Search PubMed⌕ Search

Biomedical subjects

N Gschwend

Publications and source records attributed to N Gschwend.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1988

Proven and nonproven facts in knee arthroplasty. Results with the semiconstrained GSB-prosthesis.

The great number of knee-replacement systems makes a comparative study difficult. Even more confusing are the different criteria used for the evaluation of the results. After a critical review of what can be taken as proven facts, our own experience with the semiconstrained GSB-III knee prosthesis is critically analyzed. The survivorship method is used, presenting the cumulative success rate and analyzing the reasons for the failure rates. We feel that all authors presenting results of knee arthroplasty should adopt this method, using the same or at least comparable evaluation sheets (for instance, that of ERASS). Moreover, more attention should be given to bone dynamics in a prospective study using modern technology (CT densitometry). This will help to detect possible factors responsible for the failure of knee arthroplasty and possibly to prevent failure with medication.

Biomechanical Phenomena↗
PubMed1988

General joint laxity. Quantification and clinical relevance.

General joint laxity is measured with the hyperextensometer, and by analyzing the values obtained in a group of European subjects norm curves are drawn up related to age and sex. The values found in various orthopedic diseases are put into these curves, and the importance of general joint laxity is discussed.

Adolescent↗
PubMed1988

Rotator cuff tear--relationship between clinical and anatomopathological findings.

Rotator cuff tears (RCT) are frequent and increase with age. Why do only a relatively small percentage cause a permanent severe handicap justifying surgery? Is there a relationship between size and site of the tear and the clinical symptoms? How do they influence the postoperative result? These questions were answered in a prospective study of 76 operated patients. We adopted D. Patte's classification of the RCT into four groups according to the site and size of the lesion. Our figures were compared with those obtained by Patte in an analogous study of 256 cases. Of the tears in our series, 56.5% belonged to groups I and II, which means that only the supraspinatous and occasionally also the subscapular muscles were involved. In 100% of the cases in group I we found only pain, whereas a pure symptomatology with pain alone was presented in only 51% of group II, in 48% of group III, and in 0% of group IV. Groups III (35.5%) and IV (8%) represent more extensive tears, involving not only the anterior part of the rotator cuff, e.g., the supraspinatous tendon, but also to a more or less severe extent, the infraspinatous and sometimes even the teres minor. In group IV the extensive tear is combined with osteoarthritic changes. In both groups a mixed symptomatology (pain and pseudoparalysis) is the rule. The result of operative treatment is satisfactory in all groups as far as pain relief is concerned. The improvement of active ROM is not as evident and seems, as expected, to be related to the severity of the lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Arthroplasty of the elbow].

Elbow arthroplasty is still one of the less frequently performed joint replacement procedures. It is technically demanding, and numerous complications are possible. It is therefore indicated mainly in severely handicapped patients in whom all other alternatives have been attempted. A review of the literature relating to arthroplasties monitored over follow-up periods of more than 5 years shows that the results are now quite acceptable. They are far better than those seen following most resection arthroplasties. The results achieved with our GSB III prosthesis are compared with those obtained with other prosthetic devices in current use. It appears that in a large proportion of cases our prosthesis allows a good range of painfree motion, which we attribute in part to the operative approach used. The complication rate appears to be relatively low.

Adult↗