RESUMEN

OBJECTIVE: To study the clinically diagnosed disease process but also identify additional, clinically undetected pathologies in femoral heads resected for replacement arthroplasty. DESIGN AND MATERIAL: A retrospective review was carried out of the pathological findings in 460 surgically resected femoral heads. Serial sections were submitted to low-energy fine-detail radiography, then decalcified sections stained by the WHO method were examined. The preoperative clinical and imaging diagnoses were compared with the pathological findings and special interest was placed on assessing the clinical significance of any unexpected, clinically undetected findings. RESULTS: The most common findings included the presence of bone islands (solitary osteomas) and areas of avascular necrosis in addition to the primary joint disease for which the patient underwent surgery. The preoperative symptomatology did not distinguish between the known primary disease and the additional pathological findings. CONCLUSION: Some of the clinically unidentified lesions were of a size that fell below the ability of current clinical investigations to detect. However, the finding of lesions by tissue fine-detail radiography indicates that current, more sensitive clinical imaging techniques may identify them. Careful examination of surgically resected femoral heads is important to ensure that all pathologies are identified and assessed for clinical relevance.

Asunto(s)

Neoplasias Óseas/diagnóstico , Cabeza Femoral/patología , Osteoma/diagnóstico , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Neoplasias Óseas/patología , Cabeza Femoral/diagnóstico por imagen , Cabeza Femoral/cirugía , Humanos , Artropatías/diagnóstico , Artropatías/patología , Persona de Mediana Edad , Osteoma/patología , Osteonecrosis/diagnóstico , Osteonecrosis/patología , Radiografía , Estudios Retrospectivos , Sensibilidad y Especificidad

RESUMEN

We present the histological findings of an extensor mechanism allograft which was used in a total knee arthroplasty two years after implantation. Analysis of the graft was undertaken at four distinct anatomical levels and it was found to be incorporated into host tissue at each level. A wedge of fibrinoid necrosis, probably related to impingement of the graft on the tibial polyethylene insert, was seen. Impingement may play a role in the injury and necrosis of an allograft and may be one mode of failure in an extensor mechanism allograft.

Asunto(s)

Artroplastia de Reemplazo de Rodilla/métodos , Trasplante Óseo/patología , Amputación Quirúrgica , Femenino , Supervivencia de Injerto , Humanos , Articulación de la Rodilla/patología , Prótesis de la Rodilla , Persona de Mediana Edad , Falla de Prótesis

RESUMEN

The study objective was to determine the tissue response to polyethylene and/or titanium particles and the role that these play in peri-prosthetic osteolysis in a rabbit model of implant failure. Twenty-two mature rabbits were used. Unilateral tibial arthroplasty was performed on all of them. The test animals received implants that were intentionally rotationally unstable with reference to the host tibia in order to create a model of failure. The test rabbits were divided into three groups. Group 1 consisted of seven rabbits in which only the carrier was implanted. Group 2 consisted of seven rabbits that received only polyethylene particles suspended in the carrier. Group 3 consisted of eight rabbits that received a mixture of polyethylene and titanium alloy particles suspended in the carrier. The rabbits were sacrificed at 6 months post surgery. The entire knee, together with the immediately surrounding soft tissue, was retrieved. The position of the implant in each rabbit was assessed with reference to its alignment to the tibia. The number of inflammatory, foreign-body reactive cells, the presence of neovascularization, edema, and necrosis in the periprosthetic zones were recorded and assessed in a qualitative and semiquantitative manner. Quantitative histomorphometry was used to determine the proportion of implant surface that interfaced with osseous or fibrous tissue. Also assessed was the thickness and maturity of the fibrous tissue and the endosteal remodeling activity in the peri-implant bone counting both osteoclastic and osteoblastic activity. The results showed that implanted particles and misalignment of the implants combined to produce peri-prosthetic bone resorption. Bone resorption was found to be proportional to the degree of misalignment. The animals that received combined polyethylene/titanium particles had a greater degree of foreign-body and inflammatory response with osteolysis than the other groups. The combination of bio-material particles (polyethylene and titanium alloy) produced a greater degree of bone resorption than the single biomaterial particles (polyethylene). The amount of bone resorption surrounding the implant was directly proportional to the degree of misalignment of the implant.

Asunto(s)

Reacción a Cuerpo Extraño/etiología , Implantes Experimentales/efectos adversos , Osteólisis/etiología , Polietilenos , Falla de Prótesis , Titanio , Aleaciones , Animales , Artroplastia , Reacción a Cuerpo Extraño/patología , Osteólisis/patología , Conejos , Tibia/patología , Tibia/cirugía

RESUMEN

This study evaluated the quality and quantity of osseointegration of two thicknesses of hydroxyapatite coating on press-fit, porous-coated titanium implants in a canine hip model. In 12 dogs, titanium press-fit porous-coated prostheses were implanted. The stems had a 50-microm thickness hydroxyapatite coating, 100-microm thickness hydroxyapatite coating, or no hydroxyapatite coating. The animals were randomized into one of three groups and received one of the three implants. The implants were retrieved and examined 4 months after implantation. Direct juxtaposition of bone to the surface of the hydroxyapatite-coated implants with no intervening fibrous tissue layer was observed. There was no histologic evidence that hydroxyapatite initiated any foreign body reaction, nor was there any irregularity or resorption of the hydroxyapatite coating. There was a statistically significant greater degree of total bone apposition and bone ingrowth in the implants coated with hydroxyapatite at the level of the isthmus and the calcar. No statistical difference was found between the two groups with hydroxyapatite coatings in the degree of bone ingrowth or bone apposition.

Asunto(s)

Materiales Biocompatibles Revestidos , Durapatita , Prótesis de Cadera , Oseointegración , Animales , Perros , Modelos Animales , Distribución Aleatoria

RESUMEN

AIMS: In order to facilitate the diagnosis of malignancy in solitary thyroid nodules which are non-invasive low-grade tumours, i.e. follicular variant of papillary carcinoma (FVPC) for which few histological discriminators exist, a search was made for additional diagnostically useful histological features. METHODS AND RESULTS: Haematoxylin and eosin (H & E)-stained sections of 70 resection specimens of solitary thyroid nodules were re-evaluated by a panel of three pathologists, and their consensus and original diagnoses compared. In addition, H & E- and periodic acid-Schiff-stained sections were evaluated for various histological features and sections were stained by various immunohistochemical markers to evaluate their discriminative powers. The above features were also assessed in a group of 24 papillary carcinomas of the thyroid (PTCs) associated with regional metastases. The finding of 'Orphan Annie eye' nuclei was the best indicator of malignancy, and was closely related to the presence of nuclear grooves and cells with dense, dark nuclei. In addition, distorted follicular architectural features, i.e. 'interconnecting cell masses' and 'fenestration', were also significant indicators of malignancy. Tumours diagnosed as FVPCs had a significantly lower incidence of associated lymph node metastases than the classical PTCs. CONCLUSIONS: The use of optically clear nuclei as a diagnostic criterion when found only focally may not be sufficiently stringent in distinguishing FVPCs from follicular adenomas. When classical histological indicators of malignancy are equivocal, the diagnosis of FVPC may be facilitated by the above-mentioned features.

Asunto(s)

Adenoma/patología , Carcinoma Papilar/patología , Núcleo Celular/patología , Neoplasias de la Tiroides/patología , Adenoma/metabolismo , Carcinoma Papilar/metabolismo , Núcleo Celular/química , Diagnóstico Diferencial , Humanos , Inmunohistoquímica , Antígeno Ki-67/análisis , Neoplasias de la Tiroides/metabolismo

RESUMEN

A 39-year-old woman presented with abdominal wall mass 9 years after she underwent laparoscopic cholecystectomy for symptomatic gallstones. After surgical resection, a pathologic examination identified an abscess cavity within the abdominal wall that was surrounded by a wide, diffuse, poorly defined wall of dense fibrous tissue. An examination did not show neoplastic tissue. The cavity was bile-stained and contained a 2.5-cm gallstone. This case shows a complication of laparoscopic cholecystectomy. Gallstones spilled during the extraction of the gallbladder through the abdominal wall incision may lead to a reactive process that clinically and microscopically may resemble a fibro-proliferative disorder, including a neoplastic process. This complication of laparoscopic cholecystectomy is rare. Pathologists must be aware of its occurrence because examination of the solid fibrous wall may lead to diagnoses of reactive or neoplastic fibro-proliferative processes.

Asunto(s)

Músculos Abdominales , Colecistectomía Laparoscópica/efectos adversos , Colelitiasis/etiología , Adulto , Colelitiasis/patología , Femenino , Humanos

RESUMEN

Bone ingrowth into cementless acetabular components was evaluated in a canine total hip arthroplasty model, comparing components initially stabilized with polyglycolide-lactide screws with those initially stabilized with titanium screws. The acetabular shell was anchored with 2 polyglycolide-lactide screws in 16 dogs and with 2 titanium screws in 12 dogs. The dogs were followed and sacrificed at 7 weeks, 14 weeks, 10 months, or 15 months. Histomorphometric analysis of bone ingrowth into the weight-bearing dome of the acetabular shell was conducted. No difference was detected in mean bone ingrowth into the acetabular shell comparing the 2 screw groups. The results of this study do not support a significant advantage to the use of biodegradable screws for the initial stabilization of cementless acetabular components in canine total hip arthroplasty.

Asunto(s)

Artroplastia de Reemplazo de Cadera/métodos , Tornillos Óseos , Prótesis de Cadera , Acetábulo/anatomía & histología , Acetábulo/diagnóstico por imagen , Animales , Fenómenos Biomecánicos , Perros , Oseointegración , Diseño de Prótesis , Radiografía , Titanio

Asunto(s)

Artroplastia de Reemplazo de Cadera/métodos , Trasplante Óseo/métodos , Fracturas del Fémur/complicaciones , Fracturas del Fémur/cirugía , Fracturas Espontáneas/complicaciones , Fracturas Espontáneas/cirugía , Osteítis Deformante/complicaciones , Osteítis Deformante/cirugía , Osteoartritis de la Cadera/complicaciones , Osteoartritis de la Cadera/cirugía , Anciano , Artroplastia de Reemplazo de Cadera/instrumentación , Clavos Ortopédicos , Hilos Ortopédicos , Fracturas del Fémur/diagnóstico por imagen , Fracturas Espontáneas/diagnóstico por imagen , Humanos , Masculino , Osteítis Deformante/diagnóstico por imagen , Osteoartritis de la Cadera/diagnóstico por imagen , Osteotomía/métodos , Diseño de Prótesis , Radiografía , Recurrencia

RESUMEN

This study documents a model of carrageenan-induced chronic inflammatory arthritis in the rat, using quantitative histomorphometric assessment. Ten Sprague-Dawley female rats were randomly assigned to one of two groups. Arthritis was induced in the right tibiofemoral joint by 7 intra-articular injections of 0.02 mL of 1% carrageenan in the arthritic group over 24 days. The control (normal) group was injected with 0.02 mL of saline in the right tibiofemoral joint. Sagittal sections of the right knee joint (distal femur and proximal tibia) were assessed by histomorphometry using the LECO 2001 image analysis system. Articular cartilage thickness, epiphyseal plate thickness, subchondral bone plate thickness, trabecular bone volume and thickness of the synovial lining cell layer were measured. Differences between normal and arthritic groups were statistically significant for articular cartilage thickness of the femur, epiphyseal plate thickness of both the femur and tibia, subchondral bone plate thickness of the tibia and the thickness of the synovial lining cell layer. These findings demonstrate that carrageenan-induced arthritic changes are similar to other, established models of arthritis in the rat.

Asunto(s)

Artritis/patología , Carragenina , Animales , Artritis/inducido químicamente , Cartílago Articular/patología , Cartílago Articular/ultraestructura , Diagnóstico por Imagen , Modelos Animales de Enfermedad , Femenino , Fémur/patología , Fémur/ultraestructura , Placa de Crecimiento/patología , Placa de Crecimiento/ultraestructura , Miembro Posterior/patología , Miembro Posterior/ultraestructura , Procesamiento de Imagen Asistido por Computador , Inflamación , Articulaciones/patología , Articulaciones/ultraestructura , Microscopía , Extractos Vegetales/farmacología , Ratas , Ratas Sprague-Dawley , Algas Marinas/química , Membrana Sinovial/patología , Membrana Sinovial/ultraestructura , Tibia/patología , Tibia/ultraestructura

RESUMEN

The use of a polyglycolide lactide cement plug restrictor in cemented femoral fixation during total hip arthroplasty was evaluated. Femoral cement pressurization was evaluated in vitro in a cadaveric model and the host response to polymer degradation was evaluated in vivo in a canine total hip arthroplasty model. Sixteen embalmed anatomic specimen femurs were prepared for cement femoral fixation. The intramedullary canal was plugged with either an ultrahigh molecular weight polyethylene cement plug restrictor or a polyglycolide lactide cement plug restrictor. Peak pressures in the proximal, mid, and distal portions of the cement mantle were recorded during cement insertion, cement pressurization, and implant insertion. There was no difference between the two plug groups in peak pressures throughout the cement mantle during cement insertion, pressurization, or implant insertion. Total hip arthroplasty using a cementless acetabular component and a cemented femoral stem was performed in 24 dogs. The femoral intramedullary canal was plugged with a polyethylene or a biodegradable cement plug restrictor. The dogs were sacrificed at 7 weeks, 10 months, or 15 months. Radiographically, no osteolytic lesions were seen around either plug type. Histomorphometrically, the polyglycolide lactide plugs appeared intact at 7 weeks and partially degraded by 10 and 15 months. In both plug groups, a mild fibrohistiocytic reaction with infiltration of fibrocytes, histocytes, and endothelial cells was seen. No osteolysis was observed. The results of the current study show that femoral cement pressurization can be attained in vitro using a biodegradable cement plug restrictor and that for as long as 15 months in the in vivo canine model there were no adverse reactions associated with use of these plugs compared with conventional ultrahigh molecular weight polyethylene plugs.

Asunto(s)

Artroplastia de Reemplazo de Cadera/métodos , Materiales Biocompatibles/uso terapéutico , Cementos para Huesos/uso terapéutico , Ácido Láctico/uso terapéutico , Ácido Poliglicólico/uso terapéutico , Polímeros/uso terapéutico , Animales , Materiales Biocompatibles/química , Cementos para Huesos/química , Cadáver , Fuerza Compresiva , Modelos Animales de Enfermedad , Perros , Marcha , Humanos , Ácido Láctico/química , Ensayo de Materiales , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Polímeros/química , Distribución Aleatoria , Resistencia a la Tracción , Factores de Tiempo , Soporte de Peso

RESUMEN

Capsular metaplastic changes described as "synovial metaplasia" have been reported in association with silicone gel breast prostheses. Initially this finding was thought to be more common with textured implants. Recent studies have shown no relation between implant shell type (textured vs. smooth). The incidence of this metaplasia has been shown to decrease with the age of the implant, suggesting that it is a transitional finding in capsular maturation. The metaplastic cells in the synovial metaplasia may have secretory characteristics, but the exact etiology and function of the metaplasia are not yet fully understood. Experimentally, a similar connective tissue reaction has been induced by repeated injections of air to produce the so-called "air pouch." The current study describes cartilaginous metaplasia in the capsule surrounding a silicone-filled, Cronin-type, Dacron-backed breast prosthesis. At 26 years after bilateral breast augmentation, this patient presented with breast pain and firmness. During surgical removal the implants were intact but the capsules were densely hyalinized, irregularly calcified, and on one side there was cartilaginous metaplasia within the connective tissue of the capsule. This had occurred independently of calcification. This was believed to be an unusual tissue response. Review of the English literature failed to identify a comparable case.

Asunto(s)

Implantes de Mama/efectos adversos , Mama/patología , Geles de Silicona/efectos adversos , Femenino , Humanos , Metaplasia , Persona de Mediana Edad , Tereftalatos Polietilenos

RESUMEN

Hemangiomatosis with osteolysis, osteosclerosis and loss of bony definition is an uncommon disease entity. Many forms of treatment have been used, varying almost from case to case. The use of radiation therapy has proved successful in the control of the disease process in reported cases. The current case of hind foot hemangiomatosis went on to develop sarcoma 17 years later in the uninvolved tibia at the margin of the radiation field, which proved to be fatal to the patient. Treatment by radiotherapy had permitted normal function for 15 years. This case highlights the difficulties of management of skeletal angiomatosis based on anatomic location and emphasizes the need for judicious planning and selection of the mode of delivery of radiotherapy.

Asunto(s)

Angiomatosis/radioterapia , Neoplasias Óseas/etiología , Enfermedades del Pie/radioterapia , Neoplasias Inducidas por Radiación/diagnóstico , Sarcoma/etiología , Tibia , Adulto , Neoplasias Óseas/diagnóstico , Radioisótopos de Cobalto/efectos adversos , Humanos , Masculino , Sarcoma/diagnóstico

RESUMEN

Twenty of 21 consecutive patients (21 heels) with subcalcaneal pain retractory to conservative treatment managed by resection of the proximal attachment of the plantar fascia and the heel spur, if present, were reviewed retrospectively. The results, at a mean followup of 40 months (range, 12-102 months), using a 100 point scoring system, rated excellent in 8 patients, good in 10, fair in 1, and poor in 1 (90% satisfactory outcome). Time to maximal improvement often was prolonged, yet once reached was maintained over time. The only complication encountered was 1 superficial wound infection. Radiographically it was noted that, despite complete excision, subcalcaneal exostoses often reformed and the fascial transection never did precipitate collapse of the longitudinal arch of the foot. A combination of mucoid and fibrinoid degeneration of the plantar fascia, an acceleration of an age related process, was the principal histopathologic finding. It was concluded that the subcalcaneal pain unresponsive to conservative modalities can be treated effectively by the index procedure. The radiographic and histologic findings of this study suggest that changes within the fascia, rather than the spur, are primarily responsible for the pathogenesis of the syndrome.

Asunto(s)

Exostosis/cirugía , Fasciotomía , Talón , Dolor/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Calcáneo , Exostosis/diagnóstico por imagen , Fascia/diagnóstico por imagen , Fascitis/cirugía , Femenino , Estudios de Seguimiento , Talón/diagnóstico por imagen , Talón/cirugía , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Estudios Retrospectivos , Resultado del Tratamiento

RESUMEN

Wear debris has been implicated in the pathogenesis of loosening and osteolysis of total joint replacements by stimulating a foreign body and chronic inflammatory reaction capable of bone resorption. Whether increasing concentrations of wear particles have an adverse biological effect on bone has not been elucidated. We performed a histomorphological and semi-quantitative morphometric analysis of the reaction of bone to different concentrations of phagocytosable particles of high-density polyethylene (HDPE) and titanium 6-aluminium 4-vanadium alloy (Ti-6Al-4V) implanted in the rabbit tibia. The Ti-6Al-4V particles had a diameter of 4.0 +/- 4.4 microns (mean +/- SD); the HDPE particles averaged 4.7 +/- 2.1 microns. Suspensions of 10(6)-10(9) particles per ml were mixed in saline, sterilized, and introduced through a drill hole into the proximal tibia of 30 mature female rabbits. Controls included drilled, but non-implantable limbs. The animals were killed at 16 weeks and histological sections were made of the implant area. Histomorphological assessment was carried out using an interactive image analysis system. The parameters assessed included the presence of histiocytes, foreign body giant cells and inflammatory cells, the location and number of particles, the presence of haematopoeitic elements, fat or necrosis of the marrow, whether healing of the cortical window had taken place, and whether there was evidence of formation or resorption of bone by the periosteum, cortex and marrow. A semi-quantitative rating system was employed. Phagocytosable particles of Ti-6Al-4V and HDPE, in concentrations of 10(6)-10(9) particles per ml, evoked a histiocytic reaction without extensive fibrosis, necrosis or granuloma formation. This reaction occurred without disturbing the normal repair processes of bone formation and resorption to the surgical insult. A clear dose-response effect on the histological parameters assessed in this study was not noted. Using the present model, by 16 weeks, a similar "one time' particle load could be accommodated. The ongoing generation of particulate debris over a more extended period of time might be necessary before the remodelling processes of bone would be disturbed.

Asunto(s)

Aluminio/metabolismo , Fagocitosis/efectos de los fármacos , Polietilenos/metabolismo , Titanio/metabolismo , Vanadio/metabolismo , Aleaciones , Aluminio/efectos adversos , Animales , Materiales Biocompatibles , Desarrollo Óseo/efectos de los fármacos , Médula Ósea/efectos de los fármacos , Médula Ósea/metabolismo , Resorción Ósea/inducido químicamente , Relación Dosis-Respuesta a Droga , Femenino , Peso Molecular , Periostio/efectos de los fármacos , Periostio/metabolismo , Polietilenos/efectos adversos , Prótesis e Implantes/efectos adversos , Conejos , Tibia/metabolismo , Titanio/efectos adversos , Vanadio/efectos adversos

RESUMEN

Eighty-two cases of giant cell tumor (GCT) were reviewed. Hematoxylin-eosin-and hematoxylin, phloxine, saffron, and alcian green-stained sections (82 cases) were examined for mitotic rate, the number of giant cells, and the pleomorphism of the stromal cells. In 29 cases, the tumor was stained for CD68, alpha 1-antichymotrypsin (AIACT), S100 protein, Muramidase, and von Willebrand factor (factor VIII). The staining properties of mononuclear and multinucleated giant cells were compared. Morphometric analysis was performed on 14 cases with a LECO 2001 computer-assisted image analyzer (LECO Instruments Ltd, Mississauga, Ontario, Canada) and included absolute cell count, nuclear area, perimeter, roughness, roundness, and aspect and nuclear versus cytoplasmic ratios, measured both in the stromal cells and giant cells. The cases were divided into four groups: (1) cases with metastasis, (2) cases with recurrence, (3) cases with both metastasis and recurrence, and (4) cases with neither metastasis nor recurrence. Immunohistochemistry revealed a stronger AIACT than muramidase positivity in general. The staining was stronger in stromal cells than in giant cells. Giant cells in all tumors were positive for CD68. Stromal cells showed weaker positivity for the same stain. The number of asymmetrical mitotic figures was significantly greater in group 3 than in group 4 (P < .05). Morphometric assessment has identified a statistically significant difference in the aspect ratio and the roundness of the nuclei between these two groups. The other parameters did not differ significantly. In this article, the significance of these findings in prognostication and the histogenesis of the giant cell tumor are discussed. Their clinical applicability is yet to be determined.

Asunto(s)

Neoplasias Óseas/metabolismo , Neoplasias Óseas/patología , Tumor Óseo de Células Gigantes/metabolismo , Tumor Óseo de Células Gigantes/patología , Adolescente , Adulto , Anciano , Humanos , Procesamiento de Imagen Asistido por Computador , Inmunohistoquímica , Persona de Mediana Edad , Muramidasa/metabolismo , Recurrencia Local de Neoplasia , alfa 1-Antiquimotripsina/metabolismo

RESUMEN

We have recently described a NUDE/SCID mouse model that has been useful for the study of human thyroid autoimmunity in in vivo conditions. The reappearance of lymphocytic infiltration in Graves' thyroid tissue and a humoral response in SCID mice (rexenografted with normalized thyroid tissues from NUDE mice) was detected only if autologous Graves' human peripheral lymphocytes (PBMC) were engrafted into the same animals. Therefore it was presumed that some autoreactive PBMC directed themselves to the thyroid. However, there was previously no direct evidence regarding the trafficking of the engrafted PBMC to the target tissue. To elucidate this point we have studied the migration of 51Cr-labeled PBMC in SCID mice. Human thyroid tissue from six Graves' disease (GD) patients and six patients with nontoxic nodular goiter were initially xenografted into NUDE mice for 8 weeks. The same tissues were retrieved and rexenografted into several "virgin" SCID mice, i.e., no previous xenografts. Autologous PBMC were isolated from blood of the same patients obtained at the time of the tissue rexenograftment and labeled with radioactive 51Cr. Twenty million labeled PBMC were engrafted into each SCID mouse. The distribution of labeled lymphocytes into mouse organs and trafficking into Graves' and normal xenografts was measured. A significant amount of radioactivity in Graves' xenografts was detected after 1 week with the peak of radioactivity at 2-3 weeks. This radioactivity was significantly higher than radioactivity in surrounding tissues (skin, muscle). In contrast, homing of autologous lymphocytes into normal paranodular thyroid tissue was very minimal; the radioactivity of GD thyroid xenografts with engrafted autologous lymphocytes was significantly higher than that of normal tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Radioisótopos de Cromo , Enfermedad de Graves/inmunología , Linfocitos/inmunología , Glándula Tiroides/inmunología , Glándula Tiroides/trasplante , Animales , Autoinmunidad , Enfermedad de Graves/patología , Humanos , Memoria Inmunológica , Cinética , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Ratones SCID , Glándula Tiroides/patología , Trasplante Heterólogo

RESUMEN

Cementless total hip arthroplasty was performed in 13 dogs. The acetabular component was anchored with two biodegradable devices (polylactic acid) in seven dogs and with two titanium screws in six dogs. At 14 weeks, histomorphometric determinations of bony ingrowth into the porous coating of the acetabular weight bearing dome was 54.4% when fixed with the biodegradable devices and 58.9% when fixed with the titanium screws (no statistically significant difference; p = 0.556). At the sites of fixation, less bony ingrowth occurred with the biodegradable devices. The use of biodegradable devices in total hip arthroplasty should overcome the potential metal corrosion of titanium screws that can lead to polyethylene wear.

Asunto(s)

Materiales Biocompatibles , Prótesis de Cadera , Lactatos , Ácido Láctico , Dispositivos de Fijación Ortopédica , Polímeros , Animales , Preparaciones de Acción Retardada , Perros , Masculino , Oseointegración , Poliésteres , Diseño de Prótesis

RESUMEN

One-hundred and eighty patients undergoing limb-salvage surgery for soft-tissue sarcoma from 1986 to 1991 were assessed retrospectively for risk factors associated with major wound-healing complications. Twenty-three of 137 patients (16 percent) treated with primary direct wound closure sustained complications. In univariate analysis, the cross-sectional area of tumor resection, the use of preoperative irradiation, the width of the skin excision, a history of smoking, and a history of diabetes and/or vascular disease were associated with wound failure. Multivariate analysis revealed that preoperative irradiation (p = 0.04) and resection diameter (p = 0.017) accounted for the risk of complications. Eighteen additional patients were treated empirically with distant vascularized tissue transfer following preoperative irradiation because of concerns regarding potential wound complications. The lower complication rate in this group suggested that vascularized tissue transfer may be beneficial in lowering wound complication rates.

Asunto(s)

Complicaciones Posoperatorias/cirugía , Sarcoma/cirugía , Neoplasias de los Tejidos Blandos/cirugía , Colgajos Quirúrgicos/métodos , Cicatrización de Heridas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Terapia Combinada , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Cuidados Preoperatorios , Estudios Retrospectivos , Factores de Riesgo , Sarcoma/radioterapia , Piel/irrigación sanguínea , Piel/efectos de la radiación , Neoplasias de los Tejidos Blandos/radioterapia

RESUMEN

Data gathered on 62 patients with soft tissue sarcoma of an extremity, treated in entirety by an experienced multidisciplinary sarcoma group, were analysed. With a philosophy of emphasising attainment of histologically negative margins at carefully planned limb sparing surgery, combined with either pre-operative or postoperative radiation therapy, a crude local control rate of 95% (59 of 62 patients) at a minimum of 24 months follow-up was obtained. Of 9 patients with microscopically positive margins after definitive surgery, 8 had undergone maximal resection compatible with preservation of function. One of these 9 failed locally, indicating that radiation therapy is effective in eradicating microscopic disease in this tumour. The excellent local control obtained with limb-sparing surgery in this series justifies early referral of patients with these uncommon cancers to an experienced multidisciplinary unit. 26 patients (42%) failed systemically at a minimum of 24 months follow-up, and 19 (30.6%) died of their disease, confirming the need for effective systemic therapy in soft tissue sarcoma. Tumours greater than 10 cm in diameter had a greater risk of systemic relapse.

Asunto(s)

Sarcoma/radioterapia , Sarcoma/cirugía , Neoplasias de los Tejidos Blandos/radioterapia , Neoplasias de los Tejidos Blandos/cirugía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sarcoma/mortalidad , Neoplasias de los Tejidos Blandos/mortalidad

RESUMEN

The interfacial membrane harvested from failed joint replacements contains particulate debris from the materials used for the implant. To define the tissue response to particulate titanium alloy and hydroxyapatite (HA) alone, 16 mature New Zealand white rabbits were divided into 2 groups of 8 rabbits. Using sterile technique, a drill hole was placed anteromedially in the tibia, 1 cm distal to the knee joint bilaterally. The marrow was scooped out and 0.25 mg of either titanium alloy particles or HA particles were inserted in the right tibia. The titanium alloy particles had a diameter averaging 4.0 +/- 4.4 microns (mean +/- standard deviation) and an aspect ratio (the ratio of the maximum length divided by the maximum width) of 1.84. The HA particles had a diameter of 4.4 +/- 3.3 microns and an aspect ratio of 1.76. The left leg was prepared in a similar fashion, but no biomaterial was implanted. The animals were killed after 16 wk. The harvested tibiae were processed with decalcification and the plastic-embedded sections were subjected to histomorphological analysis. Black titanium alloy particles were present within the bone marrow fat between haematopoietic cells, and within scattered macrophages. The surrounding bone appeared to be unaffected. Within the spongiosa, the HA particles were surrounded by small numbers of mononuclear histiocytes or encased within a shell of new appositional bone. Where HA deposits were exposed to the endosteal aspect of bone, there was scalloping of the surface of the HA in a pattern suggestive of resorption or dissolution of the HA particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Durapatita , Reacción a Cuerpo Extraño/etiología , Prótesis e Implantes/efectos adversos , Tibia/patología , Titanio , Aleaciones , Animales , Médula Ósea/patología , Femenino , Reacción a Cuerpo Extraño/patología , Macrófagos , Osteoclastos , Conejos