Management of periprosthetic hip fractures: current status and prospects; experience of the traumatology and orthopedics department of Mohammed VI University Hospital, Marrakech.

INTRODUCTION: The increase in hip arthroplasties predicts a rise in periprosthetic fractures in Morocco, posing challenges for orthopedic surgeons. Therapeutic strategies vary considerably, highlighting the absence of a universally accepted treatment protocol. AIM: To analyze the management of per-prosthetic hip fractures, while addressing the challenges associated with them. METHODS: This was a retrospective study, conducted in the trauma-orthopedics department between December 2015 and November 2022. Nineteen patients who presented to the hospital with fractures around a hip prosthesis were included. RESULT: Nineteen periprosthetic fractures were observed. The majority of patients (68%) were women, with an average age of 68. The Vancouver classification showed that 52.6% of the fractures were type B1, and 21.1% type C, while the other fracture types were distributed differently. These fractures were mainly associated with diagnoses such as femoral neck fracture (63.2%) and coxarthrosis (31.6%). We observed variations in treatment recommendations and results between the different series analyzed. We noted discrepancies with certain series concerning fracture types and therapeutic choices. However, in our series, we achieved satisfactory results, with successful consolidation and the absence of complications in all patients. CONCLUSION: These results underline the importance of an individualized approach to fracture management, taking into account the specificities of each case.

Periprosthetic fractures are osteoporotic fractures: missed opportunities for osteoporosis diagnosis.

Joint replacement surgery is common in older adults, leading to increasing periprosthetic fracture (PPFx) occurrence. We reviewed all PPFx seen over a 4-year period at an academic hospital. Clinical osteoporosis could be diagnosed based on existing data in 104 (67%) at the time of PPFx. Periprosthetic fractures are generally osteoporosis-related. PURPOSE: Periprosthetic fractures (PPFx) cause morbidity, mortality, and cost. This study's purpose was to describe osteoporosis-related data available at the time of PPFx. METHODS: The electronic medical record (EMR) of PPFx patients seen over 4 years in a university orthopedic practice were reviewed. Demographic data and osteoporosis relevant parameters were collected. Prior DXA studies were reviewed, and L1 Hounsfield unit (HU) measurements were performed on CT scans obtained within 2 years before PPFx. Clinical osteoporosis was defined as prior diagnosis, prescribed osteoporosis treatment, T-score ≤ - 2.5, HU ≤ 100, or prior fracture. RESULTS: Records of 156 PPFx patients (115 F/41 M), mean (SD) age 75.4 (11.9), were reviewed. Almost all 153/156 (98%) of these fractures were femoral. Falls caused 139 (89%); 12 (8%) were spontaneous. Mean time post-arthroplasty was 7.9 (6.3) years. Prior fragility fracture(s) occurred in 72 (46%); 14 were PPFx. Osteoporosis was previously diagnosed in 45 (29%) and medications prescribed in 41 (26%). Prior to PPFx, DXA data were available in 62, mean (SD) lowest T-score was - 1.9 (0.9) and was ≤ - 2.5 in 19. CT data were available in 46; mean (SD) L1 HU was 79.0 (29.4) and was ≤ 100 in 35. Based on existing data, clinical osteoporosis could have been diagnosed in 104 (67%) at the time of PPFx. CONCLUSION: Periprosthetic fractures are osteoporosis-related. They occur in older adults, often female, and result from falls; BMD, when assessed, is low. Data available at the time of PPFx often allows osteoporosis diagnosis; this should prompt evaluation and pharmacologic treatment consideration.

Diagnosis and Management of Intraoperative Periprosthetic Fractures in Primary Total Knee Arthroplasty.

Intraoperative periprosthetic fracture is an uncommon but notable complication that can occur during primary total knee arthroplasty. These fractures may occur at various stages during the procedure, including surgical exposure, implant preparation, implant trialing, and final implantation. Management of femoral and tibial fractures necessitates intraoperative recognition, including attentiveness of preoperative patient and surgical risk factors. This comprehensive review article focuses on the patient and surgical risk factors, diagnosis, management, and outcomes related to intraoperative fractures during primary total knee arthroplasty.

Can the American Joint Replacement Registry Utilize Administrative Claims Data to Accurately Classify Revision Total Hip Arthroplasty (THA) Surgical Diagnoses?

BACKGROUND: The American Joint Replacement Registry (AJRR) is a valuable tool for studying revision total hip arthroplasty (rTHA). Currently, International Classification of Diseases-10 (ICD-10) codes are utilized by the AJRR for classifying surgical diagnoses. However, the validity of this methodology is unknown. The purpose of this study was to determine the accuracy of these codes, as used by AJRR, in classifying rTHA diagnoses. METHODS: We identified 908 rTHAs performed at our institution from 2015 to 2021 using our total joint registry (TJR). Revision diagnoses were obtained from the TJR, which contains prospectively recorded surgical diagnoses collected by trained abstractors, independent from ICD-10 data. The ICD-10 diagnosis codes, as submitted to AJRR, were retrieved for the same procedures. The accuracy of ICD-10 codes for classifying rTHA diagnoses as septic versus aseptic, instability, aseptic loosening, and periprosthetic fracture was assessed using Cohen's Kappa statistic, sensitivity, and specificity. RESULTS: Concordance between AJRR-submitted data and TJR for classifying rTHA as septic or aseptic was excellent (96.9%; k = 0.87). Agreement for aseptic diagnoses varied from very good for instability (k = 0.76) and loosening (k = 0.67) to moderate for periprosthetic fracture (k = 0.54). Specificity was high (>96%) for all 3 aseptic diagnoses, but sensitivity was lower at 74%, 68%, and 44% for instability, loosening, and periprosthetic fracture, respectively. CONCLUSION: The AJRR submitted ICD-10 data correctly classifies the infection status of rTHA procedures with outstanding accuracy, but the accuracy for more granular diagnoses was variable. These data demonstrate the potential for diagnosis specific limitations when utilizing ICD-10 administrative claims for registry reporting.

Is the American Joint Replacement Registry Able to Correctly Classify Revision Total Knee Arthroplasty Procedural Diagnoses?

BACKGROUND: The American Joint Replacement Registry (AJRR) is a powerful tool for the study of revision total knee arthroplasty (rTKA). The AJRR uses International Classification of Diseases-10 (ICD-10-CM) codes for recording surgical diagnoses. However, the validity of this methodology is unknown. The purpose of this study was to determine the accuracy of ICD-10-CM codes, as used by AJRR, in classifying rTKA diagnoses. METHODS: There were 988 rTKAs performed from 2015 to 2021 identified in our institutional total joint registry (TJR). Revision diagnoses were obtained from TJR, in which trained abstractors prospectively record diagnoses independent of ICD-10-CM data. The ICD-10-CM diagnosis codes submitted to AJRR were retrieved for the same procedures. The accuracy of ICD-10-CM codes for classifying rTKA diagnoses as septic versus aseptic, aseptic loosening, instability, and periprosthetic fracture was assessed using Cohen's Kappa statistics, sensitivities, and specificities. RESULTS: Concordance between AJRR-submitted codes and TJR was excellent (97.3%, k = 0.9) for identifying septic versus aseptic revisions. Agreement for aseptic diagnoses varied from very good for loosening (k = 0.65) and instability (k = 0.64) to fair for periprosthetic fracture (k = 0.36). Specificity was high (> 94%) for all three diagnoses, but sensitivity was lower at 71%, 63%, and 28% for loosening, instability, and periprosthetic fracture, respectively. CONCLUSION: The AJRR submitted ICD-10-CM diagnosis codes correctly classified rTKA cases as septic or aseptic with remarkable accuracy, but accuracy for more granular diagnoses varied. These data demonstrate the potential for diagnosis-specific limitations when using administrative claims data for registry reporting and have important implications for researchers using ICD-10-CM data.

Periprosthetic patella fractures in total knee replacement and revision surgeries: how to diagnose and treat this rare but potentially devastating complication-a review of the current literature.

PURPOSE: Periprosthetic patella fractures (PPPFs) are infrequent but potentially devastating complications after total knee arthroplasty (TKA) and revision TKA (rTKA). These fractures may occur both in resurfaced and un-resurfaced patella. This review summarizes the current literature on PPPFs to help orthopedic surgeons diagnose and treat this uncommon but extremely challenging TKA complication. METHODS: A comprehensive search was performed in three databases: PubMed, SCOPUS, and EMBASE. All relevant information was retrieved and summarized in this narrative review. RESULTS: In the studies analyzed, there is a general trend in favor of nonsurgical treatment, except for implant loosening or extensor lag with extensor apparatus disruption, because surgery is often associated with poor clinical outcomes and high complication rates. CONCLUSION: PPPF is a rare but catastrophic event in TKA and rTKA, occurring mainly in a reconstructed patella. Patient-, implant-, and surgical technique-related factors contribute to its multifactorial etiopathogenesis. Prevention plays a crucial role in reducing the PPPFs rate. Conservative management is the treatment of choice due to high surgery complication rates unless implant loosening, or extensor apparatus disruption occurs.

Periprosthetic humeral fracture revision using a massive allograft in a patient with rheumatoid arthritis: A case report.

Total elbow arthroplasty (TEA) is a surgical option for patients with rheumatoid arthritis (RA). Periprosthetic fractures during and after TEA are one of the most common causes of reoperation. Fractures around the stem of a loose prosthesis with associated bone loss are the most technically challenging to treat. Previous reports have demonstrated that the use of massive allografts is a reasonable alternative in salvage situations. Here, we report the case of a 78-year-old woman with RA who underwent revision TEA using massive allografts with modifications to the methods described in previous reports. She suffered a right periprosthetic humeral fracture 5 years after primary TEA, with a fracture in the proximal humeral diaphysis and a long spiral fracture in the diaphysis. The fracture around the stem of a loose prosthesis was associated with bone loss. We performed revision TEA using an allograft of the proximal femoral diaphysis. In contrast to previous reports, we preserved part of the humeral diaphysis, which was thin due to osteolysis, without removal. The advantage of this approach was that it preserved attachments, such as the deltoid and brachioradialis muscles. The patient had good elbow function and minimal pain without adverse events at 1 year postoperatively. Our findings suggest that preserving part of a thinned humeral diaphysis is a reasonable option in revision TEA with a massive composite allograft.

[Periprosthetic fractures-Diagnostics, classification and treatment]. / Periprothetische Frakturen ­ Diagnostik, Klassifikation und Therapie.

BACKGROUND: Due to the increase in hip and knee prosthetic as a result of the demographic changes, with raised levels of activity among older persons with geriatric comorbidities, a continuous increase in periprosthetic fractures can be observed. OBJECTIVE: The incidence and causes of periprosthetic fractures, presentation of diagnostic pathways and derivation of a recommendation according to generally accepted classifications. MATERIAL AND METHOD: Literature search of basic scientific work, recommendations of experts as well as evaluation of own patient collective. CONCLUSION: With a growing number of prosthetic interventions in combination with increasing patient age, an increase in periprosthetic fractures is to be expected. The treatment of periprosthetic fractures is complex and requires detailed analysis of the location of the fracture and its morphology as well as the recognition of possibly loosened prosthetic material. Based on this information, the correct surgical treatment can be determined and scheduled in an appropriate center of care. In geriatric patients with corresponding comorbidities, an individual holistic treatment plan should be developed.

[Diagnosis and treatment of periprosthetic fracture after medial unicompartmental knee arthroplasty].

Unicompartmental knee arthroplasty (UKA) is an effective treatment for end-stage anteromedial osteoarthritis of the knee. Medial tibial plateau fracture or femoral condyle fracture may occur after UKA, and its treatment is very challenging. The causes leading to this complication include: surgical technique errors, such as the weakening of posterior cortical strength of the tibial platform during operation, the reduction of bone mass due to too much tibial osteotomy, and the stress concentration in the bone bed due to bad alignment of the prosthesis, etc. Prosthesis design factors, such as press-fit fixation design of cementless UKA prosthesis, and multiple nail holes fixation for tibial osteotomy guide, etc. And the morphology of tibial plateau, such as tibial platform in Asian people with narrow and small shap and medial overhanging condyles. Correct selection of patients, strict surgical principles and standardized surgical techniques are the keys to prevent periprosthetic fractures during and after medial UKA. After the diagnosis is confirmed, the treatment choice mainly depends on the fracture pattern and the stability of the prosthesis.

Femoral revision with the direct anterior approach.

OBJECTIVE: The advantages of the direct anterior approach (DAA) in primary total hip arthroplasty as a minimally invasive, muscle-sparing, internervous approach are reported by many authors. Therefore, the DAA has become increasingly popular for primary total hip arthroplasty (THA) in recent years, and the number of surgeons using the DAA is steadily increasing. Thus, the question arises whether femoral revisions are possible through the same interval. INDICATIONS: Aseptic, septic femoral implant loosening, malalignment, periprosthetic joint infection or periprosthetic femoral fracture. CONTRAINDICATIONS: A draining sinus from another approach. SURGICAL TECHNIQUE: The incision for the primary DAA can be extended distally and proximally. If necessary, two releases can be performed to allow better exposure of the proximal femur. The DAA interval can be extended to the level of the anterior superior iliac spine (ASIS) in order to perform a tensor release. If needed, a release of the external rotators can be performed in addition. If a component cannot be explanted endofemorally, and a Wagner transfemoral osteotomy or an extended trochanteric osteotomy has to be performed, the skin incision needs to be extended distally to maintain access to the femoral diaphysis. POSTOPERATIVE MANAGEMENT: Depending on the indication for the femoral revision, ranging from partial weight bearing in cases of periprosthetic fractures to full weight bearing in cases of aseptic loosening. RESULTS: In all, 50 femoral revisions with a mean age of 65.7 years and a mean follow-up of 2.1 years were investigated. The femoral revision was endofemoral in 41 cases, while a transfemoral approach with a lazy­S extension was performed in 9 patients. The overall complication rate was 12% (6 complications); 3 patients or 6% of the included patients required reoperations. None of the implanted stems showed a varus or valgus position. There were no cases of mechanical loosening, stem fracture or subsidence. Median WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score before surgery improved significantly from preoperative (52.5) to postoperative (27.2).

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.

A Review of Periprosthetic Tibial Fractures: Diagnosis and Treatment.

Periprosthetic fracture occurring during or after total knee arthroplasty is a rare injury. Literature concerning periprosthetic tibial factures is sparse, and there is limited guidance for evidence-based management. This review aims to provide readers with an overview of the epidemiology, risk factors, and classification of these fractures. Management includes nonoperative treatment of nondisplaced fractures, fixation for those with stable implants, and revision for those with loose implants.

Concomitant Hip and Knee Periprosthetic Joint Infection in Periprosthetic Fracture: Diagnostic Utility of Serum and Synovial Fluid Markers.

BACKGROUND: Diagnosing periprosthetic joint infection (PJI) in patients with a periprosthetic fracture can be challenging due to concerns regarding the reliability of commonly used serum and synovial fluid markers. This study aimed at determining the diagnostic performance of serum and synovial fluid markers for diagnosing PJI in patients with a periprosthetic fracture of a total joint arthroplasty. METHODS: A total of 144 consecutive patients were included: (1) 41 patients with concomitant PJI and periprosthetic fracture and (2) 103 patients with periprosthetic fracture alone. Serum markers erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and synovial markers white blood cell (WBC) count and polymorphonuclear percentage were assessed. RESULTS: ESR demonstrated 87% sensitivity and 48% specificity at the Musculoskeletal Infection Society threshold, area under the curve (AUC) of 0.74, and optimal threshold of 45.5 mm/h (76% sensitivity, 68% specificity). CRP showed 94% sensitivity and 40% specificity, AUC of 0.68 with optimal threshold of 16.7 mg/L (84% sensitivity, 51% specificity). Synovial WBC count demonstrated 87% sensitivity and 78% specificity, AUC of 0.90 with optimal threshold of 4552 cells/µL (86% sensitivity, 85% specificity). Polymorphonuclear percentage showed 79% sensitivity and 63% specificity, AUC of 0.70 with optimal threshold of 79.5% (74% sensitivity, 63% specificity). The AUC of all combined markers was 0.90 with 84% sensitivity and 79% specificity. CONCLUSION: The diagnostic utility of the serum and synovial markers for diagnosing PJI was lower in the setting of concomitant periprosthetic fracture compared to PJI alone. Using the Musculoskeletal Infection Society thresholds, ESR, CRP, and WBC count showed high sensitivity, yet low specificity, thus higher thresholds and utilizing all serum and synovial markers in combination should be considered.

Femoral Periprosthetic Fracture Nonunion Management and Outcomes with Nonunion Repair and Retention of Primary Components.

INTRODUCTION: Nonunion of a femoral periprosthetic fracture is a rare occurrence in orthopedic practice. Failure of a periprosthetic fracture to heal can lead to substantial disability and pain for patients as well as the potential need for component revision. Relatively little literature exists describing their management and outcome. METHODS: Eleven patients with femoral periprosthetic fracture nonunion who presented for tertiary care were enrolled in a prospective data registry. Patients were considered to have developed nonunion following failure of progression in radiographic and clinical healing for a 6-month period. All patients were seen at standard postoperative intervals, and outcomes were recorded using the Short Musculoskeletal Function Assessment (SMFA), visual analog scale (VAS) for pain, physical examination, and radiographic examination. Preoperative radiographs were reviewed for classification. RESULTS: Eleven patients had periprosthetic femoral fracture nonunion associated with prior hip (five patients) or knee (six patients) arthroplasty and were included in our study. Mean follow-up time was 30 months. Mean age at time of nonunion surgery was 64.5 years (range: 41.8 to 78.2 years). All patients underwent removal of previous fracture hardware at time of nonunion surgery. Ten (91%) of 11 received autogenous iliac crest bone grafting at time of nonunion surgery. Ten (91%) of the 11 patients went on to union without further intervention. Mean time to union was 7.9 months (SD: 8.0). The one patient that developed a persistent nonunion was complicated by infection requiring multiple irrigation and debridement procedures and total hip explant. The mean improvement in total SMFA score from baseline to final follow-up was 22.6 (p = 0.030). The greatest functional improvement was in the bothersome index at 28.0 (p = 0.028). The mean improvement in VAS pain score from baseline to final follow-up was 4.5 (p = 0.013). DISCUSSION: Periprosthetic fracture nonunions can be successfully treated with operative intervention aimed at compression plating with bone graft and retention of primary components. In addition, successful periprosthetic nonunion repair improves function and pain in these patients.

Role of positioning of femoral component in the anterior-posterior direction on postoperative anterior pain in TKA.

INTRODUCTION AND PURPOSE: The patellofemoral joint has proved to be the most problematic element of modern TKA for postoperative anterior knee pain; the positioning of the femoral component constitutes a critical phase in this issue. The objective of our study was to evaluate the possible role of either anterior positioning or posterior positioning of the femoral shield compared to the reference plane represented by the anterior cortex, on the anterior knee pain after knee arthroplasty. METHODS: Forty-eight patients treated with TKA were followed up approximately 12 months. None of them have been submitted to any patellar treatment. We observed the position of femoral shield with respect to the anterior cortical line of femur dividing patients into three groups: patients with significant notching, patients with no notching (shield corresponding to anterior cortical line) and patients with anterior positioning of shield. We evaluated clinical and functional outcomes with KSS, anterior knee pain with Kujala's score and adverse events such as periprosthetic fractures. RESULTS: We found a better clinical and functional result for patients with femoral shield positioned in line with anterior cortical cortex with respect to both TKAs with femoral notching and to protruding anterior femoral components; there were no main differences in anterior postoperative score by Kujala's system. We observed a periprosthetic fracture in a patient with an important femoral notching. CONCLUSIONS: We cannot consider our study as an objective conclusion to the argument. We need more RCTs in order to study the proper influence of either notching or protrusion of femoral shield component onto anterior postoperative pain. Anyway positioning of femoral shield in anterior-posterior direction could be an interesting new critical object of study about anterior knee pain after TKA.

Two Cases of Periprosthetic Fracture After Surgery for Acute Midfoot Charcot.

Charcot neuroarthropathy is a rare condition that often results in deformity of the foot and ankle, with a high incidence of ulceration and a high risk of amputation. Traditionally, treatment of the acute stages of Charcot foot has been nonoperative until consolidation. Still, a large number of patients develop deformities, and early operative treatment of unstable Charcot feet has been suggested. To overcome some of the inherent challenges when operating on acute-stage Charcot feet, the superconstruct technique has been proposed. Early surgery for dislocated Charcot foot is sparingly described in the literature. To investigate the utility of the superconstruct technique for acute midfoot Charcot, we planned a prospective cohort study including patients with midfoot manifestation (Brodsky 1) in the active stages of the disease. Patients eligible for the study were treated with open surgery and midfoot arthrodesis using the superconstruct technique. In this report, we present the development of periprosthetic fractures related to early surgery using the superconstruct technique, possibly causing a more proximal Charcot manifestation in 2 patients with >24 months of follow-up. To our knowledge, such complications have been sparsely noted in the literature.

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.

Extraskeletal osteosarcoma misdiagnosed as heterotopic ossification after periprosthetic femoral fracture: A case report.

Extraskeletal osteosarcoma is a malignant tumor of soft tissue characterized by osteoid production and has a very low prevalence, comprising approximately 4% of all osteosarcomas and about 1% of all soft tissue sarcomas, and a total of about 350 cases have been reported until now. Heterotopic ossification is a pathological finding of bony tissue in soft tissue regions such as muscle, skin and subcutaneous tissue. We report a case of an 86-year-old woman with a history of total hip arthroplasty (THA), in which open reduction and internal fixation were done for periprosthetic femoral Fracture. The ossified lesion misdiagnosed as heterotopic ossification initially was diagnosed as extraskeletal osteosarcoma at 6 months after the surgery. Both extraskeletal osteosarcoma and heterotopic ossification have no definite symptoms, but show radiopaque shadows on simple radiograph. Therefore, careful attention and thorough evaluation with multiple imaging tests may be necessary for the differential diagnosis of these entities.

Post-operative periprosthetic humeral fractures after reverse shoulder arthroplasty: a review of the literature.

BACKGROUND AND AIM OF THE WORK: Post-operative periprosthetic shoulder fractures incidence is gradually raising due to aging of population and increasing of reverse total shoulder arthroplasty (RTSA). Management of this complication represents a challenge for the orthopedic surgeon. Aim of the present study is to critically review the recent literature about epidemiology, risk factors, diagnosis, management and outcome of post-operative periprosthetic humeral  fractures occurring on RTSA. METHODS: A systematic search of Embase, Medline and Pubmed was performed by two reviewers who selected the eligible papers favoring studies published in the last ten years. Epidemiology, risk factors, diagnostic features, clinical management and outcome of different techniques were all reviewed. RESULTS: 31 studies including reviews, meta-analysis, case reports, clinical and biomechanical studies were selected. CONCLUSIONS: Correct clinical management requires adequate diagnosis and evaluation of risk factors. Conservative treatment is rarely indicated. Locking plate fixation and revision arthroplasty are both valuable treatment methods. Surgical technique should be chosen considering age and functional demand, comorbidities, fracture morphology and location, bone quality and stability of the implant. Given the correct indication all surgical treatment can lead to satisfactory clinical and radiographic results despite a relevant complication rate.