Periprosthetic Research Articles

Closed Cephalomedullary Nailing of a Diaphyseal Femur Fracture on a Fracture Table

Dr. Weaver treats a periprosthetic femur fracture with the patient positioned supine on a fracture table using a cephalomedullary nail. The fracture table

Результати лабораторних досліджень рідини з колінних та кульшових суглобів після ендопротезування для ранньої діагностики перипротезної інфекції

Актуальність. Перипротезна інфекція є одним із найбільш тяжких ускладнень після тотального ендопротезування кульшових та колінних суглобів, тому визначення кількості лейкоцитів у синовіальній рідині при діагностиці перипротезної інфекції може зменшити кількість сумнівних результатів, що потребують додаткових досліджень. Мета дослідження — проведення клініко-мікроскопічного і біохімічного дослідження рідини, одержаної з колінних та кульшових суглобів після ендопротезування з подальшим визначенням діагностичної чутливості лабораторних показників для ранньої діагностики перипротезної інфекції. Матеріали та методи. Дослідження виконувалось на 53 пацієнтах, яким було проведено 61 оперативне втручання на колінному і кульшовому суглобах. Виконані ендопротезування колінного (n = 41) і кульшового (n = 14) суглобів, дебридмент (n = 6), із них первинних ендопротезувань — 42, ревізійних — 13. Чоловіків було 16, жінок — 37, вік хворих — від 35 до 79 років. Усіх хворих було розподілено на три групи: І група — пацієнти, яким було діагностовано перипротезну інфекцію в термін до 4 тижнів після операції (n = 7); ІІ група — пацієнти, в яких інфекцію було діагностовано при звернені в клініку, але післяопераційний період перебігав без ускладнень (n = 8); ІІІ група — пацієнти, у яких був нормальний перебіг післяопераційного періоду (n = 46). Одержану з колінних та кульшових суглобів рідину досліджували за такими показниками: цитоз, процент нейтрофілів, лімфоцитів, синовіоцитів та макрофагів, вміст загального білка, глікопротеїнів, хондроїтинсульфатів, глюкози, гіалуронової кислоти, С-реактивного білка та інтерлейкінів (ІЛ-1β та -6). Діагностичну чутливість (ДЧ) лабораторних показників розраховували за формулою ДЧ = (ТП/Д) × 100 %, де ТП — істинно позитивні результати дослідження, Д — кількість хворих у групі. Результати. У хворих було встановлено зміни в рідині з колінного та кульшового суглобів за цитологічними та біохімічними показниками на всіх термінах спостереження в післяопераційний період. Висновки. У хворих І групи було встановлено поступове збільшення рівня цитозу та нейтрофілів, загального білка, глікопротеїнів, хондроїтинсульфатів, зниження — лімфоцитів, глюкози і гіалуронової кислоти в післяопераційний період; у ІІ групі хворих рівень цитозу до операції був найвищим, проте після операції з 2-ї до 14-ї доби він суттєво зменшився, кількість нейтрофілів була збільшена до операції та в післяопераційний період; у ІІІ групі хворих рівень цитозу збільшився на 2-гу добу після операції та знизився на 7-му та 14-ту добу, кількість нейтрофілів збільшилась на 2-гу добу після операції, кількість синовіоцитів зменшилась порівняно з показником до операції; ДЧ була найвищою на 2-гу, 7-му та 14-ту добу після операції в показників цитозу, загального білка, С-реактивного білка, гіалуронової кислоти, хондроїтинсульфатів та інтерлейкінів.

Analysis of pathogen distribution and drug resistance of acute,delayed and chronic periprosthetic joint infection

Objective: To analyze the pathogen distribution and drug resistance in acute,delayed and chronic periprosthetic joint infection (PJI). Methods: The clinical data of 316 patients with periprosthetic infection after primary hip and knee arthroplasty admitted to the Department of Arthroplasty,the First Affiliated Hospital,Xinjiang Medical University from August 2010 to August 2020 were retrospectively analyzed.There were 146 males and 170 females,aged (62.3±14.2) years (range:22 to 89 years).One hundred and sixty one patients underwent total hip arthroplasty and 155 patients underwent total knee arthroplasty.According to the time of postoperative infection,the patients were divided into acute PJI group (65 cases),delayed PJI group (83 cases) and chronic PJI group (168 cases).The results of pathogen species,composition ratio and drug susceptibility tests were collected,and the independent sample t test,Chi-square test or Fisher's exact probability test were used for comparison. Results: Gram-positive bacteria were the main pathogens of PJI (49.7%,157/316),and the positive rates of culture in patients with acute PJI,delayed PJI and chronic PJI were 33.8% (22/65),55.4% (46/83) and 53.0% (89/168),and the difference was statistically significant(χ²=8.343,P=0.015).The common bacteria were coagulase-negative Staphylococcus (54.8%,86/157) and Staphylococcus aureus (30.6%,48/157),The drug-sensitivity to linezolid,vancomycin and tigacycline was 100%.The gram-negative bacteria were mainly Escherichia coli and Enterobacter cloacae,and the drug resistance rate to carbapenems was low,ranging from 0 to 9.09%.The drug resistance rates of acute PJI patients to rifampicin,ciprofloxacin and erythromycin were significantly higher than those of late onset and chronic PJI patients,the difference was statistically significant(rifampicin:χ²=14.332,P=0.001;ciprofloxacin:χ²=12.086,P=0.002;erythromycin:χ²=9.096,P=0.010);The drug resistance rate of acute PJI patients to levofloxacin,clindamycin and tetracycline was higher than that of chronic PJI patients,and the difference was statistically significant(levofloxacin:χ²=10.500,P=0.002; clindamycin: χ²=7.103,P=0.007; tetracycline: χ²=6.909,P =0.012).The resistance rate of ampicillin/sulbactam in acute PJI (60.0%) was significantly higher than that in chronic PJI (16.7%),and the difference was statistically significant(χ²= 5.853,P=0.040). Conclusion: Gram-positive bacteria are the main pathogens of PJI,and the resistance rate of pathogens of acute PJI is higher than that of late onset and chronic PJI.

Morphometric Study of the Proximal Dry Femur and Its Potential Application in Prosthesis Designing in Tanzania

Background Total hip arthroplasty and hemiarthroplast are currently common procedures in our setting, Subluxation and periprosthetic facture of the femur has been reported. This can be linked to undersize and oversize of the prosthesis since most of these prosthetics are western standardized. This is partly because of lacking data of the size of the proximal femur. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint. Knowledge about the different diameters of the head, neck and length of femur is essential in orthopedic surgery and radiology and forensic medicine. These normative values are essential for plastic and reconstructive surgeons in their reconstruction and medical rehabilitation. However, the anatomical and anthropological statistical analysis of femoral anthropometry among different populations reveals a great variation for all human races. The present study aimed at determining morphometric measurements of proximal femur among Tanzania black people. Materials and Methods The study was done by evaluating 97 undamageddrybones left femur 35, right femur 50 and 12acetabulapreserved in the anatomy laboratories at medical universities in Dar es Salaam, Tanzania. The parameters evaluated were femoral head diameter, femoral neck width, lateral and anteroposterior femoral neck length, femur length, acetabular diameter and height. They were measured using Vernier caliper, non-elastic thread and osteometric board. Results The femoral length had range of 400-520 mm with the mean of 454.1±30.3mm, head diameter had a range of 34-54mm with the mean of 44.4±3.8mm and neck width had the range of 25.2-40mm with the mean of 31.7±3.3.The anterior and postero-anterior neck length measure 15-36mm and 25-48mm with the mean values of 23.2±4.2 and 36.8±4.3mm respectively. The mean values of acetabular width and diameter were 52.3±2.93mm and 48.9±2.78mm respectively. Conclusion The proximal femoral and acetabular morphometric measurements varied compared to those in other populations. Therefore, the values obtained for Tanzania population should be considered on orthopedic decisions for implants to be used. However, more robust studies are needed to corroborate these findings. Key words: Femur head, neck, morphometric, acetabulum.

Back to the Future…Don’t Forget the Cement

Back to the Future…Don’t Forget the Cement

Strut graft vs. traditional plating in the management of periprosthetic humeral fractures: a multicentric cohort study.

Aim The gradual increase in shoulder implants in active elderly patients has appeared in a parallel increase in periprosthetic humeral fractures. The aim of this study was to investigate the advantages of using strut grafting with plate fixation during periprosthetic humerus fractures. Methods Thirty patients diagnosed with periprosthetic humeral fracture were divided into two groups. The first group of 15 patients (PS) underwent plate, ring, screws and strut allografts. The second group with resting 15 patients (PWS) was treated with only plate and screws. The criteria to evaluate the groups during followup were the Constant Shoulder Score (CSS) and Oxford Shoulder Score (OSS); the bone healing was measured by X-rays, controls measured by radiographic union score (RUS), and complications. The follow up was terminated at 12nd month in both groups. Results The difference between the two groups in all parameters was not significant. However, all patients gained adequate shoulder motor skills for normal daily living activities. All fractures were healed. Only two complications were registered, and blood loss was minimal. Conclusion We believe a revision to reverse shoulder prosthesis with a long-stem implant with or without cortical strut allograft augmentation to be safe and appropriate in the management of these complex injuries, though technically challenging, and having good results for normal activities daily life.

Survival and outcome of total elbow arthroplasty for distal humeral fracture at long term follow-up.

Background:Total elbow arthroplasty is an accepted procedure for the treatment of acute comminuted distal humeral fractures in elderly. Few long-term outcomes are available. The purpose of this study was to examine long-term clinical and radiological outcomes of prosthesis performed (January 2002-June 2015) for complex fractures of the distal humerus (AO/C) in patients older than 65 years with low functional demands.Materials and Methods:Further inclusion criteria were: the availability of a clinical and radiological follow-up of minimum 5 years and pattern of closed fracture. Demographic data and characteristics of patients were collected. All patients were clinically and radiographically assessed after 2 and 5 years from surgery.Results:Twelve patients were included with complete available data. The mean follow-up was 7.6 years. Five patients reported a worsening of the elbow functionality through the follow-ups. Five subjects had complications. There were no cases of revision surgery. The quality of fixation showed a progressive worsening with increase of radiolucency both on humeral and ulnar side. The recorded MEPS showed no correlation with the grade of periprosthetic osteolysis. Polyethylene bushing wear was scored of grade 2 in one subject who had showed type 4 Morrey radiolucency.Discussion and Conclusions:Total elbow arthroplasty is an effective and reliable procedure for comminuted fractures of the distal humerus in elderly, although the incidence of complications can not be considered as negligible. For the majority of these patients, a well-performed implant will give them a well-functioning elbow for their remaining life.

Treatment of periprosthetic fracture after hip replacement

Treatment of periprosthetic fracture after hip replacement

Periprosthetic Joint Infection Risk After Total Joint Arthroplasty: There's Still More to Know: Commentary on an article by Ian Duensing, MD, et al.: "Patients with Type-1 Diabetes Are at Greater Risk of Periprosthetic Joint Infection. A Population-Based, Retrospective, Cohort Study".

Periprosthetic Joint Infection Risk After Total Joint Arthroplasty: There's Still More to Know: Commentary on an article by Ian Duensing, MD, et al.: "Patients with Type-1 Diabetes Are at Greater Risk of Periprosthetic Joint Infection. A Population-Based, Retrospective, Cohort Study".

Risk factors for periprosthetic joint infection of the hip and knee.

Aim To investigate risk factors for the development of prosthetic joint infection. Methods A group of 50 patients with periprosthetic infection was compared with a group of 100 randomly selected patients with total hip or knee arthroplasty without infectious complications. Twelve risk factors in both groups were analysed. Results Five factors showed to be significant: body mass index higher than 40, diabetes mellitus on insulin therapy, kidney and liver disease, vascular disease of the lower extremities and positive drain tip culture. Conclusion One of the ways to reduce the incidence of periprosthetic infection is the maximum possible elimination of risk factors in patients who have a high probability of endoprosthesis infection. If this elimination is not possible for a long time, it is advisable to consider abandoning the planned operation.

Hematogenous infection of total hip arthroplasty due to clostridium perfringens: a case report

A case report of periprosthetic hip clostridium perfringens infection 13 years after total hip arthroplasty, the patient had hip pain with fever for one week. Physical examination and imaging examination confirmed the periprosthetic joint infection. The pathogenic bacterium was clostridium perfringens according to bacterial culture, and the pathogenic bacterium of clostridium perfringens was suspected relating to the gallbladder disease in this patient. Considering such periprosthetic joint infection was early stage hematogenous periprosthetic joint infection, treatment of debridement, retention of the prosthesis, irrigating, and indwelling drainage tube were conducted. By reviewing literature about periprosthetic clostridium perfringens infection, only seven reports of periprosthetic joint infection were caused by clostridium perfringens, which were all case reports. From the previous case reports and our case, we found that the infection around the prosthesis caused by clostridium perfringens was limited to the area around the joint, and prognosis of such cases may not be as severe as the natural gas gangrene which developed very rapidly, but great attention should be paid to. The hematogenous periprosthetic joint infection caused by clostridium perfringens who had gastrointestinal symptoms in the early stage should be highly suspicious of gallbladder lesions and thorough debridement, retention of the prosthesis, irrigating and indwelling drainage tube maybe a treatment method.

Detection of periprosthetic joint infection pathogens by metagenomic next-generation sequencin

Objective To investigate and compare the capability of metagenomic next-generation sequencing (mNGS) in detecting pathogens and diagnosing of periprosthetic joint infection (PJI) from synovial fluid and sonicate fluid of patients who underwent revision arthroplasty. Methods Thirty-five consecutive patients who underwent revision arthroplasty from May 2018 to November 2018 were included prospectively. There were 22 males and 13 females, 11 hip revisions and 24 knee revisions. All the patients were divided into the PJI group and aseptic loosening (AL) group. Synovial fluid and sonicate fluid of the explanted prostheses were obtained for microbiological culture and mNGS tests. Periprosthetic tissues were only collected for culture. Synovial fluid of three patients undergoing primary arthroplasty been treated by sonication as the negative control group concurrently. Comparisons of microbiological results and diagnostic value from mNGS and culture tests were performed. Results In the 13 culture-positive PJI patients, mNGS results of synovial fluid were positive in 12 cases, while culture and mNGS results were completely consistent at species level in 7 cases, consistent at the genus level in 1 case. mNGS results of sonicate fluid were positive in 13 cases, while culture and mNGS results were completely consistent at species level in 9 cases, consistent at the genus level in 1 case. In 7 culture-negative PJI patients, 6 cases had consistent mNGS results at species level both from synovial fluid and sonicate fluid, however, one case had positive mNGS result only from sonicate fluid. All culture results and mNGS results of synovial fluid were negative in all 15 AL patients, however, mNGS results of sonicate fluid was positive in 1 AL case. Cultures and mNGS results were negative in all three pairs of negative-control samples. In all 70 samples, mNGS detected 24 pathogens in sonicate fluids and 22 pathogens in synovial fluids. There was no significant difference in number of raw reads and human reads ratio between mNGS of sonicate fluid and synovial fluid. mNGS of sonicate fluid generated significantly higher number of microbial reads and of stringently mapped reads of pathogen in species-level than that of synovial fluids. There was no significant difference in diagnostic sensitivity of PJI between mNGS of sonicate fluids and synovial fluids (90.0% vs 100.0%). Both of them were significantly higher than that of culture of synovial fluid, periprosthetic tissues. Diagnostic sensitivity of sonicate fluid mNGS was not significantly higher than that in culture of sonicate fluid (65%). The specificities were similar among various microbiological testing methods. Conclusion mNGS of either synovial fluid or sonicate fluid from patients who underwent revision arthroplasty can be used to detect the presence of pathogens effectively and diagnose PJI accurately. mNGS can identify more pathogens and generate a higher number of pathogenic reads from sonicate fluids than synovial fluid. mNGS of synovial fluids has met the clinical diagnostic demands for most PJI patients. mNGS of sonicate fluid could be applied in some cases. Key words: Metagenomics; Prosthesis-related infections; Molecular diagnostic techniques; Sonication

The treatment of periprosthetic femoral fractures after total hip arthroplasty

Periprosthetic femoral fracture (PFF) is one of severe complications after total hip arthroplasty (THA). As the number of patients receiving THA increased recently, the incidence of PFFs also increased dramatically. There are a number of risk factors for PFFs, such as age, sex, falling and prosthesis loosening. The Vancouver classification system is the most commonly used classification method for PFFs. According to the fracture location, PFFs can be divided into type A intertrochanteric fracture, type B fracture around the stem and type C fracture beyond the stem. The Vancouver type B PFF is further subdivided into type B1 with a well-fixed prosthesis, type B2 with a loose prosthesis but with adequate bone stock, and type B3 with a loose prosthesis and poor proximal bone stock simultaneously. Currently, there are some controversies in treating PFFs, mainly including whether the stem is fixed or not, whether the prosthesis needs to be revised, the selection of the stem, the reconstruction of bone defects, and the methods of fracture fixation. We searched literatures related to PFFs after THA. The incidence, risk factors, classification methods, treatment principles and strategies of PFFs were summarized in the present study. Based on our long-term clinical experience, we evaluated the advantages and disadvantages of each treatment method and provided considerations for the clinical research and selection in treating PFFs.

Kinetics of Elution of Gentamicin from a Gentamicin-Loaded PMMA Bone Cement

Antibiotic-loaded poly (methyl methacrylate) bone cement (ALBC) is widely used for anchoring joint replacements as a means of reducing the potential for peri-prosthetic joint infection (primary cases) and treating a patient who has an infected joint replacement (revision cases). One shortcoming of the cement is the high maximum exothermic temperature experienced upon polymerization (Tmax), a phenomenon that, it has been postulated, may cause or be implicated in thermal necrosis of peri-prosthetic tissues. There are many reports in the literature on methods of reducing Tmax, with one such study involving the addition of a phase change material (microencapsulated paraffin) (MEPAR) to the cement powder or adding a chain-stopping chemical (1-dodecyl mercaptan) (DDM) to the liquid. In that report, the results of gentamicin elution tests were presented. In the present work, those results were used to calculate various indices of gentamicin elution kinetics, namely 1) diffusion coefficient (Dgent); and 2) values of the coefficients in four equations that are widely used to model antibiotic elution from ALBCs. We found 1) the difference in Dgent of either a MEPAR- or DDM-containing formulation, on the one hand, and that of the control cement, on the other, was not significant; and 2) a consistent trend in the value of only one coefficient in one of the four model equations, with this change suggesting insignificant difference in gentamicin elution mechanism between an experimental cement formulation and the control cement. The implications of these findings for guiding selection of additives that simultaneously produce significant reduction of Tmax but minimal effect on gentamicin elution kinetics are discussed. This guide is a novel contribution to the literature.

Outcomes of debridement and implant retention in treating periprosthetic joint infection after primary total joint arthroplasty

Objective To present clinical effects of debridement, antibiotics, irrigation and retention of implant (DAIR) with integrated antibiotics application in treating periprosthetic joint infection (PJI) occurred within 3 months after primary surgery. Methods We retrospectively analyzed patients who received DAIR between January 2011 and October 2015. A total of 49 patients with a mean age of 62.38±14.56 years (range, 26-82 years) were included in this study, including 29 males and 20 females. There are 27 knees and 22 hips. Twenty-three patients has sinus tract. Failure was defined as subsequent surgical intervention for infection after the index procedure; persistent fistula, drainage, or excessive joint pain at the last follow-up; death related to the PJI; chronic suppression with antibiotics. Results There were 18 (36.7%) culture negative cases and 31 (63.3%) culture positive cases, including 28.6% (14/49) methicillin-sensitive staphylococcus aureus, 4% (2/49) methicillin-resistant staphylococcus aureus, 2% (1/49) methicillin-resistant staphylococcus epidermidis, 2%(1/49) mixed infection with fungus and so on. Within the 68.34±14.02 months (range, 39-94 months) follow-up duration, the Knee Society Score (KSS) score was improved from 38.37±12.39 points (range, 18-62 points) pre-operatively to 82.26±10.50 points (range, 49-96 points) post-operatively (t=-17.09, P<0.001). KSS function score was improved from 42.19±10.14 points (range, 26-67 points) pre-operatively to 75.22±11.60 points (range, 41-90 points) post-operatively (t=-12.53, P<0.001). Harris hip score was improved from 47.41±8.39 points (range, 32-58 points) pre-operatively to 86.41±6.07 points (range, 71-96 points) post-operatively (t=-23.38, P<0.001). There were 6 patients receiving subsequent surgical intervention as failure. The mean duration from the index surgery to failure was 5.75±3.00 months (range, 1.5-10 months). Conclusion The present protocol of DAIR for dealing with early-stage PJI, which is less than 3 months after primary TKA or THA, is fairly effective. Key words: Prosthesis-related infections; Debridement; Anti-infective agents, local

Partial two-stage exchange for periprosthetic joint infection after total hip arthroplasty

Objective To evaluate the early stage effects of partial two-stage exchange (PTE) for infection after total hip arthroplasty (THA) in order to improve surgical treatment outcomes. Methods Twelve patients (7 males and 5 females) of infected THA treated by PTE between September 2000 and February 2016 were included with an average of 59 years old (range, 40-74 years old). The femoral stem prosthesis was preserved when we ensured that it was not infected and with well fixation during operation. The acetabular prosthesis was totally replaced. Furthermore, the secondary surgery was performed on patients who were free from infection for at least 3 months. At the follow-up duration, the pelvic X-ray was examined to access the presence of loosening of the prosthesis. The inflammatory index was recorded. Hip function was assessed by the Harris hip score, and the visual analogue score (VAS) and patient's subjective satisfaction were recorded by the questionnaire. Results All of the 12 patients were followed up for a mean of 33.3 months (range, 24-48 months). We achieved a 92% (11/12) success rate. One patient resuffered infection, which was controlled after the second debridement. The preoperative Harris score of 12 patients was 23-57, with an average of 40.83±10.62. All patients had significant improvement in hip function after PTE. The Harris score reached 59.58±4.34 at one month after surgery, and reached 64.58±9.08 after three months and 86.75±4.58 at the last follow-up. There was significantly different when compared with the preoperative Harris score. At the last follow-up, the length difference between the lower limbs was less than 1cm in all patients. Two patients did not complain of pain, while other 10 patients got a VAS score of less than 2 points. The patient's subjective satisfaction rating was 100%. Conclusion PTE could be a valuable alternative treatment for infection after THA. The infection control rate and clinical outcomes are comparable to those of two-stage exchange. Key words: Arthroplasty, replacement, hip; Prosthesis-related infections; Device removal

Short-term clinical efficacy of three dimension printed titanium augments for the reconstruction of acetabular bone defects in revision total hip arthroplasty

Objective To evaluate the short-term clinical efficacy of three dimension printed titanium augments for the reconstruction of acetabular bone defects in revision total hip arthroplasty. Methods The retrospective study was conducted. To retrospectively analyze clinical data of 21 patients who were underwent revision total hip arthroplasty with severe acetabular bone defects reconstructed by three dimension printed titanium augment from March 2016 to September 2017 from Department of Orthopaedics, Beijing Friendship Hospital, Capital Medical University. There were 9 males and 12 females, age (58.9±6.3) years, 51-67 years, body mass index (23.8±2.9) kg/m2. According preoperative CT scan of hip joints, three dimension printed titanium augments were designed for acetabular defects personality. The data including the vertical distance from centre of rotation to the interteardrop line in X-ray examination, preoperative Harris score, final follow-up Harris score of hip postoperatively, and complications were recorded. Outpatient visits ranged from 11.8 to 19.6 months. Measurement data were expressed as (Mean±SD), and t test was used before and after surgery. Results For X-ray examination, the average vertical distance from centre of rotation to the interteardrop line was (6.1±1.2) cm preoperatively and (2.8±0.7) cm postoperatively, and the difference was statistically significant(P<0.01). The hip Harris score increased from preoperative (47.5±6.4) scores to the last follow-up (84.6±5.9) scores, and the difference was statistically significant (P<0.01). The final follow-up data showed the acetabular prosthesis and augments were stable, while there were no hip joint dislocation, periprosthetic joint infection, loosening of acetabular components and other complications. Conclusion Three dimension printed augments can reconstruct severe acetabular bone defects and restore the hip rotation centre. Key words: Arthroplasty, replacement, hip; Prosthesis failure; Acetabulum; Osteolysis; Recovery of function

Research progress in risk factors of periprosthetic infections after joint replacement

Prosthetic joint infection (PJI) is a catastrophic complication after joint replacement. It has become the primary cause of revision surgery after knee arthroplasty and the third cause of revision after hip replacement surgery. The risk factors involve the patient (intrinsic factor) and the environment (extrinsic factor), which can be further divided into uncontrollable factors such as the history of surgical infection and other factors related to age and sex of tumor, as well as the risk factors caused by patients' own characteristics and associated diseases, such as body mass index, smoking, diabetes, rheumatoid arthritis and medicine use. The authors summarize the patients' own characteristics, associated diseases and medication to comprehensively evaluate and understand how to reduce the risk of PJI in the perioperative period, so as to provide some reference for clinical treatment. Key words: Arthroplasty, replacement; Prosthesis-related infections; Risk factors

Total elbow arthroplasty in patients with tumor-like lesions of elbow, preliminary results of a single-center experience

Objective The purpose of this study was to investigate the preliminary clinical outcomes of total elbow arthroplasty (TEA) in the treatment of elbow deformity caused by tumor-like lesions. Methods Between September 2009 and June 2017, the technique of triceps facial tongue exposure was adopted for all 11 patients who underwent total elbow arthroplasty. There were 5 females and 6 males with the mean age of 56.7±14.7 years. There were 6patients with synovial chondromatosis and 5 with pathologic hypertrophy of synovium. Seven of 11 patients were performed by posterior approach only, while the other 4by combined posterior-anterior approach. A semi-constrained Coonrad-Morrey prosthesis which provides 7° varus/valgus laxity was used in 7 patients, and custom-made total constrained prosthesis which only allow flexion and extension on a single plane was used in 4 cases. Preoperative average flexion range of elbow was 50.5°±14.0° (range, 20°-70°). The ulnar nerve compression and claw hand deformity was identified in 2patients preoperatively and the nerve was transposed during operation. According to Mayo elbow function score (MEPS score), the average preoperative MEPS score was 42.1±12.7 points (range, 15-60). Results Perioperative complications were not found. None of patients lost in thefollow-up and all the patients were alive. There was no pain in the joints, no triceps fracture or weakening of muscle strength, and no recurrence of the lesions. All 11 patients were followed up for 7 to 63 months with an average of 36.3±19.5 months. The mean MEPS score was improved to 89±7.2 point after surgery (t=-11.993, P= 0.000). The average flextion-extension arc improved from preoperative 50.5° to 105.9° postoperatively (t=-8.697, P=0.000). The average pronation-supination arc improvement from preoperative 105°-123.2° postoperatively (t=-6.901, P=0.000). For the two patients with ulnar nerve deficit before surgery, one patient recovered 6 months after operation, however, the other patient did not 2 years later. One Coonrad-Morrey prosthesis with deep infection was treated by removing the implant. Three of 4 custom-made total constrained prostheses experienced implant failure due to loosening or periprosthetic fracture. The incidence of complications of semi-constrained prosthesis was lower than that of total constrained prosthesis (14% vs. 75%), however, it did not reach a significant difference. Conclusion This study reveals an acceptable outcome with triceps facial tongue exposure for TEA in the treatment of tumor-like lesions of elbow. TEA is a viable good alternative treatment for selected patients with large mass around the elbow or with severe deformation. However, the failure rate of fully constrained prosthesis tends to be higher than semi-constrained one, possible due to its design flaw. Key words: Arthroplasty, replacement, elbow; Paraneoplastic syndromes; Surgical procedures, electiv

Plate fixation in periprosthetic femur fractures Vancouver type B1: preliminary report of macroscopic evaluation of the cement mantle and short literature review.

The goal of our preliminary report is to investigate hip stem stability and intra-operative cement mantle integrity after screw insertion in plate fixation of periprosthetic Vancouver B1 femur fractures. From a cohort of 50 patients with a periprosthetic femur fracture treated in our department from February 2012 until February 2017, we included in our study patients with a periprostethic Vancouver B1 femoral fracture in cemented hip arthroplasty and hemiarthroplasty, operated with ORIF using a 4.5/5.0 LCP Proximal Femoral Hook Plate ® (Synthes, Switzerland) with at least one screw perforating the cement mantle. Anteroposterior and lateral femur views and pelvis X-rays were performed preoperatively. The stability of the hip implant and the cemented mantle integrity was evaluated intra-operatively in a macroscopic way and with a post-operative X-ray in anteroposterior and lateral views. Only 7 patients satisfied the inclusion criteria; no lesion/break of the cement mantle occurred intra-operatively at any step during drilling or screw insertion, also confirmed with C-arm assessment. No cases of stem mobilization were found and cement mantle integrity was maintained in every case. Insertion of screws around a cemented stem for plate fixation in periprosthetic femur fractures Vancouver type B1 could be considered a safe procedure. However, further and more extended studies are necessary for proving additional knowledge at the evaluation of the cement mantle in osteosynthesis procedures. (www.actabiomedica.it)