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Biomedical subjects

N Gschwend

Publications and source records attributed to N Gschwend.

At least 19 recordsLinked to original sources
PubMed1995

[Infection following shoulder and elbow arthroplasty. Diagnosis and therapy].

The rate of infection reported in recent publications is 0.8% after shoulder arthroplasty and ten times higher (8.1%) after elbow arthroplasty. The figures for shoulder arthroplasty correspond well with our own rate of revision for infection of 0.5% after 363 primary shoulder replacements. However, our average rate of revision for infection (1.8%) after 278 GSB-III elbow arthroplasties was considerably lower and included rheumatoid as well as post-traumatic indications. Our experience concerning etiologic factors, nature, diagnosis, treatment options, and long-term consequences of superficial and deep infections after shoulder and elbow arthroplasty are discussed for each joint separately and in relation to the literature.

Aged↗
PubMed1995

[Tendon diseases in chronic rheumatoid arthritis].

Rheumatoid arthritis is basically a disease of the synovium and involves the synovium-lined sheaths that surround many of the tendons in the hand and wrist. Proliferative synovitis affects the tendons, infiltrates the tendons, causes formation of nodules, changes their ultrastructure, and eventually leads to spontaneous rupture. The three common sites of tendon sheath involvement are the dorsal and palmar aspect of the wrist, and the palmar aspect of the digits. Early tenosynovectomy can prevent tendon ruptures and should therefore be the cornerstone of treatment. Once spontaneous rupture has occurred, early diagnosis and treatment are important to prevent further rupture. Reconstruction of isolated ruptures of extensor or flexor tendons gives good results. Multiple tendon ruptures, however, are difficult to treat and have a worse prognosis. The severity of the patient's disease and the degree of articular involvement have a greater effect on the outcome of surgery than reconstruction techniques. Our current approach to the management of this difficult problem is presented.

Arthritis, Rheumatoid↗
PubMed1995

[Multiple joint replacement in chronic rheumatoid arthritis: results, indications].

Rheumatoid arthritis, steadily progressive and affecting many joints, is a real challenge for the orthopaedic surgeon. Thorough assessment and long-term planning to maximize overall performance requires clear orthopaedic thinking based on wide experience. The final aim is to enable the patients to walk and be independent. Over the last 30 years, the surgery of the rheumatic diseases has become a well-established specialty within orthopaedic surgery. Open synovectomy still has a place. In badly damaged joints, however, only prosthetic joint replacement has a fair chance. Total hip replacement is now a common procedure. Yet many problems regarding long-term performance remain unclear. This is even more pertinent for total knee replacement. Operations on the upper limbs must enable the patient to become less dependent of other people's help. Artificial shoulder joints have become more popular, and elbow joint replacement has been a particularly important field at the Wilhelm Schulthess Clinic. Multiple joint replacement is often necessary and can improve the quality of life for these badly stricken patients.

Arthritis, Rheumatoid↗
PubMed1993

[Modern rheumatism surgery: prospects, hazards, results].

The conservative management of rheumatoid arthritis (RA) the value of which is a symptomatic or at best a pathogenetic one, has failed to achieve a decisive breakthrough in the past 25 years. By contrast the orthopedic-surgical management of RA has proved able to rehabilitate patients who would otherwise gradually lose their independence. The close cooperation between rheumatologists and orthopedists in specific rheumatoid arthritis centers and the recruitment of specially trained therapeutic teams have boosted the recent progress in this field. However, the main responsibility for the patient continues to lie with the rheumatologist. Operative procedures are only considered when despite a well-conducted conservative treatment signs of progressive articular destruction appear; they do not interrupt the conservative management, but are a completion of it. The art of the rheumatology-surgeon reveals itself in his ability to set up a clear-cut therapeutic plan with priorities. In particularly complex cases the indication will require a team discussion, which includes the occupational therapist who has previously assessed the patient's handicap in the performance of ADL and will be centered around the patient, whose motivation is of crucial importance to the success of our efforts. Throughout the many years of active practice and by performing thousands of operations--preventive (e. g. synovectomies) as well as reconstructive ones (e. g. arthroplasties)--we have gained a vast experience in different operative procedures, which we have come to divide into three categories. Whenever possible we start with an operation regarded as particularly promising, thus overcoming the patient's understandably reserved attitude towards surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1993

Healing of cancellous bone osteotomy in rabbits--Part I: Regulation of bone volume and the regional acceleratory phenomenon in normal bone.

We performed a simple, undisplaced, incomplete osteotomy of the distal medial condyle of mature New Zealand White rabbits and permitted healing without fixation for 4 weeks. During the recovery period, the rabbits received the bone label calcein in their drinking water. From ground stained and unstained sections, we determined histomorphometric parameters in five zones: osteotomy gap, juxtaosteotomy, lateral condyle, metaphysis, and diaphysis. At 4 weeks, newly formed cancellous bone had obliterated the osteotomy gap. Osteotomy also stimulated new bone formation in cancellous bone of the medial condyle around the osteotomy. At that site, we found a fivefold increase in new bone without a change in bone volume (BV). Stimulation of bone formation was not observed in cancellous bone of the lateral condyle that had not been operated on or in cortical bone of the metaphysis or diaphysis. The maintenance of BV, despite increased new bone formation in the osteotomized medial femoral condyle, was probably due to a local acceleration of bone remodeling.

Animals↗
PubMed1993

Healing of cancellous bone osteotomy in rabbits--Part II: Local reversal of arthritis-induced osteopenia after osteotomy.

With use of the intravital bone label calcein, we previously identified, by histomorphometry, greatly increased new bone formation and juxtaarticular osteopenia (a high turnover state) in carrageenan-induced experimental inflammatory arthritis of the knee in rabbits. In Part I of this paper, we showed that a large increase in new bone formation after a stable incomplete distal femoral condylar osteotomy of normal bone in the rabbit does not increase bone volume (BV) in normal tissue adjacent to the osteotomy (zone 1). In this study, we performed an osteotomy of bone made osteopenic by experimental inflammatory arthritis. After 4 weeks of healing, we examined new bone formation and BV in five zones around the osteotomy. In zone 0 (the osteotomy gap), new bone formation filled the gap to normal BV, as we found for the normal/osteotomy group. In zone 1 (adjacent to but excluding the osteotomy gap), we found greatly increased new bone formation and a return to normal BV, increased from the osteopenic level induced by experimental inflammatory arthritis. In this model, osteotomy apparently reversed the bone-wasting process of inflammatory arthritis. This effect was not observed in other zones: the lateral condyle that had not been operated on, the metaphysis, or the diaphysis.

Animals↗
PubMed1991

[The GSB knee joint: reoperation and infections].

The GSB-III knee prosthesis is one of the semi-constrained types and consequently ranks between the non-constrained condylar prostheses and the fully constrained hinges. Its kinematics can be classified as "physiological" in the sagittal plane as far as the relationship between femur and tibia in the various degrees of flexion is concerned, which is a replica of a normal knee joint. The high average range of postoperative mobility as well as the extremely low aseptic loosening rate after 10 years prove the truth of this statement. A simple operative technique requiring a few special instruments allows even the less experienced knee surgeon to be successful and to obtain good results in cases with severe deformity and poor bone quality. The survival curves of the GSB-III prosthesis (n = 638) show a cummulative success rate of over 90% after 10 years. Looking separately at cases complaining of more or less severe pain, we frequently find underlying patellar problems, the main cause for revisional surgery. This problem is not specific for our prosthesis, but must be considered a so far unsolved worldwide problem. Infections are another relatively frequent cause for revisions. Disturbed wound healing, arterial insufficiency and malignant rheumatoid arthritis are the outstanding risk factors. For a reliable comparison of the different knee prostheses we ought to have a globally accepted evaluation system, which unfortunately still does not exist.

Adolescent↗
PubMed1991

[Long-term results of surgical management of rotator cuff rupture].

The operative management of rotator cuff tears is gaining in importance: the growing proportion of elderly people with the consequent increase in frequency, more reliable diagnostic techniques (for clinical examinations and modern imaging techniques), more accurate indications for surgery and improved and more versatile operating techniques account for this development. Except for the rate occurrence of traumatic ruptures in young patients, which call for early surgical repair, operative treatment is indicated only in cases of failed conservative treatment, intractable pain and/or pseudoparalysis. The latter conditions are often encountered in manual workers, in whom the dominant side is affected. Very often, diminished physical demands after retirement reduce these discomforts to a tolerable level. This phenomenon also explains the surprisingly good long-term results in cases where surgical repair of the rotator cuff was performed more than 20 years ago. The reported percentages of these shoulders that are free or almost free of pain range between 80% and 90%, i.e., slightly higher than the percentage in younger, physically still active age groups a few years after surgery. Similarly, weakness is not perceived as such or at least not felt to be burden-some. Future evaluations of the outcome of rotator cuff repairs will be carried out according to the guidelines of the European Society for Shoulder and Elbow Surgery and the scoring system worked out by C. R. Constant; this puts more emphasis on the function, which itself is related to age- and sex-related standards.

Adult↗
PubMed1990

Posterior occipito-cervical fusion in rheumatoid arthritis.

The instability of atlanto-axial subluxation remains a challenging problem in patients with rheumatoid arthritis. In order to preserve as much function of the cervical spine as possible, inclusion of the occiput into the fusion should exclusively be performed when there is a radiologically or clinically manifest pathological condition of the atlanto-occipital joint or marked upward migration of the dens axis. In order to prevent irreversible damage to the spinal cord, an early indication of surgical stabilization is recommended. This article presents a retrospective analysis of the clinical and radiological results of occipito-cervical fusion in 26 patients with rheumatoid arthritis using a modified Brattström technique. The complications encountered were mainly due to the use of wire fixation, reinforcement using bone cement and insufficient reduction of atlanto-axial subluxation.

Adult↗
PubMed1989

Changes in the metaphysis and diaphysis of the femur proximal to the knee in rabbits with experimentally induced inflammatory arthritis.

We quantified the cross-sectional cortical bone area and remodeling rates in the ipsilateral femoral diaphysis and metaphysis of rabbits with carrageenan-induced inflammatory monarthritis of the knee. Although osteogenesis rates were significantly elevated (approximately threefold in diaphyses and sixfold in metaphyses), the cross-sectional bone area of the diaphysis was significantly diminished. Fivefold and sixfold increases in bone resorption rates were calculated in diaphyses and metaphyses, respectively. Other morphologic changes observed were porosity and net resorption of the anterior cortex and net accretion on the posteromedial cortex ("drift" of bone). These findings may have clinical significance with regard to the mechanisms and consequences of bone changes in patients with rheumatoid arthritis.

Animals↗
PubMed1989

Comparative study of cemented and cementless hip prostheses in the same patient.

In 20 patients with bilateral total hip replacements a cementless prosthetic implantation on one side and a cemented arthroplasty on the other side were performed. The mean follow-up period was 6 years for the cementless and 7.5 years for the cemented hip. The only significant difference found was concerning pain, which was more frequent on the cementless side. Otherwise we were unable to ascertain a significant difference concerning mobility, walking capacity, complications, and patient assessment. A longer observation time will be required. Where pain relief is concerned, the cemented version will continue to be the gold standard.

Bone Cements↗
PubMed1989

Functional evaluation of the spinal cord by magnetic resonance imaging in patients with rheumatoid arthritis and instability of upper cervical spine.

Thirty-four patients with atlanto-axial instability due to rheumatoid arthritis were examined with plain x-ray views and functional magnetic resonance imaging (MR), and were neurologically evaluated. Transcranial brain stimulation was performed in 25 patients. In 22 cases, the authors observed inflammatory tissue thicker than 3 mm behind the odontoid peg. The spinal canal diameter was significantly decreased in the flexed position. Nine patients showed signs of cranial migration of the axis. The diameter of the spinal cord was measured to be 7.4 mm in the neutral position, and 6.5 mm in flexion. The difference between the diameter of the neutral and flexed positions was highly significant. Twelve of the 34 patients displayed clinical signs of cervical myelopathy, and 13 showed a significant delay of central motor latency, as calculated from the motor evoked potentials. Surgical intervention, either by a posterior approach only or combined with a transoral dens and inflammatory tissue resection, is recommended in patients with progressive atlanto-axial instability, pathologic clinical and neurophysiologic findings, and a spinal cord diameter of less than 6 mm in flexion. Severe pain and cranial migration of the axis, as measured by the MRI, also justify a surgical intervention.

Adult↗
PubMed1989

[Total prosthesis implantation in the arthritic hip].

In 11 patients, hip arthrodeses were converted to arthroplasties. The follow-up period ranged from 1 to 21 years. In some cases the patients' own assessment contrasted with the objective findings. No difference could be determined between previously arthrodesed and ankylosed hips. The duration of arthrodesis did not have an influence on the long-term results. It is interesting to note that in this group of patients the long-term survival rate proved to be slightly better than the overall survival rate for all patients with arthroplasties performed in our clinic.

Aged↗
PubMed1989

[Loosening of hip prostheses in chronic rheumatoid polyarthritis].

The hip with rheumatoid arthritis (RA) is characterized by reduced bone resistance. Protrusion, fatigue fractures and femoral head collapse are the typical consequences. The survival rate of total hip prostheses in hips with RA seems to be higher than for hips with osteoarthritis (OA), possibly due to lower demands. When isolated loosening of the acetabular and femoral component are compared, there is a definite shift towards acetabular loosening in RA compared to OA. This is definitely due to the reduction in the mentioned bone resistance at the acetabular level. In primary joint replacement, well-cemented femoral components provide more reliable clinical results. They will remain the gold standard for long-term performance as well. On the other hand, it is very likely that non-cemented acetabular components, fixed by means of screws in the direction of the resulting force or based on a compression principle, may prove at least as effective as well-cemented acetabuli. For revision of the loose acetabular component, the use of special metal rings fixed with screws and bridging severe bony defects with a bone graft and frequently also bone cement, have proved to be of value. For loose femoral components with a thin and brittle cortical wall, special non-cemented prostheses combined with a bone graft seem to promise a more reliable long-term solution than cemented versions. The follow-up of our revision cases confirms the value of the described methods - at least at the short and medium-term follow-up. More definite conclusions can only be arrived at after long-term follow-ups which have been carried out with different systems and where the results are compared using the same documentation procedure.

Adult↗
PubMed1988

Juxtaarticular bone loss in experimental inflammatory arthritis.

The osteopenia associated with experimental inflammatory arthritis was studied by a histomorphometric method that exphasized net changes in bone composition. Juxtaarticular trabecular bone volume and turnover were studied in the carrageenan injection model of inflammatory arthritis of the mature rabbit knee. Trabecular bone volume was studied by histomorphometry of the femoral condyles and confirmed by photodensitometry on standard macroradiographs. Osteogenesis was studied by imaging of calcein fluorochrome-labeled newly formed bone in undecalcified histological sections. A significant net loss of cancellous bone (approximately 20%) occurred over 49 days in both the medial and the lateral femoral condyle in the arthritis group compared with normal controls. Total osteogenesis was increased fourfold and it was calculated that an even greater increase in total bone resorption was responsible for the negative bone balance. There is evidence that the periarticular bone loss of human rheumatoid arthritis is also associated with increased bone turnover. Quantitative studies of the kinetics of bone remodeling in inflammatory arthritis will provide the basis for therapeutic attempts to prevent or reverse arthritis-induced bone loss. Fracture risk in inflammatory arthritis may be increased not only by osteopenia, but additionally by the presence of a large proportion of newly formed (and presumably less mineralized) bone.

Animals↗