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Biomedical subjects

K Zweymüller

Publications and source records attributed to K Zweymüller.

At least 19 recordsLinked to original sources
PubMed1998

Are allergic reactions to skin clips associated with delayed wound healing?

BACKGROUND: Metal skin clips are used in surgery. They may contain metals that might cause allergic reactions and delayed wound healing. METHODS: The metal composition of 18 different surgical clamps was examined. The allergy status of 184 patients was determined by patch tests and was correlated with the clinical outcome of wound healing after application of skin clips. RESULTS: Skin clips contained chromium, nickel, molybdenum, cobalt, and titanium in concentrations high enough to cause allergic reactions. Eighteen percent of the men and 23% of the women were sensitive to nickel and 16% of the men to chromium. We found a positive correlation between the grade of nickel allergy and the reaction to the skin clips. CONCLUSIONS: Our study suggests that allergic reactions and delayed wound healing can be caused by the use of surgical skin clips. Therefore skin clips are not recommended for patients with a history of contact dermatitis to metals and/or atopy.

Adolescent↗
PubMed1996

Musculus sartorius bicaudatus.

While dissecting 88 lower limbs, a distal division of the sartorius muscle was detected in one of the specimens. The larger posteromedial portion was found to take a normal course to the so-called superficial pes anserinus. The thinner anterolateral portion attached to the medial meniscus anteromedially. The smaller anterolateral part approached the medial meniscus anteromedially, pushing the synovial membrane into the joint. Its meniscal attachment ensures that the medial meniscus is stabilized in its primary position during bending and external rotation in the knee joint, thus preventing its herniation or injury during sudden extension. The accessory part of the sartorius muscle thus acts as a protector of the medial meniscus.

Cadaver↗
PubMed1988

Reactions of surrounding tissue to the cementless hip implant Ti-6Al-4V after an implantation period of several years. Autopsy studies in three cases.

Three femoral endoprosthetic stems implanted without cement, made of Ti-6Al-4V alloy, with implantation periods of between 2 and 4 years were examined histologically in the form of undecalcified thin ground sections after having been split into segments and embedded in plastic. During the implantation period total osseointegration in the metadiaphyseal region takes place, while in the proximal area reaction forms with direct contact between metal and bone on the one hand and with an interposed membrane of connective tissue and adjacent secondary bony shell on the other must be distinguished. The osseointegration of the stem is the result of a primary healing of the bone and is due to the biocompatibility of the metal alloy and to the primary stability obtained by the press-fit method.

Aged↗
PubMed1988

[Is high-density polyethylene suitable as an implant material in cement-free anchoring of hip endoprostheses? A histomorphologic study of an explanted polyethylene screw-in acetabula].

Firmly attached screw-in polyethylene acetabula which had been implanted for between 16 and 54 months were explanted after autopsies and subjected to macroscopic, radiologic and histologic examination. Metaplasias were seen around the threads and on the floor of the acetabulum. Their tendency to ossify represents an attempt at secondary stabilization. Due to the low stability of the polyethylene this causes increased wear on the floor of the acetabulum. The small defects in the polyethylene found in the threads, resembling damage done by mice, may be a sign of biodegradation. In view of the tissue reactions pointed out, the material stability of the polyethylene needs to be improved or implantation must be restricted to a very limited range of indications.

Acetabulum↗
PubMed1988

[Computerized tomography analysis of cement-free total hip endoprostheses].

16 patients with total hip endoprosthesis were investigated by high resolution computed tomography (CT) to analyse possible advantages of CT over conventional radiography. The quality of the examinations was good only in pure titanium systems: examinations of chromium-molybdenum alloys were severely deteriorated by strike artifacts. Positioning of implants is well defined in radiographs; CT provides better visualisation of the relation between implant and cortical bone. Evaluation of the contact of the shaft to the femoral corticalis is difficult in radiographs but facilitated in axial scans. Determination of relevance of CT analysis of total hip endoprosthesis remains subject to a future long-term follow-up study.

Bone Cements↗
PubMed1986

[Epicondylitis humeri radialis with special reference to the Wilhelm operation].

48 cases of epicondylitis humeroradialis were treated by means of an operation described by Wilhelm at the Orthopaedic Department of the University of Vienna between 1975 and 1979. They received a POP back slab for the upper arm for one week. Average time required to reach a pain-free state was three months (minimum two weeks, maximum six months). The follow-up examination at least five years later, taking clinical and subjective parameters into consideration, showed very good the satisfactory results in 93.2% and non-satisfactory results in the remaining 6.6% of cases.

Adult↗
PubMed1986

Tissue reactions to titanium endoprostheses. Autopsy studies in four cases.

Four cementless prosthetic hip implants of Ti-6Al-4V-alloy with and without longitudinal grooves and Al2O2 ceramic ball heads, with implant periods of 3, 4, 5, and 10 months, were sectioned and examined histologically in undecalcified thin ground sections. Especially on the medial and lateral sides of the prostheses, there was direct bone-to-metal contact without interposed connective tissue, spreading to the dorsal and ventral areas of the prosthesis shaft, which was considered osseointegration. This is based mainly on the technique of implantation with primary stability in the cortical bone by press-fit and on the bioinertness of the titanium alloy. Ungrooved prosthesis areas seem to favor bone growth at the shaft. The secondary bone ring, occurring on the dorsal and ventral areas of the prosthesis, with evidence of further bone remodeling with the passage of time, indicates that osseointegration is a dynamic process that continues to improve prosthetic stability.

Aged↗
PubMed1982

Concept and material properties of a cementless hip prosthesis system with Al2O3 ceramic ball heads and wrought Ti-6Al-4V stems.

A cementless total hip system of modular design is presented. The design of the stem provides for a firm seating on the cortical bone over a large area. Therefore primarily stable fixation is accomplished. The stem in seven different sizes is made of hot forged Ti-6Al-4V Protasul-64 WF alloy of high corrosion fatigue strength. The Biolox ceramic ball with three different neck lengths is connected to the high strength stem by means of a special selflocking conical spigot with a structured surface. The ceramic ball is combined with a polyethylene screw socket in four different sizes, designed by Endler and anchored in the acetabulum without acrylic cement. This hip prosthesis system has proved itself in clinical application since 1979.

Alloys↗
PubMed1980

An analysis of 119 loosenings in total hip endoprostheses.

One hundred nineteen loosenings of Müller total hip endoprostheses are analyzed. These arise from 1,407 operations performed between 1969 and October 1977. Deep infections occurred in 7 cases (0.5%). Loosening after a minimum of 5 years occurred in 15.3%. Of these the stem only was involved in 73.7%, stem and socket in 11.8% and the socket only in 14.5%. Seventy-eight per cent of the loose femoral components had been implanted in a varus position, with a long neck showing a higher incidence of failure, along with cases of implantation for osteoarthritis with cystic changes of the femoral head. In six cases the femoral component broke. This occurred twice in the acetabular component. Pain and loosening seemed to occur at the same time, and was unusual more than 5 years after the operation. When loosening occurred later, it was frequently caused by a fall.

Accidents, Home↗
PubMed1979

[Bone and joint replacements with bioceramic endoprostheses].

Construction principles, mechanical and animal experiments with various types of endoprostheses consisting of dense alumina are reported as well as the first results in man. A stable implantation of this biocompatible material is possible, if the primary attachment by means of special construction features and subtile operation technique is ensured. The definite dixation of the implant is provided by the ingrowth of newly formed bone tissue in circular running indentations. Therefore the use of bone cement, one of the critical points in replacement surgery, can be avoided. In tumor surgery the replacement of the proximal humerus by a ceramic prosthesis has proven to be successful. Equally satisfactory results could be achieved in the therapy of osteoarthritis of the hip with a metal-ceramic composite endoprosthesis.

Adult↗
PubMed1979

A bioceramic endoprosthesis for the replacement of the proximal humerus.

In patients with malignant tumors in the region of the shoulder, radical resection can avoid amputation in most instances. To improve the function of the arm, endoprosthetic replacement of the defect is desirable. A three-component endoprosthesis made of a bioceramic material (aluminium oxide) was designed, implanted without bone cement. Fast anchorage to bone is achieved by using a conical sleeve, fixed upon the previously conically reamed humerus shaft. A stable primary fit is always feasible. Subsequent bone in growth into grooves inside the conical sleeve provides a permanent anchorage of the endoprosthesis. The authors experiences are based on implantations of 38 endoprostheses. The original diseases were primary malignant bone tumors in 19 patients, one case of "solitary" plasmocytoma and metastases into the proximal humerus in 16 patients. In two women, resection was made because of posttraumatic subcapital humeral pseudarthrosis. The follow-up study includes only those 27 cases operated on at least one year ago. 12 of the 14 patients with primary tumors have been surviving for 12-55 months (range 27.4) without signs of metastases or recurrent disease. Seven patients with metastases died of their original diseases after 7.7 months on the average. Owing to extensive resection of the shoulder musculature the mobility in the shoulder joint is considerably reduced. All the patients have good movement of the elbow joint and free function of the hand.

Activities of Daily Living↗
PubMed1978

Extracortical attachment of bioceramic endoprostheses to long bones without bone cement.

Dense, highly pure A12O3 ceramic not only shows excellent wear resistance and tissue biocompatibility, but also has sufficient mechanical strength for loaded endoprostheses. The necessary diameter size of the material to sustain adequate shear stresses can be achieved, if the endoprosthesis is attached extracortically to the conically truncated long bone according to the principle of the conical sleeve. Extracortical attachment of the endoprosthesis causes minor nutritive damage since long bones derive their vascular supply mainly from the medullary cavity. In this way a primary stable and loadable connection is established, which is a prerequisite for permanent anchorage of the implant through new bone formation. After experiments in 12 dogs bioceramic endoprostheses were implanted in a total of 40 human patients using this technique of extracortical attachment (12 hip joints, 24 proximal humeri, 4 special constructions). Thirty-six of these implants were stable after observation periods ranging from one to 49 months. A stable anchorage of the prostheses to the pre-existing bone through new bone formation could be demonstrated histologically. The above preliminary results show that bioceramic endoprostheses can be "incorporated" in the skeleton and possibly also withstand the functional stresses.

Adult↗
PubMed1977

[A ceramic total hip endoprosthesis for implantation without bone cement. Preliminary report (author's transl)].

A new total hip endoprosthesis for implantation without bone cement is reported. This prosthesis consists of a ceramic socket and a titanium femoral component which is covered with a ceramic layer (Al2O3). The proximal end of the femoral component is shaped to a conus on which a ceramic ball for articulation with the socket is placed. Beside the construction principles the implantation technique and first clinical experiences are described.

Bone Cements↗