.

MATERIALS AND METHODS

The study included 51 patients (49 women, 2 men) with a mean age of 82.8±9.2 years [55-97], a mean Parker score of 4.9±2.4 and a mean Katz score of 4.4±1.4 who had suffered an IFF between 2009 and 2015. According to the SoFCOT modifications of the Vancouver classification, 30 fractures were interprosthetic in the shaft segment where there were no implants (19 double C and 11 type D (corresponding to a type C with less than two diaphysis widths between the extension stems of the hip and knee implants)) while 21 were periprosthetic, with 12 around the THA (11 B1 and 1 B3) and 9 around the TKA (8 B1 and 1 B3). One patient was treated conservatively with an external fixator but died the next day, 2 patients received a new total hip arthroplasty and 47 underwent plate fixation of their fracture (one patient was treated non-operatively because of poor medical condition).

RESULTS

One patient was lost to follow-up, and nine died during the first 6 months. Six early surgical site complications occurred and 13 general ones. Within 1 year of the IFF, there were six mechanical complications, two surgical site infections and two cases of loosening. The mean follow-up was 27.6±17.2 months. The mean time to union was 19.25±8.8 weeks. The mean final Parker score was 3.37±2.6 and the mean Katz score was 2.98±1.8; both were significantly lower than the initial scores. Six patients died between months 12 and 50. The overall mortality at the final review was 31% (16/51) with a median survival of 3.45 years.

DISCUSSION

Our hypothesis was not confirmed because the mortality and morbidity in our study were higher than in other published studies. In the six relevant studies identified, the surgical site infection rate was 12.3%, the major revision rate was 11.6% and the mortality rate was 6.5%. In our study, these values were 24%, 24% and 31%, respectively. These worse results may be explained by the very fragile nature of the studied population and the surgeons not following appropriate technical rules for fracture fixation.

LEVEL OF EVIDENCE

IV, Retrospective study.

One year after proximal or distal periprosthetic fracture of the femur -two conditions with divergent outcomes?

INTRODUCTION

Arthroplasty of the hip and knee is 1 of the 20 most frequent operations in Germany. Periprosthetic fracture is one of the most feared complications following primary or revision arthroplasty. Present publication aims to analyse differences between patients with periprosthetic fracture around total knee arthroplasty (PFTKA) and patients with periprosthetic fracture around total hip arthroplasty (PFTHA) concerning demographics, clinical course, complications and return to pre-fracture mobility.

METHODS

Prospective single-centre observation study of periprosthetic femoral fractures with stable implants. Present subgroup analysis includes patients with PFTKA and PFTHA. All patients were treated with polyaxial angular stable plates using two standardized techniques: a minimally invasive percutaneous distal insertion technique and a mini-open technique. Data collection included implant- and operation-related information as well as demographics, clinical course, complications and return to pre-fracture mobility. Data were collected during a 12-month follow-up.

RESULTS

We were able to analyse the data of 73 patients. The PFTKA group had 37 patients with a mean age of 76 ± 10 years; 88% were female. After 1 year, 3 patients in this cohort had died; 68% of survivors had reached their pre-fracture mobility; 22% had undergone operative revisions for various reasons. The PFTHA cohort included 36 patients with a mean age of 80 ± 13 years, 72% were female. After 1 year, 9 patients had died in this cohort, 42% of survivors had reached their pre-fracture mobility. Non-operative complications occurred for 16% in the PFTKA group and 64% in the PFTHA group (p < 0.001). 11% had undergone operative revisions for various reasons, among them, two cases of nonunion but no primary infection.

CONCLUSION

On average, compared to the PFTHA patients, PFTKA patients were younger, underwent significantly lower rates of non-operative complications, had a tendency towards lower mortality, and returned to pre-fracture mobility at higher rates, although they tended to have more revisions when compared to treatment for PFTHA. Overall, when periprosthetic fractures of the femur were treated using polyaxial locking plate osteosynthesis, patients showed very low rates of nonunion and no primary infection.

Interprosthetic Fractures of the Femur

As the rate of hip and knee arthroplasty procedures increases, so will the rate of interprosthetic fractures. Several factors, including bone quality, bone quantity, and stability of the prosthetic components, play a role in determining the appropriate operative treatment. Patients with stable components should undergo reduction and internal fixation, while patients with loose components should undergo either revision arthroplasty, with or without additional fixation, or conversion to total femur replacement. Despite implant and technique advances, complications remain frequent. [Orthopedics. 2018; 41(1):e1-e7.].

Validation of a new classification system for interprosthetic femoral fractures

Interprosthetic femoral fracture (IFF) incidence is gradually increasing as the population is progressively ageing. However, treatment remains challenging due to several contributing factors, such as poor bone quality, patient comorbidities, small interprosthetic fragment, and prostheses instability. An effective and specific classification system is essential to optimize treatment management, therefore diminishing complication rates. This study aims to validate a previously described classification system for interprosthetic femoral fractures.

Management of Interprosthetic Femur Fractures

Femoral fractures between a total hip arthroplasty prosthesis and total knee arthroplasty prosthesis, also called interprosthetic fractures, are challenging clinical problems. The number of patients who have undergone ipsilateral primary or revision joint arthroplasty procedures in both the hip and the knee continues to rise, and the number of interprosthetic fractures is increasing, as well. The growing body of biomechanical and clinical literature on interprosthetic fractures reflects the increased frequency of and interest in these injuries. Similar to the management of periprosthetic fractures, the management of interprosthetic fractures depends on the location of the fracture, the stability of the implant, and the ability to achieve stable fracture fixation. These factors are the basis of recently described classification systems and treatment strategies. In patients with stable implants, fracture fixation alone is performed. When the implant is loose, both revision arthroplasty and fracture fixation may be required to provide stability of the limb.

Clinical outcome of interprosthetic femoral fractures treated with polyaxial locking plates

INTRODUCTION

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are common procedures in the increasing older population. According to the AAOS, approximately 19,200 Americans are actually living with ipsilateral prosthetic hip and knee leading to 240 interprosthetic fractures annually. Few reviews and case reports give an idea of the obvious problem to achieve consolidation in interprosthetic fractures. Preconfigured plates have been shown to be superior compared with other treatments in patients with stable components. Utilization of internal fixators for interprosthetic fractures might be advantageous. The purpose of this study was to evaluate interprosthetic femoral fractures with polyaxial locking plate treatment in regard to surgical procedure, complications, and clinical outcome.

METHODS

Between 2005 and 2012, 143 patients underwent surgical treatment for periprosthetic femur fractures. Thirty-two fractures were identified as interprosthetic fractures. Five patients were excluded. Fractures were classified according to OTA/AO system, Vancouver, Rorabeck, Soenen and Pires. Trauma fellowship trained orthopaedic surgeons performed the surgeries using a NCB-construct (Zimmer Inc., Warshaw, IN). Plate choice was determined according to radiographic classification. Submuscular plate insertion was performed if possible. Complications were recorded concerning infection, union, fixation failure, and revision surgery.

RESULTS

Twenty-seven patients were identified. There were 92.6% females. Follow-up by regular outpatient clinic visits was 24 months. Surface replacements were found in 18 TKA. Nine patients had a stemmed femur component of their TKA. 89% healed after the index procedure. Three patients developed a nonunion with 1 construct leading to hardware failure. Previous revision THA or Pires/modified Vancouver classification did not influence nonunion formation, but all patients with nonunion formation were classified as AO/OTA type B (p=0.001). These fractures were treated with longer plates (p=0.015), but with similar working length (p=0.400). Plate design, additional cerclages, or submuscular insertion did not influence nonunion formation.

CONCLUSION

Interprosthetic fracture treatment remains challenging. NCB-locked plating can achieve satisfactory results. Additional soft tissue damage can be prevented by submuscular plate insertion. Treatment of type B fractures resulted in significantly greater nonunion rate. Therefore, consideration of the individual fracture type is essential to determine plate length, plate type, and additional bone grafting or BMP supplementation.

[Importance of revision- and tumor-endoprosthetics in the treatment of periprosthetic fractures of the lower extremity]

Periprosthetic fractures of hip and knee prostheses are gaining clinical significance due to the increasing numbers of of primary arthroplasties. Additionally, these fractures are often associated with poor bone quality or present in patients after multiple revision procedures and concomitant excessive bone defects precluding those patients to be adequately treated by conventional osteosynthesis. Revision implants provide a wide range of options for the treatment of these fractures in order to achieve good clinical results. In the acetabular region cavitary defects associated with periprosthetic fractures can be treated by the use of megacups. Extensive segmental defects and pelvic discontinuity necessitate the use of cups with additional iliac support or even customized implants. Proximal femoral fractures can usually be fixed with modular stems and diaphyseal anchorage. Periprosthetic knee joint fractures can be treated with revision implants with modular sleeves or augment-combinations allowing sufficient bridging of bony defects. Functional reconstruction or refixation of the extensor mechanism is of crucial importance.

What is new in distal femur periprosthetic fracture fixation?

Distal femoral periprosthetic fractures are on the rise. Increased mortality of these injuries is also evident from recent data. Their incidence and risk factors have been extensively reported in the past but new data are being available that merit attention. The increased incidence and the even higher projected incidence should direct the focus of future strategies to the education of surgeons, relevant capacity of hospital and reconfiguration of health care resources. New and potentially modifiable risk factors should be taken into consideration to the informed consent process and new studies should be developed to clarify the causative relationship of the new risk factors such as the peptic ulcer disease and the COPD. The main internal fixation techniques remain the lateral locking plating and the retrograde intramedullary nailing. New techniques in plating are the supplementary medial plate in selected cases and the far cortical locking. Nailing is considered a valid option especially in fractures located well above the anterior flange of the femoral component of the arthroplasty. Results and outcomes from good quality studies are still sparse regarding the comparison between plating and nailing. Interprosthetic fractures constitute an entity that is lately gaining considerable attention. The best method of management of these injuries is still evolving with considerable amount of work being done in the clinical and biomechanical level.

The outcome of Polyax Locked Plating System for fixation distal femoral non-implant related and periprosthetic fractures

The objective of this study was to report on the safety, efficacy and clinical outcomes of the Polyax Locked Plating System (Biomet, Warsaw, IN, USA) in the management of acute (non-implant related and periprosthetic) distal femoral fractures. We retrospectively reviewed 71 patients with 73 distal femoral fractures. Thirty-three of the included fractures occurred around previously placed implants. The average patients' age was 67 years (range 18-98). There were 7 early postoperative complications (9.5%) including one deep surgical site infection, 2 pulmonary embolisms and 4 urinary or respiratory infections. At final follow-up (mean 12, range 9-55 months) all fractures progressed to clinical and radiological union. However, major revision surgery for healing problems was required in 5 cases (6.8%) and minor in 3 cases (4.1%). The average time to healing was 6 (range 3-23) months. Angulation less than 5 degrees in any plane was observed in 66 cases (89.7%), within 5-10 degrees in 5 cases (7.3%) and within 10-15 degrees in 2 cases (2.9%). The mean pre-injury and final follow-up values of Glasgow Outcome Scale were 1.5(1-3) and 1.7(1-3) respectively. Overall 61 patients (83.53%) retained their pre-injury activity status. The Polyax Locked Plating System offers a safe and efficient fixation in distal femoral fractures.