La hidroxiapatita asociada al sulfato cálcico como material de substitución ósea. Aspectos biológicos.

La cirugía ortopédica y máxilo-facial necesitan realizar en muchas ocasiones resecciones masivas de tejido óseo. Esto ha hecho que se haya propuesto la utilización de materiales inertes como substitutos óseos, gracias a la habilidad que tienen de permitir la regeneración del hueso, tanto en el campo de la medicina como en el de la odontología. Nuestro trabajo tiene por objetivo estudiar un biomaterial compuesto de hidroxiapatita y sulfato cálcico como material de substitución ósea en forma de cilindros. Se han intervenido 75 animales de experimentación (conejo Albino de Nueva Zelanda), divididos en tres grupos, cada uno de ellos compuesto por 25 animales. En el grupo I o control, los animales fueron intervenidos quirúrgicamente realizándoseles una cavidad a nivel metafisodiafisario en el fémur sin realizar implantes. A los animales del grupo II y III se les realizó la misma intervención, pero se les implantó un cilindro de hidroxiapatita (HA) y sulfato cálcico a dos concentraciones diferentes, 50% - 50% y 70% - 30% respectivamente. El estudio ha demostrado una regeneración ósea de la cavidad rellenada a expensas de la rápida reabsorción del yeso, y de una lenta reabsorción de la hidroxiapatita.Peer Reviewe

Can physical activity attenuate the negative association between sitting time and cognitive function among older adults? A mediation analysis

The purpose of this study was to examine the combined association of sitting time and physical activity with cognitive function and to determine whether moderate-to-vigorous physical activity (MVPA) is a mediator of the association between sitting time and cognitive function in a nationally representative sample of older adults from Chile. Data from 989 older adults (≥65 years old, 61.3% female) from the 2009-2010 Chilean Health Survey were analyzed. Physical activity and sitting time were measured using the Global Physical Activity questionnaire. Cognitive function was assessed using the modified Mini-Mental State levels Examination. Physical activity levels were categorized as "inactive" (<600 metabolic equivalent value minutes per week) or "active" (≥600 metabolic equivalent value minutes per week). Sitting time was categorized as "sedentary", defined as ≥4 h of reported sitting time per day, or "non-sedentary", defined as <4 h. We created the following groups (i) non-sedentary/active; (ii) non-sedentary/inactive; (iii) sedentary/active; and (iv) sedentary/inactive. Hayes's PROCESS macro was used for the simple mediation analysis. Compared with the reference group (individuals classified as non-sedentary/active), older adults who were classified as sedentary/active had elevated odds of cognitive impairment (OR = 1.90, [95% CI, 1.84 to 3.85]). However, the odds ratio for cognitive impairment was substantially increased in those classified as sedentary/inactive (OR = 4.85 [95% CI, 2.54 to 6.24]) compared with the reference group. MVPA was found to mediate the relationship between sitting time and cognitive function (Indirect Effect = -0.070 [95% CI, -0.012 to -0.004]). The present findings suggest that, whether overall physical activity is high or low, spending large amounts of time sitting is associated with elevated odds of cognitive impairment and that MVPA slightly weakens the relationship between sitting time and cognitive function

Combined femoral and tibial component total knee arthroplasty device rotation measurement is reliable and predicts clinical outcome

Background The optimal total knee arthroplasty (TKA) rotational alignment and how best to obtain and measure it are debatable. The aim was to analyse the reliability of the Berger femoral, three different tibial and four different com- bined two-dimensional computer tomography (2D-CT) TKA component rotation measurements, and to ascertain which rotational values best predict a successful clinical outcome. Methods The 2D-CT scans were obtained post-operatively on 60 patients who had TKA. We determined one femoral [Berger’s femoral angle (BFA)], three tibial [Berger’s tibial angle (BTA), anatomical tibial angle (ATA) and bimalleolar posterior tibial component angle (BM_PTCA)] and four combined [transepicondylar posterior tibial component angle (TE_PTCA), bicondylar posterior tibial component angle (BC_PTCA, transepicondylar bimalleolar angle (TE_BM) and bicondylar bimalleolar angle (BC_BM)] TKA rotation angles. We made all measures in 23 patients twice by three observers and determined inter- and intra-observer agreement using the Bland–Altman plot method. We analysed measures of 55 patients using the area under the ROC curve (AUC) analysis to ascertain the discriminative capacity of BFA, ATA, TE_PTCA and BC_PTCA for predicting a successful clinical outcome according to the Knee Society Score (KSS) threshold. Results ATA showed the smaller inter- and intra-observer average of differences (-0.1° and 1.6°, respectively) of the studied methods followed by BFA (-0.9° and 1.4°), TE_PTCA (-2.1° and 2.7°) and BC_PTCA (-0.5° and 1.8°). BFA (-4° to 2.1° and -6.1° to 8.8°) and BC_PTCA (-4.4° to 3.4° and -7.9° to 4.4°) showed the narrower inter- and intra- observer limits of agreement. A TKA device rotation (BC_PTCA) < 0.8° of external rotation (ER) predicted a KSS and KSS knee successful outcome, and < 3.8° ER for KSS functional (AUC = 0.889; 0.907 and 0.764, respectively). BFA and ATA < 0.9° ER and < 3.9° internal rotation (IR) predicted a successful KSS knee outcome (AUC = 0.796 and 0.889, respectively). Conclusion The ATA tibial component rotation measurement was the most reliable of those studied. BFA, TE_PTCA and BC_PTCA were reliable measures for TKA femoral and combined rotation. The presence of a minimal rotation between the TKA components (BC_PTCA) and a small femoral ER or tibial IR predicted a successful KSS outcome.Peer ReviewedPostprint (published version

Location, Clinical Presentation, Diagnostic Algorithm and Open vs. Arthroscopic Surgery of Knee Synovial Haemangioma: A Report of Four Cases and a Literature Review

Objective: The aim was to report 4 patients with intra-articular knee synovial haemangioma (KSH) and to perform a systematic review to describe the patient characteristics, patterns of tumor location, clinical presentation, usefulness of imaging examinations, pros and cons of arthroscopic vs. open resection, and follow-up in the literature. Design: From 1996 to 2016, four patients with KSH were retrospectively reviewed. A literature search was conducted in PubMed from 2000/01 to 2020/06 using the search terms "synovial haemangioma" and "knee." Fifty full-text articles that included a total of 92 patients were included for further discussion. Results: Four adults (20-40 years) were diagnosed with KSH. Three lesions located in the suprapatellar pouch, two eroding the patella and one the supratrochlear bone, and one in the posterior compartment. Persistent anterior knee pain was the main complain. MRI revealed a benign tumor mass in all cases except one. Open excisional biopsy and regional synovectomy were performed in three patients, and by arthroscopy of the posterior compartment in the fourth. Histological type was arteriovenous in three cases and capillary in one. A pain-free knee without recurrence was achieve in all cases except one, which was successfully reoperated. Average follow-up time was 3.5 years. A literature review showed that KSH appears most frequently in children and teenagers (64.6%) and does not differ by gender. The suprapatellar and patella-femoral joint compartment was the most frequent location (47.9%). The bony tissue of the knee was rarely affected (13.5%). Pain, swelling and haemarthrosis were frequently reported (88.2, 66.7, and 47.1%). MRI was the most commonly used imaging test (98%). Treatment consisted of regional synovectomy by open surgery or arthroscopy in 66.7 and 15.6% of cases, respectively. Conclusions: KSH should be considered in the differential diagnosis of adult patients with chronic low-intensity knee pain. MRI is the most useful exam because it establishes the location, extent and benign characteristics of the tumor. Definitive diagnosis requires histological examination. We believe excisional biopsy and regional synovectomy by arthroscopy should be the treatments of choice for intra-articular tumors, but we recommend open surgery when the lesion extends to the tendons, muscle or bone

Giant aneurysmal bone cyst of the mandible with unusual presentation

Aneurysmal bone cysts are rare benign lesions of bone tissue, infrequent in craneofacial skeleton with regard to other structures like long bones or the spine. They are composed of sinusoidal and vascular spaces blood-filled and surrounded by fibrous tissue septa. We present a case of a 29-year-old Caucasian male with a big swelling in the left mandible associated to pain and rapid growth. He referred previous extraction of the left inferior third molar. On the X-ray study, an expansive multilocular and high vascularized bony lesion within the mandibular angle was observed. It produced expansion and destruction of lingual and buccal cortex. An incisional biopsy was performed showing a fibrous tissue with blood-filled spaces lesion suggestive of an aneurysmal bone cyst. After selective embolization of the tumour, surgical resection was done with curettage and immediate reconstruction of the defect with an anterior iliac crest graft. Aneurysmal bone cysts are non-neoplastic but locally aggressive tumours with occasional rapid growth that may be differenciated from other multilocular process like ameloblastoma, ossifying fibroma, epithelial cyst, giant cell granuloma and sarcomas. Treatment of choice consists on conservative surgical excision of the mass with curettage or enucleation. When resection creates a big defect, primary surgical reconstruction is recommended

Insights into pneumococcal fratricide from the crystal structures of the modular killing factor LytC

7 pags, 3 figs, 1 tabThe first structure of a pneumococcal autolysin, that of the LytC lysozyme, has been solved in ternary complex with choline and a pneumococcal peptidoglycan (PG) fragment. The active site of the hydrolase module is not fully exposed but is oriented toward the choline-binding module, which accounts for its unique in vivo features in PG hydrolysis, its activation and its regulatory mechanisms. Because of the unusual hook-shaped conformation of the multimodular protein, it is only able to hydrolyze non-cross-linked PG chains, an assertion validated by additional experiments. These results explain the activation of LytC by choline-binding protein D (CbpD) in fratricide, a competence-programmed mechanism of predation of noncompetent sister cells. The results provide the first structural insights to our knowledge into the critical and central function that LytC plays in pneumococcal virulence and explain a long-standing puzzle of how murein hydrolases can be controlled to avoid self-lysis during bacterial growth and division. © 2010 Nature America, Inc. All rights reserved.This work was supported by grants from the Spanish Ministry of Science and Technology (BFU2008-01711, SAF2006-00390), EU-CP223111 (CAREPNEUMO, European Union), the COMBACT program (S-BIO-0260/2006) and CIBER de Enfermedades Respiratorias (CIBERES). CIBERES is an initiative of Instituto de Salud Carlos III. The work in the US was supported by the US National Institutes of Health. W.V. was supported by the European Commission (EUR-INTAFAR project). I.P.-D. was a fellow of the Consejo Superior de Investigaciones Científicas

Osteocondrítis disecante de la rodilla: Cambios artrósicos a largo plazo y factores pronósticos

El objetivo del estudio es analizar el efecto del pinzamiento articular en los resultados clínicos obtenidos a largo plazo tras diferentes métodos de tratamiento quirúrgico de la osteocondritis disecante de rodilla; asimismo se valora qué influencia tiene en su aparición factores como la edad del paciente, localización, estabilidad, extensión, tratamiento y tiempo de evolución de la lesión. Se realizó una revisión retrospectiva de 30 pacientes (22 hombres y ocho mujeres), cinco pacientes con afectación bilateral. La edad media fue de 26 años. E l tratamiento quirúrgico fue: reinserción del fragmento osteocondral en su lecho en 11 rodillas (siete con agujas de Smillie y cuatro con tornillos), exéresis del fragmento osteocondral en 24 (aislada en nueve, asociada a perforaciones del lecho en nueve e injerto osteocartilaginoso autólogo obtenido de la cara externa de la tróclea femoral en seis). Se realizó una valoración clínica y radiográfica postoperatoria. E l tiempo de evolución medio fue de 14 años. Los resultados clínicos obtenidos con las diferentes técnicas de tratamiento fueron similares, a excepción de los obtenidos con el injerto osteocartilaginoso autólogo, que fueron peores. Referían ausencia o dolor leve un 66 a 77% de los pacientes y sólo un 50% de los tratados con injerto osteocartilaginoso autólogo. El dolor y el balance articular se relacionaron con el pinzamiento articular; así, cuanto menor es la distancia entre las superficies articulares mayor es el dolor y peor el balance articular (p < 0,05). Aquellos pacientes que tenían mayor edad en el momento del tratamiento presentaron un mayor pinzamiento articular (p < 0,05). Aquellos pacientes que tenían mayor edad en el momento del tratamiento presentaron un mayor pinzamiento articular (p < 0,05), localización de la lesión en zonas de carga (inferocentral medial y lateral), tiempo de evolución superior a 16 años y los tratados mediante injerto osteocartilaginoso autólogo. No existieron diferencias estadísticamente significativas en el pinzamiento articular según la extensión y estabilidad del fragmento osteocondral

Different femoral rotation with navigated flexion-gap balanced or measured resection in total knee arthroplasty does not lead to different clinical outcomes

PURPOSE: Femoral rotation in total knee arthroplasty (TKA) is hypothesized to vary in the same knee depending on the method used to establish it. METHODS: Thirty-eight patients who underwent TKA surgery using a measured resection technique (RT) were compared with 40 patients who underwent a flexion-gap balancing technique with computer-assisted (for navigation) surgery (FB-CAS) to assess clinical and radiographic alignment differences at two years postoperatively. In 36 of the 40 patients in the FB-CAS group, both methods were used. Intraoperatively, the transepicondylar femoral rotation (TEFR) in reference to the transepicondylar axis was established as the rotation that balanced the flexion gap. Once the TEFR was obtained, an analogous rotation as measured by a posterior reference femoral rotation (PRFR) cutting guide was determined. RESULTS: Femoral component rotation determined by the TEFR and PRFR methods differed in each of the knees. The median TEFR was 0.08°±0.6° (range -¿1.5°, 1.5°), and the median PRFR was 0.06°±2.8° (range -¿6°, 5°). The mean difference in the rotational alignment between the TEFR and PRFR techniques was 0.01° ± 3.1°. The 95% limits of agreement between the mean differences in measurements were between 6.2° external rotation and -¿6.1° internal rotation. At 2 years postoperatively, we found no differences in the radiographic or clinical American Knee Society score between the two groups. CONCLUSION: Rotation of the femoral component in TKA can vary in the same knee depending on the surgical method used to establish it. This variation in femoral rotation is sufficiently small enough to have no apparent effect on the 2-year clinical outcome score.Postprint (author's final draft