Treatment of B1 Distal Periprosthetic Femur Fractures.

The burden of periprosthetic distal femoral fractures is projected to increase accordingly with the increase in total knee arthroplasties (TKAs) performed globally in the future. Less invasive plating and intramedullary (IM) nailing techniques still seem to provide similar outcomes based on current literature. Double-plating and combination techniques may prove to be beneficial in the future pending further large-scale studies but currently have not demonstrated superiority over single plating and IM nailing based on current evidence. Distal femoral replacement may provide a useful option for future treatment, provided it is performed by a trained knee arthroplasty surgeon.

Classification and Management of Periprosthetic Patella Fractures.

Complications related to the extensor mechanism and patellofemoral joint continue to be the most common cause of pain and indication for surgical revision following total knee arthroplasty. Numerous risk factors related to the patient, implant, and technical performance of the procedure have been identified. The Ortiguera and Berry classification system is widely used for the systematic classification and management of these fractures. Because of the difficult nature of revision surgery for fracture and the high risk of complication, a careful assessment of the fracture and implants is vital to determining the best course of treatment.

Reliability and validity of the Unified Classification System for postoperative periprosthetic femoral fractures around cemented polished taper-slip stems.

AIMS: This aim of this study was to assess the reliability and validity of the Unified Classification System (UCS) for postoperative periprosthetic femoral fractures (PFFs) around cemented polished taper-slip (PTS) stems. METHODS: Radiographs of 71 patients with a PFF admitted consecutively at two centres between 25 February 2012 and 19 May 2020 were collated by an independent investigator. Six observers (three hip consultants and three trainees) were familiarized with the UCS. Each PFF was classified on two separate occasions, with a mean time between assessments of 22.7 days (16 to 29). Interobserver reliability for more than two observers was assessed using percentage agreement and Fleiss' kappa statistic. Intraobserver reliability between two observers was calculated with Cohen kappa statistic. Validity was tested on surgically managed UCS type B PFFs where stem stability was documented in operation notes (n = 50). Validity was assessed using percentage agreement and Cohen kappa statistic between radiological assessment and intraoperative findings. Kappa statistics were interpreted using Landis and Koch criteria. All six observers were blinded to operation notes and postoperative radiographs. RESULTS: Interobserver reliability percentage agreement was 58.5% and the overall kappa value was 0.442 (moderate agreement). Lowest kappa values were seen for type B fractures (0.095 to 0.360). The mean intraobserver reliability kappa value was 0.672 (0.447 to 0.867), indicating substantial agreement. Validity percentage agreement was 65.7% and the mean kappa value was 0.300 (0.160 to 0.4400) indicating only fair agreement. CONCLUSION: This study demonstrates that the UCS is unsatisfactory for the classification of PFFs around PTS stems, and that it has considerably lower reliability and validity than previously described for other stem types. Radiological PTS stem loosening in the presence of PFF is poorly defined and formal intraoperative testing of stem stability is recommended. Cite this article: Bone Joint J 2021;103-B(8):1339-1344.

Outcomes of operatively treated interprosthetic femoral fractures.

AIMS: The prevalence of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is rising in concert with life expectancy, putting more patients at risk for interprosthetic femur fractures (IPFFs). Our study aimed to assess treatment methodologies, implant survivorship, and IPFF clinical outcomes. METHODS: A total of 76 patients treated for an IPFF from February 1985 to April 2018 were reviewed. Prior to fracture, at the hip/knee sites respectively, 46 femora had primary/primary, 21 had revision/primary, three had primary/revision, and six had revision/revision components. Mean age and BMI were 74 years (33 to 99) and 30 kg/m2 (21 to 46), respectively. Mean follow-up after fracture treatment was seven years (2 to 24). RESULTS: Overall, 59 fractures were classified as Vancouver C (Unified Classification System (UCS) D), 17 were Vancouver B (UCS B). In total, 57 patients (75%) were treated with open reduction and internal fixation (ORIF); three developed nonunion, three developed periprosthetic joint infection, and two developed aseptic loosening. In all, 18 patients (24%) underwent revision arthroplasty including 13 revision THAs, four distal femoral arthroplasties (DFAs), and one revision TKA: of these, one patient developed aseptic loosening and two developed nonunion. Survivorship free from any reoperation was 82% (95% confidence interval (CI) 66.9% to 90.6%) and 77% (95% CI 49.4% to 90.7%) in the ORIF and revision groups at two years, respectively. ORIF patients who went on to union tended to have stemmed knee components and greater mean interprosthetic distance (IPD = 189 mm (SD 73.6) vs 163 mm (SD 36.7); p = 0.546) than nonunited fractures. Patients who went on to nonunion in the revision arthroplasty group had higher medullary diameter: cortical width ratio (2.5 (SD 1.7) vs 1.3 (SD 0.3); p = 0.008) and lower IPD (36 mm (SD 30.6) vs 214 mm (SD 32.1); p < 0.001). At latest follow-up, 95% of patients (n = 72) were ambulatory. CONCLUSION: Interprosthetic femur fractures are technically and biologically challenging cases. Individualized approaches to internal fixation versus revision arthroplasty led to an 81% (95% CI 68.3% to 88.6%) survivorship free from reoperation at two years with 95% of patients ambulatory. Continued improvements in management are warranted. Cite this article: Bone Joint J 2021;103-B(7 Supple B):122-128.

Selected Vancouver B2 periprosthetic femoral fractures around cemented polished femoral components can be safely treated with osteosynthesis.

AIMS: We aimed to compare the implant survival, complications, readmissions, and mortality of Vancouver B2 periprosthetic femoral fractures (PFFs) treated with internal fixation with that of B1 PFFs treated with internal fixation and B2 fractures treated with revision arthroplasty. METHODS: We retrospectively reviewed the data of 112 PFFs, of which 47 (42%) B1 and 27 (24%) B2 PFFs were treated with internal fixation, whereas 38 (34%) B2 fractures underwent revision arthroplasty. Decision to perform internal fixation for B2 PFFs was based on specific radiological (polished femoral components, intact bone-cement interface) and clinical criteria (low-demand patient). Median follow-up was 36.4 months (24 to 60). Implant survival and mortality over time were estimated with the Kaplan-Meier method. Adverse events (measured with a modified Dindo-Clavien classification) and 90-day readmissions were additionally compared between groups. RESULTS: In all, nine (8.01%) surgical failures were detected. All failures occurred within the first 24 months following surgery. The 24-month implant survival was 95.4% (95% confidence interval (CI) 89.13 to 100) for B1 fractures treated with internal fixation, 90% (95% CI 76.86 to 100) for B2 PFFs treated with osteosynthesis-only, and 85.8% (95% CI 74.24 to 97.36) for B2 fractures treated with revision THA, without significant differences between groups (p = 0.296). Readmissions and major adverse events including mortality were overall high, but similar between groups (p > 0.05). The two-year patient survival rate was 87.1% (95% CI 77.49 to 95.76), 66.7% (95% CI 48.86 to 84.53), and 84.2% (95% CI 72.63 to 95.76), for the B1 group, B2 osteosynthesis group, and B2 revision group, respectively (p = 0.102). CONCLUSION: Implant survival in Vancouver B2 PFFs treated with internal fixation was similar to that of B1 fractures treated with the same method and to B2 PFFs treated with revision arthroplasty. Low-demand, elderly patients with B2 fractures around well-cemented polished femoral components with an intact bone-cement interface can be safely treated with internal fixation. Cite this article: Bone Joint J 2021;103-B(7):1222-1230.

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.

The inverted Vancouver C fracture. Case series of unstable proximal femur fractures above a knee revision stem treated by short cephalomedullary nail and lateral submuscular overlapping plate.

Unstable proximal femur fractures above a knee revision stem are an emerging complication that is especially difficult to treat. Since this pattern does not adapt to any previously reported classification, we named it "inverted Vancouver C fracture". In this single-centre case series, we pose a nail-plate combination for the treatment of such clinical picture. The incidence was low among proximal and implant-related femoral fractures. All the fractures healed without records of major local complications. Thus, we consider this technique safe and reproducible.

Atypical periprosthetic femoral fracture associated with long-term bisphosphonate therapy.

BACKGROUND: Atypical femoral fracture is one of the many complications after the long-term use of bisphosphonates. The American Society for Bone and Mineral Research has officially excluded periprosthetic femoral fractures (PFFs) from the definition of atypical femoral fractures (AFFs). Several case reports found that PFFs can occur with characteristics similar to those of AFFs. The purpose of our study was to evaluate the proportion of atypical fractures among Vancouver type B1 fractures, and to determine the association between the long-term use of bisphosphonates and the occurrence of atypical periprosthetic femoral fractures (APFFs). METHODS: In this retrospective study, we reviewed 41 patients with Vancouver type B1 periprosthetic fractures between January 1, 2011 and December 31, 2018. We classified them into two groups, namely atypical and typical PFFs, based on the fracture morphology. We noted the proportion of atypical periprosthetic fractures among B1 fractures and identified risk factors. RESULTS: Among the 41 PFFs, 5 (13%) fractures were classified as atypical PFF based on the radiological characteristics. The longer duration of bisphosphonate use was probably the only independent risk factor that significantly increases the occurrence of APFF (p = 0.03, 0.08 (CI 0.008 - 0.16)). There were no significant differences in age, gender, body mass index, comorbidities, corticosteroid use, positioning of the femoral stem, the method of fixation (cemented or cementless) and time lapse from before the primary prosthesis implantation to the PFF in the development of atypical fracture type. CONCLUSIONS: There seems to be a correlation between the long-term intake of bisphosphonates and the atypical periprosthetic fracture. Atypical femoral fracture can also occur in the periprosthetic form. TRIAL REGISTRATION: Study number: 22/2019-SZTE, http://www.klinikaikutatas.hu/hu/kutatasetika/jovahagyott-vizsgalatok-koezerdeku-adatai/category/25-jovahagyott-vizsgalatok-kozerdeku-adatai-rkeb-2019.html?download=985:22-2019 .

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.

Peri-implant fractures around hindfoot fusion nails: A systematic literature review and classification system.

BACKGROUND: Tibio-talo calcaneal (TTC) arthrodesis is increasingly performed for hindfoot arthrosis and other indications. Peri-implant fracture around hindfoot fusion nails has been previously reported and can be problematic to treat given multiple surgical considerations including the status of hindfoot arthrodesis at time of fracture. We present a systematic review of the literature regarding peri-implant fractures around hindfoot fusion nails and propose a classification system to help guide treatment based on findings from the current literature as well as the collective experience of the senior authors. METHODS: A review of the literature was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify clinical investigations in which peri-implant fractures or other hardware failures were observed as complications following TTC arthrodesis using hindfoot nails. The electronic database of PubMed/Medline/Cochrane Library was explored using specific search terms. Inclusion criteria was any clinical investigation that reported on outcomes after TTC arthrodesis using a hindfoot nail in at least one patient. Cadaveric and non-clinical investigations were excluded. RESULTS: A total of 36 studies were identified which met inclusion criteria and reported clinical outcomes after TTC arthrodesis using a hindfoot fusion nail. Of the 36 studies, there was a total of 13 intraoperative fractures, 43 tibial stress fractures and 24 peri-implant fractures recorded in 12 of the 36 studies. CONCLUSION: Peri-implant fracture following tibio-talo calcaneal arthrodesis using a hindfoot intramedullary nail is an uncommon but problematic condition to treat. General heterogeneity of patients and indications as well as a lack of descriptive detail in the current literature makes meta-analysis difficult. Given the lack of consensus on treatment, a classification system may be helpful to guide clinical practice.

Incidence and pattern of periprosthetic hip fractures around the stem in different stem geometry.

BACKGROUND: The number of total hip arthroplasties (THA) is expected to increase worldwide; thus, complications are likely to increase at the same ratio. In this scenario, periprosthetic femoral fractures (PFFs) are an increasing concern. Identifying the predisposing factors is important in order to prevent as much as possible the risk of PFF in the future. PATIENTS AND METHODS: The purpose of this study was to correlate the risk of periprosthetic femoral fractures to the most common patients' comorbidities and stem geometry. We reviewed all THA for non-oncologic indications between 2004 and 2014 with a mean follow-up of six years (range, 2-12). Three thousand two hundred forty-eight patients (3593 implants) were enrolled in the study, and 45 PFF were registered during this time period. Two thousand five hundred seventy-seven implants (71%) were straight stems, and 1015 (28.3%) were anatomic stems. All X-rays were then analyzed and classified according to the modified Vancouver classification. RESULTS: Periprosthetic femoral fractures incidence was associated with anatomic stem geometry (p < 0.001, OR = 2.2), BMI (p < 0.001), and diabetes (p < 0.001, OR = 5.18). PFFs were not significantly associated with age, gender, and all the other variables. Fracture pattern was different between straight and anatomic stems. Clamshell fractures were more likely to occur in anatomic stems compared to straight stems (p < 0.005). CONCLUSIONS: Periprosthetic femoral fractures are highly associated with obesity and osteoporosis. Anatomic stems reported a higher incidence of PPF than straight stems. The typical fracture type for anatomical stems is the clamshell pattern, while straight stems are more likely affected by type B fractures.

Periprosthetic fractures about total knee arthroplasty.

Periprosthetic fracture after total knee arthroplasty presents a difficult complication for many orthopaedic surgeons. These fractures occur most frequently around the distal femur followed by the patella and then tibia. These fractures are frequently complicated by poor bone quality or compromised bone due to the presence of the implants. Surgical treatment is typically necessary and requires varied techniques of open fixation, intramedullary fixation, or revision arthroplasty. Outcomes of these injuries vary widely. This review aims to describe the epidemiology, classification, treatment options and outcomes for periprosthetic fractures following total knee arthroplasty.

Previous Implant Fractures: A New Descriptive Classification System.

OBJECTIVES: To propose a previous implant fractures (PIFs) classification system with good interobserver reliability. DESIGN: Retrospective classification. SETTING: Four academic medical centers. PATIENTS/PARTICIPANTS: A retrospective review of PIFs treated at 4 academic medical centers over 10 years was performed. Data collected included initial implant and PIF radiographs. There were 103 PIFs in 96 patients during the study period. Seventy-three (70.9%) were about plate/screw (PS) constructs and 30 (29.1%) were about intramedullary (IM) devices. INTERVENTION: Assignment of PIF classification. MAIN OUTCOME MEASUREMENTS: PIFs were classified based on initial implant (PS or IM) and fracture location with respect to the initial implant (proximal or distal to the implant, at the tip of the construct, or within the construct). Reliability of this scheme was assessed among 5 observers using Fleiss' kappa tests. RESULTS: Of PIFs about plate/screw constructs, 26.0% were proximal/distal to the implant (classification: PS1), 57.5% involved bone between the most proximal/distal screw and the same end of the plate (classification: PS2), and 16.4% involved only bone between the most proximal and distal screws (classification: PS3). Of PIFs about IM, 43.3% were distal to the device (classification: IM1), 46.7% involved bone between the most proximal/distal locking bolt and the same end of the device (classification: IM2), and 10.0% involved only bone between locking bolts (classification: IM3). Interobserver reliability for the classification system was excellent between observers, κ = 0.839, P < 0.0005. CONCLUSIONS: The proposed system offers a simple method to classify and describe fractures that occur about a previously implanted fracture device. Development of a classification system will allow for comparison of treatment modalities between injury types.

Incidence, Classification, and Risk Factors for Intraoperative Periprosthetic Femoral Fractures in Patients Undergoing Total Hip Arthroplasty With a Single Stem: A Retrospective Study.

BACKGROUND: The collum femoris preserving (CFP) stem was a specially designed femoral neck preserving component. The incidence, classification, and risk factors for intraoperative periprosthetic femoral fractures with this special stem remain unclear. METHODS: This was a retrospective study. We analyzed the clinical and radiological data of all patients who underwent primary hip arthroplasty with a CFP stem in our hospital between January 2006 and November 2018. Demographic characteristics and radiological features were obtained from the medical records and the Picture Archiving and Communication System, respectively. The incidence, Vancouver classification, and risk factors for intraoperative periprosthetic femoral fractures were identified. RESULTS: A total of 1633 hips were included. The incidence rate of periprosthetic femoral fractures in patients undergoing total hip arthroplasty with a CFP stem was 3.2%. According to the Vancouver classification, there were 24 patients (45.3%) with Vancouver type A fractures, 27 patients (50.9%) with Vancouver type B fractures, and 2 patients (3.8%) with Vancouver type C fractures. Five independent risk (protective) factors were found, including surgical history (odds ratio [OR] = 3.275, 95% confidence interval [CI] = 1.192-8.997), neck-shaft angle (OR = 1.104, 95% CI = 1.058-1.152), neck length preserved (OR = 0.913, 95% CI = 0.850-0.980), canal flare index (OR = 0.636, 95% CI = 0.413-0.980), and bone mineral density (OR = 0.083, 95% CI = 0.016-0.417). CONCLUSION: The detailed characteristics of intraoperative periprosthetic femoral fractures in patients who received a CFP stem were identified in this study. Cracks of the femoral neck and fractures on the front side of the proximal femur were more common in patients with CFP stems. As a kind of a femoral neck preserving stem, the anatomical features (eg, neck-shaft angle, preserving length) of the remaining femoral neck might influence the incidence and characteristics of intraoperative periprosthetic femoral fractures in patients with CFP stems.

Reliability of the commonly used classification systems for interprosthetic fractures.

OBJECTIVES: An interprosthetic fracture occurs between a hip and knee arthroplasty. There is currently no universally agreed classification. The aim of this study was to determine the interobserver and intraobserver reliability of the most commonly used interprosthetic fracture classifications. METHODS: Nineteen interprosthetic fractures were classified by four reviewers for inter- and intraobserver reliability. The most commonly used interprosthetic fracture classifications were the Soenen classification, Platzer classification, and Pires classification. Cohen's kappa coefficient was calculated. RESULTS: A moderate interobserver reliability was found for all the classification systems. The Platzer classification had a kappa value of 0.586, the Pires classification 0.499, and Soenen classification 0.489. The intraobserver error was 0.767 for the Platzer classification (substantial agreement), 0.636 for the Pires classification (substantial agreement), and 0.318 for the Soenen classification (fair agreement). CONCLUSIONS: This study has demonstrated moderate interobserver reliability and substantial intraobserver reliability for both the Platzer and Pires classifications. This paper would recommend the use of either classification for interprosthetic fractures.

Reliability and Validity of the Vancouver Classification in Periprosthetic Fractures Around Cementless Femoral Stems.

BACKGROUND: The Vancouver classification of periprosthetic femur fractures divides B1 and B2 subtypes based on the stability of the femoral stem. However, this classification was described and validated with cemented femoral stems. We sought to assess reliability and validity of the Vancouver classification in patients with cementless femoral stems. METHODS: This is a blinded radiographic study which included patients treated for Vancouver B cementless periprosthetic femur fractures between February 2007 and December 2017. Adult reconstruction-trained and trauma fellowship-trained orthopedic surgeons graded all preoperative radiographs using the Vancouver classification on 3 separate occasions. Interobserver and intraobserver reliability was assessed via the Fleiss' kappa statistic. Validity was assessed via accuracy between radiographic and intraoperative assessments. The Landis and Koch criteria were used to interpret the kappa values. RESULTS: Fifty-three patients with Vancouver B fractures (B1, 8; B2, 45) around a cementless femoral stem were included in the study. Five reconstruction-trained and 5 trauma-trained orthopedic surgeons graded all radiographs. The interobserver reliability kappa value was 0.45 (moderate agreement), with all raters agreeing on only 43% of radiographs. Validity analysis showed demonstrated 79% agreement. Overall, 20% (range, 14%-24%) of unstable B2 fractures were misread as B1 fractures. Intraobserver reliability was 0.71 between readings. CONCLUSION: The reliability of the Vancouver classification for cementless total hip arthroplasty is lower than previously described in cemented femoral stems. Radiographic assessment alone may be inadequate for determination of stability of cementless stems in periprosthetic femur fractures. LEVEL OF EVIDENCE: Level III therapeutic study: retrospective comparative study.

Diagnosis and management of periprosthetic femoral fractures after hip arthroplasty.

INTRODUCTION: Periprosthetic femoral fracture represent a severe complication, at present the third cause of revision surgery, with an estimated incidence from 0,1 to 2,1%. The number of these fracture can be expect to increase in line with the aging of population and amount of THA implants also in younger high demanding patients. MATERIALS AND METHODS: The aim of this study is analyze the diagnostic and therapeutic decision making processes performed in 64 patients with periprosthetic fractures treated surgically from January 2012 and October 2016 in our center. We analysed instrumental exams and surgical reports focusing on type of procedure, surgical access, operative time and type of fixation. RESULTS: Average age was 809 years and a mean follow-up 231 months. According to Vancouver system and after X-rays, CT scan and intraoperative evaluation, 26 fractures were classified as type B1, 31 as type B2, 3 type B3 and 4 type C. Follow up results were divided on the basis of the surgical treatment: in ORIF group (23 type B1 fractures and 4 type C fracture) fracture union was obtained in 16 cases (593%) and the final HHS mean value was 6161; in Revision group (3 type B1, 31 type B2 and 3 type B3) bone healing was reported in 26 cases (703%) with mean HHS score of 7194. CONCLUSIONS: In this surgery the objectives are provide an adequate bone healing and return to previous functional status as soon as possible. Many reasons make these goals challenging, in particular advanced age, osteoporosis, co-morbidity and weakness that lead to low energy trauma, the most frequent cause of these injuries. In our opinion a crucial aspect is the evaluation of stem stability, considering an implant mobilized until the opposite is clearly evident. Reduction of surgical time and early mobilization are goals of this surgery, often associated with several complications and high mortality rate.

Proposal for the classification of peri-implant femoral fractures: Retrospective cohort study.

Background Peri-implant fractures occur in association with an implant used to treat a previous injury and that is still attached to the bone. Peri-implant fractures are considered to be relatively "new" fractures and they lack any classification system that is accepted in practice. Generally, the fracture classification systems currently used in our clinical practice were not developed or validated using rigorous scientific evaluation methods. Aim To provide data for a proposed classification of peri-implant femoral fractures. Methods This is an international and multicentre study (12 centres) based on a cohort of consecutive peri-implant fractures with the criterion being: a fracture in any segment of the femur in association with previously-used osteosynthesis material, whether a nail, plate or screws. A proposed system for the classification was tested, based on a topographical classification using alphanumeric coding, following a similar nomenclature to that explained in the "Vancouver-Classification-for-Total-Hip-Arthroplasty-Periprosthetic-Fractures", and classified according to whether the implant is a nail, a screw or a plate, and the location of the fracture in relation to the original implant and the affected femoral segment. The study coordinator performed the first classification exercise, which was discussed subsequently for the study coordinator group to reach a consensus. A descriptive analysis of the fractures was produced. The proportion of peri-implant femoral fractures was estimated, and 95% confidence interval (95%CI) was calculated. Results Between January 2013 and December 2016, data on a total of 143 peri-implant femoral fractures were collected. Only 5 (3.5%) fractures had to be discussed to reach a consensus. The most common peri-implant femoral fractures were located at the diaphyseal segment (#32) and associated with nails or plates: 51%, 73/143, 95%CI:43-59%; at the proximal segment (#31): 39%, 56/143, 95%CI:32-47%; and at the distal femoral segment (#33): 10%, 14/143, 95%CI:6-16%. The highest proportion of peri-implant femoral fractures corresponded to #31-AN (trochanteric and neck area) and #32-CNP (diaphysis fractures distant from the implant, often distal and spiral). Conclusion The proposed classification for peri-implant femoral fractures appears to be useful and easy to accomplish. Future studies will be necessary to validate it and demonstrate the effectiveness of its application in clinical practice.

Reproducibility of the Dorr classification and its quantitative indices on plain radiographs.

BACKGROUND: The Dorr classification is widely used to evaluate femoral bone quality, but it has no clear quantitative criteria. This study aimed to evaluate the reproducibility of the Dorr classification and examine its quantitative indices on plain radiographs, which are suitable for objective classification. HYPOTHESIS: Reproducibility of the Dorr classification is influenced by the clinical experience of the examiners, and radiographic indices are required for this classification. MATERIALS AND METHODS: One hundred and one patients were examined using their preoperative plain antero-posterior and lateral radiographs. To evaluate the reproducibility of the Dorr classification, the Dorr type of each patient was judged twice each by three expert hip surgeons and three junior hip surgeons. Indices measured using the plain radiographs were canal-to-calcar ratio, cortical index (CI), and canal flare index. A receiver operating characteristic curve was used to evaluate which measured parameters were suitable as indices for the Dorr classification which was determined by the consultation among three expert hip surgeons. RESULTS: Regarding intra-examiner reproducibility, kappa coefficients for the three junior hip surgeons were 0.36, 0.62, and 0.65, whereas those for the three expert hip surgeons were 0.70, 0.86, and 0.87. Regarding inter-examiner reproducibility, the kappa coefficient for the junior hip surgeons was 0.32, whereas that for the expert hip surgeons was 0.52. The CI on the lateral radiograph had the largest area under the curve (AUC) between types A and B, whereas the CI on the anteroposterior radiograph had the largest AUC between types B and C. The respective cutoff points of the CI on the anteroposterior radiograph were 0.58 between types A and B and 0.49 between types B and C. The respective cutoff points of CI on the lateral radiograph were 0.45 between types A and B and 0.28 between types B and C. CONCLUSION: The intra-examiner reproducibility of the Dorr classification ranged from "fair" to "almost perfect", whereas the inter-examiner reproducibility ranged from "fair" to "moderate". Both were influenced by the level of clinical experience of the examiners. The most suitable index for classification using plain radiographs of the hip is the CI on anteroposterior and lateral radiographs. LEVEL OF EVIDENCE: IV, retrospective study.

Periprosthetic acetabular fractures: A New classification proposal.

INTRODUCTION: Acetabulum periprosthetic fractures are rare, but are increasing, due to increase in high-energy trauma and a decrease in mortality index. Reconstruction of an acetabular fracture, in the presence of hip arthroplasty can be very complex and represents a real challenge for orthopedic surgeon. Aim of this multicentric study is to classify periprosthetic acetabulum fractures and to propose a treatment algorithm. MATERIALS AND METHODS: 24 cases of acetabular periprosthetic fracture were treated surgically from 01.01.2010 to 31.04.2017 in three different hospitals; 4 males and 20 females, average age 76 years (range 56-90 years). TREATMENT: 4 cases treated conservatively, 8 cases ORIF, 2 cases treated with acetabular ring and screws, 9 cases ORIF and acetabular cup revision, 1 implant removal without revision. RESULTS: All cases were reviewed at minimum 12 months follow-up. In 22 cases, there was no need for new surgical procedures and radiographically all implants appeared stable and with good bone integration. In a case of a type 1b fracture, a dislocation of prosthetic implant was observed after 3 months. In a case prosthesis was explanted and it was not possible to perform a revision. DISCUSSION AND CONCLUSIONS: Fracture classification systems must facilitate communication between surgeons and encourage documentation and research. However, they should also have prognostic value, so from them should come directly a treatment algorithm. In our experience, most important factors as prognostic and therapeutic predictors were: implant stability and timing of fracture: intraoperative or postoperative. In postoperative fractures CT is mandatory to evaluate cup mobilization and fracture patterns. Our classification proposal is simple and easy to remember for daily use. From it is derived a simple treatment plan.