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At least 19 recordsLinked to original sources

Results of histological grading on 100 cases of hip prosthesis failure.

One hundred cases of hip prosthesis failure were classified on the basis of the different types of tissue reaction occurring around alloplastic material. The results revealed infectious phlogosis in 32% of the cases, phlogosis due to wear in 42%, phlogosis due to allergy in 1% and mixed phlogosis in 25%. The distribution of the type and degree of intensity of the phlogosis, in relation to the duration of the implant, is also highlighted. This new grading technique yields reproducible results.

Biocompatible Materials↗

[Macroscopic, histologic and ultrastructural study of 89 prostheses of anterior cruciate ligament excised because of prosthesis failure].

PURPOSE OF THE STUDY: This study concerns the etiology of failed synthetic anterior cruciate ligament (ACL) prostheses, and attempts to identify the primary mechanisms that lead to their premature rupture. MATERIAL AND METHODS: A total of 89 failed and surgically excised ACL prostheses were retrieved from young and active patients (27 +/- 7 years) at various orthopaedic centres in France. Their average duration of implantation was 34 +/- 24 months. They were examined macroscopically, histologically and by scanning electron microscopy (SEM) to determine the model, the manufacturer, the surgical technique used at implantation, the extent of healing, the site of rupture, as well as the morphology of the damage fibers. RESULTS: Seventy two of these explants represented 6 different models. While all 6 were fabricated from polyester fibres, each had a different textile construction, and each were associated with a unique healing and mechanical response in vivo. SEM observations confirmed that abrasion of the textile fibres were a phenomenon common to all models, and were the primary cause of prosthesis failure. Such wear zones were particularly prevalent at the exit of the tibial tunnel and around the femoral condyle. Collagenic infiltration into the synthetic ACL was poorly organized and unpredictable. It did not increase with the duration of implantation. In fact in certain models, it appeared to have caused deterioration and fraying of the textile structure rather than serving as a reinforcing matrix around the prosthesis. DISCUSSION: A synthetic ACL prosthesis is to be preferred for patients who do not have tissue available for autologous ligamentoplasty. Yet none of the synthetic devices examined in the present study were capable of stabilizing the knee over the long term. Among the factors that influenced their failure we found that the three most common mechanisms were flat abrasion against an osseous surface, flexural and rotational fatigue of the fibres, and loss of integrity of the textile structure due to unpredictable tissue infiltration during healing. CONCLUSION: The results of the present study show that none of the current models succeed in replacing the natural ACL. Future improvements may be achieved by developing surgical procedures for implantation combined with a prosthesis made from fibres and textile structures which are more abrasion resistant and promote predictable and controlled tissue infiltration.

Adult↗

[Quantification of mitral prosthesis failure by different methods of evaluation by transesophageal echocardiography].

PURPOSE: To evaluate the different methods for grading mitral regurgitation (MR) by transesophageal echocardiography (TEE) in patients with clinical suspicion of mitral prosthesis dysfunction. METHODS: Cardiac catheterization (Cath) was performed in 15 patients for grading the severity of prosthetic MR, divided in two groups based on the presence or absence of severe MR. Prosthetic MR was quantified by TEE using methods commonly used for MR of native valves: subjective assessment by color Doppler, objective assessment based on absolute jet area and on its relative area (jet area/left atrial area) and assessment based on the presence of systolic flow reversal in pulmonary vein. RESULTS: Prosthetic MR was mostly transprosthetic (14 patients) and eccentric (11 patients). There was significant correlation (p < 0.05) between Cath and TEE for identification of severe MR based on subjective assessment and on the presence of systolic flow reversal in pulmonary vein. Identification based on absolute (jet area > 7 cm2) and relative (jet area > 35% of left atrial area) jet areas did not reveal significant correlation with the angiographic grade and showed clear underestimation by TEE when the last method was used. However, there was good correlation (p < 0.05) if relative jet areas > 30% were considered as cut point. CONCLUSION: TEE correctly identified angiographic severe mitral prosthesis regurgitation, mainly by the presence of systolic flow reversal in pulmonary vein and subjective assessment. The estimation of severity of the prosthetic MR by absolute or relative jet area seems to be limited and should be used with caution due to eccentricity of the regurgitant jet, frequently seen in mitral prosthesis dysfunction.

Adult↗

Aseptic loosening of total hip replacement. Macrophage expression of inducible nitric oxide synthase and cyclo-oxygenase-2, together with peroxynitrite formation, as a possible mechanism for early prosthesis failure.

Aseptic loosening is a major cause of failure of total hip arthroplasty. The adverse tissue response to prosthetic wear particles, with activation of cytokine and prostanoid production, contributes to bone loss around the implants. We have investigated the possibility that inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) are expressed in macrophages in the pseudomembrane at the bone-implant interface, thereby contributing to the periprosthetic bone resorption. We also assessed whether peroxynitrite, a nitric oxide (NO)-derived oxidant associated with cellular injury, is generated in the membrane. Enzymatic activity of iNOS was measured using the arginine-citrulline assay technique and prostaglandin E2 (PGE2), as an indicator of COX-2 activity, was measured using an enzyme immunoassay. Cellular immunoreactivity for iNOS, nitrotyrosine (a marker of peroxynitrite-induced cellular injury) and COX-2 was assessed by quantitative peroxidase immunocytochemistry while immunofluorescence methods were used for subsequent co-localisation studies with CD68+ macrophages. The presence of calcium-independent iNOS activity and PGE2 production was confirmed in the homogenised interface membrane. Immunocytochemistry showed that periprosthetic CD68+ wear-debris-laden macrophages were the most prominent cell type immunoreactive for iNOS, nitrotyrosine and COX-2. Other periprosthetic inflammatory and resident cell types were also found to immunolocalise nitrotyrosine thereby suggesting peroxynitrite-induced protein nitrosylation and cellular damage not only in NO-producing CD68+ macrophages, but also in their neighbouring cells. These data indicate that both iNOS and COX-2 are expressed by CD68+ macrophages in the interface membrane and peroxynitrite-induced cellular damage is evident in such tissue. If high-output NO and peroxynitrite generation were to cause macrophage cell death, this would result in the release of phagocytosed wear debris into the extracellular matrix. A detrimental cycle of events would then be established with further phagocytosis by newly-recruited inflammatory cells and subsequent NO, peroxynitrite and prostanoid synthesis. Since both NO and PGE2 have been implicated in the induction and maintenance of chronic inflammation with resulting loss of bone, and peroxynitrite in the pathogenesis of disease states, they may be central to the pathogenesis of aseptic loosening.

Adolescent↗

Vascular prostheses performance assessment of vascular prosthesis failure.

During 30 years of active participation in clinical vascular surgery and the screening and development of vascular prostheses, greater than 450 different fabrications have been evaluated. Vascular prosthesis retrieval and analysis during this period of time have been systematized, and greater than 40 different causes of failure of vascular prostheses have been classified into six classes: failure of diagnosis, error of implantation, patient contribution, complications of healing, fabrication failure, and infection. Such analyses allow for scientific evaluation, testing development, and the elaboration of performance standards so badly needed at present. Such a task is being organized by American Society for Testing and Materials (ASTM) Subcommittee F04.04 on Cardiovascular Materials and Devices and will require the active participation of all knowledgeable individuals.

Blood Vessel Prosthesis↗

The porous-coated anatomic total hip prosthesis: failure of the metal-backed acetabular component.

One hundred and ninety-nine total hip arthroplasties were performed, between 1983 and 1987, in 173 patients by three surgeons using the initial design of the porous-coated anatomic prosthesis. The acetabular component was a preassembled, metal-backed polyethylene device, with beads sintered to the metal backing to allow bone ingrowth and two pegs for initial fixation. Twenty-three acetabular components (12 percent) failed because of either migration or severe osteolysis. The radiographic appearance of osteolysis was positively associated with the duration that the implant had been in situ (p < 0.001). The prevalence of osteolysis was also significantly greater in acetabular components with an outer diameter of fifty-five millimeters or less (a polyethylene thickness of 8.5 millimeters or less) (p = 0.03). Thirteen hips were revised at a mean of 69.5 months (range, thirty-three to ninety-one months) after the index operation. Examination of the retrieved acetabular components revealed extensive polyethylene damage on the articular and back surfaces of the liners. Cracks in the polyethylene rim of the liner and deformation of the anti-rotation notch in the polyethylene rim were common findings. The density of the polyethylene was greater than expected, and more particles than anticipated had not fused with the surrounding polyethylene. The results of this study suggest that factors related to both the design and the material contributed to the failure of these porous-coated anatomic acetabular components.

Acetabulum↗

Isolated mitral valve replacement. With Carpentier-Edwards bioprosthesis :independent risk factors for long-term survival and prosthesis failure.

From 1976 through 1986, 188 patients (female/male ratio: 2/1, age 20-77 years, mean 58 years) with isolated mitral valve disease underwent valve replacement using the Carpentier-Edwards porcine bioprothesis (CEPB). Nine hospital deaths (4.8%) were excluded from further analysis. Follow-up was 0.2-11.3 years (mean 5.2 years); preoperatively, 74% had atrial flutter/fibrillation, and 75% were in NYHA-classes III-IV. All patients were put on life-long coumadin treatment. Preoperative predictability of long-term survival and prosthesis-related complications was examined using Cox regression analysis. Five preoperative variables were found to have independent predictive value as regards long-term survival: myxomatous degeneration of the valve (p = 0.002), chronic regurgitation (p = 0.003), age (p = 0.004), NYHA-class III-IV (p = 0.05), and atrial flutter/fibrillation (p = 0.05). A prognostic index calculated form the final Cox model identified six risk groups (I-VI) having cumulative 10-year survivals +/- SE of: I (n = 9) 100%, II (n = 10) 90 +/- 9%, III (n = 30) 73 +/- 10%, IV (n = 70) 51 +/- 9%, V (n = 43) 17 +/- 10%, and VI (n = 17, 7-year survival) 16 +/- 13% (p less than 0.0001). The incidence of late valve-related complications (%/patient-years) were: hemorrhage, 1.2; thromboembolism, 0.5; Endocarditis, 1.0; paravalvular leak, 0.2; and primary tissue failure, 1.5. Previous closed comissurotomy adversely influenced the occurrence of hemorrhage, while calcified mitral annulus were predictive of endocarditis. Younger age (less than or equal to 45 years) had a strong predictive influence of primary tissue failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioprosthesis↗

The pathology of the joint tissues and its clinical relevance in prosthesis failure.

Thirty-four hip and knee total arthroplasty failures due to infection, loosening, intractable pain and dislocation were examined for synovial and capsular tissue debris. Simiquantitative assessments were made for metal polyethylene, acrylic and cellular debris and inflammation. The most important finding was that in the amounts normally shed into joints, debris particles do not appear to stimulate a polymorphonuclear response. The magnitude of this response correlates best with clinical and/or bacteriological evidence of infection. The quantity of acrylic particles could be correlated with clinical evidence of loosening. Since the correlation between infection and polymorphonuclear leukocytes, debris particles, and the reasons for failure is high, frozen section may aid the surgeon in determining the methods and timing of revision operations.

Acrylates↗

Implant-supported single-tooth replacements: risk of implant and prosthesis failure.

Data from 236 patient cases of implant-supported single-tooth replacements in the maxillary anterior region were sequentially recorded and documented. The time in situ ranged from a minimum of five to a maximum of 19 years. Twenty-two implants failed during the observation period. The causes of such failure were peri-implantitis, implant fracture, and trauma. The probability of success according to the Kaplan-Meier method decreased to 0.89 over a period of 10 years. The failure rate for implants replacing lateral incisors was lower than that for implants replacing central incisors. Seventy-six cases were clinically documented for 10 years or more. In 15 cases, replacement of the prosthetic superstructure was necessary during the 10-year period. The course of therapy and clinical follow-up care is described by a multi-state distribution.

Adolescent↗

The inverse prosthesis as a revision prosthesis in failures of shoulder hemiarthroplasty.

The authors describe their series of seven cases of complications and failures of shoulder hemiarthroplasty that were submitted to revision surgery involving an inverse prosthesis. This prosthesis has for some time now been indicated in elderly patients with arthropathy caused by rupture of the cuff. In our cases this prosthesis was implanted in patients who had undergone shoulder hemiarthroplasty for fracture and for arthrosis. The Constant score was used for pre- and postoperative evaluation. Results at mid-term, from 2 to 4 years, indicate evident improvement in Constant score that rose from a mean of 23.14 preoperatively to a mean of 49.14 postoperatively. Despite the limited follow-up the authors suggest the use of the inverse prosthesis as an effective alternative solution in shoulder arthroplasty revision surgery.

Aged↗

A three-dimensional analysis of a fibre-reinforced aortic valve prosthesis.

Failure of synthetic heart valves is usually caused by tearing and calcification of the leaflets. It is postulated that leaflet fibre-reinforcement leads to a decrease of tears and perforations as a result of reduced stresses in the weaker parts of the leaflets. A three-dimensional finite element model of a reinforced three-leaflet valve prosthesis was developed to analyse the stress reduction. Different fibre reinforcements were investigated and the model responses were analysed for stresses that are expected to contribute to failure of fibre-reinforced valve prostheses. Results of these simulations show that, in peak stress areas of reinforced models, up to 60% of the maximum principal stresses is taken over by fibres and that, in some cases of reinforcement, a more homogeneous stress distribution is obtained.

Alkenes↗

A three-dimensional mechanical analysis of a stentless fibre-reinforced aortic valve prosthesis.

Failure of bioprosthetic and synthetic three-leaflet valves has been shown to occur as a consequence of high tensile and bending stresses, acting on the leaflets during opening and closing. Moreover, in the stented prostheses, whether synthetic or biological, the absence of contraction of the aortic base, due to the rigid stent, causes the leaflets to be subjected to an unphysiological degree of flexure, which is related to calcification. It is shown that the absence of the stent, which gives a flexible aortic base and leaflet attachment, and leaflet fibre-reinforcement result in reduced stresses in the weaker parts of the leaflets in their closed configuration. It is postulated that this leads to a decrease of tears and perforations, which may result in a improved long-term behaviour. The effect of a flexible leaflet attachment and aortic base of a synthetic valve is investigated with a finite element model. Different fibre-reinforced structures are analysed with respect to the stresses that are likely to contribute to the failure of fibre-reinforced prostheses and compared with the results obtained for a stented prosthesis. Results show that for the stentless models a reduction of stresses up to 75% is obtained with respect to stented models with the same type of reinforcement.

Aortic Valve↗

[Total hip arthroplasties in 190 cases: follow-up study].

One hundred and ninety-six cemented total hip arthroplasties performed in 190 patients (mean age, 62 years) followed-up with an average of 8.7 years were reviewed. The results were compared with the same group previously reported at an average follow-up of 4 years. Clinically satisfactory results were observed at the short- and medium-terms. Evaluation of the study with Harris score system showed that the score records fell from 85 to 78.4 points in the same group and the revision rate rose from 6.84% to 14.73%. The main causes of the prosthesis failure were loosening of the prosthesis and of breakage of the prosthesis stem. This follow-up study showed that the short-term prosthesis failure was mainly related to the cement-fixing technique, while the medium-term failure was due to side effects of the cement. This series showed that cemented prosthesis is a good selection especially for elderly patients.

Aged↗