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.

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.

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.

Fluid collection bags pose a threat for bacterial contamination in primary total hip arthroplasty: a prospective, internally controlled, non-blinded trial.

INTRODUCTION: Surgical equipment, and especially the so-called 'splash basins' that are used intraoperatively, are a potential source of bacterial contamination in primary total hip arthroplasty (THA). With this risk in mind, many commercially available draping kits include plastic bags that can be used to collect fluid or to temporarily store instruments. Following this rationale, we hypothesised that first: the fluid collection bags are a potential reservoir of bacteria and second: there is a time dependency for bacterial contamination. MATERIALS AND METHODS: After ethics approval, we investigated in a prospective, internally controlled, non-blinded trial 43 patients who received primary THA. At the beginning of the surgery, we took deep, representative, intracapsular tissue samples, which served as negative controls. At the end of surgery, tissue samples were taken from the bottom of the 'fluid collection bag' for microbiological analysis. RESULTS: All 86 control samples were negative. Out of the samples taken from the bags, a pathogen could be detected in four patients (9.3%). All pathogens were detected after a surgery time lasting longer than 90 min. CONCLUSION: We were able to show that fluid collection bags are a potential reservoir for bacteria in THA when surgery time was greater than a 90-min threshold. Our data suggest that the risks from fluid collection bags outweigh the advantages of using them. Therefore, we recommend against the use of fluid collection bags intraoperatively in primary THA.

[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.

MALDI imaging of predictive ferritin, fibrinogen and proteases in haemophilic arthropathy.

Arthropathy as a result of repeated joint bleeding is a severe complication in patients with haemophilia. In the evaluation of synovial tissue specimens, histology alone is non-specific and there is considerable morphological overlap with other joint diseases. Formalin-fixed paraffin-embedded specimens are available in pathological institutes and can be studied to understand the pathogenesis of haemophilic arthropathy. A powerful technique to identify hundreds of proteins in a tissue section combining proteomics with morphology is imaging mass spectrometry (IMS). We determined whether matrix-assisted laser desorption/ionization (MALDI) IMS can be used to identify and map protein signatures in the synovial tissue of patients with haemophilic arthropathy. MALDI IMS was applied to synovial tissue of six patients with haemophilic arthropathy. We detected several peaks predictive in mass with ferritin light (m/z 1608) and heavy chain (m/z 1345), alpha- (m/z 1071) and beta (m/z 1274) haemoglobin subunits, truncated coagulation factor VIII peptide (m/z 1502, 1176), beta- and gamma fibrinogen peptides (m/z 980, 1032, 1117 and 1683), and annexin A2 (m/z 1111, 1268, 1460, 2164). In addition, the distribution of these proteins in synovial tissue sections was demonstrated. MALDI IMS identified and mapped specific proteins in the synovial membrane of patients with haemophilic arthropathy known to be involved in the pathogenesis of other joint diseases. This technique is a powerful tool to analyse the distribution of proteins in synovial tissue sections.

[Acetabular metastatic defect reconstruction using the modular revision support cup MRS-C]. / Rekonstruktion von metastasenbedingten Defekten des Azetabulums mittels der MRS-C-Abstützschale.

OBJECTIVE: Stabilization of metastatic acetabular defects with a bone cement-augmented revision support cup for remobilization of oncological patients in advanced cancer stages. INDICATIONS: Metastatic acetabular defects (Metastatic Acetabular Classification, MAC 2-4) in patients with a prognostic medium or long-term survival. CONTRAINDICATIONS: Highly limited survival due to metastatic disease (< 6 weeks). Local bone or soft tissue infection. Primary bone tumor with curative treatment option. Advanced pelvic discontinuity. Recent wound compromising systemic therapy. SURGICAL TECHNIQUE: Standard hip approach. Curettage of the metastatic defect and careful reaming of the acetabulum before insertion of the cup. Predrilling of the dome und flange screws before application of the bone cement through the center hole of the implant and filling of the acetabular defect. Complete insertion of the screws for compound osteosynthesis. Implant of a modular inlay or dual mobility system. POSTOPERATIVE MANAGEMENT: Full weight bearing or mobilization with two crutches according to the level of pain. Adjuvant local radiation therapy after wound consolidation. Continuation of systemic therapy according to tumor board decision. RESULTS: Between 2012 and 2019, we treated 14 patients with metastatic acetabular defects using the modular revision support cup "MRS-TITAN® Comfort", MRS-C, Peter Brehm GmbH, Weisendorf, Germany) at our institution. Mean Harris Hip Score improvement was 23.2 with a mean patient's survival of 9.7 months due to the reduced cancer-related prognosis; 13 of the 14 implants endured the patient's prognosis. One implant had to be removed due soft tissue defect-related periprosthetic joint infection.

[What can be done when hip prostheses fail? : New trends in revision endoprosthetics]. / Was tun, wenn die Hüftendoprothese versagt? : Neue Trends in der Revisionsendoprothetik.

Revision surgery after total hip arthroplasty is increasing steadily in numbers. These procedures demand high performance from both the treating surgeon as well as the implants used. Novel developments from basic research and industrial partners extend the possibilities for treating affected patients. This article gives an overview of the state of the art in revision hip arthroplasty: new techniques and trends are outlined and presented.

[Algorithm for the treatment of the haemophilic arthropathia of the upper ankle joint]. / Behandlungsalgorithmus der hämophilen Arthropathie des oberen Sprunggelenkes.

The upper ankle joint is one of the target-joints of the haemophilic patient. Therefore, the secondary arthritis of the upper ankle joint is one of the most frequent forms of haemophilic arthropathy. It is a secondary form of arthritis not only because of chronic synovitis and cartilage injury resulting from chronic recurrent intraarticular bleeds, but also due to the misalignment of the joint and abnormal joint stress. The consequences are manifest even in young patients and finally lead to upper ankle joint arthritis. In such clinical situations, the upper ankle joint-arthroplasty is a viable alternative to arthrodesis. After several years of bleeding of the upper ankle joint many patients with haemophilia suffer from symptomatic arthritis. Open joint cleansing considerably improves mobility in the upper ankle joint and alleviates the pain in the talonavicular joint. However, the recovered mobility of the arthritic upper ankle joint also activates arthritis, associated with severe pain. With no contraindication to upper ankle joint replacement, a cement-free prosthesis can be implanted. Three months after surgery, the patients are mobile, with good foot rolling properties without orthopaedic aids and without pain in the upper joint ankle. Concludion: In terms of biomechanics the upper ankle joint-arthroplasty is a superior alternative to arthrodesis in haemophilia patients. In order to minimize the complication rate, their treatment should be restricted to specially equipped interdisciplinary centers with adequately trained and experienced surgeons as well as haemostaseologists.

[Reconstruction of tibial metaphyseal defects with artificial components in revision arthroplasty (GenuX MK System)]. / Rekonstruktion tibialer metaphysärer Defekte im Revisionsfall mit metallischen Metaphysenkomponenten (GenuX MK-System).

OBJECTIVE: Restoration of knee function by using tibial metaphyseal components in advanced metaphyseal bone defects after multiple bone-damaging revision surgery on the knee joint. INDICATIONS: Advanced tibial metaphyseal bone defects (Anderson Orthopaedic Research Institute [AORI] IIb and III defects) in revision arthroplasty of the knee joint. CONTRAINDICATIONS: Persistent or current joint infection, general infection (e.g., pneumonia), nonreconstructable insufficient extensor apparatus. SURGICAL TECHNIQUE: Standard access including existing skin scars, arthrotomy, removal of cement spacer if necessary and removal of multiple tissue samples; preparation of femur first, followed by preparation of the tibia. Referencing the tibial rotation and joint line height. Tibial osteotomy referenced intramedullarily. Determination of the metaphyseal defect size and choice of component size. Positioning of the rasp guide for the preparation of the metaphyseal component (sleeve); gradual preparation of the bed for the metaphyseal component. Afterwards the prepared component at the desired depth (when using augments +5 or +10 mm accordingly 5 or 10 mm above the tibial plateau) is left and the tibial plateau is fixed on the embedded sleeve. Test coupling, control of the implant position and the height of the joint line radiologically. If satisfactory the definitive implants accordingly to the components of used implants before can be implanted. POSTOPERATIVE MANAGEMENT: Full weight bearing. Regular wound control; limitation of the degree of flexion only with weakened or reconstructed extensor apparatus. RESULTS: Between May 2018 and August 2019, 14 metaphyseal tibial components were implanted in 14 patients. The mean follow-up was 10.4 months. The follow-up included clinical examination, KSS (Knee Society Score) and an X­ray and failure analysis. A significant improvement in range of movement from 75 ± 16° to 100 ± 14° (p < 0.01) was achieved. The KSS improved significantly from 78 ± 12 points preoperatively to 137 ± 23 points postoperatively. Two patients complained of persistent pain after exercise (walking distance >200 m) after 6 months; tibial shaft pain was negated by all patients. The group examined afterwards showed an implant survival rate of 100% in the observation interval.

[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%.

[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%.

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 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.

[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.

[Stem cell-based therapy in orthopaedics and trauma surgery - current concepts]. / Aktueller Stand der Stammzelltherapie in Orthopädie und Unfallchirurgie.

Over the last few years, numerous new treatment methods have been developed for musculoskeletal diseases. Some of these new methods are based on the targeted use of stem cells to initiate healing processes, to compensate for deficits or to activate the regeneration of tendons, muscles, bones and cartilage. This goal can be achieved through the direct use of stem cells on or in a carrier material or through a combination with tissue engineering. In this article, we give a short overview of the possible fields of application of inducible pluripotent haematopoietic, and adult stem cells as well as on their use in musculoskeletal tissue. Furthermore, we provide a summary of the current legal situation concerning the application of stem cells in humans.

[Low-intensity pulsed ultrasound for treatment of fractures and nonunions - current evidence and insights from basic research and clinical application]. / Niedrigintensiver gepulster Ultraschall zur Behandlung von Frakturen und Pseudarthrosen - Evidenz und Erkenntnisse aus Forschung und Klinik.

In Germany, 800,000 fractures are treated per year, and up to 10 % of these patients may suffer subsequently from a delayed union or a nonunion at the fracture site. Surgical treatment of these complications is tedious and associated with high costs. Therefore non-operative treatment is recently receiving more scientific and clinical attention. The adjuvant treatment with ultrasound has been propagated for the past years to enhance fracture healing and bony union, and has been discussed controversially. This review article demonstrates the significance of the low intensity pulsed ultrasound application in fracture treatment, on the basis of basic science results, animal experiments and the results of clinical trials.

[Is surgical education associated with additional costs? A controlled economic study on the German DRG System for primary TKA]. / Kostet operative Ausbildung Geld? Eine kontrollierte gesundheitsökonomische Studie auf Grundlage des deutschen DRG-Systems am Beispiel der primären Knieendoprothetik.

AIM: Total knee arthroplasty (TKA) is one of the most common procedures in orthopaedic surgery, the cost of surgical training has as yet not been quantified. In a pilot study, we investigated the economic impact of surgical training under DRG system influences, analysing the cost-proceeds structure in surgical training for orthopaedic residents. METHODS: Consecutive TKAs were performed by the most educated surgeon (Group A) having implanted ≥ 1000 TKAs, another attending (Group B) with ≥ 200 TKAs and a resident (Group C) having assisted in 25 TKAs (n = 30 patients per Group A-C). All patients were embedded in a standardised clinical pathway. By analysing the costs parameters such as numbers of blood transfusions, the operating time and the length of stay in the hospital we investigated the health care-related costs matched to the DRG-based financial refunding. Data were analysed after undergoing a analysis of variance followed by a post-hoc Scheffé procedure. RESULTS: On the one hand the resident generated additional costs of 1111,7 ± 97 € in comparison to the Group A surgeon and 1729,8 ± 152 € compared to the attending Group B (p > 0,05), these were generated by longer stay in hospital, longer operation time and higher need of resources. On the other hand there were significantly higher proceeds of the Group C in comparison to the attending Group B and also to Group A: 474,78 ± 82 € vs. A and 150,54 ± 52 € vs. Group B (p < 0,05). This was generated both by a higher patient clinical level of complexity (PCCL) and increased complication rates resulting in a consecutively augmented profit by grouping these patients to a more lucrative DRG. Overall the deficit per patient treated by the resident is 637 ± 77 € vs. Group A and 1579,3 ± 137 € vs. Group B (p > 0,05). CONCLUSION: The German DRG matrix results in higher profits accounted to the learning surgeon by increased PCCL relevant status and grouping the case to a more profitable DRG. Hereby, the additional costs are only partly redeemed. Surgical education of residents is associated with additional costs for the hospital. These costs have to be redeemed to allow good surgical training for hospitals having good teaching conditions.