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PubMed1999

[Measures for biomechanically correct positioning of knee joint endoprostheses].

Normal post-operative function, permanent stable fixation and long life for the implant material are determined mainly by the correct biomechanical positioning of the knee joint prosthesis. We have identified six measures within the surgical procedure that are of vital importance for achieving biomechanically correct positioning. Because of their great importance, we call these measures "The Golden Six", and describe their application using the ESKA Resurfacing Knee System (RKS). This system, which is so designed that it enables a maximal bone saving resection technique, makes use of a diagonal screw-fixation of the endoprosthetic elements, resulting in increased primary stability. For the safe and reliable implementation of our measures, we have developed a special set of instruments. Anatomical, kinematic and surgical studies have shown that with the aid of the above-mentioned six measures biomechanically correct positioning of all the implanted elements can be achieved, thus ensuring trouble-free post-operative function of the knee joint and the least possible mechanical stressing of the implanted materials.

Arthroplasty, Replacement, Knee↗
PubMed2000

Boundary lubrication in vivo.

Evidence is reviewed for the concept that the body employs essentially the same lubrication system in many sites in the body where tissues slide over each other with such ease. This system consists of fluid adjacent to surfaces coated with an oligolamellar lining of surface-active phospholipid (SAPL) acting as a back-up boundary lubricant wherever the fluid film fails to support the load--a likely event at physiological velocities. Particular attention is paid to the load-bearing joints, where the issue of identifying the vital active ingredient in synovial fluid is reviewed, coming down--perhaps predictably--in favour of SAPL. It is also explained how Lubricin and hyaluronic acid (HA) could have 'carrier' functions for the highly insoluble SAPL, while HA has good wetting properties needed to promote hydrodynamic lubrication of a very hydrophobic articular surface by an aqueous fluid wherever the load permits. In addition to friction and wear, release is included as another major role of boundary lubricants, especially relevant in environments where proteins are found, many having adhesive properties. The discussion is extended to a mention of the lubrication of prosthetic implants and to disease states where a deficiency of boundary lubricant is implicated, particular attention being paid to osteoarthritis.

Adsorption↗
PubMed1997

The role of polyethylene wear in joint replacement failure.

Aseptic loosening is the major cause of failure of joint replacement prostheses. Polyethylene implants removed at revision surgery regularly show wear. It is proposed that the polyethylene particles released into the tissues as a consequence of this wear induce a tissue response that precedes aseptic loosening. This paper presents the results of recent in vivo and in vitro studies of the biological response to polyethylene wear particles undertaken in the authors' laboratories. A clinical perspective is provided by the inclusion of the authors' recent observations of retrieval analyses of joint replacement implant wear and the tissue response to polyethylene in humans.

Animals↗
PubMed1976

[Synovectomy in rheumatoid arthritis of the knee, radiologic investigations (author's transl)].

Pathologic and radiologic investigations of rheumatoid arthritis are compared with regard to their development. Radiologic demonstration of several cases prior to and following synovectomy shows improvement as well as exacerbation of the disease. An increasing mineral content signifies an improvement of the bone lesion. The mineral content depends on reduction of inflammatory activity, increasing motility, and postoperative discontinuation of cortisone therapy. In some cases various lesions at the border line between bone and cartilage as blurring, notching and destructions are disappearing. Reduction of cartilage accompanied with narrowing of the joint spaces will subside postoperatively, too. We have to suppose a regeneration of cartilage under increasing physical strain by functional stimulation. Following synovectomy the structure of subcartilage spongiosa becomes more organized as a sign of regression of inflammatory activity, improved motility and load capacity. Following synovectomy, exacerbation of radiologic symptoms occur mainly in advanced stages of rheumatoid arthritis. We may often see progression of secondary osteoarthritis existing preoperatively in contrast to clinical recovery. The increasing load capacity may cause an identation of the articular surface in cases of extreme osteoporosis. This might result in a false position. These lesions might necessitate further surgical treatment as possibly total joint prosthesis. Following synovectomy in rheumatoid arthritis of the knee, dissolving radiologic symptoms in addition to improvement of the clinical picture may be observed. The poor results of synovectomy in advanced rheumatoid arthritis favours the of early synovectomy during the proliferative and destructive stage of the disease.

Adult↗
PubMed1998

Allogeneic vascularized grafting of human knee joints under postoperative immunosuppression of the recipient.

Vascularized knee joint transplantations have been performed in various animal systems. Up to now no allogeneic vascularized transplantation of a fresh and perfused human knee joint has been realized. This paper reports on the first four grafted human knee joints, performed between April 1996 and July 1997 at the Trauma Center Murnau. The indication for transplantation of a human knee joint is total loss of the joint, including the extensor apparatus, following severe trauma. Management of this defect is first to effect closure of the soft tissue defect combined with external transfixation and bone cement spacers. For the second phase the external stabilization is switched to internal stabilization using femoral tibial nails and a temporary knee joint prosthesis manufactured of polyethylene. The transplantations are performed with respect to ABO compatibility, ignoring the HLA system after a negative crossmatch. Osteosyntheses are employed by femoral and tibial nails. The vascular anastomoses are established in an end-to-side technique between the recipient's superficial femoral vessels and the graft vascular pedicles. Immunosuppression starts as quadruple induction therapy for 3 days. Subsequently it is reduced to a two-drug maintenance protocol with cyclosporin A and azathioprine. We utilize radiography, digital subtraction angiography, duplex sonography, scintigraphy, and arthroscopy for graft monitoring. Six months after transplantation the osteotomies were bridged with callus, and the patients were completely mobilized. The motion in the transplanted knee joint ranges from complete extension to 110 degree flexion.

Adolescent↗
PubMed2005

A novel artificial prosthetic replacement for the proximal interphalangeal joint of the hand--from concept to prototype.

This article describes the development of a proximal interphalangeal (PIP) joint prosthesis based on the principles of replicating anatomical surface components, the use of macrolocking intramedullary stem and the use of a cobalt-chrome alloy material. The design features are intended to obtain an optimal range of motion while retaining stability and longevity. The final prototype, for which a patent has been filed, is described.

Chromium Alloys↗
PubMed1998

Temporomandibular disorders: clinical and laboratory analyses for risk assessment of criteria for surgical therapy, a pilot study.

Temporomandibular disorder (TMD) is a broad category involving dysfunction of the skeletomuscular structures of the head and neck, and the temporomandibular joint (TMJ). A total of 66 patients, 54 with TMD, participated in this study. Group 1 (G1) had 31 patients suffering from early to intermediate stage disease, and no prior surgeries. G1 patients had arthrotomy/meniscectomy performed on the diseased joint(s). Group 2 (G2) consisted of 23 patients with late stage disease. All G2 patients had previously had unsuccessful TMJ surgery and were treated with either a partial or total joint prosthesis. Group 3 (G3) consisted of 12 patients who were clinically and radiographically asymptomatic. Medical histories including inflammatory bowel disease, headaches, vertigo, tinnitus and anemia, as well as surgical tonsillectomies, appendectomies and cholecystectomies, were significantly greater in G1 and G2 when compared to G3. Serological testing included HLA subtype, positive (ANA) antinuclear antibody, erythrocyte sedimentation rate (ESR), anemia profile, hormonal levels of prolactin and estradiol, and rheumatoid factor (RF). HLA frequencies, as well as some serological analyses, were significantly different among the three groups. These findings suggest that surgical failure may be secondary to autoimmune dysfunction with a predisposition to multisystem disease. The utilization of genetic markers, serological testing, and thorough medical and surgical histories should allow the clinician to determine which patients are potentially better surgical risk candidates for treatment of TMD.

Adolescent↗
PubMed1977

Reactions of the articular capsule to wear products of artificial joint prostheses.

Examination of a great number of tissue samples taken from the newly formed capsules surrounding artificial joints reveals small particles of prosthetic material. Abraded from the joint by wear and tear, these particles of plastic, metal, and acrylic cement initiate a foreign-body reaction and result in the formation of granulation tissue, including macrophages and foreign-body giant cells. Typical features of tissue reactions exist for each of the materials from which prostheses are made. The consequent formation of scar tissue produces a thickening of the capsule, which, in turn, may cause a reduction in the mobility of the joint. In small amounts, the foreign-body particles are eliminated via the perivascular lymph spaces. Where this transport system is insufficient to handle the volume, however, the foreign-body response may extend to the whole environment surrounding the joint. In such cases, there may be loosening of the cemented prosthetic parts because of deterioration of contiguous bone anchors by the tissue membrane lining the bone cement.

Foreign-Body Reaction↗
PubMed2006

Factors affecting stiffness properties in impacted morsellized bone used in revision hip surgery: an experimental in vitro study.

When revising loosened joint prosthesis, impacted morsellized bone is frequently used as organic scaffolding. We studied the relative influence that different bone particle size, impaction energy, and liquid content had on impacted bone stiffness. Bovine bone was morsellized in a bone mill by three grinding drums to produce bone with different chip size distribution. Next, portions of bone chips of controlled sizes were produced by a five-leveled sieve. Layer by layer of bone are constructed into pellets by our experimental impaction method. This method allows us to vary one independent factor at a time in a controlled manner while keeping the other factors constant. Stiffness for all bone pellets were measured during impaction and loading. In earlier studies, we focused on how impaction force, number of impaction strokes, and bone liquid contents influence mechanical behavior. Here, we compare the outcome of all studies using general linear models. All five factors significantly contribute to stiffness of impacted morsellized bone. Changing bone moisture has major, while increasing the number of impaction strokes beyond five per layer has minor effect. Low water content is the main contributor to highest load stiffness. Optimal stability of impacted morsellized bone is achieved with dried and well-graded particles. The number of heavy impaction strokes can be restricted.

Animals↗
PubMed2004

Influence of orthopedic particulate biomaterials on inflammation and synovial microcirculation in the murine knee joint.

The purpose of the present study was to examine changes in the synovial microcirculation as well as synovial tissue responses to exposure to titanium, polymethylmethacrylate (PMMA), ceramic (Al(2)O(3)), cobalt-chromium alloy (Co-Cr), and polyethylene (PE) particles in an in vivo model. The particulate biomaterials were injected into the left knee joint of female Balb/c mice and assessment of the synovial microcirculation using intravital fluorescence microscopy as well as histological evaluation of the synovial tissue response were performed on day 7 after particle administration. Intravital microscopic measurements revealed that all tested biomaterials caused significantly (p < 0.05) enhanced leukocyte-endothelial cell interactions and an increase of functional capillary density compared to controls. In the histological examination PMMA, Al(2)O(3), PE, and Co-Cr particles provoked significantly (p < 0.05) enhanced inflammatory tissue responses in comparison to tissue from control animals. Titanium particles showed significantly (p < 0.05) less leukocyte-endothelial cell interactions than the other particulate biomaterials and caused significantly (p < 0.05) minor membrane thickening compared to PE and PMMA particles. In conclusion, all tested particulate biomaterials were capable of inducing inflammatory responses in the present study. Our data suggest that titanium particles may cause less leukocyte activation and inflammatory tissue responses than other particulate biomaterials used in total joint arthroplasty.

Animals↗
PubMed2005

Quantitative analysis of monomer vapor release from two-solution bone cement by using a novel FTIR technique.

Methyl methacrylate monomer can evaporate from bone cement to reach cytotoxic levels of concentrations in the implant bed of total joint prosthesis. Therefore, this study was performed by using a novel Fourier transform infrared spectroscopy method to quantify the release of monomer vapor from experimental two-solution bone cement in vitro during polymerization, to examine the effect of surface area versus cement mass, and to explore the effect of initiation chemistry. The results revealed that monomer vapor release is a surface phenomenon. In addition, initiation chemistry plays a major role in controlling the reaction time, and therefore heat concentration and dissipation, which resulted in a higher absorbance peak as initiation chemicals concentration increased. It was concluded that using the FTIR to monitor MMA vapors is an effective technique to obtain quantitative information about monomer vapor release from bone cements during polymerization and provides insight on the polymerization kinetics of two-solution acrylic bone cement.

Biocompatible Materials↗
PubMed1983

Simultaneous determinations of cefsulodin and cefotiam in serum and bone marrow blood by high-performance liquid chromatography.

A high-performance liquid chromatographic method is described for the simultaneous determinations of cefsulodin and cefotiam in serum and bone marrow blood samples. After extraction with acetonitrile, the cephalosporins were applied to a reverse-phase column with an internal standard, cefazolin; the mobile phase was a mixture of 0.005 M tetrabutylammonium phosphate and methanol (35:65, v/v). The method yielded satisfactory resolutions for these agents, and the results were compared with those obtained using the microbiological method. The statistical analysis of the relationship between the methods gave a good correlation for all of these agents and samples. The concentrations of cefsulodin and cefotiam, concurrently administered by the intravenous route to patients subjected to artificial total joint prosthesis, in serum and bone marrow blood collected at 0.5 and 1 hr postinjection were almost equivalent.

Biological Assay↗
PubMed1988

Heating effects of metallic implants by MRI examinations.

Magnetic radiofrequency fields applied in magnetic resonance imaging examinations induce electrical currents in metallic implants. These eddy currents may heat up the implants and thus may be capable of causing localized tissue heating. The rf power deposition and the joule heating of the implant can be calculated by solving Maxwell's equations for the specific problem. First, extreme in vitro worst-case experiments were performed with a large and very thin aluminum sheet, which was placed in a 1.5-T MRI device in a position parallel to the magnetic rf field. In agreement with the theoretical results the temperature rise of a thermally insulated sheet amounted to only 0.08 degrees C after a 15-min MRI examination at 64 MHz. No temperature rise in the aluminum sheet could be measured for a sheet immersed in a saline solution. Second, in vitro experiments with a hip joint prosthesis and an osteosynthetic plate were performed to confirm the theoretical results, which predict nearly no temperature rise in the metallic implants. No temperature rise in the implants could be measured.

Aluminum↗
PubMed1981

[Technique of the alloplastic ligament substitution with carbon fibres (author's transl)].

Chronic instabilities or remaining luxations of joints are not acceptable for an active human being. The desired result is often not achieved by surgical methods applying most different autologous and homologous materials. This is why our working group has been trying for several years to develop a more promising method using an alloplastic material in the form of carbon ligaments. Numerous mechanical, biological, biomechanical, and histological examinations showed that the implantation of woven carbon ligaments in man could be accepted. During the most recent years, we have effected 150 ligament grafts with this material and, in course of time, we have been able to modify and to ameliorate the operation techniques. Today we may state that the described operation methods using ligaments of carbon fibres in the sternoclavicular, acromioclavicular, knee and ankle joint can bring about favorable results with regard to their function and stability. Further improvements can probably be achieved by a careful examination of the results obtained hitherto which will possibly include another refinement of the operation technique. A definite evaluation of this method, however, will only be possible within several years, when clinical check-up examinations will be made.

Acromioclavicular Joint↗
PubMed1999

Liposarcoma in association with total hip replacement.

A possible relation between joint replacement and malignancy has previously been suggested in a few cases. In the majority of these cases, the authors found either malignant fibrous histiocytomas or osteosarcomas. We hereby report the first case of a liposarcoma in the vicinity of a joint prosthesis.

Disease Progression↗