Search PubMed⌕ Search

Biomedical subjects

W Rüther

Publications and source records attributed to W Rüther.

At least 19 recordsLinked to original sources
PubMed2007

[The treatment of periprosthetic infections].

Periprosthetic infections are severe complications following total joint arthroplasty. The infection rate is estimated to be 0.5-2%. Systemic diseases such as rheumatoid arthritis and previous surgery are considered risk factors for infection. The infection rate in the present patient cohort was low (0.72%). The recurrence rate (23.4%) is due to patients with rheumatoid arthritis and septic total knee arthroplasties. Successful treatment is dependent on various factors, one of which involves accurate preoperative bacterial diagnostics. Joint fluid aspiration is the appropriate procedure. Open biopsy or arthroscopically guided biopsy can be performed in cases of unclear diagnostic results. Early infection can be treated with thorough joint debridement without exchanging fixed implant components; "low-grade" or late infections require revision with implant removal in a one or two stage septic revision according to clearly determined algorithms. Antibiotic therapy is mandatory, and a combination with rifampicin is a very useful basis.

Adult↗
PubMed2006

Impact of low back pain on functional limitations, depressed mood and quality of life in patients with rheumatoid arthritis.

Low back pain (LBP) and rheumatoid arthritis (RA) are common orthopedic problems, but there is little information on the importance of LBP in RA patients. The aim of this study was to investigate how LBP affects functional limitations, depressed mood, and quality of life in patients with RA. A complex questionnaire was answered by 281 RA patients, including questions about their RA and their experience of LBP. Functional limitations were assessed using the Hannover Activities of Daily Living questionnaire (ADL), depressed mood using the Center for Epidemiological Studies Depression Scale (CES-D) and health-related quality of life using the Short Form 12 health questionnaire (SF-12). The prevalence of LBP in RA patients was 53.4%. RA patients with LBP displayed a significantly higher degree of disability and depression than RA patients without LBP. There were no differences between the two groups with regard to the duration of RA, the number of operations or medication. LBP is an important factor for the physical and psychological behavior of RA patients. Therefore, the onset of LBP should not be overlooked or underestimated.

Arthritis, Rheumatoid↗
PubMed2006

[Conventional X-rays and conventional tomography in orthopaedics. Current status].

Although sonography, computed tomography (CT) and magnetic resonance imaging (MRI) are common tools in radiology, conventional X-rays still have a place in orthopaedic diagnostic investigation. The advantages of radiographic imaging are high local resolution concerning bone, economy of time besides relatively low costs and worldwide experience. The conventional X-ray is indispensable for planning surgical procedures and clinical monitoring. For several pathological processes an X-ray is sufficient for diagnosis and therapy (i.e. degeneration, fracture). Early changes of the bone (i.e. osteonecrosis) cannot be detected by X-ray. CT and MRI have closed the diagnostic gap. Indications for conventional tomography are rare.

Humans↗
PubMed2006

[Fluorosis--a forgotten entity. Case report of a woman with coxarthrosis and newly diagnosed fluorosis].

The clinical manifestation of fluorosis has become rare over the past years. Although the use of fluoride medication in osteoporosis therapy remains controversial, past study results have led to a reduction in fluoride prescriptions. Several studies have shown minor biomechanical properties of newly built woven bone compared to original bone. Despite new prescription protocols, fluoride therapy should not be disregarded in the anamnesis of osteoporosis patients. In addition to conventional diagnostics in fluorosis, new techniques such as microanalysis and micro-CT-analysis show a diagnostic benefit. In this case, the edx-microanalysis results show an F concentration of over 1.0 wt% in bone. The ratio of bone to tissue volume, evaluated by micro-CT, is clearly elevated at 46% BV/TV. The histopathological preparation of the femoral head has made the possible effects of fluoride medication on bone visible and quantifiable. A direct causal relationship between coxarthrosis and fluoride medication, found both in our patient as well as in the literature, has not been demonstrated. In order to better understand the broad effects of fluoride medication in combination with coxarthrosis more studies are needed.

Aged↗
PubMed2006

[Imaging in rheumatology. Degenerative diseases of the spine].

Degeneration of the spine is a common reason for pain in the musculoskeletal system. Radiography is an important tool for diagnosis and differential diagnosis. Cost efficacy and economy of time are advantages in using conventional x-rays. Although narrowing of intervertebral disc spaces, irregular ossification of the vertebral end-plate as well as osteophytes, facet joint osteoarthritis and spondylolisthesis can be observed, early changes in the discs or the subdiscal bone can not be detected by x-rays. Moreover, 3-dimensional imaging is not possible. Computer tomography (CT) and magnetic resonance imaging (MRI) are reliable for identifying disorders of the spine and soft-tissue. Differentiation between inflammation, trauma and tumor is possible. There is still a problem with the relationship between the information obtained by x-rays or MRI and clinical symptoms. Therefore, interpretation of radiological examinations assumes a knowledge of clinical symptoms and the different kinds of diseases which are possible.

Cost-Benefit Analysis↗
PubMed2006

Proposal for a histopathological consensus classification of the periprosthetic interface membrane.

AIMS: The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery. METHODS: Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria. RESULTS: Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%). CONCLUSION: The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.

Adult↗
PubMed2006

Biomechanical, morphological, and histological analysis of early failures in hip resurfacing arthroplasty.

The present revival of hip resurfacing arthroplasty may be related to an increase in early failures owing to the challenging technique of the procedure. Fifty-five retrieved implants were analysed with respect to wear, cement mantle and cement penetration, fracture and head morphology, as well as standard histology. Femoral neck fractures occurred in median after 102 days. The time to failure was shorter for older women. Major deviations from the suggested cement mantle thickness and cement penetration were found. Indications for high trauma during implantation leading to early failure due to weakening of the femoral neck were also observed. Some failures had signs of pseudarthrosis beneath the implant. Four different fracture patterns with different mean survival times were identified. Observed wear was minor with the exception of that due to alignment mistakes (rim loading). The cups were not damaged by the failures. Histological results indicate that avascular necrosis is not necessarily connected with this kind of endoprosthetic surgery. Most of the failures analysed can probably be attributed to the 'learning curve' effect, which is an unsatisfactory situation.

Aged↗
PubMed2005

Neural driven angiogenesis by overexpression of nerve growth factor.

Mechanisms regulating angiogenesis are crucial in adjusting tissue perfusion on metabolic demands. We demonstrate that overexpression of nerve growth factor (NGF) in brown adipose tissue (BAT) of NGF-transgenic mice elevates both mRNA and protein levels of vascular endothelial growth factor (VEGF) and VEGF-receptors. Increased vascular permeability, leukocyte-endothelial interactions (LEI), and tissue perfusion were measured using intravital microscopy. NGF-stimulation of adipocytes and endothelial cells elevates mRNA expression of VEGF and its receptors, an effect blocked by NGF neutralizing antibodies. These data suggest an activation of angiogenesis as a result of both: stimulation of adipozytes and direct mitogenic effects on endothelial cells. The increased nerve density associated with vessels strengthened our hypothesis that tissue perfusion is regulated by neural control of vessels and that the interaction between the NGF and VEGF systems is the critical driver for the activated angiogenic process. The interaction of VEGF- and NGF-systems gives new insights into neural control of organ vascularization and perfusion.

Adipocytes, Brown↗
PubMed2005

Femur window--a new approach to microcirculation of living bone in situ.

BACKGROUND: The processes of osteogenesis, bone remodelling, fracture repair and metastasis to bone are determined by complex sequential interactions involving cellular and microcirculatory parameters. Consequently studies targeting the analysis of microcirculatory parameters on such processes should mostly respect these complex conditions. However these conditions could not yet be achieved in vitro and therefore techniques that allow a long-term observation of functional and structural parameters of microcirculation in bone in vivo at a high spatial resolution are needed to monitor dynamic events, such as fracture healing, bone remodelling and tumor metastasis. METHODS: We developed a bone chamber implant (femur window) for long-term intravital microscopy of pre-existing bone and its microcirculation at an orthotopic site in mice preserving the mechanical properties of bone. After bone chamber implantation vascular density, vessel diameter, vessel perfusion, vascular permeability and leukocyte-endothelial interactions (LEIs) in femoral bone tissue of c57-black mice (n=11) were measured quantitatively over 12 days using intravital fluorescence microscopy. Furthermore a model for bone defect healing and bone metastasis in the femur window was tested. RESULTS: Microvascular permeability and LEIs showed initially high values after chamber implantation followed by a significant decrease to a steady state at day 6 and 12, whereas structural parameters remained unaltered. Bone defect healing and tumor growth was observed over 12 and 90 days respectively. CONCLUSION: The new femur window design allows a long-term analysis of structural and functional properties of bone and its microcirculation quantitatively at a high spatial resolution. Altered functional parameters of microcirculation after surgical procedures and their time dependent return to a steady state underline the necessity of long-term observations to achieve unaltered microcirculatory parameters. Dissection of the complex interactions between bone and microcirculation enables us to evaluate physiological and pathological processes of bone and may give new insights especially in dynamic events e.g. fracture healing, bone remodeling and tumor metastasis.

Animals↗
PubMed2004

[Diagnosis and therapy of rheumatoid arthritis].

In the past years, the substantially increased number of potent drugs for the therapy of rheumatoid arthritis has made the goal of an early, highly effective therapy more feasible. In addition, combination therapy trials including biologics revealed that joint protection and downregulation of inflammation can be achieved also in stages of active articular destruction, and the detection of novel markers such as antibodies against cyclic citrullinated peptides supports an earlier diagnosis of the disease. The price for these advances, however, are more complex, demanding and expensive therapeutic regimens that need to be handled carefully by the rheumatologist, especially with regard to a new field of side effects inherent with the use of TNF inhibiting agents. Finally, the current therapeutic standard includes also the ongoing clinical and scientific exchange with the orthopedic surgeon to optimize the long-term treatment for the individual patient.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

[Proposal for the classification of the periprosthetic membrane from loosened hip and knee endoprostheses].

After 10 years, loosening of total joint endoprostheses occurs in about 3 to 10 percent of all patients, requiring elaborate revision surgery. A periprosthetic membrane is routinely found between bone and loosened prosthesis. Further histomorphological examination allows determination of the etiology of the loosening process. Aim of this study is the introduction of clearly defined histopathological criteria for a standardized evaluation of the periprosthetic membrane. Based on histomorphological criteria and polarized light microscopy, four types of the periprosthetic membrane were defined: periprosthetic membrane of wear particle type (type I), periprosthetic membrane of infectious type (type II), periprosthetic membrane of combined type (type III), periprosthetic membrane of indifferent type (type IV). Periprosthetic membranes of 268 patients were analyzed according to the defined criteria. The correlation between histopathological and microbiological diagnosis was high (89%, p<0,001), the inter-observer reproducibility was sufficient (95%). This classification system enables a standardized diagnostic procedure and therefore is a basis for further studies concerning the etiology of and pathogenesis of prosthesis loosening.

Arthroplasty, Replacement, Hip↗
PubMed2004

[The infected rheumatoid forefoot--how much surgery is advisable?].

A biomechanically altered rheumatic forefoot with a resulting shoe conflict and an impaired immune system due to underlying disease and medical treatment are often cause for infection. Often infected bursae perforate into the corresponding joints and may consequently lead to severe infectious states of the foot. The multiplicity of possible biomechanical adjustments makes it difficult to develop an undisputed concept. Conservative versus operative therapeutic options are possible and may be individually applied. It should be questioned, if the same general rules in septic joint surgery also apply to the rheumatoid forefoot. This retrospective clinical study will evaluate a concept for possible operative treatment of the infected rheumatoid forefoot in selected cases. Our conception advocates operative procedures on a patient adapted basis in order to prevent recurrent infections. Suggestions for operative procedures are given.

Aged↗
PubMed2004

[Aseptic osteonecrosis after steroid treatment].

A 28-year-old female patient had load-dependent pain of the left knee. MRI showed an osteochondral defect of the medial condyle based on extensive osteonecrosis of the femoral and tibial bone. An association with a prior steroid treatment after cervical injury is most likely.

Adult↗
PubMed2004

[Therapy of cervical rheumatoid arthritis].

The rheumatoid involvement of the cervical spine can be divided into three phases. In the early stage of the disease there is an isolated atlantoaxial subluxation (AAS), followed by vertical instability and subaxial instability. If patients show clear symptoms of cervical myelopathy, which can occur during any stage of the disease, the progression cannot be stopped by conservative treatment, which is of great importance at the beginning of the cervical manifestation. Patient education, physiotherapy and immobilization with a stiff collar can significantly reduce pain. Early and effective DMARD therapy can have a positive effect on the natural history of the disease. In case of progressive instability, cervical myelopathy or severe pain operative treatment is indicated. If there is an isolated AAS, fusion can be restricted to the C1/C2 segment. The Magerl transarticular screw fixation is the preferred technique for stabilization. If there is evidence for vertical instability or severe destruction of the C0/C1 joints, occipital cervical fusion has to be performed. Durin the preoperative planning it is necessary to look for signs of subaxial instability. If this is the case, fusion should include the entire cervical spine. Transoral decompression may be necessary when there is persistent anterior compression of the myelon, typically seen in fixed AAS. Non-ambulatory myelopathic patients are more likely to develop severe surgical complications. Therefore, it is important to avoid the development of severe cervical instability by early surgical intervention. The right timing for surgery is still a matter of controversy. Future prospective randomized trials should address this topic to improve the treatment concept for the rheumatoid patient.

Arthritis, Rheumatoid↗
PubMed2004

[Radiological diagnostics of cervical rheumatoid arthritis].

Rheumatoid arthritis leads to characteristic findings at the synovial joints, the intervertebral discs and the processes of the cervical spine. Isolated findings are not specific for rheumatoid arthritis. In fact, due to common underlying pathophysiologic changes they also develop in other inflammatory diseases affecting the cervical spine. Therefore, each radiological examination is to be understood and used as a piece in the diagnostic puzzle. Only in conjunction with clinical information does it add to a conclusive diagnosis. Nevertheless certain patterns of findings help in narrowing the list of differential diagnosis. Besides their role in initial diagnosis, radiological examinations are crucial tools in the peri- and post-operative work-up and in the detection of typical complications of rheumatoid arthritis with cervical manifestations, i. e. various instabilities and their consequences, as those have an impact on the therapeutic approach and prognosis.

Arthritis, Rheumatoid↗
PubMed2003

[Pigmented villonodular synovitis of the hip--diagnosis and therapy of an invasive disease].

In the diffuse form of pigmented villonodular synovitis, the transformed synovia invades local bone and cartilage, leading to destruction of the osseous and cartilage tissue. Secondary osteoarthritis and ultimately joint destruction is a result. Malignant development is under discussion. The knee is the most frequently involved joint, followed by involvement of the hip, which is well documented in several studies. This paper introduces a case of pigmented villonodular synovitis involving the hip. Its general diagnostic features and treatment options are introduced and discussed, including the role of reconstructive joint surgery in advanced cases of PVS. The key function of early diagnosis and treatment resulting in joint-salvaging procedures is emphasized.

Adult↗