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At least 55 records · Page 3Linked to original sources
PubMed2001

Titanium/titanium nitride temporomandibular joint prosthesis: historical background and a six-year clinical review.

The titanium/titanium nitride temporomandibular joint (TTN-TMJ) prosthesis, for the combined replacement of both the joint and the glenoid fossa, was developed in 1992 and introduced clinically in 1994. This joint prosthesis is manufactured from pure titanium and the condylar surfaces, as well as the fossa, are coated with titanium nitride for hardening of the contact surfaces. In two different research projects, the joint were first placed in experimental animals, before they were successfully placed in human subjects. Twenty seven joint prostheses used in human subjects have been analysed for this review.

Alloys↗
PubMed1999

The theoretical optimal center of rotation for a temporomandibular joint prosthesis: a three-dimensional kinematic study.

A unilateral temporomandibular joint (TMJ) prosthesis may cause dysfunction of the contralateral, natural TMJ because of lack of translatorial movements of the prosthetic side. The natural translatorial capacity of the mandible can be restored in part by a TMJ prosthesis with a fixed center of rotation (CR), positioned inferiorly to the center of the natural mandibular condyle. The aim of this study was to determine the optimal position for the fixed CR of a unilateral TMJ prosthesis. A mathematical model was used to analyze different positions of the CR. These positions were evaluated based on the calculated rotation of the mandible in the frontal (theta f) and horizontal (theta h) plane, and the mediolateral movement (MLM) of the contralateral natural condyle. For current TMJ prostheses, with the CR positioned in the center of the natural condyle, theta h exceeded the natural limits. When the CR was shifted inferiorly, all parameters improved, particularly theta h. The addition of an anterior shift to an inferior shift slightly worsened theta f, while the addition of a posterior shift to an inferior shift slightly improved theta f and worsened MLM. We concluded that the functioning of the contralateral TMJ improves by shifting the CR inferiorly. An anterior shift may be added to remain within the contour of the mandibular ramus. The proposed position of the CR is 15 mm inferior to the center of the natural condyle, combined, if necessary, with an additional anterior shift of 5 mm.

Humans↗
PubMed1990

Deterioration mechanisms of joint prosthesis materials. Several solutions by ion implantation surface treatments.

Materials for orthopaedic implants can fail for several combined reasons: corrosion, fatigue and wear for metals, wear and creep for polymers, fracture for ceramics. Some typical cases are analysed and it is demonstrated that ion implantation improves metals and polymers used for joint prosthesis. Implantations of nitrogen, oxygen and argon ions modify the structure of a 2-500 nm thick layer in the materials. The results of friction tests on the couple metal-polymer are correlated with the surface properties.

Ions↗
PubMed1993

[An unknown cause of deep lymphadenopathies: polyethylene histiocytosis related to a joint prosthesis].

A case of deep seated lomboaortic lymph node enlargement, due to a storage hitiocytosis by fragments of polyethylene, draining the site of hip joint prosthesis is reported. These lymph node enlargement, made visible by tomodensitometry, were satellites of an ovarian adenocarcinoma. The artificial hip joint operation had taken place 17 years before and 10 years later the patient underwent a secondary operation to replace the prosthesis of the right hip. To the knowledge of the authors this is the first recorded case of lymph node enlargement due to a storage histiocytosis in response to debris shed from hip prosthesis being made visible by way of a radiological examination.

Ascites↗
PubMed1991

The Nicolle finger joint prosthesis: a reappraisal.

The Nicolle prosthesis was used to replace 101 metacarpophalangeal joints in patients with rheumatoid arthritis over a ten-year period. Mean active flexion achieved was 30 degrees. Mean ulnar deviation was 27 degrees. 4% of joints had to be removed after a mean interval of 42 months, for infection. None of the implants had fractured.

Arthritis, Rheumatoid↗
PubMed1996

Infection of a total knee joint prosthesis by peptostreptococcus micros and propionibacterium acnes in an elderly RA patient: implant salvage with longterm antibiotics and needle aspiration/irrigation.

We describe the favourable long-term outcome after late total knee joint prosthesis infection in an elderly RA patient. Peptostreptococcus micros and Propionibacterium acnes were cultured from the synovial fluid, and the finding of a coexistent abscess at the root of a wisdom tooth suggested a dental origin to the joint infection. Long-term antibiotics in conjunction with aspiration/irrigation resulted in salvage of the implant and an excellent functional outcome.

Aged↗
PubMed2000

A short-term study in sheep with the Groningen temporomandibular joint prosthesis.

As part of the pre-clinical testing process of a newly developed temporomandibular joint (TMJ) prosthesis, animal experiments were performed. In 14 sheep, the right TMJ was replaced by the developed TMJ prosthesis. The prosthesis consisted of a skull part, a mandibular part and an intervening polyethylene disc. In the first series (6 sheep), three designs were tested, differing in the applied metal (stainless steel or titanium) and in the fitting method of the skull part (a fitting member or bone cement). The sheep were sacrificed after 8-16 weeks. In the second series (8 sheep), the preferred titanium fitting member design was applied, and the sheep were sacrificed after 2-10 weeks. One sheep was excluded because no correct position of the prosthesis parts could be achieved. At sacrifice, the removal torque of the screws was measured, and the surrounding tissues were harvested for histologic examination. The sheep recovered well and functioned until the end of the scheduled sacrifice date. Encountered problems were two disc dislocations, one fistula formation, and one screw failure. All mandibular parts were clinically stable, as were most skull parts with a fitting member, and one of both skull parts fitted with bone cement. The clinically observed stability was confirmed by the removal torque values, which indicated well-integrated screws. It is concluded that the TMJ prosthesis could remain stable and functional over the initial healing period. The main restriction of the sheep model is the much larger translatory capacity compared with patients, which adversely influences tissue healing.

Animals↗
PubMed2002

Rhodotorula minuta: an unusual fungal infection in hip-joint prosthesis.

Fungal infections of total joint arthroplasty are uncommon complications, and most cases have been associated with Candida species. In this article, we present a case in which a total hip arthroplasty was infected with Rhodotorula minuta. Intraoperative gram stain showed yeast formsand led to early detection and immediate treatment with amphotericin B and bacitracin. Successful reimplantation was performed 12 months later. To our knowledge, this is the first reported case of arthroplasty infection caused by R minuta.

Aged↗
PubMedDate not supplied

Determination of cantilever length-anterior-posterior spread ratio assuming failure criteria to be the compromise of the prosthesis retaining screw-prosthesis joint.

The maximum cantilever length-anterior-posterior spread (CL-AP) ratio is often used as an indication of the ability to cantilever in completely implant-supported prostheses. The CL-AP ratios were determined assuming that failure occurs when the prosthesis retaining screw-prosthesis joint was compromised by either compressive (exceeding the pretorque value) or tensile (opening of the joint via plastic deformation) vertical forces using the Skalak model. Geometric arrangements of three, four, five, and six implants were analyzed. Force variables were 143, 200, and 400 N for the applied force, the pretorque value, and the joint tensile yield strength, respectively. The pretorque value was always exceeded before the yield strength. Allowable CL-AP ratios were (1) lower than those previously reported and (2) found to be 0.5 to 1.8, 0.7 to 1.6, 1.1 to 1.7, and 1.8 for three, four, five, and six implants, respectively. Although implant distributions with the highest AP often provide adequate occlusion, the results of this study indicate that the use of a single CL-AP ratio alone is not necessarily a good indicator of the ability to cantilever.

Algorithms↗
PubMed1995

[Infected hip joint prosthesis. Viewpoints for 1-stage and 2-stage prosthesis exchange].

When treating an infected hip prosthesis, there are a number of medical, technical and biomechanical considerations. No ideal solution for all problems is available. In individual cases an optimal compromise must be found. The means for curing the infection and the one for maintaining hip stability can counteract each other. Basically, three options are available: removal of the prosthesis without replacement and one- or two-stage replacement. With all three options thorough surgical debridement is vitally important. The introduction of antibiotic cement and cementless titanium implants, together with very effective local antiseptics, has remarkably improved our treatment of this problem. Therefore, removal of infected prostheses without replacement is not as well accepted now as it has been in the past.

Anti-Bacterial Agents↗
PubMedDate not supplied

Does a pro-angiogenic state exist in the bone-implant interface of aseptically loosened joint prosthesis?

Neovascularization is indispensable to both bone remodeling and the development of chronic inflammation. A pro-angiogenic state in the periprosthetic tissue may augment the inflammatory response to wear debris. To investigate if a pro-angiogenic state exists in the bone-implant interface of aseptically loosened joint prosthesis, the expression of vascular endothelial growth factor (VEGF) and its receptor Flk-1/KDR were studied by immunohistochemistry. The VEGF-Flk/KDR pathway has been implicated as a key signaling requirement for pathological angiogenesis. The level of vascularization in periprosthetic tissue was semi-quantitatively compared to osteoarthritic (OA) and rheumatoid arthritic (RA) synovium. The level of vascularization in areas of periprosthetic tissue with heavy or low/moderate wear debris were also compared semi-quantitatively by image analysis. High levels of VEGF expression (16/16 cases) particularly in the implant synovial-like lining layer together with Flk-1/KDR expression by endothelial cells (13/16), suggests that neovascularization is occurring. Morphometric comparison of periprosthetic tissue with RA and OA synovium revealed no significant difference in microvessel density, but did reveal significantly increased microvessel area in RA synovium (P > 0.05). Areas of high wear debris infiltrate also contained a significantly smaller microvessel area (P > 0.01). Suggesting that wear debris may cause behavioral modification of microvessels. Modifying angiogenesis in the periprosthetic tissue could be a potential therapeutic target in reducing inflammation.

Journal Article↗