Plate Positioning in Periprosthetic or Interprosthetic Femur Fractures With Stable Implants-A Biomechanical Study

Postoperative early weight-bearing using double plating for periprosthetic, interprosthetic, and interimplant distal femur fractures following total knee arthroplasty: A report of three cases

Background

Distal femur fractures (DFFs) following total knee arthroplasty (TKA) in older patients often require prolonged non-weight-bearing, thereby decreasing their activities of daily living (ADL) and increasing mortality. This report clarifies early weight-bearing safety and utility by using double-plate fixation on medial and lateral sides (LM180 double-plate fixation) for DFFs following TKA.

Case presentation

Three cases of Su Type III periprosthetic, interprosthetic, and interimplant DFFs following TKA, where bone stock was limited, were treated with LM180 double-plate fixation using locking plates through medial and lateral incisions on the distal femur. In interprosthetic and interimplant DFF cases, the proximal section was secured by overlapping the lateral plate +/- medial plate with the proximal femur stem of the intramedullary nail by using monocortical screws and cerclage wires. Early postoperative partial weight-bearing was recommended, and full weight-bearing was allowed 4-5 weeks postoperation. All cases regained independent walking without hardware failure. Average ADL scores, namely, Barthel index (BI) and functional independence measure (FIM), were recovered to 85/100 and 114.7/126, respectively, approaching near-normal values.

Conclusion

LM180 double-plate fixation for DFFs such as Su Type III periprosthetic, Vancouver type C interprosthetic, and interimplant DFFs following TKA with limited bone stock can be used to achieve early weight-bearing without fixation failure and help maintain ADL.

Treatment of Periprosthetic Hip Fractures Vancouver B1 and C: The Significance of Bicortical Fixation. A Bicentric Study Comparing Two Osteosynthesis Systems

INTRODUCTION The incidence of periprosthetic fractures (PFFs) is estimated to range from 0.1% to 4.1%1, due to the increasing prevalence of joint arthroplasties, coupled with an aging population. Numerous risk factors, including advanced age (>80 years), female gender, implant type, prior diagnoses of osteonecrosis and rheumatoid arthritis, revision surgery, aseptic stem mobilization, and the use of non-cemented stems, have been identified. Survivors of periprosthetic fractures often experience functional deterioration, facing a fourfold higher risk of hospitalization for postoperative complications compared to patients undergoing primary implantation, especially in the first postoperative year. MATERIALS AND METHODS Between 2018 and 2022, at the Maggiore Hospitals in Bologna and the San Matteo Policlinic in Pavia, we performed osteosynthesis on 84 patients with periprosthetic fractures of Vancouver type B1 or C. In 38 patients, we employed angular stable plates with the Zimmer Biomet NCB-PP® system. In 46 patients, we utilized INTRAUMA plates: DF distal femur and PFF proximal. Relevant postoperative follow-up outcomes considered included reintervention, infectious complications, radiographic healing, and functional recovery, with reference to changes in the Glasgow Outcome Scale (GOS) and the Harris Hip Score (HHS). All patients underwent clinical and radiographic evaluations during the follow-up period, averaging 28 months (range: 12-48 months), with a minimum follow-up duration of 12 months. RESULTS At the 4-month postoperative assessment, 71% of patients maintained their preoperative functional level, 19% experienced a 1-point GOS scale drop, and 10% died (GOS 5). The average HHS at 4 months was 80.2 points (range: 65-90). At the 6-month follow-up, 98.2% of patients achieved complete healing on radiographic examination. Only 1 patient (1.2%) developed a pseudoarthrosis site with synthesis device rupture. Only 1 patient (1.2%) required additional surgical treatment 2 years later due to the development of un aseptic perisynthetic fluid collection, while the remaining 5 patients (6%) who developed complications benefited from conservative treatment: 4 patients (3.6%) with infectious complications were treated with intravenous antibiotics. In the 2 patients (2.3%) with mobilization or rupture of synthesis devices, clinical and radiographic monitoring was opted for. 8 patients (10.7%) died: one 48 hours after the surgery, and the other 7 more than one month after the surgery. CONCLUSION Our clinical findings align with to existing scientific literature on periprosthetic fractures (B1 and C according to Vancouver classification). Moreover, good stability has been guaranteed at the radiological follow up by Zimmer Biomet NCB-PP® and INTRAUMA DF distal femur and PFF proximal plates. The locking construct allows for improved stability especially in osteoporotic bone.

Long locking plate combined with locking attachment plate in patients with periprosthetic femoral fracture around ipsilateral stem after total knee arthroplasty

BACKGROUND

The purpose of this study was to introduce the surgical technique using long locking plate and locking attachment plate (LAP) in patient with periprosthetic femoral fracture around ipsilateral stem after total knee arthroplasty (TKA). Moreover, we sought to investigate the outcomes of this fixation technique and to propose a new subtype in the existing classification of periprosthetic femoral fractures.

METHODS

From January 2013 to January 2022, thirty-four consecutive periprosthetic femoral fractures around ipsilateral stem following TKA with minimum 1-year follow-up were enrolled in this study. Most cases were fixed with long-locking plate and LAP using the MIPO technique. For subgroup analysis, we classified patients with stemmed hip implant (group H) and stemmed knee implant (group K). Bone union, American Knee Society Score (AKSS) scale, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the Western Ontario and McMaster Universities Osteoarthritis Index for pain and function, and range of motion were investigated.

RESULTS

The number of group H and K were 24 patients (70.6%) and 10 patients (29.4%), respectively. The mean age at operation was 71.5 years (range, 65‒85 years), and the mean follow-up period was 27.5 months (range, 12‒72 months). Bone union was confirmed radiographically in all patients, and the mean union time was 4.9 months (range, 3.5‒6 months). There were no significant differences in radiographic and clinical outcomes between the groups.

CONCLUSIONS

Long-locking plate combined with LAP showed favorable radiographic and clinical outcomes in patients with periprosthetic femoral fracture around ipsilateral stem after TKA.

LEVEL OF EVIDENCE

Level IV, Retrospective Case Series.

Risk of Interprosthetic Femur Fracture Is Associated with Implant Spacing-A Biomechanical Study

BACKGROUND

Ipsilateral revision surgeries of total hip or knee arthroplasties due to periprosthetic fractures or implant loosening are becoming more frequent in aging populations. Implants in revision arthroplasty usually require long anchoring stems. Depending on the residual distance between two adjacent knee and hip implants, we assume that the risk of interprosthetic fractures increases with a reduction in the interprosthetic distance. The aim of the current study was to investigate the maximum strain within the femoral shaft between two ipsilateral implants tips.

METHODS

A simplified physical model consisting of synthetic bone tubes and metallic implant cylinders was constructed and the surface strains were measured using digital image correlation. The strain distribution on the femoral shaft was analyzed in 3-point- and 4-point-bending scenarios. The physical model was transferred to a finite element model to parametrically investigate the effects of the interprosthetic distance and the cortical thickness on maximum strain. Strain patterns for all parametric combinations were compared to the reference strain pattern of the bone without implants.

RESULTS

The presence of an implant reduced principal strain values but resulted in distinct strain peaks at the locations of the implant tips. A reduced interprosthetic distance and thinner cortices resulted in strain peaks of up to 180% compared to the reference. At low cortical thicknesses, the strain peaks increased exponentially with a decrease in the interprosthetic distance. An increasing cortical thickness reduced the peak strains at the implant tips.

CONCLUSIONS

A minimum interprosthetic distance of 10 mm seems to be crucial to avoid the accumulation of strain peaks caused by ipsilateral implant tips. Interprosthetic fracture management is more important in patients with reduced bone quality.

Interprosthetic Femur Fractures: A Review Article

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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.

Performance Assessment of Biocompatible Metals Used in the Treatment of Femoral Neck Fractures

Femoral neck fractures (FNFs) are among the most common types of hip fractures. Particularly in young patients, these fractures require adequate fixation. These fractures, which are prevalent in elderly patients, are usually treated with implant applications. In implant applications, it is possible to find many different fixation configurations with various implant materials. The purpose of this study is to investigate the effects of metallic implant materials on fixation performance in the application of cannulated screws in an inverted triangle (CSIT), which are most preferred by orthopedic surgeons. Therefore, a femur bone with a type 2 fracture was numerically modeled and performances of CSIT implants with different biocompatible metals were investigated over nonlinear finite-element analyses (FEA). Within the study, stainless steel (SS), pure titanium (pTi), titanium alloy (Ti6Al4V), cobalt–chromium alloy (Co–Cr), and magnesium alloy (WE43) materials, frequently used as biocompatible implant materials, were taken into consideration and their performances were evaluated under static, vibration, and fatigue analyses. Throughout the comparison of analysis results and an optimality indicator formula, the optimum material was found to be the Co–Cr alloy on the basis of considered performance characteristics.

The race for the classification of proximal periprosthetic femoral fractures : Vancouver vs Unified Classification System (UCS) - a systematic review

Background

Periprosthetic femoral fractures (PFFs) represent a major cause for surgical revision after hip arthroplasty with detrimental consequences for patients. The Vancouver classification has been traditionally used since its introduction in 1995. The Unified Classification System (UCS) was described in 2014, to widen the spectrum by aiming for a more comprehensive approach. The UCS also aimed to replace the Vancouver classification by expanding the idea of the Vancouver classification to the whole musculoskeletal apparatus. After introduction of the UCS, the question was raised, whether the UCS found its place in the field of analysing PFFs. Therefore, this systematic review was performed to investigate, the use of the UCS compared to the established Vancouver classification.

Methods

Medline was searched for reports published between 1 January 2016 and 31 November 2020, without language restriction. Included were original articles, irrespective of the level of evidence and case reports reporting on a PFF and using either the Vancouver or the UCS to classify the fractures. Excluded were reviews and systematic reviews.

Results

One hundred forty-six studies were included in the analysis. UCS has not been used in a single registry study, giving a pooled cohort size of 3299 patients, compared to 59,178 patients in studies using the Vancouver classification. Since 2016, one study using UCS was published in a top journal, compared to 37 studies using the Vancouver classification (p=0.29). During the study period, the number of yearly publications remained stagnant (p=0.899).

Conclusions

Despite valuable improvement and expansion of the latter UCS, to date, the Vancouver system clearly leads the field of classifying PFFs in the sense of the common use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05240-w.

Computational analysis of the effects of interprosthetic distance on normal and reduced cortical thickness femur models

Distal femoral fractures associated with the femoral stem in a well-fixed hip arthroplasty pose a risk of an interprosthetic fracture, the treatment of which is known as difficult. To effectively prevent and treat IP fractures, biomechanical effects must be demonstrated. We defined eight variations of the interprosthetic distance ranging from 48 mm overlap to 128 mm gap. Femoral geometries with normal and reduced cortical thickness were modeled to evaluate the effects of cortical thickness. In addition to the intact model, a total of 16 finite element models were analyzed under physiological boundary conditions. Maximum and minimum principal strains on the lateral and medial cortex surfaces were always found to be greater in models with reduced cortical thickness than in normal femurs. The model with 48 mm overlapping interprosthetic distance produced the least peak strain and the model with 16 mm interprosthetic gap produced the greatest strain with both normal and reduced cortical thickness. The screw holes produced local strain concentrations and increased the peak strains on the cortex surfaces, especially close to the stem tip. Statistically, a significant correlation (R² = 0.9483) was found between strain shielding and interprosthetic distance. Axial stiffness, interfragmentary shear motion, and maximum von-Mises stress on the distal plate showed a high correlation with the interprosthetic distance. It was concluded that the overlapping structures are superior to other fixations we analyzed in that they offer better mechanical stability and eliminates the local strain concentrations.

Static and dynamic examination of a locking plate in various setups for the stabilization of bone shaft fractures, including periprosthetic

Introduction: Hip and knee arthroplasty, formerly known as the “gold standard” in the treatment of articular cartilage damage, after a period of being highly popular, are changing the way they are perceived over time due to their related complications. The number of complications is directly proportional to the number of prostheses placed. This is the case of numerus arthroplasty surgeries, also involving other joints. Since there is no tissue compatibility between the metal prosthesis and the bone tissue, the former represents a negative biological element that hinders the healing of the fracture. Objective of the study: The study aims at addressing the following questions: 1. What is the elasticity of the fixation with a locking plate depending on the number of screws in both fragments, in the case of interfractural diastasis?, 2. What is the elasticity of the fixation with a locking plate depending on the number of screws in both fragments, in the case of fracture-on-fracture compression? 3. What is the difference in elasticity of the fixation using the cable system on a fracture with prosthesis?, 4. Determining the influence of different stabilization setups with the locking plate screws on the spacing of the fracture on the static and dynamic experimental model, 5. Is it possible to achieve elasticity of the stabilization stimulating bone union in a plate-based fixation, and when? Material and methods: The study was performed in the research laboratory of ChM. The subject of the study was the ChM 5.0 ChLP straight narrow compression locking plate with limited contact L-238, holes-15. The plate was mounted using ChM 3.5 locking screws: 5.0 ChLP 3.5 x 18T self-tapping screw and 5.0 ChLP 3.5 x 36T self-tapping screw. The test was carried out under static and dynamic conditions. Results and Conclusions: 1. The elasticity of the fixation with a locking plate at the interfractural diastasis is inversely proportional to the number of screws (plate deflection), 2. The elasticity of the fixation with a locking plate at the fracture-on-fracture compression is inversely proportional to the number of screws (fracture-on-fracture compression), 3. Application of the “cable system” on the fracture with prosthesis and the derotation screw optimizes the elasticity of the fixation and seems to be an optimal solution (in periprosthetic fractures), 4. Studies on the experimental static and dynamic model demonstrated that placing screws in all the openings of the plate is a restrained/clinically useless fixation. 5. The elasticity of the stabilization stimulating bone union can be obtained in the plate fixation supported by the "cable system".

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

The location of the fracture determines the better solution, osteosynthesis or revision, in periprosthetic femoral fractures

Purpose

Periprosthetic femoral fractures are difficult to treat, but few reports have included many periprosthetic femoral fractures. The purpose of this study was to investigate the trends and characteristics of a large number of periprosthetic femoral fractures and to determine the best treatment strategy for such fractures.

Methods

The fracture type according to the Vancouver classification, the stem fixation style of previous surgery, the elapsed time from previous surgery, and the treatment method for periprosthetic fractures of 51 patients with periprosthetic femoral fractures who were seen between 2006 and 2018 were investigated.

Results

The types of fractures according to the Vancouver classification were: type A 5.9%, type B1 47%, type B2 20%, type B3 2.0%, and type C 25%. Of the previous surgeries, 76% were cementless fixation, and 24% were cemented fixation. The mean duration from previous surgery to periprosthetic femoral fracture was 8 years and 7 months (1-358 months), and injury within 1 year from previous surgery was most commonly observed (24%). As treatment for periprosthetic femoral fractures, conservative treatment was performed in 8%, and surgery was performed in 92%. Of the surgery cases, 53% underwent osteosynthesis, and 39% underwent revision surgery. Of type B1 surgery cases, 58% were treated with osteosynthesis, and 33% underwent revision surgery, although type B1 had no stem loosening.

Conclusion

Many periprosthetic femoral fractures occurred within 1 year after the previous surgery. Therefore, preventive measures for periprosthetic femoral fractures should be started immediately after total hip replacement. In addition, revision surgery was performed even if the stem was not loosened in cases where it was judged that sufficient osteosynthesis could not be performed.

Periprosthetic fracture fixation of the femur following total hip arthroplasty: A review of biomechanical testing - Part II

BACKGROUND

Periprosthetic femoral fracture is a severe complication of total hip arthroplasty. A previous review published in 2011 summarised the biomechanical studies regarding periprosthetic femoral fracture and its fixation techniques. Since then, there have been several commercially available fracture plates designed specifically for the treatment of these fractures. However, several clinical studies still report failure of fixation treatments used for these fractures.

METHODS

The current literature on biomechanical models of periprosthetic femoral fracture fixation since 2010 to present is reviewed. The methodologies involved in the experimental and computational studies of periprosthetic femoral fracture fixation are described and compared with particular focus on the recent developments.

FINDINGS

Several issues raised in the previous review paper have been addressed by current studies; such as validating computational results with experimental data. Current experimental studies are more sophisticated in design. Computational studies have been useful in studying fixation methods or conditions (such as bone healing) that are difficult to study in vivo or in vitro. However, a few issues still remain and are highlighted.

INTERPRETATION

The increased use of computational studies in investigating periprosthetic femoral fracture fixation techniques has proven valuable. Existing protocols for testing periprosthetic femoral fracture fixation need to be standardised in order to make more direct and conclusive comparisons between studies. A consensus on the 'optimum' treatment method for periprosthetic femoral fracture fixation needs to be achieved.

Optimal plate fixation of distal femoral fractures in the presence of a well fixed cemented hip arthroplasty femoral stem

INTRODUCTION

The requirement for lateral plate fixation in the presence of a hip arthroplasty stem is increasing, yet the optimal plate construct necessary to reduce inter-prosthetic strain and prevent subsequent fractures is unknown. Therefore, the purpose of this study was to determine the optimal position of a lateral femoral plate in relation to a femoral stem.

METHODS

We used 4th Generation Composite Sawbones^®, a collarless polished cemented femoral stem and a broad Peri-loc™ plate with varying overlap of the stem. Each construct was subjected to torsion, axial compression and 3-point lateral bending, with the strain measured at the tip of the femoral stem and the force-to-failure recorded.

RESULTS

In all three loading directions a plate, which extended at least two shaft diameters proximal to the tip of the stem, experienced the lowest strain ( p < 0.001). Constructs with no overlap, and particularly those with a small gap between the tip of the stem and the proximal extent of the plate experienced the highest strain ( p < 0.001). This high strain resulted in lower forces required to cause fracture in the clinically significant scenarios of femoral torsion and lateral bending.

CONCLUSIONS

Optimal plate fixation is achieved by extending a lateral femoral plate at least two shaft diameters proximal to the tip of the stem and using a spread of proximal screws. Distal fixation increases the strain experienced at the tip of the stem and higher strains are noted the smaller the gap between the proximal extent of the femoral plate and the tip of stem.

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.].

Biomechanical Characterization of Failure the 316L Stainless Steel for Femoral Compression Plates

The aim of this paper is to examine a premature breakage of two compression plates for fixing broken bones with different patients for the period of their recovery. Each compression plate's breakage can induce grave consequences such as a new surgery, unexpected undesired complications and a prolonged healing time. The investigation of the compression plate breakage causes required an examination of the chemical composition and steel hardness, metallographic examination as well as that of the compression plate breakage surface by means of macroscopic and microscopic observations using microscope. On the origin of the results it can be established that the breakage was caused by high static load.