[Hip dislocation after revision arthroplasty : Risk assessment and treatment strategies]. / Luxation nach Hüfttotalendoprothesenrevision : Analyse von Risikofaktoren und Lösungsstrategien.

With a dislocation rate of up to 35% after revision total hip arthroplasty (THA), instability is one of the major causes why this procedure fails. Independent factors for patients at risk are age, sex, and the type of revision needed. The surgical approach, implant choice, and positioning of the components are factors that the surgeon can influence to keep the dislocation rate low. Large femoral heads or double mobility (DM) cups can increase the stability of the joint. After detailed failure analysis, targeted use of different technical innovations enhances stability in revision THA and prevents further revisions.

[Hip arthroscopy]. / Hüftarthroskopie.

Hip arthroscopy represents an important component in the treatment of diseases of the hip joint and is nowadays an indispensible tool in modern hip-preserving surgery. This article provides a review of the basic technical principles, typical indications and complications of hip arthroscopy. Furthermore, current developments as well as possibilities and limitations of the arthroscopic technique are reviewed.

[Importance of revision- and tumor-endoprosthetics in the treatment of periprosthetic fractures of the lower extremity]. / Stellenwert der Revisions- und Tumorendoprothetik bei der Versorgung periprothetischer Frakturen der unteren Extremität.

Periprosthetic fractures of hip and knee prostheses are gaining clinical significance due to the increasing numbers of of primary arthroplasties. Additionally, these fractures are often associated with poor bone quality or present in patients after multiple revision procedures and concomitant excessive bone defects precluding those patients to be adequately treated by conventional osteosynthesis. Revision implants provide a wide range of options for the treatment of these fractures in order to achieve good clinical results. In the acetabular region cavitary defects associated with periprosthetic fractures can be treated by the use of megacups. Extensive segmental defects and pelvic discontinuity necessitate the use of cups with additional iliac support or even customized implants. Proximal femoral fractures can usually be fixed with modular stems and diaphyseal anchorage. Periprosthetic knee joint fractures can be treated with revision implants with modular sleeves or augment-combinations allowing sufficient bridging of bony defects. Functional reconstruction or refixation of the extensor mechanism is of crucial importance.

[Septic endoprosthesis exchange : Preoperative diagnosis and reimplantation]. / Septischer Endoprothesenwechsel : Präoperative Diagnostik und Reimplantation.

BACKGROUND: The treatment of prosthetic joint infection (PJI) is truly challenging. Patients with infected arthroplasty face physical and psychosocial problems. Furthermore, treatment costs represent a tremendous socioeconomic burden. AIM: This article presents an overview of the preoperative diagnosis of PJI and one- or two-stage endoprosthetic exchange options. METHOD: A selective literature search was performed focusing on diagnostics and innovative surgical treatment concepts in PJI. RESULTS: The identification of the underlying pathogen is still the main focus in the diagnosis of PJI. State-of-the-art therapy for PJI with mature biofilm consists of implant removal with one- or two-stage exchange arthroplasty. One-stage exchange offers lower morbidity and improved functional outcome, whereas a two-stage procedure is, according to current knowledge, more favourable in terms of infection control. The novel short-term two-stage exchange regimen combines the advantages of both possibilities. DISCUSSION: Prosthetic joint infection represents a significant challenge for the othopaedic surgeon. Novel treatment options can help to improve outcome and lower the costs to the health care system.

[Periprosthetic infections of the hip joint : Clinical approach]. / Periprothetischer Infekt des Hüftgelenks : Klinisches Vorgehen.

BACKGROUND: Increasing rates of periprosthetic joint infections (PJI) will present orthopedic surgeons and the health care system with challenges in the next few years. New concepts in diagnostic and surgical pathways allow specialized centers to offer differentiated therapy of PJI. AIM: This article presents an overview of recent treatment concepts for PJI of the hip emphasizing diagnosis and the clinical approach. METHOD: A selective literature search was performed focusing on evidence-based concepts including diagnostics, surgical treatment, and biofilm active antibiotics. RESULTS: PJI of the hip are classified as mature biofilm or immature biofilm infections. The most important step in the diagnostic procedure is to identify the pathogen and its antimicrobial susceptibility. Preoperative joint aspiration and leukocyte count, differentiation, and microbiological culture should be standard. Arthroscopic biopsy may be necessary to identify the pathogen. Depending on the biofilm maturity and the antimicrobial susceptibility, implant retention or two-stage revisions should be performed. Combination of surgical therapy and biofilm-active antibiotics are of utmost importance for successful treatment. DISCUSSION: PJI represents a significant challenge for the orthopedic surgeon. Evidence-based and standardized clinical pathways are necessary for accurate and rapid diagnosis as well as patient-specific treatment concepts.

[Conservative treatment of chronic tendinopathies]. / Konservative Therapie der chronischen Enthesiopathien.

The majority of insertional and noninsertional tendinopathy cases are associated with repetitive or overuse injuries. Certain tendons are particularly vulnerable to degenerative pathology; these include the Achilles and patella tendon, the rotator cuff, and forearm extensors/flexors. Disorders of these tendons are often chronic and can be difficult to manage successfully in the long term. Eccentric exercise has the strongest evidence of therapeutic efficacy. Extracorporeal shock wave treatment, sclerosing agents as well as nitric oxide patches show promising early results but require long-term studies. Corticosteroid and nonsteroidal antiinflammatory medications have not been shown to be effective except for temporary pain relief for rotator cuff tendinopathy. Platelet-rich plasma injections show encouraging short-term results.

[Conservative therapy of osteoarthritis]. / Konservative Therapie der Gonarthrose.

Osteoarthritis of the knee is a degenerative joint disease with progressive degradation of articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking and joint effusion depending on the stage of the disease. In an effort to delay major surgery, patients with knee osteoarthritis are offered a variety of nonsurgical modalities, such as weight loss, exercise, physiotherapy, bracing, orthoses, nonsteroidal anti-inflammatory drugs (NSAIDs) and intra-articular viscosupplementation or corticosteroid injection. In general, the goals of these therapeutic options are to decrease pain and improve function. Some of these modalities may also have a disease-modifying effect by altering the mechanical environment of the knee. Chondroprotective substances, such as lucosamine, chondroitin sulphate and hyaluronic acid are safe and provide short-term symptomatic relief while the therapeutic effects remain uncertain.

[Biopsies from bone and soft tissue sarcoma : a nationwide survey in Germany]. / Biopsie von Knochen- und Weichteilsarkomen : Eine deutschlandweite Umfrage.

AIM OF THE STUDY: A biopsy is an essential step in the diagnostic cascade of malignant bone and soft tissue tumors. The objective is always the extraction of a representative tissue specimen in line with the approach for the definitive operation. The aim of this study therefore was to assess the diagnostic approaches regarding the biopsy of tumors in orthopedic centers in Germany. MATERIAL AND METHODS: In total 60 hospitals with an orthopedic focus on tumors were contacted and provided with a newly developed questionnaire with 13 items regarding biopsy technique, indication criteria, execution, supportive imaging and histopathological results. Evaluation of the responses was performed by means of binary systems and proportional consent to every answer possibility was calculated. RESULTS: The results of the questionnaire showed that open biopsies are performed in all centers and in 72 % of the hospitals percutaneous techniques are additionally applied. The most important criterion for an open or percutaneous procedure was the tumor location (80 %). The indications for either technique are assessed by a tumor orthopedic consultant in 68 % of the centers and special imaging is applied in 36 % of the institutions. The approach for the biopsy is defined by the orthopedic surgeon in 88 %. Percutanous biopsies are carried out by interventional radiologists in 60 % of the centers. Open biopsies are performed by residents under supervision by a tumor orthopedic consultant in 88 %. The histopathological results are discussed in 88 % of the hospitals in an interdisciplinary tumor board and in 64 % patients are informed about the diagnosis in an outpatient clinic. CONCLUSIONS: Overall, biopsy of musculoskeletal tumors is performed according to the guidelines in most institutions. Only small differences were identified regarding the definition of the surgical approach and the application of imaging techniques during biopsy.

[Joint-preserving surgery of the adult hip. Intertrochanteric femoral osteotomy]. / Gelenkerhaltende Hüftchirurgie im Erwachsenenalter. Intertrochantäre Femurosteotomie.

Due to advances in total joint replacement, intertrochanteric osteotomy (ITO) is performed more infrequently in spite of good clinical results. Nevertheless, there are several good indications for this joint-preserving procedure in adults. Detailed biomechanical knowledge and precise clinical examination are prerequisites for correct indications and planning of ITO. The main target of this surgical procedure is improvement of joint congruency and normalization of load transfer to protect damaged cartilage. Very good results can be obtained in hip dysplasia, non-union of the femoral neck and proximal femoral deformities if the therapeutic principles are followed. Higher failure rates have to be expected in femoral head necrosis and osteoarthritis, depending on the degree of pre-existing cartilage damage.

[Heterotopic ossifications in total hip arthroplasty: prophylaxis and therapy]. / Heterotope Ossifikationen im Rahmen der Hüftendoprothetik: Prophylaxe und Therapie.

Heterotopic ossification (HO) is a frequent and occasionally severe complication after total hip arthroplasty. Clinical symptoms of this benign abnormal bone formation are loss of mobility and local pain. The etiology and pathomechanisms are not yet completely understood. Overexpression of bone morphogenetic proteins and dysregulation of prostaglandin metabolism seem to be relevant. Medication with non-steroidal anti-inflammatory drugs (NSAIDs) and perioperative single dose radiotherapy are used for prophylaxis, whereby radiotherapy should only be performed in patients with a history of HO or additionally after resection of HO. From currently available data selective cyclooxygenase-2 inhibitors seem to have a preventive efficacy equal to the classical NSAIDs diclofenac and indometacin. This work discusses current knowledge about the pathophysiology, risk factors and the clinical approach for prevention and treatment of HO.

[Primary malignant bone tumors]. / Primär maligne Knochentumoren.

Among human neoplasms, primary malignant bone tumors are fairly rare. They present an incidence rate of roughly 10 cases per 1 million inhabitants per year. During childhood (<15 years), the percentage of malignant bone tumors amounts to 6% of all infantile malignancies. Only leukemia and lymphoma show a higher incidence in adolescence. Of all primary malignant bone tumors, 60% affect patients younger than 45 years and the peak incidence of all bone tumors occurs between 15 and 19 years. The most common primary malignant bone tumors are osteosarcoma (35%), chondrosarcoma (25%), and Ewing's sarcoma (16%). Less frequently (≤ 5%) occurring tumors are chordoma, malignant fibrous histiocytoma of bone, and fibrosarcoma of bone. Vascular primary malignant tumors of bone and adamantinoma are very rare. Staging of the lesion is essential for systemic therapeutic decision-making and includes complete imaging and histo-pathological confirmation of the suspected entity. In most cases, this is established by open- or image-guided biopsy. Based on this information, an interdisciplinary tumor board will determine the individual therapeutic approach. Endoprosthetic or biological reconstruction following wide tumor resection is the most common surgical therapy for primary malignant bone tumors. There is vital importance in a thorough postoperative follow-up and continous after-care by a competent tumor center which is permanentely in charge of therapy.

[Surgical therapy of ischiofemoral impingement by lateralizing intertrochanteric osteotomy]. / Chirurgische Therapie des ischiofemoralen Impingements mittels lateralisierender intertrochantärer Korrekturosteotomie.

OBJECTIVE: Lateralizing, derotating intertrochanteric varus osteotomy to increase the ischiofemoral space to counter painful impingement of the lesser trochanter and the os ischium with resulting entrapment of quadratus femoris muscle. INDICATIONS: Symptomatic ischiofemoral impingement (IFI) caused by Coxa valga et antetorta, Coxa valga or Coxa antetorta, or a short femoral neck. CONTRAINDICATIONS: Anatomic configuration suggestive of IFI in asymptomatic patients. Symptomatic IFI caused by another underlying pathology. Valgus deformity of the knee. SURGICAL TECHNIQUE: Measurement of femoral antetorsion. Planning of the osteotomy, lateralization, varus angle for correction, rotation and offset correction, leg length change, and osteosynthesis plate. General or spinal anesthesia in supine or lateral position. Skin incision (15 cm) beginning lateral of the greater trochanter tip, distally along the axis of the femur. Preparation onto the femur by L­shaped dissection of the vastus lateralis from the bone. A Kirschner(K-)wire is then positioned along the anterior femoral neck to designate the femoral neck antetorsion. A triangle set on the lateral femoral cortexis is used to determine the osteotomy angle. In the thus determined angle, a second K­wire is shot centrally along the femoral neck axis just inferior to its cranial cortex. About 5 mm distal to the second wire, the entry for the blade is prepared using a drill. Using the blade setting instrument, the blade is introduced into the femoral neck, then slightly pulled back. The rotation is then marked on the anterior femoral cortex proximal and distal to the planned osteotomy and the osteotomy is performed. A blade plate without displacement is impacted. The osteotomy is then reduced, the distal fragment pulled laterally onto the plate, and the screws inserted after compression of the osteotomy with a tension device. POSTOPERATIVE MANAGEMENT: Touch-toe bearing for 6 weeks, then radiological assessment of osteotomy healing before an increase in weight bearing (15 kg/week). Hip flexion limited to 90° for 6 weeks. Elective implant removal after 12-18 months. RESULTS: Studies of this lateralizing varus osteotomy have not been published. The 25-year results of the conventional derotating intertrochanteric varus osteotomy technique show good functional results and low complication rates, with non-union being the most common. Arthroscopic resection of the lesser trochanter has been reported as a surgical alternative in the treatment of IFI in case reports and small series. Advantages of the osteotomy are the restoration of biomechanics and preservation of iliopsoas tendon insertion.

Effects of cefuroxime on human osteoblasts in vitro.

The local application of antibiotics in bone cement achieves high local effective antibiotic concentrations. Cefuroxime is widely used for antibiotic prophylaxis in orthopedic surgery, and several reports highlighted a beneficial outcome if cefuroxime-impregnated bone cement was used, but there is a lack of information of direct cefuroxime effects on human bone cells. We, therefore, cultured osteoblasts, previously derived from human trabecular bone specimens and used as a cell-pool further on, with different concentrations of cefuroxime (0-1000 microg/mL) for 24, 48, or 72 h. For reversibility testing, osteoblasts were cultivated for 24 h with cefuroxime followed by 48 h without antibiotics. Cell proliferation (MTT), cytotoxicity (lactate dehydrogenase (LDH)-activity), cell metabolism (alkaline phosphatase (ALP)-activity), and extracellular matrix calcification (Alizarin staining) were assessed after antibiotic treatment. Cefuroxime concentrations of 25-100 microg/mL had little or no effect on cellular proliferation. Proliferation was significantly stimulated at 250 and 1000 microg/mL at each time. LDH-activity significantly increased at the highest concentration of 1000 microg/mL at 72 h. ALP-activity first increased at lower concentrations and then significantly decreased at 1000 microg/mL at 48 and 72 h. Similar to ALP-activity, calcification increased at lower concentrations and was not detectable at 1000 microg/mL. All revealed effects at 24 h were at least partially reversible. In the present study, we demonstrated that cefuroxime at lower concentrations had no inhibiting effects on human osteoblasts. In contrast, higher concentrations significantly altered osteoblastic function. When administered locally in total joint arthroplasty, for example, in antibiotic-impregnated bone cement, cefuroxime might critically impair osteoblastic function and periprosthetic bone metabolism.

Blockade of BCL-2 proteins efficiently induces apoptosis in progenitor cells of high-risk myelodysplastic syndromes patients.

Deregulated apoptosis is an identifying feature of myelodysplastic syndromes (MDS). Whereas apoptosis is increased in the bone marrow (BM) of low-risk MDS patients, progression to high-risk MDS correlates with an acquired resistance to apoptosis and an aberrant expression of BCL-2 proteins. To overcome the acquired apoptotic resistance in high-risk MDS, we investigated the induction of apoptosis by inhibition of pro-survival BCL-2 proteins using the BCL-2/-XL/-W inhibitor ABT-737 or the BCL-2-selective inhibitor ABT-199. We characterized a cohort of 124 primary human BM samples from MDS/secondary acute myeloid leukemia (sAML) patients and 57 healthy, age-matched controls. Inhibition of anti-apoptotic BCL-2 proteins was specifically toxic for BM cells from high-risk MDS and sAML patients, whereas low-risk MDS or healthy controls remained unaffected. Notably, ABT-737 or ABT-199 treatment was capable of targeting the MDS stem/progenitor compartment in high-risk MDS/sAML samples as shown by the reduction in CD34(+) cells and the decreased colony-forming capacity. Elevated expression of MCL-1 conveyed resistance against both compounds. Protection by stromal cells only partially inhibited induction of apoptosis. Collectively, our data show that the apoptotic resistance observed in high-risk MDS/sAML cells can be overcome by the ABT-737 or ABT-199 treatment and implies that BH3 mimetics might delay disease progression in higher-risk MDS or sAML patients.