Risk factors for failure after treatment of a periprosthetic fracture of the femur

A Consecutive Series of Vancouver B2 Periprosthetic Femur Fractures Treated With Contemporary Monoblock Versus Modular Revision Stems: Clinical and Radiographic Outcomes

BACKGROUND

Tapered fluted titanium (TFT) stems are the implant design of choice for managing Vancouver B2 periprosthetic femur fractures (PFFs), producing reliable results over the past few decades. The aim of this study was to compare the radiographic and clinical outcomes of Vancouver B2 PFFs treated with contemporary monoblock versus modular TFTs.

METHODS

A consecutive series of 113 patients (72 women, 64%, mean age 70 years [range, 26 to 96]) who had a B2 PFF were treated with either a monoblock (n = 42) or modular (n = 71) TFT stem between 2008 and 2021. The mean body mass index was 30 ± 7. The mean follow-up was 2.9 years. A radiographic review was performed to assess leg length and offset restoration, endosteal cortical contact length, and stem subsidence. Kaplan-Meier analyses were used to determine survivorship without revision, reoperation, or dislocation.

RESULTS

There was no difference in the restoration of leg length (0.3 ± 8.0 mm) or offset (2.8 ± 8.2 mm) between the monoblock and modular cohorts (P > .05). Mean endosteal cortical contact length (47.2 ± 26.6 versus 46.7 ± 2 6.4 mm, P = .89) and stem subsidence (2.7 ± 3.5 versus 2.4 ± 3.2 mm, P = .66) did not differ. No difference in patient-reported outcome measures (Hip Disability and Osteoarthritis Outcome Score-Joint Replacement; Veterans RAND 12 Item Health Survey Physical and Mental; visual analog score; and Lower Extremity Activity Scale) between the groups was observed. Survivorship at 2 years free from reoperation, revision, and dislocation was 90.4, 90.3, and 97.6%, respectively, for the monoblock cohort; and 84.0, 86.9, and 90.0%, respectively, for the modular cohort.

CONCLUSIONS

No significant differences in radiographic or clinical outcomes were observed between patients treated with monoblock or modular TFTs in this large series of B2 PFFs.

Comparative outcomes after treatment of peri-implant, periprosthetic, and interprosthetic femur fractures: which factors increase mortality risk?

Objectives

To compare mortality rates between patients treated surgically for periprosthetic fractures (PPF) after total hip arthroplasty (THA), total knee arthroplasty (TKA), peri-implant (PI), and interprosthetic (IP) fractures while identifying risk factors associated with mortality following PPF.

Design

Retrospective.

Setting

Single, Level II Trauma Center.

Patients/Participants

A retrospective review was conducted of 129 consecutive patients treated surgically for fractures around a pre-existing prosthesis or implant from 2013 to 2020. Patients were separated into 4 comparison groups: THA, TKA, PI, and IP fractures.

Intervention

Revision implant or arthroplasty, open reduction and internal fixation (ORIF), intramedullary nailing (IMN), percutaneous screws, or a combination of techniques.

Main Outcome Measurements

Primary outcome measures include mortality rates of different types of PPF, PI, and IP fractures at 1-month, 3-month, 6-month, 1-year, and 2-year postoperative. We analyzed risk factors associated with mortality aimed to determine whether treatment type affects mortality.

Results

One hundred twenty-nine patients were included for final analysis. Average follow-up was similar between all groups. The overall 1-year mortality rate was 1 month (5%), 3 months (12%), 6 months (13%), 1 year (15%), and 2 years (22%). There were no differences in mortality rates between each group at 30 days, 90 days, 6 months, 1 year, and 2 years (P-value = 0.86). A Kaplan-Meier survival curve demonstrated no difference in survivorship up to 2 years. Older than 65 years, history of hypothyroidism and dementia, and discharge to a skilled nursing facility (SNF) led to increased mortality. There was no survival benefit in treating patients with PPFs with either revision, ORIF, IMN, or a combination of techniques.

Conclusion

The overall mortality rates observed were 1 month (5%), 3 months (12%), 6 months (13%), 1 year (15%), and 2 years (22%), and no differences were found between each group at all follow-up time points. Patients aged 65 and older with a history of hypothyroidism and/or dementia discharged to an SNF are at increased risk for mortality. From a mortality perspective, surgeons should not hesitate to choose the surgical treatment they feel most comfortable performing.

Level of Evidence

Level III.

Higher Annual Total Hip Arthroplasty Volume Decreases the Risk of Intraoperative Periprosthetic Femur Fractures

BACKGROUND

Periprosthetic femur fracture (PFF) is a complication of total hip arthroplasty (THA). These occur intraoperatively or postoperatively, and documented risk factors of PFFs include women, age greater than 65 years, cementless stems, and inflammatory arthropathies. The aim of this retrospective cohort study was to assess the relationship of years of surgical experience and surgeon annual THA volume on intraoperative and postoperative PFFs.

METHODS

Data were collected from a database query, and PFFs were identified as either intraoperative or postoperative. Intraoperative and postoperative PFFs were both compared to a control group of non-PFF patients. Years of surgical experience at the time of surgery and annual THA volume for the primary surgeon were calculated for all cases. Logistic regression analyses were used to calculate odds ratios for each of the surgeon variables when adjusted for patient demographics.

RESULTS

Thirty-seven intraoperative and 108 postoperative PFFs were identified and compared to 7,629 controls. From regression analyses, high-volume surgeons (≥50 THA/year) had lower odds of intraoperative PFF (adjusted odds ratio (aOR) = 0.40, P = .020) but not postoperative PFF (aOR = 1.02, P = .921). Surgeon experience (≥15 years since board certification at the time of surgery), was not significantly related to either PFF outcomes. For patient factors, age ≥65 years (aOR = 2.30, P < .001) and women (aOR = 2.69, P < .001) were both significant predictors of postoperative PFFs only.

CONCLUSION

Surgeons who performed 50 or more THAs per year had significantly fewer intraoperative PFFs than surgeons who did less than 50 THAs per year. Surgeon experience was not significantly related to PFFs.

Survival rates of anatomically shaped and tapered slip cemented femoral implants: an analysis of 76,281 femoral implants of the Dutch arthroplasty register (LROI)

INTRODUCTION

In cemented total hip arthroplasty (THA) various shapes and geometries of femoral implants are in use. Collarless, polished, and tapered (CPT) implants, and anatomically shaped (AS) implants are most commonly used. Due to their different design features, this might lead to different survival outcomes. In this register-based study, overall implant survival and short-term complications of CPT and AS cemented implants were evaluated.

METHODS

Data of the Dutch Arthroplasty Register (LROI) were used. Cemented femoral implants, which could be classified as CPT or AS were included in this study. Implants were excluded when no classification could be made or if implanted <100 times. Survival analyses were performed using Kaplan-Meier survival analysis and multivariable Cox-proportional hazard analysis.

RESULTS

76,281 cemented THAs were included. At a mean of 5.1 years follow-up (SD 3.1, range 0-12 years), the overall survival of the AS implants was higher compared with the CPT implants, with a survival, of 99.2% and 99.0% respectively (log-rank; p < 0.001). Multivariable regression analysis revealed a higher rate for revision because of loosening of the AS implants (HR 2; CI, 1.4-3.1). AS implants had a lower rate for periprosthetic fractures compared with the CPT implants (HR 0.13; CI, 0.07-0.23).

CONCLUSIONS

Both designs show excellent overall survival rates at short-term follow-up. There is a higher overall survival of AS implants when compared with CPT implants. Revision for implant loosening, however, was statistically significantly higher in AS implants when compared with the CPT implants.

Intraoperative Periprostehtic Femur Fracture - When is the Cerclage Enough?

BACKGROUND AND PLANNING

Intraoperative periprosthetic femoral fractures are among the most serious complications in both primary and revision arthroplasty. They are often not detected, despite intraoperative radiological control. Since an unnoticed intraoperative fracture often requires revision surgery, which has been associated with increased mortality rates, intraoperative diagnosis and corresponding direct and sufficient treatment are crucial. There are patient-, surgery-, and implant-specific risk factors that increase the possibilities of intraoperative fractures. The most common risk factors on the patient side are age, gender, and various pre-existing conditions, such as osteoporosis or rheumatic diseases. A minimally invasive approach and a cementless press-fit fixation are the most significant surgery- and implant-specific risk factors. The Vancouver classification or the modified Mallory classification are available for the classification of intraoperative periprosthetic femoral fractures. Based on these classifications, treatment recommendations can be derived. Different strategies are available for fracture management.

THERAPY

Generally, if the stem is stable, osteosynthesis can be performed with preservation of the implant. This procedure can be applied to the majority of cases with non-displaced fractures by using cerclages as fixation. An unstable implant may require replacement of the stem. In higher grade fractures, stabilisation by using plate osteosynthesis may be necessary. The aim is to achieve the most anatomical reposition possible for the best possible bony consolidation. The ultimate goal is high implant stability and restoration of the biomechanics.

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.

Subsidence in Centraliser Sign: A Novel Tool to Help Predict Early Subsidence in Periprosthetic Femoral Fractures Around Polished Tapered Stems Treated With Internal Fixation

Background When treating periprosthetic femoral fractures (PPF) around polished taper slip stems (PTS), determining which patients can be successfully treated with internal fixation can be challenging. We have described the subsidence-in-centraliser (SINC) sign as a radiographic feature of PPF around PTS stems. We hypothesise that a positive SINC sign can help predict a poorer outcome for the fixation of these fractures. Patients and methods Retrospective identification of PPFs around cemented PTS with an appreciable centraliser on radiographs was conducted at a single centre. A positive SINC sign was defined as a post-injury radiograph demonstrating >50% reduction in the radiographic lucency representing the stem centraliser when compared to pre-injury films or complete obliteration of distal lucency when no pre-injury film was available. The primary outcome was the rate of subsequent stem subsidence on follow-up radiographs comparing SINC-positive and SINC-negative fractures, which were managed with open reduction and internal fixation (ORIF). Results Fifty-four patients were included in the analysis. The mean age was 76.8 years, and the mean follow-up for all patients was 12.7 months. Thirty-five fractures were deemed SINC-positive, and 19 were SINC-negative. 17/17 (100%) SINC-positive fractures managed with fixation underwent further subsidence (mean 5.4 mm, SD 2.8). A positive SINC sign demonstrated a sensitivity of 90.5% and specificity of 100% for subsequent stem subsidence in fractures treated without revision. SINC positive fractures underwent significantly more subsidence compared with SINC negative fractures when fixed (5.4 mm vs. 0.28 mm, U = 6.50, p<0.001) at a mean follow-up of 12.7 months. The SINC sign demonstrated strong inter- (k=0.96) and intra-rater (k=0.86) reliability. Conclusion The SINC sign can serve as a useful adjunct in the decision to fix or revise PPF around PTS. A positive SINC sign may represent a cement mantle that cannot be reconstituted anatomically, leading to subsidence after treatment with ORIF.

The Influence of Computerized Tomography Imaging on Treatment of Periprosthetic Proximal Femur Fractures

Introduction Periprosthetic femur fractures (PPFF) are increasing in incidence and management of such injuries requires a specialized skill set combined with detailed knowledge of component design. To assist with planning, computed tomography (CT) can be used pre-operatively to give a surgeon more information. No study to date has shown the utility of obtaining preoperative CT. The goal of this study is to show that CT is a useful diagnostic adjunct and report any differences in how subspecialties such as orthopedic traumatologists and arthroplasty surgeons use it. Methods Seventeen PPFF cases met our inclusion criteria. They were shown to six faculty, three trauma and three arthroplasty surgeons. They viewed the plain radiographs and then CTs. After each they filled out the same questionnaire that included their assessment of diagnosis and proposed treatment plan both before and after access to CT imaging. Fleiss and Cohen kappa were used to compare inter- and intra-observer reliability. Results The interobserver kappa values (k) in diagnosis were 0.348 pre- and 0.371 post-CT, while trauma and arthroplasty were 0.328 to 0.260 and 0.821 to 0.881 respectively. The interobserver reliability in treatment was 0.336 pre- and 0.254 post-CT, while trauma and arthroplasty were 0.323 to 0.288 and 0.688 to 0.519. For intraobserver the average k for diagnosis and treatment were 0.818 and 0.671. Broken down by subspecialty they were 0.874 and 0.831 and 0.762 and 0.510 for trauma and arthroplasty. There were 11 diagnostic and 24 treatment changes. Conclusion CT provides diagnostic changes 10% and treatment changes 24% of the time. However, it does not lead to greater agreement among the surgeons on either. Arthroplasty uses CT more to guide both their treatment and the diagnosis, and they agree more than trauma surgeons. Most of the treatment changes come from adding or removing a plate, and the most common diagnostic change was shared by A to B1 and B2 to B3. This suggests fracture extension and bone stock are better evaluated by CT.

Outcomes of fixation of Vancouver B periprosthetic fractures around cemented versus uncemented stems

BACKGROUND

The incidence of periprosthetic femur fracture (PPFF) in the setting of total hip arthroplasty (THA) is steadily increasing. We seek to address whether there is a difference in outcomes between Vancouver B fracture types managed with ORIF when the original stem was a press-fit stem versus a cemented stem.

METHODS

In this retrospective cohort study at a level 1 trauma center, we identified 136 patients over 65 years-of-age with Vancouver B-type fractures sustained between 2005 and 2019. Patients were treated by ORIF and had either cemented or press-fit stems prior to their injury. Outcomes were subsidence of the femoral implant, time to full weight bearing, rate of the hip implant revision, estimated blood loss (EBL), postoperative complications, and the one-year mortality rate.

RESULTS

A total of 103 (75.7%) press-fit and 33 (24.3%) cemented patients were reviewed. Patient baseline characteristics, Vancouver fracture sub-types, and implant characteristics were not found to be significantly different between groups. The difference in subsidence rates, postoperative complications, and time to weight bearing were not significantly different between groups. EBL and one-year mortality rate were significantly higher in the cemented group.

CONCLUSIONS

In geriatric patients with Vancouver B type periprosthetic fractures managed with ORIF, patients with an originally press fit stem may have lower mortality, lower estimated blood loss, and similar subsidence and hospital length of stays when compared to those with a cemented stem.

Periprosthetic fracture management of the proximal femur

The most common periprosthetic fractures occur around the hip. The most widely used classification is the Vancouver classification, and management requires careful planning and skill in both arthroplasty and fracture surgery. This article presents an overview of the diagnosis, classification, and management of periprosthetic fractures of the proximal femur. This work represents a summary review from Latin American Society Members of the International Orthopaedic Trauma Association.

Mini-invasive approach vs. traditional open reduction for periprosthetic hip fracture osteosynthesis with the NCB® plate

BACKGROUND

Postoperative hip periprosthetic fracture (PPF) is a frequent complication whose treatment does not achieve optimal results among eldery fragile patients. Locking compression plate (LCP) osteosynthesis is the gold standard treatment for Vancouver B1 and VC fractures and there is a growing consensus in doing the same with B2 fractures in patients with high comorbidity. Following that trend of being as non-aggressive as possible we investigated whether a mini-open (MO) approach would lead to better outcomes in LCP plate osteosynthesis of hip PFFs when compared to the traditional open approach.

METHODS

We retrospectively evaluated a cohort of 43 VB1, VB2 or VC hip PPFs treated with non contact bridging (NCB®) plate osteosynthesis by two possible approaches. MO vs traditional open approach. The main objective was to assess whether MO approach decreases operative time, bleeding and local complications. The secondary objective was to demonstrate that this may have a positive effect on patient function.

RESULTS

The mean age was 79.6 years old and 74.5% patients had an ASA score of III or IV. The surgical time was 148.53 min (SD 33.2) in the open approach versus 107.42 min (SD 25.6) in the MO, which was 31 min shorter (p<0.001). Hemoglobin dropped 0.9 points less, on average (p. 0.005) and 0.82 fewer blood concentrates were required (p. 0.022) with MO approach. There were no differences among complications but there was a trend towards greater independence and better mobility in the MO approach group with a postoperative Barthel of 74.37 (sd. 13.21) compared to the 66.67 points (sd. 13.7) in the traditional approach group.

CONCLUSION

MO approach in osteosynthesis of hip PFFs decreases operative time and intraoperative bleeding so it must be considered in fragile patients with high comorbidity.

Periprosthetic joint infection is the main reason for failure in patients following periprosthetic fracture treated with revision arthroplasty

INTRODUCTION

Periprosthetic fracture after primary total hip and knee arthroplasty (THA; TKA) can be challenging, requiring open reduction internal fixation (ORIF), revision, or both. The aim of this study was to evaluate the outcomes and risk factors associated with re-revision surgery following failed revision arthroplasty for periprosthetic fracture.

METHODS

A total of 316 consecutive THA patients and 79 consecutive TKA patients underwent a revision for periprosthetic fracture, of which 68 THA patients (21.5%) and 15 TKA patients (18.9%) underwent re-revision surgery. The most common indication for hip and knee re-revision was periprosthetic joint infection (PJI) in 28 THA patients (46.6%) and 11 TKA patients (47.8%).

RESULTS

The complication rates of THA and TKA revision were 24.3% and 25.3% respectively, and 35.0% and 39.1% respectively for re-revision surgery at an average follow-up of 4.5 years. Periprosthetic joint infection was the most common indication for THA and TKA re-revision (46.7%; 47.8%) and third revision surgery (15.0%; 13.0%). Factors significantly contributing to an increased risk of THA and TKA re-revision included revision with plate fixation and revision with combined ORIF.

CONCLUSION

The overall complication rate of THA and TKA re-revision surgery following failed revision surgery for periprosthetic fracture was higher than of revision surgery. The most common indication for re-revision and third revision was periprosthetic joint infection. These findings may assist surgeons in the management and preoperative counseling of patients undergoing THA and TKA revision surgery for a periprosthetic fracture to optimize the outcomes for these patients.

LEVEL OF EVIDENCE

Level III, case-control retrospective analysis.

Impact of bone health on the mechanics of plate fixation for Vancouver B1 periprosthetic femoral fractures

BACKGROUND

Condyle-spanning plate-screw constructs have shown potential to lower the risks of femoral refractures after the healing of a primary Vancouver type B1 periprosthetic femoral fracture. Limited information exists to show how osteoporosis (a risk factor for periprosthetic femoral fractures) may affect the plate fixation during activities of daily living.

METHODS

Using total hip arthroplasty and plate-implanted finite element models of three osteoporotic femurs, this study simulated physiological loads of three activities of daily living, as well as osteoporosis associated muscle weakening, and compared the calculated stress/strain, load transfer and local stiffness with experimentally validated models of three healthy femurs. Two plating systems and two construct lengths (a diaphyseal construct and a condyle-spanning construct) were modeled.

FINDINGS

Osteoporotic femurs showed higher bone strain (21.9%) and higher peak plate stress (144.3%) as compared with healthy femurs. Compared with shorter diaphyseal constructs, condyle-spanning constructs of two plating systems reduced bone strains in both healthy and osteoporotic femurs (both applying 'the normal' and 'the weakened muscle forces') around the most distal diaphyseal screw and in the distal metaphysis, both locations where secondary fractures are typically reported. The lowered resultant compressive force and the increased local compressive stiffness in the distal diaphysis and metaphysis may be associated with strain reductions via condyle-spanning constructs.

INTERPRETATION

Strain reductions in condyle-spanning constructs agreed with the clinically reported lowered risks of femoral refractures in the distal diaphysis and metaphysis. Multiple condylar screws may mitigate the concentrated strains in the lateral condyle, especially in osteoporotic femurs.

The influence of composite bone plates in Vancouver femur B1 fracture fixation after post-operative, and healed bone stages: A finite element study

Conventional stainless steel or titanium plates are used for bone fracture fixation to provide support at fracture location. Plates with high elastic modulus reduce the transfer of compressive load at the fracture location (due to stress shielding), causing failure. The objective of the study is to find for composite bone plates with different types of fibers and varied fiber orientations for post-operative (PO) and healed bone (HB) conditions which can reduce the stress shielding. Femur fracture fixation was constructed with 12 holes narrow type with metal and composite bone plates. The fracture gap was constructed with soft bone region for post-operative (PO) condition and harder bone for healed bone (HB). Composite bone plates with different configurations (fiber directions) and types (thickness and width) were analyzed to study the stress distribution and movement in the fracture location. The models were analyzed and the stresses in plate and callus, movement and strain in axial and shear direction in both metal and composite bone plates were studied. The metal and composite plates (carbon fiber/epoxy, fiberglass/epoxy, and flax/epoxy) used for most common Vancouver type B1 fracture to observe the biomechanical behavior of different models in PO and HB condition. The FE simulation on different configurations and types of composite plates provide in-depth idea about choosing the suitable composite bone plate. There are variations in behavior for varying types and configurations, but the performance of most of the plates are either better or similar to that of metal plate, except the plates with higher width.

Comparison of morbidity-mortality and functional results between implant exchange and internal fixation by plate for periprosthetic femoral fracture in total knee arthroplasty: A 52-case series

INTRODUCTION

Surgical options for periprosthetic femoral fracture in total knee arthroplasty (TKA) are controversial. The present retrospective study compared morbidity, mortality and functional results between implant exchange (group IE) and internal fixation by plate (group IF). The study hypothesis was that implant exchange does not give rise to more complications than plate fixation and that functional results are equivalent.

METHODS

Fifty-two femoral fractures in contact with a TKA implant were studied. The IE and IF groups (n 32 and 20, respectively), were comparable for age, gender and ASA score. Mean age was 80.5 years (range, 53-96 years). Morbidity and mortality were assessed on Clavien score; functional assessment used the KOOS questionnaire.

RESULTS

Mortality was 50% in group IF and 40% in group IE (p=0.4817). One patient was lost to follow-up. Complications were seen in 15 group IF patients (48.4%) versus 5 in group IE (26.3%) (p=0.14760), with infection in 5 (16.1%) and 2 patients (10.5%) respectively (p=0.69475). In both groups, 9 patients (i.e., 28.1% and 40% respectively) showed grade 2 complications (p=1). Revision surgery was performed in 8 grade 3b patients (25%) in the IF group and in 3 (15%) in the IE group (p=1). Mean KOOS score was 40 (range, 20-72) in IF and 65 (range, 50-93) in IE (p=0.0004).

CONCLUSION

Morbidity and mortality were comparable between implant exchange and plate fixation for periprosthetic femoral fracture in TKA. KOOS functional scores were better with implant exchange. Implant exchange may be suited to complex fracture with stable implant.

LEVEL OF EVIDENCE

IV, observational study.

Drilling the cement mantle in well-fixed periprosthetic femur fractures is not associated with arthroplasty-related complications

OBJECTIVE

To determine if screw fixation across a cement mantle is safe and effective during plate fixation of well-fixed periprosthetic femur fractures.

DESIGN

Retrospective cohort study.

SETTING

Academic Level I Trauma Center.

PATIENTS

Twenty-eight patients with AO/OTA 32A[B1] or 32A[C] periprosthetic femur fractures treated with open reduction and internal plate and screw fixation after cemented or uncemented hip arthroplasty.

INTERVENTION

Screw placement into the cement mantle during internal fixation.

OUTCOME MEASUREMENTS

Primary outcome was revision arthroplasty for aseptic loosening. Secondary outcomes included radiographic evidence of aseptic loosening, infection, nonunion, implant failure, and overall reoperation rate.

RESULTS

There were 28 patients who met inclusion criteria. A total of 9 patients had screws placed in the cement mantle while the remaining 19 patients had screws placed around an uncemented stem. At a mean of 3.7-year follow-up, there were no cases of revision arthroplasty or aseptic loosening in either group. There were no significant differences in rates of infection, nonunion, implant failure, or reoperation rate between patients who had screw placement into a cement mantle vs around an uncemented stem.

CONCLUSION

Drilling into the cement mantle during fixation of a periprosthetic femur fracture around a well-fixed cemented hip stem appears safe and effective. When possible, surgeons can consider bicortical screws around a cemented stem, given the biomechanical advantages over unicortical screw or cerclage fixation. Larger prospective trials confirming the safety of this technique are warranted prior to routine implementation.

LEVEL OF EVIDENCE

III.

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.

Outcomes After Operative Fixation of Vancouver B2 and B3 Type Periprosthetic Fractures

OBJECTIVES

The incidence of periprosthetic femur fracture in the setting of total hip arthroplasty is steadily increasing. Although the traditional dogma is that loose femoral components must be revised, we propose that in a frail geriatric population, anatomic reduction and fixation of Vancouver B2 and B3 periprosthetic fracture variants can restore stem stability and provide similar outcomes as revision arthroplasty.

DESIGN

Retrospective cohort study.

SETTING

Level 1 trauma center, tertiary academic medical center.

PATIENTS/PARTICIPANTS

We identified 94 patients over 65 years of age with Vancouver B2 and B3 fractures sustained between 2005 and 2019.

INTERVENTION

Patients were treated by either open reduction and internal fixation (ORIF) or revision arthroplasty (RA) with or without fixation.

MAIN OUTCOME MEASUREMENTS

Outcomes were mortality, time to full weight-bearing after surgery, intraoperative estimated blood loss, perioperative complications, reoperation, subsidence rate, and Patient-Reported Outcomes Measurement Information System pain and physical function scores.

RESULTS

A total of 75 (79.8%) ORIF and 19 (20.2%) RA patients were reviewed. One-year mortality for our cohort was 26.3%, and there was no significant difference between groups. Mean time to weight bear and surgical complication rates were similar between groups. The ORIF group had a significantly shorter time to surgery than the RA group. The RA group had greater incidence and amount of subsidence as well as estimated blood loss than the ORIF group.

CONCLUSIONS

In geriatric patients with Vancouver B2 and B3 type periprosthetic fractures with known loose stems, ORIF may offer a similarly safe method of treatment than revision arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

Simplified Mechanical Tests Can Simulate Physiological Mechanics of a Fixation Construct for Periprosthetic Femoral Fractures

Plate fractures after fixation of a Vancouver Type B1 periprosthetic femoral fracture (PFF) are difficult to treat and could lead to severe disability. However, due to the lack of direct measurement of in vivo performance of the PFF fixation construct, it is unknown whether current standard mechanical tests or previous experimental and computational studies have appropriately reproduced the in vivo mechanics of the plate. To provide a basis for the evaluation and development of appropriate mechanical tests for assessment of plate fracture risk, this study applied loads of common activities of daily living (ADLs) to implanted femur finite element (FE) models with PFF fixation constructs with an existing or a healed PFF. Based on FE simulated plate mechanics, the standard four-point-bend test adequately matched the stress state and the resultant bending moment in the plate as compared with femur models with an existing PFF. In addition, the newly developed constrained three-point-bend tests were able to reproduce plate stresses in models with a healed PFF. Furthermore, a combined bending and compression cadaveric test was appropriate for risk assessment including both plate fracture and screw loosening after the complete healing of PFF. The result of this study provides the means for combined experimental and computational preclinical evaluation of PFF fixation constructs.

Clinical and radiographical outcome after surgical treatment of periprosthetic type B proximal femur fractures: a retrospective study

PURPOSE

Periprosthetic fractures after hip prosthesis represent a constantly increasing clinical problem and a challenging complication to treat surgically. Among these, type B proximal femur fractures should be diagnosed correctly to be treated surgically. The aim of this study was to re-evaluate the type of surgical treatment of periprosthetic fractures.

METHODS

We examined the cases treated between January 2012 and February 2018, classifying them according to the U.C.S. AO/OTA. We evaluated the radiographic outcome according to the Beals and Tower criteria. Patients still alive were also re-evaluated according to the H.H.S. and the WOMAC score.

RESULTS

We treated 48 patients (12 men, 35 women, average age 81 years), divided into 24 type B1, 14 type B2 and 10 type B3 fractures. The overall consolidation rate was 95.4%, while the major complication (implant dislocation, pseudoarthrosis and deep infection) rate was 12.5%. Clinically, it was possible to reassess 34 patients with a mean follow-up of 38.4 months, an average HHS of 75.89 and a mean WOMAC score of 79.93.

CONCLUSIONS

Periprosthetic type B fractures are difficult to manage and require careful preoperative planning and appropriate intraoperative management. However, the overall clinical and radiographic result was satisfactory, although patients should still be aware of the risk of complications associated with this type of fracture.

Mortality After Postoperative Periprosthetic Fracture of the Femur After Hip Arthroplasty in the Last Decade: Meta-Analysis of 35 Cohort Studies Including 4841 Patients

BACKGROUND

Postoperative periprosthetic fracture of the femur (POPFF) is associated with increased mortality. There is a lack of general estimates of mortality after POPFF and a need for higher-level evidence in this area. The aim of this study was to estimate mortality after POPFF using data reported in cohort studies from the last decade.

METHODS

Literature search was conducted using Medline and Embase. The primary outcome was all-cause mortality during time as an inpatient, within 30 days, within 90 days, and within one year of POPFF. Mortality (95% confidence interval [CI]) was estimated using metaregression.

RESULTS

A total of 4841 patients from 35 cohort studies were included. Study quality was generally low. The weighted mean follow-up was 2.3 years, and the most common POPFF was Vancouver B. The pooled mortality as an inpatient was 2.4% (95% CI 1.6% to 3.4%). The pooled mortality within 30 days was 3.3% (95% CI 2.0% to 5.0%). The pooled mortality within 90 days was 4.8% (95% CI 3.6% to 6.1%). The pooled mortality within one year was 13.4% (95% CI 11.9% to 14.8%). Mortality after POPFF was like that of neck of femur fracture up to 30 days, but better at one year.

CONCLUSION

Mortality is like that experienced by patients after neck of femur fracture up to 30 days, but better at one year, which may represent the lower underlying risk of death in the POPFF cohort. These results may form the basis for evaluation of services treating POPFF in the future.

Open reduction and locked compression plate fixation, with or without allograft strut, for periprosthetic fractures in patients who had a well-fixed femoral stem: a retrospective study with an average 2-year follow-up

Background

The use of cortical strut allograft has not been determined for Vancouver type B1 or C fracture. This study aimed to evaluate the short-term efficacy of locking compression plating with or without cortical strut allograft in managing these types of fractures.

Methods

We retrospectively assessed 32 patients (17 males, 15 females; 23–88 years, mean: 67.2 years) with Vancouver type B1 or C fractures. Seventeen patients (Group A; B1 fractures in 15 hips, C fractures in 2 hips) were treated with open reduction and internal fixation with locking compression plates (group A). The other 15 patients (Group B; B1 in 14 hips, C in 1 hip) were fixed by locking compression plating combined with cortical strut allografting (group B). The fracture healing rate, healing time, complications and function were compared between these two groups.

Results

The mean follow-up time was 32.4 months (12 to 66), and the overall fracture union rate of the 32 patients was 96.9%. Group B had a higher fracture union rate than Group A, but the difference was not statistically significant. Group A had one case of nonunion of type B1 fracture and one case of malunion; the mean time to fracture healing was 5.3 months (3 to 9). In group B, all patients reached bony union without malunion, with a mean time of fracture healing of 5.1 months (3 to 8).

Conclusion

Treatment of Vancouver type B1 or C fractures by locking compression plating, with or without cortical strut allografting, resulted in similar union rates in these patients. This suggest that, the use of cortical strut allografting should be decided cautiously.

The impact of stem fixation method on Vancouver Type B1 periprosthetic femoral fracture management

INTRODUCTION

Our understanding of the impact of the stem fixation method in total hip arthroplasty (THA) on the subsequent management of periprosthetic femoral fractures (PFF) is still limited. This study aimed to investigate and quantify the effect of the stem fixation method, i.e., cemented vs. uncemented THA, on the management of Vancouver Type B1 periprosthetic femoral fractures with the same plate.

METHODS

Eight laboratory models of synthetic femora were divided into two groups and implanted with either a cemented or uncemented hip prosthesis. The overall stiffness and strain distribution were measured under an anatomical one-legged stance. All eight specimens underwent an osteotomy to simulate Vancouver type B1 PFF's. Fractures were then fixed using the same extramedullary plate and screws. The same measurements and fracture movement were taken under the same loading conditions.

RESULTS

Highlighted that the uncemented THA and PFF fixation constructs had a lower overall stiffness. Subsequently, the mechanical strain on the fracture plate for the uncemented construct was higher compared to the cemented constructs.

CONCLUSION

PFF fixation of a Vancouver type B1 fracture using a plate may have a higher risk of failure in uncemented THAs.

Management of Vancouver B2 Periprosthetic Femoral Fractures, Revision Total Hip Arthroplasty Versus Open Reduction and Internal Fixation: A Systematic Review and Meta-Analysis

OBJECTIVE

To identify and analyze the current evidence for the use of open reduction and internal fixation (ORIF) constructs compared with conventional revision total hip arthroplasty (rTHA) for the management of Vancouver B2 periprosthetic femoral fractures (PFFs).

DATA SOURCES

A systematic literature search of the MEDLINE, CINAHL, and EMBASE databases was conducted. Prospective and retrospective studies were eligible. No limitation was placed on publication date, with only articles printed in English eligible.

STUDY SELECTION

Included studies were retrospective studies comparing ORIF and rTHA for the management of Vancouver B2 PFFs.

DATA EXTRACTION

The primary outcome was the overall complication rate. Other outcomes included as rate of dislocation, revision operation, refracture, infection, nonunion, and subsidence/loosening. Twenty-four studies were included totaling 1621 patients, of which 331 were treated with ORIF and 1280 with rTHA.

CONCLUSION

The 1621 patients included comprised a mixture of different fracture patterns, prostheses, and patient comorbidities. The overall complication rate for ORIF was 24% versus 18% for rTHA (P = 0.13). The results demonstrate that rTHA has a similar revision rate to ORIF in PFFs with a loose femoral component and adequate bone stock. ORIF was superior to rTHA in prevention of postoperative dislocation; however, there was no difference between other complications. This review suggests a potential role of both ORIF and rTHA in the management of Vancouver B2 PFFs.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

Impact of periprosthetic femoral fracture fixation plating constructs on local stiffness, load transfer, and bone strains

Secondary femoral fractures after the successful plate-screw fixation of a primary Vancouver type B1 periprosthetic femoral fracture (PFF) have been associated with the altered state of stress/strain in the femur as the result of plating. The laterally implanted condyle-spanning plate-screw constructs have shown promises clinically in avoiding secondary bone and implant failures as compared with shorter diaphyseal plates. Though the condyle-spanning plating has been hypothesized to avoid stress concentration in the femoral diaphysis through increasing the working length of the plate, biomechanical evidence is lacking on how plate length may impact the stress/strain state of the implanted femur. Through developing and experimentally validating finite element (FE) models of 3 cadaveric femurs, this study investigated the impact of plating on bone strains, load transfer and local stiffness, which were compared between FE models of 2 different plating systems that each had a diaphyseal configuration and a condyle-spanning configuration. Under simulated gait-loading, the condyle-spanning constructs of both plating systems were shown to lower the bone strains around the distal fixation screws (up to 24.8% reduction in maximum principal strain and 26.6% reduction in minimum principal strain) and in the distal metaphyseal shaft of the femur (up to 15.9% and 25.7% reductions in maximum and minimum principal strains, respectively), where secondary bone fractures have been typically reported. In the distal diaphyseal and metaphyseal shaft of femur, FE models of the condyle-spanning constructs were shown to increase the local compressive stiffness (up to 152.9% increases under simulated gait-loading) and decrease the transfer of compressive load (37.1% decreases under simulated gait-loading), which may be indicative of the lowered risks of bone damage.

Periprosthetic Hip Fractures With a Loose Stem: Open Reduction and Internal Fixation Versus Stem Revision

BACKGROUND

It is recommended revision for periprosthetic hip fractures (PPHF) with a loose stem. However, several authors have argued that under certain conditions, this fracture could be treated using osteosynthesis. The aim is to compare stem revision versus internal fixation in the treatment of PPHF with a loose stem.

METHODS

All patients with PPHF with a loose stem treated by osteosynthesis and stem revision between January 2009 and January 2019 were included. We assessed hospital stay, American Society of Anesthesiologists, Charlson comorbidity index, surgery time, blood transfusion, complications, reoperation rate, first-year mortality, radiological, and functional results.

RESULTS

A total of 57 patients were included (40 osteosyntheses and 17 stem revision), with an average follow-up time of 3.1 years. Their mean age was 78.47 years (R 45-92). In the osteosynthesis group, fewer patients required blood transfusion (32.5% vs. 70.6%), surgical times were shorter (108 minutes vs. 169 minutes), and the cost was lower, both in terms of total cost (€14,239.07 vs. €21,498.45 and operating room cost (€5014.63 vs. €8203.34). No significant differences were found between the groups in terms of complications, reoperation rate, or functional outcomes.

CONCLUSION

Compared with stem revision, osteosynthesis requires less surgery time, has a lower need for blood transfusions, and a reduced hospital cost. Stem revision remains the treatment of choice in PPHF with a loose stem, but in V-B2 fractures in elderly patients with low functional demand, high anesthetic risk (American Society of Anesthesiologists ≥3), and many comorbidities (Charlson comorbidity index ≥5) in whom anatomic reconstruction is possible, osteosynthesis can be a viable option.

EVIDENCE LEVEL

Historical cohorts. Level III.

Osteosynthesis in Vancouver type B1 periprosthetic fractures

INTRODUCTION

The incidence of hip periprosthetic fractures (PPF) has been increasing in recent years. In Vancouver type B1 there are several osteosynthesis options. The aim of this paper is to assess both the treatment and results of Vancouver type B1 PPF in patients operated at our centre.

MATERIAL AND METHOD

An observational retrospective study of patients operated at Hospital Universitario Miguel Servet for type B1 PPF via osteosynthesis with plate between January 2014 and March 2017. Such details were documented and analysed as type of implant used for fixation, patient demographics, complications, time to union and function score using the Harris Hip Score. The minimum follow up was 2 years.

RESULTS

Overall, 37 patients (21 women)  were available for review with a mean age of 80.7 years (range 54-99). 8 of these patients died, with an average age of 85.6 (83-95). Out of these 8 dead patients, 4 died in the first year, with an average age of 87 (83-95). 19 fractures had cemented stems whereas 18 were uncemented. According to prosthesis type, 8 had a cemented partial arthroplasty, 11 a cemented total hip arthroplasty (THA), 18 a non-cemented THA; with an average period until PPF of 2.5 years (0.2-5.6), 7 years (0.09-18.1) and 8.1 years (2.6-12.7) respectively. Devises used for stabilisation of the fracture included 27 Cable-Ready® plates (Zimmer-Biomet), 5 Dall-Miles® plates (Stryker) and 5 femur NCB® plates (Zimmer-Biomet). Complications included 5 acute superficial infections of surgical wound, 1 chronic infection, 5 pressure ulcers (4 sacral, 1 heel), 7 patients required intra-operational blood transfusion. The mean time to union was 10.35 weeks (range 6-13). The mean Harris Hip Score postoperatively was 65 (44-95).

DISCUSSION

Treatment via open reduction and internal fixation with locked lateral plate covering most of the femur in elderly patients or those with poor bone quality, or a plate with proximal cerclages and distal screws in patients with better bone quality are appropriate treatment methods. To achieve good results using these techniques, we consider minimisation of soft tissue dissection highly important likewise using a meticulous osteosynthesis technique with special attention to biology and biomechanics.

Periprosthetic Femur Fractures After Total Hip Arthroplasty: Does the Mode of Failure Correlate With Classification?

BACKGROUND

Periprosthetic femur fracture is one of the most common indications for reoperation after total hip arthroplasty. Our objectives were to evaluate the incidence of reoperation after the surgical treatment of periprosthetic femur fractures and to compare the mechanisms of failure between fractures around a stable femoral component and those with an unstable femoral component.

METHODS

We identified a consecutive series of 196 surgically treated periprosthetic fractures after total hip arthroplasty between 2008 and 2017. Mean age was 72 years (range, 29-96 years), and 108 (55%) were women. The femoral component was unstable in 127 cases (65%) and stable in the remaining 69 cases (35%). Mean follow-up was 2 years.

RESULTS

The 2-year cumulative probability of any reoperation was 19%. The most common indication for reoperation among the cases with a stable femoral component was nonunion, and the most common indication for reoperation among the cases with an unstable femoral component was infection. Fractures that originated at the distal aspect of the femoral component were associated with a high risk of nonunion (6 of 28 cases, P < .01) and reoperation (9 of 28 cases, P = .03).

CONCLUSION

Surgeons should take measures to mitigate the failure modes that are distinct based on fracture type. The high infection rate after surgical management of B₂ fracture suggests that additional antiseptic precautions may be warranted. For B₁ fractures, particularly those originating near the distal aspect of the femoral component, augmenting fixation with orthogonal plating, spanning the entire femur, or revising the stem in cases of poor proximal bone should be considered.

Open reduction and internal fixation might be a valuable alternative to stem revision in Vancouver B2 periprosthetic femoral fractures, irrespective of the stem's design

BACKGROUND

The purpose of this study was to compare the clinical and radiological outcomes following open reduction and internal fixation (ORIF) of Vancouver B2 periprosthetic femoral fractures versus stem revision (SR) surgery.

METHODS

Between 2004 and 2018, 39 patients were treated with SR and 31 with ORIF for a Vancouver type B2. Mean follow-up was 40.4 months for the ORIF group and 43.5 months for the SR group. 22 of 31 stems in the ORIF group were uncemented, of which 7 (23%) were short stems. Perioperative complications, intraoperative blood loss, revision rate, and mortality were recorded. Functional outcomes included Harris Hip Score, Parker Mobility Score and hip abductor strength.

RESULTS

Both groups did not differ in the American Society of Anesthesiologists (ASA) score, Charlson comorbidity index, body mass index, age, and sex. Compared to SR, patients treated with ORIF had a decreased blood loss, transfusion rate, operation duration, and mortality. Total complication and re-operation rates were similar. The relative risk for complication and re-operation was 0.5 and 0.7, respectively, in favour of ORIF.

CONCLUSIONS

ORIF might be a valuable alternative to SR in the treatment of Vancouver type B2 periprosthetic fractures with shorter operation duration, lower blood loss and similar complication rate compared to SR. Moreover, re-stabilization seems possible irrespective of stem's design or fixation technique.

LEVEL OF EVIDENCE

Level III.

Multiple failures of internal fixation for treatment of periprosthetic femoral refracture: a case report and literature review

We herein report a case involving three failures of internal fixation after periprosthetic femoral fracture (Vancouver type B1). The patient had low bone mass (T-score of −1.7) and was overweight (body mass index of 28.7 kg/m²) but had no sign of femoral stem loosening. The first open reduction with internal fixation was performed according to the recommended treatment. Unexpectedly, three treatment failures subsequently occurred, after which the patient finally attained endurable walking activity. A literature review indicated that the intrinsic biomechanical problems of Vancouver B1 fractures have not been thoroughly addressed. Choosing the correct surgical strategy for Vancouver B1 fractures is essential to avoid complications and ensure healing. A sufficient locking plate and cable system should be used after the first failure if revision was not performed the first time.

Biomechanical models: key considerations in study design

This manuscript summarizes presentations of a symposium on key considerations in design of biomechanical models at the 2019 Basic Science Focus Forum of the Orthopaedic Trauma Association. The first section outlines the most important characteristics of a high-quality biomechanical study. The second section considers choices associated with designing experiments using finite element modeling versus synthetic bones versus human specimens. The third section discusses appropriate selection of experimental protocols and finite element analyses. The fourth section considers the pros and cons of use of biomechanical research for implant design. Finally, the fifth section examines how results from biomechanical studies can be used when clinical evidence is lacking or contradictory. When taken together, these presentations emphasize the critical importance of biomechanical research and the need to carefully consider and optimize models when designing a biomechanical study.

Finite element analysis of double-plate fixation using reversed locking compression-distal femoral plates for Vancouver B1 periprosthetic femoral fractures

Background

Internal fixation is recommended for treating Vancouver B1 periprosthetic femoral fractures. Although several fixation procedures have been developed with high fixation stability and union rates, long-term weight-bearing constructs are still lacking. Therefore, the aim of the present study was to evaluate the stability of a double-plate procedure using reversed contralateral locking compression-distal femoral plates for fixation of Vancouver B1 periprosthetic femoral fractures under full weight-bearing.

Methods

Single- and double-plate fixation procedures for locking compression-distal femoral plates were analysed under an axial load of 1,500 N by finite element analysis and biomechanical loading tests. A vertical loading test was performed to the prosthetic head, and the displacements and strains were calculated based on load-displacement and load-strain curves generated by the static compression tests.

Results

The finite element analysis revealed that double-plate fixation significantly reduced stress concentration at the lateral plate place on the fracture site. Under full weight-bearing, the maximum von Mises stress in the lateral plate was 268 MPa. On the other hand, the maximum stress in the single-plating method occurred at the defect level of the femur with a maximum stress value of 1,303 MPa. The principal strains of single- and double-plate fixation were 0.63 % and 0.058 %, respectively. Consistently, in the axial loading test, the strain values at a 1,500 N loading of the single- and double-plate fixation methods were 1,274.60 ± 11.53 and 317.33 ± 8.03 (× 10^− 6), respectively.

Conclusions

The present study suggests that dual-plate fixation with reversed locking compression-distal femoral plates may be an excellent treatment procedure for patients with Vancouver B1 fractures, allowing for full weight-bearing in the early postoperative period.

B2 or not B2? That is the question: a review of periprosthetic fractures around cemented taper-slip femoral components

AIMS

Periprosthetic fractures (PPFs) around cemented taper-slip femoral prostheses often result in a femoral component that is loose at the prosthesis-cement interface, but where the cement-bone interface remains well-fixed and bone stock is good. We aim to understand how best to classify and manage these fractures by using a modification of the Vancouver classification.

METHODS

We reviewed 87 PPFs. Each was a first episode of fracture around a cemented femoral component, where surgical management consisted of revision surgery. Data regarding initial injury, intraoperative findings, and management were prospectively collected. Patient records and serial radiographs were reviewed to determine fracture classification, whether the bone cement was well fixed (B2W) or loose (B2L), and time to fracture union following treatment.

RESULTS

In total, 47 B2W fractures (54.0%) and one B3 fracture (1.1%) had cement that remained well-fixed at the cement-bone interface. These cases were treated with cement-in-cement (CinC) revision arthroplasty. Overall, 43 fractures with follow-up united, and two patients sustained further fractures secondary to nonunion and required further revision surgery. A total of 19 B2L fractures (21.8%) and 19 B3 fractures (21.8%) had cement that was loose at the cement-bone interface. These cases were managed by revision arthroplasty with either cemented or uncemented femoral components, or proximal femoral arthroplasty. One case could not be classified.

CONCLUSION

We endorse a modification of the original Vancouver system to include a subclassification of B2 fractures around cemented femoral prostheses to include B2W (where cement is well-fixed to bone) and B2L (where the cement is loose). Fractures around taper-slip design stems are more likely to fracture in a B2W pattern compared to fractures around composite beam design stems which are more likely to fracture in a B2L pattern. B2W fractures can reliably be managed with CinC revision. Cite this article: Bone Joint J 2021;103-B(1):71-78.

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

Union rate, complication rate, and opioid usage after Vancouver B periprosthetic femur fractures: a comparison of fracture types

INTRODUCTION

Periprosthetic femur fractures are complex injuries that can be difficult to treat and recover from. With a growing number of total hip arthroplasties (THA) and revision arthroplasties being performed in an aging population, the incidence of these injuries is on the rise. Multiple studies exist detailing outcomes associated with periprosthetic femur fractures after THA, but no study has directly compared the post-operative course between fracture types as classified by the Vancouver classification system. This study compares the three Vancouver B fracture types to see if any type is associated with an increase in post-operative complications than others.

MATERIALS AND METHODS

This retrospective chart review was conducted at a suburban orthopedic surgery department. Overall, 122 patients who presented to our hospital with periprosthetic proximal femur fractures after hip arthroplasty over the past 13 years were reviewed. Patients were included if they underwent surgical stabilization of their femur fracture. Patients were excluded if they underwent non-operative treatment or had missing chart information. For each patient, demographic information, fracture information, surgical information, post-operative course, and post-operative opioid usage were recorded and compared among groups.

RESULTS

Overall, 88 fractures were included. Fifty-five (62.5%) were Vancouver type B1, 27 (30.7%) were Vancouver type B2, and 6 (6.8%) were Vancouver type B3. Most of our patients were female (n = 62, 70.5%) and older than 81 years of age (n = 53, 60.2%) with uncemented prosthesis (n = 83, 94.3%). All three fracture groups had statistically similar union rates (p = 0.77), infection rates (p = 0.32), subsequent fractures (p = 0.63), repeat surgeries (p = 0.64), and post-operative opioid use (measured in milli-morphine equivalents) after surgical stabilization (p = 0.96).

CONCLUSIONS

While periprosthetic femur fractures after hip arthroplasty are associated with high complication rates and poor outcomes, there is no difference in union rate, infection rate, subsequent fractures, repeat surgery rate, and opioid usage between the different Vancouver B fracture types.

LEVEL OF EVIDENCE

Prognostic level III.

Lymphedema: A Significant Risk Factor for Infection and Implant Failure After Total Knee Arthroplasty

BACKGROUND

Lymphedema is characterized by fluid buildup and swelling, leading to skin fibrosis and recurring soft-tissue infections. There is a paucity of data examining the impact of lymphedema in total knee arthroplasty (TKA). The purpose of this study was to review the outcomes of TKA in patients with lymphedema compared with a matched cohort with primary osteoarthritis.

METHODS

One hundred forty-four knees underwent primary TKA with a preceding diagnosis of ipsilateral lymphedema. The mean follow-up was 7 years. A blinded 1:2 match of knees with lymphedema to a group of knees without lymphedema undergoing primary TKA was performed. Matching criteria included sex, age, date of surgery, and body mass index. The mean follow-up for the comparison cohort was 8 years.

RESULTS

Lymphedema increased revision hazard ratio [HR] 7.60; P < 0.001), reoperation (HR, 2.87; P < 0.001), and infection (HR, 6.19; P < 0.001) in addition to periprosthetic fracture (P = 0.04) and tibial component loosening (P = 0.01). The mean time to infection trended toward later time points in knees with lymphedema (19 versus 2 months, P = 0.25).

DISCUSSION

Lymphedema increased the risk of revision, reoperation, and infection. These data highlight the need for appropriate patient counseling and the need for further investigation into the effects of preoperative and postoperative optimization of lymphedema management in the TKA setting.

LEVEL OF EVIDENCE

Therapeutic Level III.

High Failure Rates of Locking Compression Plate Osteosynthesis with Transverse Fracture around a Well-Fixed Stem Tip for Periprosthetic Femoral Fracture

This study investigated the incidence of failure after locking compression plate (LCP) osteosynthesis around a well-fixed stem of periprosthetic femoral fractures (PFFs). We retrospectively evaluated outcomes of 63 Vancouver type B1 and C PFFs treated with LCP between May 2001 and February 2018. The mean follow-up duration was 47 months. Only patients with fracture fixation with a locking plate without supplemental allograft struts were included. We identified six periprosthetic fractures of proximal Vancouver B1 fractures with spiral pattern (Group A). Vancouver B1 fractures around the stem tip were grouped into seven transverse fracture patterns (Group B) and 38 other fracture patterns such as comminuted, oblique, or spiral (Group C). Vancouver C fractures comprised 12 periprosthetic fractures with spiral, comminuted, or oblique patterns (Group D). Fracture healing without complications was achieved in all six cases in Group A, 4/7 (57%) in Group B, 35/38 (92%) in Group C, and 11/12 (92%) in Group D, respectively. The failure rates of transverse Vancouver type B1 PFFs around the stem tip were significantly different from those of Vancouver type B1/C PFFs with other patterns. For fracture with transverse pattern around the stem tip, additional fixation is necessary because LCP osteosynthesis has high failure rates.

Onlay fibula autografting technique and its comparison with cortical allograft for the reconstruction of periprosthetic bone defects around the femur

BACKGROUND

Bone defect around the femur related to revisions or periprosthetic fractures (PFF) is an issue. We present a bone defect reconstruction technique in femoral revisions and/or PFF using fibula autograft and compared our radiological and clinical results to that of allograft.

METHODS

A total of 53 patients who underwent revision hip arthroplasty and/or PFF fixation with the use of cortical fibula autograft (FG group) or cortical allograft (CG group) were evaluated. After exclusions, 20 patients who had minimum two years of follow-up were investigated for each group, for their radiological and clinical outcomes.

RESULTS

In FG and CG groups, the median ages were 69.5(44-90) and 62(38-88) years, follow-ups were 59(28-72) and 120(48-216) months, defect lengths were seven (1-10) and ten (1-17) cm, and grafts lengths were 16.5(10-30) and 20(12-37) cm, respectively. The rate of graft incorporation was 90% in each group and median time to incorporations were seven (4-12) and 12(6-24) months (p < 0.001), and graft resorption (moderate and severe) rates were 10% and 25% (p = 0.41), respectively. Median Harris Hip (77.6 vs 78.0), WOMAC (23.2 vs 22), SF-12 physical (50.0 vs 46.1), and SF-12 mental (53.8 vs 52.5) scores were similar between the groups, respectively. Kaplan-Meier survivorship analyses revealed an estimated mean survival of 100% at six years in FG group and 90% at 14 years in CG group.

CONCLUSION

In the reconstruction of periprosthetic bone defects after femoral revision or PPF, onlay cortical fibula autografts provide comparable clinical and radiological outcomes to allografts. Its incorporation is faster, it is cost-effective and easy to obtain without apparent morbidity.

Periprosthetic fracture fixation in Vancouver B1 femoral shaft fractures: A biomechanical study comparing two plate systems

Introduction

Periprosthetic fractures of the femur are an increasing problem in today's trauma and orthopaedic surgery. Owing to the hip stem, implant anchorage is very difficult in the proximal femur. This study compares two plate systems regarding their biomechanical properties and the handling in periprosthetic fracture fixation of the proximal femur.

Materials and methods

Using eight pairs of fresh, frozen human proximal femora the Locking Compression Plate/Locking Attachment Plate construct (LCP/LAP) (group I, DePuy Synthes) was compared to the new LOQTEQ® periprosthetic distal lateral femur plate (group II, AAP Implantate AG). After implantation of press fit femoral hip stems a Vancouver B1 fracture model was used. Biomechanical testing was performed by cyclic axial loading with a constant increment of 0.1 N/cycle starting from 750 N axial loading. Every 250 cycles an a.p. x-ray was done to evaluate failure.

Results

The Group II showed significant higher axial stiffness (+42%) compared with Group I. In addition, Group II withstood significantly more load-cycles until failure (20%). The mode of catastrophic failure was plate breakage in Group II, whereas, in Group I, all plates showed an early bending followed by plate breakage.

Discussion and conclusion

Both plate systems enable screw placement around hip stems. The hinge plate showed superior biomechanical results compared with the locking compression plate/locking attachment plate construct. Furthermore, the hinge plate offers variable hinges and variable angel locking making bicortical screw placement around hip stems more comfortable and safe.

The translational potential of this article

The results of this study can be directly transferred to patient care. With the innovative hinge plate, the surgeon has a biomechanically superior implant, which also offers improved options for screw placement compared to a standard locking plate.

Biomechanics of Implant Fixation in Osteoporotic Bone

PURPOSE OF REVIEW

The purpose of this review is to critically evaluate the current literature regarding implant fixation in osteoporotic bone.

RECENT FINDINGS

Clinical studies have not only demonstrated the growing prevalence of osteoporosis in patients undergoing total joint replacement (TJR) but may also indicate a significant gap in screening and treatment of this comorbidity. Osteoporosis negatively impacts bone in multiple ways beyond the mere loss of bone mass, including compromising skeletal regenerative capacity, architectural deterioration, and bone matrix quality, all of which could diminish implant fixation. Recent findings both in preclinical animal models and in clinical studies indicate encouraging results for the use of osteoporosis drugs to promote implant fixation. Implant fixation in osteoporotic bone presents an increasing clinical challenge that may be benefitted by increased screening and usage of osteoporosis drugs.

Validity and reliability of the Unified Classification System applied to periprosthetic femur fractures: a comparison with the Vancouver system

Objective: The Unified Classification System (UCS) presents itself as an evolution of the Vancouver Classification (VCS) for the evaluation of periprosthetic fractures of the proximal femur (PPF). The aim of our study was to highlight any loss of reproducibility or validity of the new classification system, compared to the previous one.Material and methods: We tested the interobserver and intraobserver agreement using 40 PPF clinical cases. Each classifying subtype of the UCS and VCS was present in at least two cases. Six experienced hip surgeons (Senior Surgeon, SS) and 5 surgeons in training (Junior Surgeon, JS) classified the clinical cases, using VCS and UCS. The validity of both classifications was then tested with intraoperative surveys.Results: The mean κ value for interobserver agreement for the VCS in the JS group was 0.65 and 0.81 for the SS group. The mean κ value for interobserver agreement for the UCS in the JS group was 0.63 and 0.65 for the SS group. The mean κ value for intraobserver agreement for the VCS in the JS group was 0.71 and 0.73 for the SS group. The mean κ value for intraobserver agreement for the UCS in the JS group was 0.72 and 0.7 for the SS group. Validity analysis showed a moderate agreement for the VCS and a good agreement for the UCS.Conclusion: The UCS completes the Vancouver classification, expanding it. It is reliable, despite the increase in classification categories and number of parameters to evaluate, with a slightly higher validity.

Risk Factors for Wound Complications After Periprosthetic Fractures

The number of hip and knee arthroplasties performed annually continues to rise. Revision rates are projected to increase by 137% to 601%, with periprosthetic fractures to be among the leading cause of revision. Wound complications following surgical treatment of periprosthetic fractures are a major source of patient morbidity and health care costs. This study evaluated risk factors for wound healing complications in patients undergoing surgical management of periprosthetic fractures around the hip and knee. This was a retrospective analysis of 67 consecutive lower-extremity periprosthetic hip and knee fracture surgeries. Descriptive data, comorbidities, dressing type, and rates of wound complications treated nonoperatively and operatively were collected. Logistic regression analysis was performed to calculate odds ratios (ORs) of having a wound complication. There was an overall wound complication rate of 22%; the majority of these complications (16%) were treated operatively. On multivariate analysis, prior bariatric surgery (OR, 12.02; 95% confidence interval [CI], 1.24-116.71; P=.03), peripheral vascular disease (OR, 6.84; 95% CI, 1.32-35.39; P=.02), and pulmonary disease (OR, 11.23; 95% CI, 1.85-68.31; P=.01) were all associated with an increased risk of developing a wound complication. Closed-incision negative-pressure therapy was associated with a decreased risk of developing a wound complication (OR, 0.04; 95% CI, 0.00-0.49, P=.01). Surgery to treat hip and knee periprosthetic fractures is associated with a high rate of wound complications. History of bariatric surgery, peripheral vascular disease, and pulmonary disease are all associated with an increased risk of developing a wound complication. Future payment models should reflect this elevated level of complications and risk. [Orthopedics. 2020;43(4):e258-e262.].

[Periprosthetic fractures of the proximal femur]

The incidence of periprosthetic fractures of the proximal femur is increasing due to the growing numbers of hip replacements in old age. The treatment of these fractures is a challenge for the treating physician and standardized procedures are necessary. The unified classification system (UCS) is a suitable tool to establish treatment strategies: On the basis of the fracture localization and extent, bone quality, stability of the prosthesis and the presence of further implants, the fractures can be classified according to the UCS and a treatment algorithm can be derived. This article gives an overview of the diagnostics, classification and characteristics of the various periprosthetic fracture types as well as the treatment.

Surgical treatment of peri-prosthetic femur fractures with dedicated NCB plates: our experience

Background and aim of the work:

The incidence of periprostethic femur fractures has increased over the last years; the treatment includes an open reduction and internal fixation or revision implant. The treatment of these fractures can be complex, expensive and associated with risks of systemic and local complications.

Methods:

We evaluated clinical and radiological results in patients treated in our department for periprosthetic femoral fractures from 2011 to 2017. We included 52 cases of periprosthetic fractures regardless of their classification with a mean follow-up of 2 years. The analisys of the result was performed using Harris Hip Score and searching for radiographic signs of loosening, infections or mechanical failure of the implants.

Results:

There was no evidence of septic complications or mechanical failure in cases treated. The average HHS was equal to 92 points with a certificate pain relief and a sufficient independence in daily living activities.

Conclusions:

The treatment of periprosthetic fractures is complex: it depends on type of fracture, on stability of the stem and on the bone quality. A right classification of the fractures, a good experience of the surgeon in prosthetic and trauma surgery is the basis for the best treatment. (www.actabiomedica.it)

Treatment Outcomes for Periprosthetic Femoral Fractures in Cementless Press-Fit Total Hip Replacement

OBJECTIVE

 The aim of this study was to report outcomes in dogs with periprosthetic femoral fractures associated with a press-fit cementless femoral total hip replacement implant.

MATERIALS AND METHODS

 Electronic medical records and digital radiographs were used to identify dogs with periprosthetic femoral fractures associated with press-fit cementless total hip replacement. Data collected included signalment, weight, time of fracture, cause of fracture, presence of intra-operative fissure, fracture type, repair technique, and clinical and radiographic outcomes. Long-term patient outcome was assessed by communication with owners or referring veterinarians.

RESULTS

 Twenty-eight dogs with femoral fracture repair associated with cementless press-fit total hip replacement were identified. Eight of the fractures occurred intraoperatively and 20 occurred at a median of 2 days postoperatively. An oblique or spiral configuration was noted in 19 cases and 15 occurred at the distal end of the femoral stem (type B), with thirteen type B1, one type B2 and one type B3 fractures. Fractures were repaired with non-locking (18/28) or locking-plate fixation (10/28). Cerclage wire was applied around the plate and proximal bone segment in 17/28 dogs. Major complications occurred in 7/28 cases (five deep infection, two mechanical failures). Bone healing was noted in 21/23 cases, for which follow-up radiographic interpretation was available. Return to function was complete in 17 cases, acceptable in 8 cases and unacceptable in 3 cases.

CONCLUSIONS

 While cementless total hip replacement periprosthetic femoral fractures can be successfully repaired with lateral plate fixation, the risk of infection appears to be high.

Treatment and outcomes of Vancouver type B periprosthetic femoral fractures

Aims

Vancouver type B periprosthetic femoral fractures (PFF) are challenging complications after total hip arthroplasty (THA), and some treatment controversies remain. The objectives of this study were: to evaluate the short-to-mid-term clinical outcomes after treatment of Vancouver type B PFF and to compare postoperative outcome in subgroups according to classifications and treatments; to report the clinical outcomes after conservative treatment; and to identify risk factors for postoperative complications in Vancouver type B PFF.

Methods

A total of 97 consecutive PPFs (49 males and 48 females) were included with a mean age of 66 years (standard deviation (SD) 14.9). Of these, 86 patients were treated with surgery and 11 were treated conservatively. All living patients had a minimum two-year follow-up. Patient demographics details, fracture healing, functional scores, and complications were assessed. Clinical outcomes between internal fixation and revisions in patients with or without a stable femoral component were compared. Conservatively treated PPFs were evaluated in terms of mortality and healing status. A logistic regression analysis was performed to identify risk factors for complications.

Results

In surgically treated patients, all fractures united and nine complications were identified. The mean postoperative Visual Analogue Scale (VAS) for pain was 1.5 (SD 1.3), mean Parker Mobility Score (PMS) was 6.5 (SD 2.4), and mean Harris Hip Score (HHS) was 79.4 (SD 16.2). Among type B2 and type B3 fractures, patients treated with internal fixation had significantly lower PMS (p = 0.032) and required a longer time to heal (p = 0.012). In conservatively treated patients, one-year mortality rate was 36.4% (4/11), and two patients ultimately progressed to surgery. Young age (p = 0.039) was found to be the only risk factor for complications.

Conclusion

The overall clinical outcome among Vancouver type B PFF was satisfactory. However, treatment with internal fixation in type B2 and B3 fractures had a significantly longer time to heal and lower mobility than revision cases. Conservative treatment was associated with high rates of early mortality and, in survivors, nonunion. This probably reflects our selection bias in undertaking surgical intervention. In our whole cohort, younger patient age was a risk factor for postoperative complications in Vancouver type B PFF. Cite this article: Bone Joint J 2020;102-B(3):293–300

Cable plate fixation for Vancouver Type-B1 periprosthetic femoral fractures-Our experience and identification of a subset at risk of non-union

INTRODUCTION

Management of periprosthetic femoral fractures is challenging. Vancouver classification is universally accepted for fracture description and management algorithm. Guidelines for the treatment of type B1 fracture is open reduction and internal fixation. The difficulty involved in managing this group is evidenced by the array of treatment options described in the literature.

METHODS

Thirty two patients with Vancouver type B1 fracture treated with osteosynthesis using cable plate (between 2007 and 2015) were reviewed retrospectively. There were 21 females and 11 males with an average age of 81yrs (56-96 years). The average follow-up was 21 months. All patients were reviewed clinically and radiologically until fracture united or patient re-operated. Postoperative protocol followed was six weeks toe touch weight bearing, 6 weeks partial weight bearing and then full weight bearing if there was no displacement. Post-operative radiographs were evaluated for fracture union. Statistical analysis was done using contingency tables with Fishers exact test and a p-value < 0.05 for significance.

RESULTS

In twenty four patients fracture union was achieved. Non-union was recorded in four patients. Comparing the different fracture patterns all non-unions occurred in the fractures which were short oblique or transverse at the cemented stem tip (p = 0.001). Fractures were more common in female patients and associated more with the uncemented femoral stems, but it was not associated with increased rate of non-union (p = 0.68). All failed osteosynthesis were revised successfully using long stem prosthesis. Two patients died within 2 months, one patient died within 4 months, one patient was lost to follow-up.

CONCLUSION

Transverse or short oblique periprosthetic fractures around tip of cemented femoral stems can have high failure rates with just internal fixation. Revision arthroplasty may be the preferred option if possible otherwise may need to supplement fixation with cortical onlay graft. We should consider subcategorising Vancouver type B1 periprosthetic fractures into groups based on the pattern and fracture level in relation to the femoral stem.