CD56+/CD16- Natural Killer cells expressing the inflammatory protease granzyme A are enriched in synovial fluid from patients with osteoarthritis.

OBJECTIVE: Natural killer (NK) cells have been involved in the pathology of different inflammatory and autoimmune disorders. Inflammation is an important regulator of osteoarthritis (OA), but the molecular and cellular mechanisms regulating this process are not well defined. DESIGN: To understand the role of NK cells in OA, we have compared the phenotype (CD56 subsets and perforin and granzyme expression) and cytotoxic function of NK cells in peripheral blood and synovial fluid from patients with OA undergoing total knee arthroplasty. RESULTS: In contrast to peripheral blood lymphocytes (PBLs), the majority of NK cells from the synovial fluid were CD56brightCD16(-) cells. As expected the expression of the cytolytic mediators perforin and granzyme B in CD56brightCD16(-) cells was low and correlated with a poor cytotoxic potential against K562 sensitive target cells. Surprisingly, this low cytotoxic NK cell subset expressed high levels of granzyme A (a protease recently characterized as a key modulator of inflammation in mouse models) in synovial fluid but not in peripheral blood. The presence of the CD56(+)brightCD16(-) cells expressing granzyme A correlated with increased levels of pro-inflammatory cytokines in synovial fluid from OA patients. CONCLUSION: Our results indicate that NK cells from the synovium of patients with OA, which present an immunoregulatory non-cytotoxic phenotype, show different phenotype comparing with NK cells from peripheral blood, especially expressing granzyme A, a pro-inflammatory molecule which may contribute to the establishment of chronic articular inflammation in this type of patients.

Influencia del concentrado de plaquetas sobre la reconstrucción de defectos de cartílago articular en la rodilla de cordero / Influence of concentrated platelets on the reconstruction of cartilage defects in the lamb knee joint

Objetivo. Analizar el efecto de las plaquetas sobre el crecimiento de cartílago en los defectos articulares provocados en la rodilla ovina. Material y método. Se provocó un defecto de 4mm de diámetro y 3mm de profundidad en la tróclea femoral de ambas rodillas en corderos macho de 6 meses de edad. La distribución de los grupos fue: grupo A (n=6): el defecto de la rodilla derecha se rellenó con concentrado de plaquetas 5min después de ser activado con ClCa. Grupo B (n=6): el defecto se rellenó con colágeno y plaquetas. Material y método. Las plaquetas se obtuvieron por centrifugación de 10ml de sangre arterial obtenida de cada animal antes de la cirugía. En los defectos de la rodilla izquierda no se administraron plaquetas. Las ovejas fueron sacrificadas 10 semanas después de la cirugía. Se realizaron estudios macro y microscópicos. Resultados. En el grupo A, se observó cartílago hialino en 4 de los defectos de la rodilla derecha a las 10 semanas de la cirugía. Ninguno de los defectos de la rodilla izquierda mostró crecimiento de cartílago hialino. En el grupo B, no se observó cartílago hialino en nigún defecto. No obstante, todos los defectos presentaron mejor celularidad condral y menor fibrosis en los defectos tratados con plaquetas que en los no tratados. Conclusiones. Esta técnica para la reconstrucción con plaquetas de defectos articulares de oveja ha mostrado en nuestro estudio resultados esperanzadores que empeoran combinadas con un andamiaje de colágeno (AU)

Objective. To study the influence of platelets on cartilage growth in articular defects in the sheep knee. Material and methods. Male Rasa Aragonesa sheep (6 months) were operated under general anaesthesia. A 4mm diameter and 3mm deep defect was made in the femoral trochlea in both knees. The right knee defect was filled with platelet concentrate 5min after being activated with ClCa in group A (n=6), and similarly activated platelets + collagen scaffold in group B (n=6). Platelets were obtained by centrifuging 10ml arterial blood from the sheep prior to the surgical procedure. The left knee defect was not filled. The sheep were sacrificed 10 weeks after surgery. Macroscopic and microscopic studies were performed. Results. In group A, hyaline cartilage was observed in the right knee defect at the end of the experiment in four cases. None of the defects of the left knees showed hyaline cartilage growth. In group B, hyaline cartilage was not observed in any right knee defect. However, in group B, all sheep showed better chondral cellularity and regeneration and lower fibrosis in the defects treated with platelets than in non-treated ones. Conclusions. This technique for articular defect reconstruction with platelets has shown satisfactory results in our study. However, collagen scaffolds may decrease this positive effect (AU)

Risk factors for postoperative infections in patients with hip fracture treated by means of Thompson arthroplasty.

Specific conditions associated with surgery may predispose elderly people to septic complications after hip fracture surgery. This study investigated the risk factors predisposing infection in aged patients with subcapital hip fracture. We performed a prospective study of 290 patients with displaced subcapital hip fracture, operated by means of Thompson hip hemi-arthroplasty (83.5% fractures in women). The mean age was 85.42+/-6.06 years (ranging from 69 to 104). Follow-up was realized until death or at least for 2 years. The chi(2) test, analysis of variance, Kruskal-Wallis test, correlation analysis and the Spearman test were applied. Odds ratios (OR) were calculated. During the hospital stay, there were diagnosed 94 urinary tract infections, 25 pneumonias, 50 superficial wound infections, 11 deep wound infections. Transfusions were made in 120 patients (in average: 2.54+/-1.45 units of red cell concentrate/transfused patient). Transfusion appeared to be correlated with superficial wound infection (OR=1.96), urinary infection (OR=1.76) and pneumonia (OR=2.85). Higher number of days waiting for surgery were related significantly with pneumonia (9.8+/-7.44 days vs. 6.39+/-3.75), or urinary tract infection (7.76+/-4.39 days vs. 6.17+/-4.14). We concluded that the transfusion and longer waiting time for surgery have been associated with the septic complications in elderly patients treated surgically for hip fracture.

Pharmacological immunomodulation of surgical trauma.

Surgery and accidental trauma induce changes in the immune response, showing a predominant pattern of activation through the Th2 cell pathway to the detriment of Th1 cell pathway activation. Anapsos is a hydrosoluble extract obtained from Polypodium leucotomos. Anapsos has shown immunomodulating effects in vitro. On a rat experimental model (tibia and fibula fracture), cytokines (interleukin [IL]-2, IL-4, IL-6, IL-10, and IL-12) (enzyme-linked immunosorbent assay, ELISA) and cell percentages of CD4, CD8 CD25, CD122, and CD132 (monoclonal antibodies, MoAb) were determined in peripheral blood 7 days before surgery (PRE), 1 day after surgery (1PO), and 7 days after surgery (7PO). On postoperative day 1, rats undergoing fracture show an increase of CD8 percent expression and IL-6 and IL-10 levels, in contrast to rats undergoing fracture plus anapsos treatment. On postoperative day 7, rats undergoing fracture show an increase of IL-6 levels, whereas rats undergoing fracture plus anapsos do not. The IL-12 level decreases on postoperative day 7 in the group with fracture but not in the fracture plus anapsos group. Thus, we conclude that anapsos is able to modulate the immune response after trauma, inhibiting Th2 pathway activation with no effect on Th1 pathway activation. In trauma, Anapsos could prevent the shifting Th1/Th2 balance.

Estado inmunológico de ancianos candidatos a artroplastia tras fractura subcapital de cadera: estudio de su relación con la edad y con la morbimortalidad postoperatoria* / Immunological status of elderly patients eligible for arthroplasty after a femoral neck fracture: relationship between the patients' status, their age and postoperative morbimortality

Objetivo. Analizar la relación de la situación inmunológica preoperatoria tras fractura subcapital de cadera con las complicaciones postoperatorias. Material y método. Estudio prospectivo aleatorio de 94 pacientes (81 mujeres) con fractura subcapital de cadera Garden IV (edad media: 82,9 años (± 7,48), máximo: 100, mínimo: 64 años). Al ingreso se determinó en sangre venosa periférica: fórmula leucocitaria, inmunoglobulinas (IgG, IgA, IgM e IgE), CD19, CD3, CD4, CD8, niveles de transferrina, alfa-2-macroglobulina, ceruloplasmina, proteína transportadora de retinol, prealbúmina, albúmina, proteínas totales, colesterol total y triglicéridos. Se estudiaron las complicaciones postoperatorias. En la estadística se realizó análisis de la varianza y Chi cuadrado. Resultados. Se detectaron 12 casos de infección de la herida quirúrgica, 27 casos de infección de orina, 3 casos de neumonía y una infección periprotésica. Los pacientes con infección postoperatoria presentaron en el preoperatorio menores niveles de IgM (infección de orina y neumonía), de IgA (neumonía) y de IgE (infección de la herida), menor número de CD4 y CD8/mm3 (infección de orina y neumonía) y un menor porcentaje de CD19 (infección de herida). La albúmina, la prealbúmina, el colesterol total, los triglicéridos y la transferrina disminuyeron significativamente con la edad. Conclusiones. La IgM, la IgA, la IgE, el porcentaje de CD19 y el número de CD4 y CD8 podrían servir como indicadores de un mayor riesgo de desarrollar infecciones durante el postoperatorio de una fractura subcapital de cadera

Purpose. To analyze the relationship between a patient's immunological status prior to arthroplasty secondary to a femoral neck fracture and postoperative complications. Materials and methods. Prospective randomized study of 94 patients (81 of which female) with a Garden IV femoral neck fracture (mean age: 82.9 years (± 7.48), range: 100-64). On admission, the following parameters were evaluated in the patients' peripheral venous blood: differential leukocyte count; inmunoglobulin (IgG, IgA, IgM and IgE); percentage of CD19, CD3, CD4 and CD8; transferrin levels; alfa-2-macroglobulin; ceruloplasmin; retinol transport protein; prealbumin; albumin; total proteins; total cholesterol and triglycerides. Postoperative complications were studied. Statistics: Variance and chi square analysis. Results. There were twelve cases of surgical wound infection, 27 of urinary infection, 3 cases of pneumonia and one periprosthetic infection. Patients with a postoperative infection had lower preop levels of IgM (urinary infection and pneumonia), IgA (pneumonia) and IgE (wound infection), as well as a lower count of CD4 and CD8 per cubic mm (urinary infection and pneumonia) and a lower percentage of CD19 (wound infection). Albumin, prealbumin, total cholesterol, triglycerides and transferrin decreased significantly with age. Conclusions. The IgM, IgA, IgE, the CD19 percentage and CD4 and CD8 counts could be used indicators of a higher risk of developing infections after surgery for a femoral neck fracture (AU)

Sutura meniscal artroscópica asociada a la cirugía de reconstrucción del ligamento cruzado anterior / Arthroscopic meniscal suture associated with reconstruction surgery of the anterior cruciate ligament

Revisamos 7 casos de rotura meniscal asociada a inestabilidad crónica anterior de rodilla por rotura del ligamento cruzado anterior con cuatro años después de la cirugía. Todos los casos fueron tratados, durante el mismo procedimiento quirúrgico, procediendo en primer lugar a efectuar la reparación meniscal y seguidamente a la ligamentoplastia mediante autoinjerto antólogo HTH. Debido a los buenos resultados obtenidos, consideramos que la sutura meniscal, siempre que ésta sea posible, debería ser un gesto quirúrgico añadido, en el transcurso de la cirugía de reconstrucción del ligamento cruzado anterior

We review 7 cases of meniscal ruptured associated with chronic anterior instability of the knee due to rupture of the ACL with two years evolution after surgery. In all the cases, and by means of arthroscopic techniques, we have proceeded to carry out, at the same time, the repair both of the damaged meniscus with meniscal suture and the reconstruction of the ACL by means of autologous ligamentoplasty with Bone-Tendon-bone. Due to the good results obtained, we consider that meniscal suture, whenever possible, should be an added surgical gesture, in the reconstruction surgery process of anterior cruciate ligament

Fractography evolution in accelerated aging of UHMWPE after gamma irradiation in air.

We studied the fracture surface evolution of ultra high molecular weight polyethylene (UHMWPE) specimens, manufactured from GUR 1050 compression moulded sheets, after gamma sterilisation in air followed by different aging times after thermal treatment at 120 degrees C. Degradation profiles were obtained by FTIR and DSC measurements after 0, 7, 14, 24 and 36h aging. We observed by SEM the morphology patterns at these aging times, in surface fractographies after uniaxial tensile test of standardised samples. The results pointed out clear differences between short and long aging times. At shorter times, 7h, the behaviour was similar to non-degraded UHMWPE, exhibiting ductile behaviour. At longer times, 24-36h, this thermal protocol provided a highly degraded zone in the subsurface, similar to the white band found after gamma irradiation in air followed by natural aging, although closer to the surface, at 150-200mum. The microstructure of this oxidation zone, similarly found in gamma irradiated samples shelf-aged for 6-7 years, although with different distribution of microvoids, was formed by fibrils, associated with embrittlement of the oxidised UHMWPE. In addition, the evolution of the oxidation index, the enthalpy content, the mechanical parameters, and the depth of the oxidation front deduced from the fractographies versus aging time showed that a changing behaviour in the degradation rate appeared at intermediate aging times.

Results of the surgical treatment of Lisfranc fracture-dislocations.

The authors present a series of 25 patients with Lisfranc fracture-dislocation who were treated by reduction (open or closed) and stabilization with Kirschner wiring. Minimum follow-up was two years. The dislocations were divided based on the Quenu and Kuss classification system. Nonsurgical reduction was possible in 17 patients. Neither the type of dislocation nor the type of reduction influenced the results in progression in our series. Nonetheless, long-term functional results were better when the quality of the reduction was excellent.

Modelos de osteomielitis experimental basados en la utilización de implantes precolonizados y/o suspensiones bacterianas / Models of experimental osteomyelitis using pre-colonized implants

Objetivo: El objetivo de este trabajo es valorar distintos modelos de osteomielitis crónica utilizando una cepa de Staphylococcus aureus productora de slime (SP) para establecer cuál de ellos resulta más efectivo en el establecimiento de la infección, así como determinar el papel que desempeña el biofilm y la suspensión bacteriana en el éxito de la infección. Diseño experimental: Un total de 32 animales fue utilizado para un estudio comparativo de modelos de osteomielitis crónica en rata basada en una cepa SP de S. aureus, tanto para formar biofilms de 12 h sobre los implantes de acero inoxidable, que se colocaban precolonizados en los animales el día de la intervención, como para preparar las suspensiones bacterianas que se inoculaban. Resultados: Ninguno de los modelos presentó septicemia transcurridos 63 días a partir de la intervención quirúrgica. Sólo con el modelo que utiliza exclusivamente un implante colonizado se alcanzó un 100 por ciento de infección en hueso e implante; en el modelo que incorporaba además la inoculación de suspensión bacteriana, también se consiguió un 100 por ciento de éxito en la infección de los implantes, pero solamente se infectaron 5 de las 8 tibias intervenidas en este grupo. Cuando se inoculó una suspensión de 106 ufc sólo se consiguieron infectar (implante y tibia) 6 de los 8 animales, y cuando se redujo a 105 ufc, tan sólo 2 implantes y 1 tibia. Conclusiones: El modelo que implica la utilización exclusiva de un implante precolonizado con S. aureus SP ha demostrado la mayor eficacia para reproducir la infección (AU)

A simple infection model using pre-colonized implants to reproduce rat chronic Staphylococcus aureus osteomyelitis and study antibiotic treatment.

Staphylococcus aureus biofilms formed on medical implants represent a serious problem, being difficult to eradicate with antibiotic therapy and leading to chronic infections. Simplified in vivo and in vitro antibiotic susceptibility assays using biofilm bacteria are needed. In this work, a novel chronic osteomyelitis infection model was developed in rats in the absence of bacterial suspension, requiring the use of only 10(6) bacteria in biofilms at the site of surgery, with a full success in reproducing infection. Stainless-steel implants pre-colonized for 12 h with a highly adherent S. aureaus isolate were introduced into the rat tibiae. In animals not submitted to antibiotic treatment, infection was found in the implants and spread to bone in all cases, indicating the high efficacy of the model to reproduce osteomyelitis. The effect of a 21-day treatment with cefuroxime, vancomycin, tobramycin or ciprofloxacin on infection was studied in this model 42 days after surgery. Bone colonization was inhibited by vancomycin and cefuroxime. Cefuroxime (the most efficient antibiotic, able to sterilize 1 out of 8 implants) reduced the number of bacteria in biofilms adhered to implants at a higher extent than vancomycin, trobramycin and ciprofloxacin. Analogous observations were made in this work in vivo and in vitro on the relative antibiotic efficacy against S. aureus biofilm bacteria. suggesting the usefulness of both tests as a potential tool to study antibiotic suceptibility, and the need for new antimicrobials against these bacteria.

Results in displaced radial neck fractures in children. Metaizeau technique versus arthrotomy.

The aim of the present article is to ascertain the differences between two surgical treatments commonly used in displaced radial neck fractures in children. We report the retrospective results of 20 displaced radial neck fractures with > 30 degrees of tilt (Judet grades 3-4) in children aged between 7 and 14 years treated with closed intramedullary pinning according to the Metaizeau technique (6 cases) or with arthrotomy and pinning (14 cases). Sex distribution was 14 girls and 6 boy. The average follow-up was 43 months. We found no relationship between delay in the surgical treatment and functional results. On the other hand, a relationship between residual final tilt and poorer functional results appears. The Metaizeau technique produced better results and fewer complications than arthrotomy and pinning, and, in our opinion, is the treatment of choice in this type of fracture.

Nonunion of the patella as a late chance observation after reconstructive surgery of the anterior cruciate ligament.

The use of autologous bone-tendon-bone grafts for reconstructive surgery of the anterior cruciate tendon is a widely diffused technique. Fracture of the donor patella constitutes an uncommon complication. It is the purpose of this study to present the clinical case of a patient submitted to reconstructive surgery of the anterior cruciate ligament where the existence of asymptomatic nonunion of the patella was by chance observed.

Hidatidosis muscular primaria recidivante de vasto interno / Recurrent primary muscle echinococcosis of the vastus medialis

La hidatidosis por Equinococcus granulossus es una parasitosis que afecta principalmente a hígado y pulmón y que en una mínima proporción implica de forma primaria al músculo. Presentamos el caso de una paciente de 60 años intervenida en tres ocasiones de una masa en la cara interna del muslo derecho y que tras llegar al diagnóstico de hidatidosis fue tratada con antihelmínticos durante un largo período, reapareciendo la tumoración al suspenderlos. En este momento acudió a nuestro servicio donde se diagnosticó hidatosis muscular recidivada con fístula a piel. Se practicó intervención radical resecando en bloque la periquística y el trayecto fistuloso. En el seguimiento postoperatorio se apreciaron imágenes quísticas compatibles con reaparición de la enfermedad siendo necesarias nuevas intervenciones que hasta el momento no han logrado una resolución definitiva de la enfermedad. El tratamiento de elección de la hidatidosis en cualquier localización es la resección quirúrgica radical (quistoperiquistectomía), lo que requiere un diagnóstico previo adecuado. Ante una masa quística muscular no se debe olvidar esta localización de la hidatosis, ya que el primer tratamiento que se realice determinará la evolución de una patología benigna que, como en nuestro caso, puede evolucionar con recurrencias múltiples, muy invalidantes y de difícil resolución (AU)

Desgaste del polietileno en prótesis de cadera y rodilla / Polyethylene wear in hip and knee prostheses

El fracaso de las artroplastias totales de cadera y rodilla debido al desgaste del polietileno de interposición, asociado o no a osteolisis periprotésica, es uno de los problemas que ha suscitado mayor interés en la comunidad ortopédica mundial en este fin de siglo. El gran beneficio que obtienen los pacientes y la sociedad de estas artroplastias se ve limitado, a medio y largo plazo, por un desgaste que fuerza al recambio protésico tras el fracaso del implante. Se ha desarrollado una intensa investigación en materiales durante esta última década, sobre todo en polietileno, por lo que es importante para todo cirujano ortopédico conocer la situación y tendencias actuales en este campo, así como las propuestas para el futuro. Se revisan los conceptos generales de desgaste del polietileno, la influencia de la fabricación y esterilización del material en su desgaste, las repercusiones del desgaste en el fracaso de las artroplastias, el desgaste en estudios de series clínicas y, por último, los esfuerzos actuales por disminuirlo (AU)

Ganglion cysts associated with cruciate ligaments of the knee: a possible cause of recurrent knee pain.

Intraarticular ganglia of the knee are uncommon; however, these ganglion cysts may produce knee discomfort without a clear etiology. We present the cases of 10 patients with ganglion cysts arising from cruciate ligaments of the knee joint who underwent arthroscopic excision after MR examination. The MR findings, clinical features and arthroscopic findings were evaluated comparatively. Diagnoses were confirmed by means of a histological study after arthroscopic excision. The cysts were fluid-filled, with low T1-weighted signal intensity and high T2-weighted signal intensity. Except for two patients with recent accidents, the remaining eight presented chronic pain without any history of trauma. Pain was the most frequent clinical sign. It was associated with knee extension in 3 cases and with flexion in 3 cases. In 7 cases, cysts were exclusively associated with the anterior cruciate ligament (ACL). Only in one case was a cyst associated with an ACL rupture. Four patients presented meniscal lesions. All ganglia appeared solitary in each knee. Postarthroscopy evolution was painless in 8 patients. Histologic diagnoses corresponded to ganglion cysts. The tissues from the patient with the ACL rupture presented a fibrous reaction with myxoid degeneration forming intraligamentary ganglion cysts.

S-adenosylmethionine immunomodulator treatment in sepsis.

BACKGROUND: S-adenosylmethionine (SAMe) is a forerunner of glutathione. AIMS: The aim of the present study is to ascertain this drug effect on T-lymphocytes and cytokines in an experimental model of surgical sepsis. METHODS: Rats were allotted in two groups. In the control group, rats underwent anaesthesia and laparatomy with cecal ligation and puncture (CLP). In the second group, rats underwent the same CLP and received SAMe (14 mg/kg) i.m., on the 1st (1PO) and 2nd (2PO) postoperative days. A week before surgery (PRE), on the 1PO and on the 3PO: IL-1, IL-2, IL-4, IL-6, IL-10 and TNF levels (ELISA & MoAb), and CD3, CD4, CD8 cell and IL-2R percentages (%) (flow cytometry & MoAb) were determined in peripheral blood. RESULTS: Rats receiving SAMe do not show changes of CD3%, CD4% and IL-1 levels but show a significant increase of CD8% on the 3PO, showing a significant difference with regard to controls (p < 0.01). Both groups show a similar IL-2R variation pattern: increasing on 1PO (p < 0.05) and decreasing on 3PO (p < 0.05). CONCLUSION: In sepsis: SAMe inhibits the decrease of circulating immune-active cells and the IL-1 increase. This drug seems to have effects useful in avoiding immunological alterations in sepsis, that need to be tested in humans.

Autologous blood transfusion as an immunomodulator in experimental sepsis.

BACKGROUND: Homologous blood transfusion is associated with immunosuppressive consequences. Some clinical and experimental studies have suggested an immunostimulating action of autologous blood transfusion. The aim of this paper is to ascertain the effects of either homologous blood transfusion or autologous blood transfusion on the lymphocyte subsets and cytokines in a model of intra-abdominal sepsis. MATERIALS AND METHODS: There were three study groups. Group A: 10 Wistar-Furth (WF) rats underwent cecal ligation and puncture (CLP) aimed at causing an intra-abdomial sepsis; Group B: 10 WF rats underwent CLP plus 1 ml homologous blood perioperative transfusion obtained from Fisher-344 rat while Group C: 10 WF rats underwent CLP plus 1 ml autologous blood perioperative transfusion. Changes of peripheral lymphocyte subsets, percentages of total T-lymphocytes (CD3), Helper T-lymphocytes (CD4), supressor/cytotoxic T-lymphocytes (CD8), CD4/CD8 ratio, Interleukin-2 receptor expression (IL-2R) and cytokines IL-1 and TNF-alpha were measured in peripheral blood on the preoperative, 1st, 3rd and 7th postsepsis (PO) days. RESULTS: Rats in homologous transfused group showed a decrease of %CD4 on the 3rd PO (from preoperative to 3rd PO;p < 0.01; and from 1st to 3rd PO; p < 0.05) and on the 7th PO (from preoperative to 7th PO; p < 0.05); %CD8 increased from preoperative to 3rd PO (p < 0.05), from 1st to 3rd PO (p < 0.01) and from 1st to 7th PO (p < 0.05). An initial decrease on day 1 (p < 0.01) followed by an increase on the 3rd PO (p < 0.01) with regard to IL-2R and a significant increase of IL-1 levels within the first 24h (p < 0.01). Rats in autologous transfused group showed an increase of %CD3 from preoperative to 7th PO (p < 0.05), and from 3rd to 7th PO (p < 0.01). CONCLUSIONS: We observed that homologous blood transfusions induce a greater alteration in the cellular immune response and of the cascade of cytokines than autologous transfusions. This modulates the variations of the immune response induced by sepsis.

Bizarre parosteal osteochondromatous proliferation. Difficulty in diagnosis.

Nora's tumor, also known as bizarre paraosteal osteochondromatous proliferation, is an exophytic outgrowth from the cortical surface that consists of a mixture of bone, cartilage, and fibrous tissue. It is a benign lesion with atypical microscopic features and a tendency to recur. Nora reported 35 cases emerging from the bones of the hands and feet. The largest published series is of 65 cases, with 17 lesions involving the long bones. With this exception, most authors report isolated cases. Age range from 8 to 74 years but most patients are between 20 and 35 years of age, and with the lesion affecting males and females in equal proportions. Usually the presenting symptoMs are due to bony mass, with a variable growth rate (months-years), and infrequent pain. In 15-20% of the cases there was trauma in the patient history: nevertheless, Fechner and Mills report no association with trauma. Radiography shows a calcified, rounded mass emerging directly from the surface of the bone. Isotope bone scans show intense tracer uptake in the lesion. With time, the appearance progresses to the more characteristic mature bone architecture.