[Use of an new modular revision arthroplasty system for the knee reconstruction]. / Einsatz eines neuen modularen revisionsendoprothetischen Systems zur Kniegelenksrekonstruktion.

OBJECTIVE: Reconstruction of stable knee joint kinematics using modular axis-guided revision implants after failed knee arthroplasty surgery. INDICATIONS: Revision implant for bone defects (type Anderson Orthopaedic Research Institute [AORI] III) in case of revision arthroplasty. Primary implant in case of mediolateral instability (>grade I) or multidirectional instability. CONTRAINDICATIONS: Persistent or current joint infection, general infection (e.g. pneumonia), missing metaphysis femoral and/or tibial, insufficient extensor apparatus. SURGICAL TECHNIQUE: Standard approach extending the previously used skin incision. Arthrotomy, synovectomy and collection of multiple samples for microbiological and histopathological analyses. Preparation of the femur with reamers of increasing diameter. Subsequently, a reference stem is anchored and after referencing the correct rotation and joint line height; the femoral osteotomy is performed after fixation of the 5­in­1 cutting block. Following the femoral osteotomy, the box of the femoral prosthesis is prepared. In addition, the tibia is prepared using an intramedullary reference system. Level of constraint and additional tibial augmentation is chosen according to the amount of defect bone and according to ligament stability. POSTOPERATIVE MANAGEMENT: Full load bearing; standard wound control and sterile dressings; limitation of active/passive range of motion only in case of weakened extensor apparatus. RESULTS: Between 03/2011 and 05/2018, a total of 48 patients underwent revision arthroplasty using the described system. The mean follow-up was 24 months (range 21-35 months). In 30 of the 48 cases, a rotating hinge variant was implanted, while in 18 cases a semiconstrained variant was implanted. Indications to revision arthroplasty: infection (n = 22), aseptic loosening (n = 11), instability (n = 11), periprosthetic fracture (n = 3) and PMMA allergy (n = 1). In 11 cases, revision had to be performed due to persistent infection (n = 6) and aseptic loosening (n = 5): 9 cases could be successful treated by a two-step revision procedure, while in 2 cases it was necessary to perform an arthrodesis. The 2­year implant survival rate was 77%.

[Periprosthetic fractures of the acetabulum: revision endoprosthetics]. / Periprothetische Frakturen des Acetabulums: Revisionsendoprothetik.

BACKGROUND: Periprosthetic acetabular fractures are an increasing severe complication in revision arthroplasty. A differentiation is made between periprosthetic acetabular fractures (acute/traumatic fractures) and insufficiency fractures (chronic fractures). OBJECTIVE: This article introduces a novel treatment algorithm that provides assistance in therapeutic decision making for implant selection and the anchoring philosophy based on diagnostic decision criteria and the relevant load-bearing osseous structures, taking the defect situation into account. MATERIAL AND METHODS: The article provides an overview of original and review articles. RESULTS: The essential criteria for decisions in treatment planning are based on the stability of the primary cup, the load-bearing ability of the main anatomical structures and the resulting defect situation. For insufficiency fractures the reason for the revision and therefore the exclusion of periprosthetic joint infections (PJI) must additionally be considered. In the case of proven PJI a two-stage or multistage prosthesis exchange must be carried out. Based on the extent of apparent bony defects and pelvic discontinuity, the spectrum of treatment options ranges up to implantation of individual patient custom-made acetabular components. DISCUSSION/CONCLUSION: This overview introduces a new treatment algorithm that provides assistance in decision making for traumatic periprosthetic acetabular fractures and insufficiency fractures. It also provides decision criteria for selection of implants and the surgical approach. Due to the complexity of revision arthroplasty often requiring specialized expertise in trauma and orthopedic surgery and experienced revision surgeons, the operative treatment of periprosthetic acetabular fractures should only be carried out in specialized orthopedic and trauma surgery centers with appropriate experience.

Analysis of synovial biomarkers with a multiplex protein microarray in patients with PJI undergoing revision arthroplasty of the hip or knee joint.

INTRODUCTION: Diagnosing a (low-grade) periprosthetic joint infection (PJI) after hip or knee arthroplasty remains a diagnostic challenge. The aim of this study was to evaluate the utility of using a novel multiplex protein microarray system for synovial biomarkers in determining PJI in patients undergoing revision knee or hip arthroplasty. MATERIALS AND METHODS: The individual synovial fluid levels of 12 cytokines (IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-17, GM-CSF, TNF-α, and INF-γ) were analysed with a novel multiplex protein microarray system in 32 patients undergoing revision hip (n = 22) or knee (n = 10) arthroplasty. Cases were classified into septic and aseptic groups on basis of pre- and interoperative findings: [PJI (n = 14) vs. non-PJI (n = 18)]. Receiver operator characteristic (ROC) curves were calculated to assess the discriminatory strength of the individual parameters. A multiple regression model was used to determine the utility of using a combination of the tested cytokines to determine the infection status. RESULTS: The levels of all of the evaluated cytokines were significantly elevated in the PJI-group. Best sensitivity and specificity were found for IL-6, followed by IL-1b, IL-10, and IL-17. The multiple regression models revealed a combination of IL-2, IL-4, IL-5, IL6, lL-12, and GM-CSF to be associated with the best sensitivity (100%) and specificity (88.9%) for a cut-off value of 0.41, with a likelihood ratio of 9.0. CONCLUSION: Analysis of individual synovial fluid cytokine levels showed both high sensitivity and high specificity in diagnosing PJI. A combined model using several cytokines showed even higher sensitivity and specificity in diagnosing PJI and could thus be a useful predictive tool to determine the probability of PJI in patients with a painful prosthesis. LEVEL OF EVIDENCE: Diagnostic IV.

[Modular arthrodesis system TITAN (KAM-TITAN) after failed revision total knee arthroplasty : Operative technique and clinical experience]. / Modulares Kniearthrodesesystem TITAN (KAM-TITAN) nach fehlgeschlagener Knieendoprothetik : Operative Technik und klinische Ergebnisse.

OBJECTIVE: Restoration of a painless, weight-bearing extremity with a modular knee arthrodesis system based on a cementless modular revision stem for rotationally stable, diaphyseal anchorage. INDICATIONS: Severe bone loss and compromised soft tissue after failed total knee arthroplasty, two-stage revisions and non-reconstructible knee extensor mechanism deficiency. CONTRAINDICATIONS: Extensive osteolysis preventing diaphyseal anchorage of the prosthesis. Contralateral arthrodesis of the knee joint and/or ipsilateral arthrodesis of the hip joint and contralateral lower extremity amputation. SURGICAL TECHNIQUE: In revision cases, removal of the total knee arthroplasty, spacer, the bone cement and all intramedullary granulation tissue. Reaming the medullary cavity with intramedullary reamers to cortical contact. Restoring leg length and rotation with trial implants. After implantation of the femoral and tibial stems, placing and tensioning of the rotationally aligned coupling elements. POSTOPERATIVE MANAGEMENT: Mobilization on two forearm crutches from postoperative day 1. Removal of the Redon drains after 48 h. Partial weight bearing of 20 kg for 6 weeks postoperatively. If plain radiographs show unchanged seating of the prosthesis after 6 weeks, loading can be increased by 10 kg per week until full weight bearing is achieved. RESULTS: Between 2007 and 2012 clinical data were collected and analyzed retrospectively. A total of 27 patients had been treated within a two-stage exchange procedure with implantation of a modular intramedullary arthodesis nail TITAN (KAM-TITAN). The mean follow-up was 30.9 ± 12.0 months. A functional evaluation was performed using the Oxford Knee Score (OKS). The analyzed patients showed a mean score of 39.2 ± 8.3. To determine the pain level the Visual Analog Scale (VAS) for pain was used and showed a mean score of 2.9 ± 1.3. The rate of definitely free of infection (using Laffer criteria) at last follow-up was 85.2%.

Mid-term results after revision total hip arthroplasty with custom-made acetabular implants in patients with Paprosky III acetabular bone loss.

INTRODUCTION: Severe acetabular bone loss, both with or without pelvic discontinuity, remains a challenge in revision total hip arthroplasty (RTHA). The goal of our study was to evaluate the mid-term results for consecutive patients with Paprosky III acetabular bone loss with or without pelvic discontinuity who needed RTHA with custom-made acetabular implants and to compare the results to those of other studies. MATERIALS AND METHODS: Sixty-eight (68) patients with severe acetabular bone loss (Paprosky Type IIIa and IIIb), who required RTHA, were included in our study. All prostheses were constructed on the basis of thin-layer computed tomography (CT) scans of the pelvis. The visual analogue scale (VAS), Harrison hip score (HHS), and clinical and radiographic follow-up assessments were used to evaluate the outcome. RESULTS: The average follow-up time was 43 months (range 1-120 months). Implant survival at last follow-up was 75% (51 of 68). Kaplan-Meier survival analysis, with explantation as the endpoint, revealed survival rates of 82.7% (3 years) and 77% (5 years). Patients with revision of the acetabular component only had a significant higher survival rate (p 0.012). Overall revision rate was 36.7%. Reinfection rate was 34.4%. Complications included 15 (22%) periprosthetic joint infections (PJI), 7 dislocations (10.2%), and 2 aseptic loosenings (2.9%). Mean VAS at last follow-up was 1.45 compared to 3.2 preoperatively, while mean HHS improved from 21.1 points preoperatively to 61 at last follow-up. The change in both scores was thus significant (p < 0.001). CONCLUSION: Defect reconstruction with custom-made modular acetabular implants can be a good, nevertheless expensive, treatment option with clinically and radiologically satisfying results in comparison to recent studies in the literature. Nevertheless, high postoperative complication rates, especially in terms of PJI, remain a challenge.

[Acetabular revision arthroplasty with a novel cementless augment-and-modular-cage system (MRS-C) : Surgical technique and preliminary clinical results]. / Hüftpfannenwechsel mit einem neuartigen zementfreien "Augment-and-modular-cage"-Revisionssystem (MRS-C) : Chirurgische Technik und erste klinische Ergebnisse.

OBJECTIVE: Optimal reconstruction of acetabular anatomy and primarily stable bridging even of large bone defects in hip revision surgery by intraoperative cementless application of highly modular components of the MRS-TITAN Comfort (MRS-C) system according to the augment-and-modular-cage principle. INDICATIONS: Acetabular defect situations in hip revision surgery, hereditary/acquired acetabular deformities, severe secondary hip osteoarthritis. CONTRAINDICATIONS: Extended periacetabular defects of the dorsal pillar, pelvic discontinuities, persisting posttraumatic or periprosthetic infections, lack of intraoperative bony anchorage options. SURGICAL TECHNIQUE: Conventional positioning. Flexible selection of approach (posterolateral, anterolateral or transgluteal) to the hip joint, if possible using a previous approach. Implant removal, preparation and intraoperative acetabular defect evaluation. Optional impaction bone grafting for biological downsizing. Selection of modular components and augments depending on the defect. Preparation of the obturator foramen for anchorage of the caudal flange. Optional preparation of the os ilium for additional fixation of the cage with flanges. Fixation with polyaxial screws and selection of version/inclination of the cup component. Selection of the inlay (polyethylene/ceramic). POSTOPERATIVE MANAGEMENT: Partial weight-bearing with 20 kg body-weight for 6 weeks with crutches. Prophylaxis for deep vein thrombosis and heterotopic ossification. Additional adapted antibiotic therapy in cases of infection. RESULTS: A minimum 1­year follow-up of 42 patients showed significant improvements of Harris Hip Scores (p < 0.0001), adequate reconstruction of the physiologic center of rotation (x-ray controlled in the vertical plane, referenced to the contralateral side), and a clear reduction of preoperative leg length discrepancies. No significant changes in range of motion. No implant-associated complications noted. Based on the short follow-up results, the implant proves as suitable for reconstruction of even large acetabular bone defects.

[Endoprosthetic replacement of the proximal humerus in revision shoulder arthroplasty]. / Der proximale Humerusersatz in der Revisionssituation.

OBJECTIVE: Reconstruction of proximal humeral bone defects in the setting of shoulder revision arthroplasty by implantation of a modular humeral component. INDICATIONS: Severe segmental humeral bone defects in revision total shoulder arthroplasty, after tumor resection, trauma, pathological fractures, post-infectious or after failed osteosynthesis. CONTRAINDICATIONS: Acute or chronic local infections, large diaphyseal bone defects preventing adequate anchorage of the prosthesis, very short life expectancy (<3 months). SURGICAL TECHNIQUE: Removal of the implant using an extended deltopectoral approach. Periarticular arthrolysis with preservation of neurovascular structures. Resection of the meta-diaphyseal bone and reconstruction of the humeral length with the help of different extension sleeves and a modular humeral component. Soft tissue management is crucial, especially with reverse shoulder arthroplasty. POSTOPERATIVE MANAGEMENT: Three weeks postoperatively immobilization in a shoulder sling, active assisted movement therapy by gradual pain-adapted increase of movement, muscle coordination, and strength. RESULTS: The results of 11 consecutive patients treated with a modular humeral component due to a failed shoulder arthroplasty between 2008 and 2016 were evaluated retrospectively. Mean length of reconstruction was 100 mm. Due to recurrent dislocations one patient required revision and conversion to a reverse component. No cases of aseptic loosening or periprosthetic infection were observed.

Osseous hydatidosis of the proximal femur: a rare diagnosis in revision total hip arthroplasty.

Musculoskeletal hydatidosis is a rare but severe disease in central Europe. This case report presents the incidental finding of an osseous hydatidosis after cementless revision total hip arthroplasty in a patient without a preoperative history of hydatidosis or any clinical symptoms. Revision total hip arthroplasty had been necessary due to a septic osteonecrosis of the femoral head 2 years after osteosynthesis of a traumatic proximal femur fracture with a sliding hip screw. The positive sample was taken out of the greater trochanter in the area of the possible former entry point for the lag screw, which was macroscopic inconspicuous. Sero-analysis could afterwards confirm the suspected diagnosis. Postoperative chemotherapy with albendazole was performed for 6 months. A full-body MRI did not reveal any further cysts. This case demonstrates a possible impact of migration on the expected pathogens in revision arthroplasty. This demonstrates that in revision arthroplasty, an infection with this parasite also has to be taken into account, if the patients come from an area endemic for hydatidosis.

Staphylococcus aureus versus Staphylococcus epidermidis in periprosthetic joint infection-Outcome analysis of methicillin-resistant versus methicillin-susceptible strains.

Periprosthetic joint infections (PJIs) are a major complication in total joint arthroplasty. Staphylococcus aureus and coagulase-negative staphylococci are known to cause the majority of all PJIs. This study aimed to analyze the eradication rates of S. aureus and S. epidermidis with methicillin susceptibility and methicillin resistance in a 2-stage therapy algorithm. Seventy-four patients with PJI caused by methicillin-resistant S. aureus (MRSA), methicillin-resistant coagulase-negative staphylococci (MRSE), methicillin-susceptible S. aureus (MSSA), and methicillin-susceptible coagulase-negative staphylococci (MSSE) were included, and the outcome was analyzed retrospectively. After a minimal follow-up of 2 years, n = 56 patients (75.7%) were definitively free of infection. The analysis revealed significant differences between the groups, with eradication rates as follows: MSSA (92.6%), MSSE (95.2%), MRSA (80%), and MRSE (54.2%). MRSE showed a significantly lower rate of patients graded as "definitively free of infection" as compared to patients with infections caused by MSSA, MSSE, and MRSA.

[The S2k guideline: Indications for knee endoprosthesis : Evidence and consent-based indications for total knee arthroplasty]. / S2k-Leitlinie: Indikation Knieendoprothese : Evidenz- und konsensbasierte Indikationsstellung in der Knie-Endoprothetik (EKIT-Knie).

Total knee arthroplasty (TKA) is one of the most frequent surgical procedures in orthopaedic surgery. Until now there have not been any standardized indication criteria, which might contribute to the large geographical differences in the frequency of TKA. This guideline aims to consent minimal requirements (main criteria), additional important aspects (minor criteria), as well as relative and absolute contraindications for TKA. The following main criteria have been consented: knee pain, radiological confirmation of osteoarthritis or osteonecrosis, inadequate response to conservative treatment, adverse impact of knee disease on the patient's quality of life and the burden of suffering due to the knee disease. Relative contraindications have been consented as severe general disease with reduced life expectancy and a BMI ≥40; absolute contraindications are an active infection and if the patient is not able to undergo major surgery.

[Biological downsizing : Acetabular defect reconstruction in revision total hip arthroplasty]. / Biologisches Downsizing : Azetabuläre Knochendefekte in der Hüftrevisionsendoprothetik.

BACKGROUND: Periacetabular bony defects remain a great challenge in revision total hip arthroplasty. After assessment and classification of the defect and selection of a suitable implant the primary stable fixation and sufficient biological reconstitution of a sustainable bone stock are essential for long term success in acetabular revision surgery. Biological defect reconstruction aims for the down-sizing of periacetabular defects for later revision surgeries. TECHNIQUE: In the field of biological augmentation several methods are currently available. Autologous transplants feature a profound osseointegrative capacity. However, limitations such as volume restrictions and secondary complications at the donor site have to be considered. Structural allografts show little weight bearing potential in the long term and high failure rates. In clinical practice, the usage of spongious chips implanted via impaction bone grafting technique in combination with antiprotrusio cages for the management of contained defects have shown promising long time results. Nevertheless, when dealing with craniolateral acetabular and dorsal column defects, the additional implantation of macroporous metal implants or augments should be considered since biological augmentation has shown little clinical success in these particular cases. PROSPECT: This article provides an overview of the current clinically available biological augmentation methods of peri-acetabular defects. Due to the limitations of autologous and allogeneic bone transplants in terms of size and availability, the emerging field of innovative implantable tissue engineering constructs gains interest and will also be discussed in this article.

Lower limb reconstruction in tumor patients using modular silver-coated megaprostheses with regard to perimegaprosthetic joint infection: a case series, including 100 patients and review of the literature.

PURPOSE AND OBJECTIVE: Bone resection regarding adequate surgical margins is the treatment of choice for malignant bone tumors. In the case of metastasis-related complications, so-called skeletal-related events, it is highly important to achieve pain relief and a stable joint situation to re-mobilize the patients immediately following surgery. To bridge the often large osseous defect zones after tumor resection, both cemented and uncemented modular endoprosthetic systems are widely used. Patients undergoing tumor-related endoprosthetic orthopedic surgery are facing high risk for developing a periprosthetic joint infection (PJI). The immunocompromised condition due to anti-neoplastic treatment and long operation time with large exposure of tissue contributes to a high risk of infection. METHODS: The authors present a case series of 100 patients (31% primary bone tumor and 69% metastasis-related surgery) undergoing tumor-related lower limb salvage surgery with special regard to periprosthetic joint infection and the management of this "difficult to treat" situation. Furthermore, a review of the current literature regarding infection following bone tumor resection and endoprosthetic reconstruction is performed and discussed. RESULTS: The median follow-up was 24 months (range 12-108 months). Ten patients (10%) suffered from a periprosthetic joint infection. We recorded six acute infections (type I) <4 weeks after surgery, one infection >4 weeks after surgery (type II), and three late infections (type III). According to the definition of Laffer et al., three of our patients (30%) are probably free of infection, one patient died of PJI-associated sepsis, and five patients were free of infection, but without restoration of the affected joint. CONCLUSION: In conclusion, our own results show that perimegaprosthetic joint infection among silver-coated implants, in patients undergoing tumor-related surgery of the lower limb, is lower compared to non-silver-coated implants. Due to heterogeneity of patients and potential treatment options, the treatment regime should be tailored for the patients' individual situation.

[The Role of a Modular Universal Tumour and Revision System (MUTARS®) in Lower Limb Endoprosthetic Revision Surgery - Outcome Analysis of 25 Patients]. / Tumorprothesen in der endoprothetischen Revisionschirurgie der unteren Extremität ­ Ergebnisse von 25 Patienten nach Versorgung mit einem modularen Tumor- und Revisionssystem (MUTARS®).

Introduction/Background: With extended life expectancy, the number of primary joint arthroplasties has also increased. Revision surgery is also more often necessary, due to aseptic or septic loosening of the prosthesis or periprosthetic fracture. Large bone defects often occur in these patients and several non-modular, conventional implants are available to handle this difficult situation. Custom made implants offer an individually designed and defect-adapted shape with perfect covering of the lesion, but may delay the operation. The Modular Universal Tumor And Revision System (MUTARS®) offers the possibility to vary the length and angle of the femoral neck and the antetorsion angle. Thus, it permits intraoperative adaption to the individual patient's defect. The aim of our study is to present clinical, functional results and the rate of complications in a cohort of patients undergoing revision surgery for failed endoprosthetic replacement or failed trauma surgery, using the Modular Universal Tumor And Revision System with short-to midterm follow-up. Patients and Methods: Between August 2005 and September 2014, 25 patients (17 female, 8 male) with an average age of 72 years (min. 56, max. 92 years) were included in a retrospective study using the MUTARS® system. The patients underwent surgical revision of osseous defects that were not susceptible to conventional care. The mean follow-up was 16 months (min. 12, max. 72 months). The indications which led to revision surgery were as follows: loosened metal-on-metal prosthesis with an acetabular defect caused by a metal-induced granuloma (n = 1), pseudoarthrosis after implantation of femur nail (n = 2), cut-out of a femur nail (n = 1), aseptic loosening of an implanted endoprosthesis (n = 4), septic loosening of an implanted endoprosthesis (n = 1), periprosthetic fracture (n = 6) and periprosthetic infection after two stage revision surgery (infection consolidated Girdlestone situation) (n = 10). All patients were followed up at regular intervals, both clinically and radiologically. Apart from comorbidities, clinical and functional parameters were measured, including the Harris Hip Score. An outcome analysis was also performed with respect to peri- and postoperative complications. Serial plain X-rays were followed-up. Results: In all patients, stable reconstruction without the use of an allograft was possible. In total, 23 patients underwent surgery by using a proximal femur prosthesis; three patients also received a custom made acetabular component. One patient was treated by using a distal femur and one patient was treated by implantation of a total femur prosthesis. The average length of hospital stay was 25 days (min.11, max. 47 days). The Harris Hip Score improved from 28 points preoperatively to 81 points after surgery.In total we recorded 24 % of complications after surgery. Two patients suffered recurrent periprosthetic infection and the prosthesis had to be revised in a further two stage exchange; one patient had a tractus gap and was revised by surgery. Two patients suffered periprosthetic fracture due to trauma and the patient with the total femur prosthesis suffered recurrent periprosthetic infection of the silver - coated mega-prosthesis and committed suicide triggered by an episode of major depression. Conclusion: Because of its modular nature, the Modular Tumor And Revision System (MUTARS®) can be used for highly variable intraoperative defect adaption. Good clinical and functional results were achieved in patients with excessive bone defects. However, the high rate of infection, even with silver coated mega-implants, is still a problem and should be studied further.

The QuickLine IL-6 lateral flow immunoassay improves the rapid intraoperative diagnosis of suspected periprosthetic joint infections.

BACKGROUND: When deciding upon the best treatment strategy in revision arthroplasty, it is absolutely crucial to use the best possible preoperative detection whether a periprosthetic joint infection (PJI) is present or not. New molecular markers investigated in serum samples and synovial fluid can help to improve the preoperative diagnosis. In 2001, a novel IL-6 lateral flow immunoassay testing device was introduced which has never been tested in synovial fluid so far. OBJECTIVE: For our study we investigated whether the test can be used safely, feasibly and time effectively with synovial fluid gathered from potentially infected THAs or TKAs and whether the already published cutoff for IL-6 in synovial fluid predicting a PJI can be reproduced using the QuickLine IL-6 immunoassay. METHODS: After ethic approval and within the scope of a prospective controlled trial we investigated 26 patients (m = 9, 34.6%; f= 17, 65.4%) with n = 13 (50%) potentially infected total hip arthroplasties (THAs) and n = 13 (50%) suspected PJIs of total knee arthroplasties (TKAs). Sterile aspirated synovial fluid was examined for total leukocyte count and cell differentiation by a blood count analyzer in body fluid mode as well as for IL-6 (Immulite, Siemens Medical Solutions Diagnostics GmbH, Eschborn, Germany). Another part of the joint aspirate was tested using the QuickLine IL-6 Test by Milenia Biotec (Milenia Biotec, Gießen, Germany). RESULTS: The mean concentration of IL-6 as determined from our reference laboratory testing (Siemens Immulight) for aseptic cases was 1,219 pg/mL (SD 1,369 pg/mL, min 134 pg/mL-max 4,214 pg/mL). The mean IL-6 concentration measured via the IL-6 QuickLine for aseptic cases was 410 pg/mL (SD 371 pg/mL, min 100 pg/mL-max 1562 pg/mL). The test showed no false negative or false positive results in the cases tested. In six patients, PJI was considered proven. The QuickLine Test indicated IL 6 concentrations > 10,000 pg/mL in these cases without further quantification above this maximum detection threshold. Results from the QuickLine Test and the laboratory tests were matched and a non-linear best fit curve (log-log-curve) was applied. The subsequent Spearman correlation showed a correlation coefficient of r = 0.92 (95% CI 0.81-0.97) which corresponds to a two-tailed p-value of < 0.0001, respectively. As a primary finding we were able to show that the Milenia QuickLine IL-6 Test can be used safely, feasibly and time effectively with synovial fluid gathered intraoperatively from potentially infected THAs or TKAs. The test as provided worked well in 84.6% of the samples tested and failed only due to very viscous synovial fluid. As a secondary result we found that the previously published cut-off for IL-6 in synovial fluid predicting a PJI with a sensitivity of 46.88% and a specificity of 97.62% can be reproduced using the QuickLine IL-6 immunoassay. CONCLUSION: Taking the limitations of the low sample size as a given this relatively simple point of care (POC) assay showed promising results in our pilot trial and may help diagnosing PJI. It may help physicians and surgeons to choose the best and least invasive treatment strategy for patients presenting with painful arthroplasty.

[Intra-articular Sampling with Novel Biopsy Forceps: a Simple and Reliable Diagnostic Procedure for Patients with Periprosthetic Infections of the Knee Joint]. / Intraartikuläre Probenentnahme mit einer neuartigen Biopsiezange: ein leichtes und sicheres diagnostisches Verfahren bei Patienten mit periprothetischen Infektionen des Kniegelenks.

Introduction: Rapid and reliable differentiation between septic and aseptic presentations can be challenging in patients with painful total knee arthroplasties. Clinical symptoms, serum tests, as well as the analysis of synovial fluid, are important parameters. Nevertheless, deep intra-articular tissue samples exhibit greater sensitivity and specificity regarding the diagnosis of a suspected periprosthetic joint infection. In 2014, Hügle et al. introduced novel retrograde forceps to acquire tissue samples and synovial fluid simultaneously in an outpatient setting. In this article, we present the first use of their device in patients with total knee arthroplasty. Methods: After approval by a local ethics board, retrograde forceps were used via the standard lateral suprapatellar approach. The technique was comparable to conventional aspiration of a total knee arthroplasty. Beside joint aspiration, tissue samples were gathered for further microbiological and histopathological examination. Results and Discussion: It is easy to collect synovial fluid and tissue samples using the retrograde forceps in patients with suspected periprosthetic infections of the knee joint. This is a safe and feasible method and can be performed in an outpatient setting. We have not yet observed any complications and consider that the risks are comparable to those with conventional joint aspiration. In our opinion, this technique may be useful in detecting infections in patients with painful total knee arthroplasty.

[Quality in Revision Arthroplasty: A Comparison between Claims Data Analysis and External Quality Assurance]. / Ergebnisqualität in der Revisionsendoprothetik: Eine Analyse von Routinedaten mit dem Vergleich zur externen Qualitätssicherung.

BACKGROUND: External quality assurance for revisions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) are carried out through the AQUA institute in Germany. Data are collected by the providers and are analyzed based on predefined quality indicators from the hospital stay in which the revision was performed. The present study explores the possibility to add routine data analysis to the existing external quality assurance (EQS). Differences between methods are displayed. The study aims to quantify the benefit of an additional analysis that allows patients to be followed up beyond the hospitalization itself. MATERIAL AND METHODS: All persons insured in an AOK sickness fund formed the population for analysis. Revisions were identified using the same algorithm as the existing external quality assurance. Adverse events were defined according to the AQUA indicators for the years 2008 to 2011.The hospital stay in which the revision took place and a follow-up of 30 days were included. For re-operation and dislocation we also defined a 365 days interval for additional follow-up. The results were compared to the external quality control reports. RESULTS: Almost all indicators showed higher events in claims data analysis than in external quality control. Major differences are seen for dislocation (EQS SD: 1.87 vs. claims data [cd] SD: 2.06 %, cd+30 d: 2.91 %, cd+365 d: 7.27 %) and reoperation (hip revision: EQS SD: 5.88 % vs. claims data SD: 8.79 % cd+30 d: 9.82 %, cd+365 d: 15.0 %/knee revision: EQS SD: 3.21 % vs. claims data SD: 4.07 %, cd+30 d: 4.6 %, cd+365 d: 15.43 %). Claims data could show additional adverse events for all indicators after the initial hospital stay, rising to 77 % of all events. CONCLUSIONS: The number of adverse events differs between the existing external quality control and our claims data analysis. Claims data give the opportunity to complement existing methods of quality control though a longer follow-up, when many complications become evident.

[Antimicrobial prosthesis coatings]. / Antimikrobielle Prothesenbeschichtungen.

BACKGROUND: Antimicrobial coatings have a great potential in the treatment and prevention of periprosthetic joint infection. OBJECTIVE: To present established and novel concepts of antimicrobial coatings. METHODS: A literature review and discussion of published concepts in basic research, pre-clinical animal studies, and clinical practice were carried out. RESULTS: To date there has been a wide range of technical solutions (anti-adhesive surfaces, bioactive surfaces with antimicrobial effects, surfaces releasing antimicrobial substances, nanostructures, bioactive surfaces affecting biofilm development) demonstrating a high potential in pre-clinical studies. Only a few with the bactericidal activity of silver ions have been prepared for the market. Conclusive results with regard to biocompatibility and toxicity are lacking. DISCUSSION: Despite the great potential of antimicrobial coatings, no conclusive decisions can be made because of the limited data and the lack of evidence of their clinical efficacy on the basis of prospective controlled clinical studies. In addition to their unlimited biocompatibility, innovative concepts have to be feasible in everyday clinical routine.

[Intercalary reconstruction for diaphyseal bone defects with a modular replacement system: Clinical results]. / Interkalare Rekonstruktion diaphysärer Knochendefekte mit einem modularen Diapyhsenersatzsystem: Klinische Ergebnisse.

OBJECTIVE: Reconstruction and long-term stabilization of segmental diaphyseal bone defects of the humerus, femur, and tibia. INDICATIONS: Segmental bone defects due to aggressive benign or primary malignant bone tumors, trauma, pathological fractures, osteomyelitis, or failed osteosynthesis. CONTRAINDICATIONS: Acute or chronic local infections, large metadiaphyseal bone defects preventing adequate anchorage of the prosthesis, very short life expectancy (<3 months). SURGICAL TECHNIQUE: Exposure and resection of the bony defect according to the preoperative planning. Reaming of the intramedullary canals proximally and distally followed by implantation of the stems (cemented or noncemented). Reducing sleeves can be used to bridge the difference in diameter between the nail and the spacer. Mounting of the spacer half shell with the threaded holes from underneath after adjusting for alignment and rotation. Assembling of the other half shell by guided pins to ensure proper alignment. Tightening of the clamping screws using a torque screwdriver. Connection of two spacers is possible. POSTOPERATIVE MANAGEMENT: Active physiotherapy and full weight bearing; antibiotic prophylaxis. RESULTS: The results of 14 consecutive patients treated with 15 modular intercalary endoprostheses (Osteobridge™, Merete, Berlin, Germany) between January 2007 and January 2012 with a mean follow up of 24 ± 12 months (range 12-51 months) were evaluated retrospectively. One patient had a primary malignant bone tumor, while all the other patients underwent resection for metastatic disease. The mean age at surgery was 65.9 ± 15.7 years (range 25-83 years). The mean diaphyseal reconstruction length was 110 ± 50 mm (range 50-190 mm). Three patients (20%) required revision of the distal stem due to aseptic loosening. Evaluation of the functional outcome using the MSTS score by Enneking revealed 3 very good (22%), 7 good (50%), 4 fair (28%), and no poor results.

Multidrug resistant Acinetobacter baumannii reaches a new frontier: prosthetic hip joint infection.

Acinetobacter baumannii is an emerging nosocomial pathogen primarily in countries with a high prevalence of multidrug resistance. Here we report the detection of a bla OXA23 carbapenemase-producing A. baumannii strain in a German patient with prosthetic hip joint infection following several hip joint surgeries but no history of foreign travel.