Morphometric studies of the nutrient foramen in lower limb long bones of adult black and white South Africans

The present study analyzed the direction, number, location and position of the nutrient foramina in 1080 lower limb long bones of 20th century adult black and white South Africans. In each population 90 complete skeletons were used resulting in 360 femora, 360 tibiae and 360 fibulae being analyzed. The majority of the nutrient foramina pointed away from the growing end of the diaphysis in the lower limb bones with a few pointing in the opposite direction in both black and white populations. A single nutrient foramen was common on the shafts of the tibia and fibula in both populations, while, in the femur, double nutrient foramina were most frequent in the white population as opposed to one in the black counterparts. Nutrient foramina were located most frequently on the linea aspera of the femur and the posterior surface of both the tibia and the fibula in both black and white populations. The mean foraminal indices were as follows: in the black population, 41.87% for the femur, 31.66% for the tibia and 43.33% for the fibula, and in the white population, 44.58% for the femur, 33.15% for the tibia and 46.86% for the fibula. These foraminal indices represent the relative positions of the nutrient foramina on the shaft of the bone. The information about direction, number, location and position of the nutrient foramina is important clinically during free vascularized bone grafting to preserve the blood supply of the graft, during fracture repair, joint replacement surgeries, and also in medico-legal cases

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Impaired osteoblastogenesis potential of progenitor cells in skeletal unloading is associated with alterations in angiogenic and energy metabolism profile.

Skeletal unloading provokes bone loss. These bone alterations have been shown to be associated with impairment of osteoblastic activity. In the present study, we evaluated the effect of skeletal unloading on bone marrow progenitor cells, for exploration of the underlying mechanism. Wistar rats were randomized to be either hindlimb unloaded for 9 days or to act as controls. Micro-CT was used to detect tibial trabecular architecture changes in response to skeletal unloading. Microgravity conditions for 9 days resulted in a decreased number and an increased spacing of the bone trabeculae in the proximal tibia. The proliferative capacity of the femoral bone marrow samples was assessed (fibroblast-colony-forming assay). By using qPCR, the expression of selected markers of vascularization (Vegfa; Hif1a; Angpt1), energy metabolism (Prkaa2; Mtor), bone formation (Runx2; Alp; Bglap; Bmp2; Bmp4; Bmp7) and bone resorption (Acp5; Tnfsf11; Tnfrsf11b) in these bone marrow suspensions was measured. We demonstrated a striking decrease in the number of fibroblastic progenitors in response to hindlimb unloading. This deficit in proliferation was shown to be accompanied by altered hindlimb perfusion and cellular energy homeostasis. Ex vivo culture assays of the bone marrow-derived progenitor cells screened for osteogenic (Runx2; Alp; Bglap) and adipogenic (Pparg; Fabp4) differentiation alterations in response to microgravity. Induced progenitor cells from unloaded rats showed a delay in osteogenic differentiation and impaired adipogenic differentiation compared to control. The data of this multi-level approach demonstrate that skeletal unloading significantly affects the bone tissue and its metabolism at the progenitor stage. The molecular expressions of the bone marrow population support a role of cellular metabolic stresses in skeletal alterations induced by inactivity.

A study of retrieved allografts used to replace anterior cruciate ligaments.

PURPOSE: The purpose of the study was the examination of retrieved whole anterior cruciate ligament (ACL) replacement grafts to determine the rate and the extent of cellular replacement and remodeling of the grafts. TYPE OF STUDY: Gross and histopathologic examination of specimens. METHODS: Nine specimens of ACL replacement allografts and 1 autograft were obtained at autopsy and surgical procedures. RESULTS: Examination of these specimens from 20 days to 10 years after transplantation revealed a pattern of revascularization similar to that reported in previous biopsy studies. However, examination of the entire allografts showed that, at 2 years after transplantation, the central portions of the grafts remained acellular and that complete attachment was not present, but was found in a 3.5-year post-transplantation specimen. CONCLUSIONS: Because attachment of the graft to bone tunnel walls required over 2 years, the tunnel remodeling may be explained on a mechanical basis. The remodeling of ACL replacement grafts is a gradual or slow process. Complete remodeling and cellular replacement of the entire graft may require 3 years or longer.

Uncoupling of chondrocyte death and vascular invasion in mouse galectin 3 null mutant bones.

Galectin 3 is a beta-galactoside binding protein which localizes to the cytoplasm of proliferative, mature, and hypertrophic chondrocytes in the growth plate cartilage of developing long bones. To elucidate the function of galectin 3 during bone development, we examined the epiphyseal femurs and tibias of fetal mice carrying a null mutation for the galectin 3 gene. Detailed histological and ultrastructural studies identified abnormalities in the cells of the proliferative, mature, and hypertrophic zones and in the extracellular matrix of the hypertrophic zone, as well as a reduction in the total number of hypertrophic chondrocytes. The expression patterns of several chondrocyte and bone cell markers were analyzed and revealed a subtle modification of Ihh expression in the galectin 3 mutant growth plate. A striking difference was observed at the chondrovascular junction where many empty lacunae are present. In addition, large numbers of condensed chondrocytes exhibiting characteristic signs of cell death were found in the late hypertrophic zone, indicating that the rate of chondrocyte death is increased in the mutants. These results suggest a role for galectin 3 as a regulator of chondrocyte survival. In addition, this unique phenotype shows that the elimination of chondrocytes and vascular invasion can be uncoupled and indicates that galectin 3 may play a role in the coordination between chondrocyte death and metaphyseal vascularization.

Magnetic resonance imaging-detected avascular osteonecrosis in systemic lupus erythematosus: lack of correlation with antiphospholipid antibodies.

We determined prospectively the prevalence of avascular osteonecrosis (AON) by magnetic resonance imaging (MRI) of both lower limbs in a group of 40 systemic lupus erythematosus (SLE) patients, and correlated the results with their serum antiphospholipid antibody (APL Ab) status and their glucocorticoid (GC) intake. APL Ab were detected by anticardiolipin ELISA and by lupus anticoagulant assays. Cumulated prednisolone doses were computed by chart review. The prevalence of AON was 37.5%, with most patients being asymptomatic despite involvement of multiple sites. The number of epiphyseal, metaphyseal and diaphyseal AON sites per patient did not differ between APL Ab-positive and APL Ab-negative patients nor between patients with high and low APL Ab titres. By contrast, a striking correlation was found between the prevalence and severity of AON and GC therapy. In conclusion, this prospective MRI study indicates that the prevalence of AON in SLE patients correlates strongly with GC therapy, but not with APL Ab status.

The Ilizarov method. Orthopedic and soft tissue applications.

The Ilizarov method has broad applications for the generation of bone and soft tissue via an external fixator composed of small pins, tensional wires, rings, hinges and distractors. The success of the technique depends on adherence to Ilizarov's principles of tension-stress phenomenon: preservation of the tissues' blood supply, frequent distraction in small increments, and full function of the extremity.

Estudio anatómico de la circulación de la tibia y su relación con los diferentes tipos de fracturas y osteosíntesis / Anatomical study of the tibia circulation and its relation with the different types of fractures and osteosinthesis

Se realiza estudio dividido en cinco áreas en las cuales se define la anatomía vascular de la tibia en humanos haciendo constar que la arteria nutricia y de un sistema vascular de la tibia mediante inyecciones de latex, tinta china y se realiza demostración radiológica del sistema circulatorio intramedular en el humano y en el ovejo. Luego de obtener los resultados de 15 situaciones de fracturas experimentales, creemos se contestan algunas de las interrogantes que existen en el tratamiento de esta estructura ósea tan impredecible en su cicatrización como es la tibia

Estudio de la circulación arterial de la fíbula, fundamentos para la técnica de injerto óseo vascularizado / Study of the arterial circulation of the fibula: foundations for the vascular bone flaps technic

Se estudia la circulación de la fíbula con el objetivo de obtener un modelo anatómico que sirva de base a la técnica de trasposición de este hueso con sutura microvascular de su pedículo. Se comprueba que la circulación ósea proviene tanto de los vasos periósticos como de la arteria nutricia y que ambas se anastomosan en el interior del hueso como se ha establecido en estudios previos. Este modelo anatómico permite comprender la necesidad del esfuerzo quirúrgico a fin de dar aporte sanguíneo a la totalidad del hueso