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A case of malignant lymphoma in association with the plating of a fractured tibia 17 years previously is presented. The literature is briefly reviewed, and attention is drawn to the reported association between tumor and internal fixation in animals.
This paper evaluates the behavior of hydroxyapatite (HAP) coated and noncoated Ti6Al4V implants in dog tibia after 3 and 5 months implantation. HPA-coated implants were obtained by plasma spraying. XRD, SEM, and EPMA were employed to estimate the coating characteristics and their behavior in vivo. Investigation of material characteristics showed that the as-received coatings consisted mainly of amorphism and HAP phase. Other phases such as TCP and CaO were identified due to thermal changes of HAP particles in plasma flame. SEM micrographs showed a typical microstructure of plasma-sprayed coating. The as-received coating was formed by well-melted pancake-like splats that lead to a dense coating with a rough surface. Lamellar structure, micropores, and microcracks, observed inside the coating, are characteristic of plasma spraying. Push-out tests revealed that HAP coating had a significant promotion of interfacial shear strength. The shear strength between bone and HAP-coated implants was much higher than that between bone and noncoated implants due to the different bone-implant interfaces formed after implantation. SEM observation revealed a direct attachment between HAP coating and newly formed bone. However, noncoated implants were separated from newly formed bone by fibrous tissues. Ti ions were found to be released into the surrounding environment after long time immersion in body fluid, and thus caused low shear strength. Prolongation of implantation time had different effects on shear strength. It improved the shear strength between HAP-coated implant and newly formed bone. However, it had little effect on that between noncoated implant and surrounding tissues.
We report a boy with predominantly unilateral severe tibia defect with a high grade of preaxial polydactyly. Family history suggests the possibility of autosomal dominant inheritance with reduced penetrance and quite variable expressivity. The boy's phenotype and other previously reported examples of predominantly unilateral involvement in autosomal dominant and autosomal recessive limb mutations strongly suggest a hypothesis of developmental resistance in the uninvolved parts.
Two unrelated families are presented, each with 2 affected offspring with bifid femur, absent tibia, and ectrodactyly. The healthy parents are consanguineous. It is postulated that this combination of malformations is causally heterogenous with both autosomal dominant and autosomal recessive modes of inheritance; hence, it is established as a developmental field defect.
We report on a newborn girl with syndactyly type IV, hexadactyly of feet, and right tibial hemimelia. She has 5 other relatives with identical anomalies of the hands and feet transmitted as an autosomal dominant trait. Syndactyly type IV is rare as is absence of the tibia. We suggest the possibility that syndactyly type IV may be a more complex entity, including lower limb malformations, and transmitted as autosomal dominant with variable expressivity.
We report on a family in which the autosomal dominant Werner syndrome (WS) (MIM# 188770) affects ten members in three generations. Besides the absent tibiae the propositus had duplication of the fibulae. Possible pathogenetic mechanism is discussed.
We report the longterm clinical and radiological progression in three unrelated patients with the tibia-metacarpal form of chondrodysplasia punctata (CDP-TM). The patients were followed for 37, 25, and 32 years, respectively. At follow-up intellectual function was normal, and physical function was well preserved. There was also marked resolution of several significant early radiographic features. The patients attained adult heights of 152, 138, and 148 cm. Two patients had chronic serous otitis media requiring tympanostomy tubes during childhood. One patient suffered persisting back pain related to spinal stenosis and required lumbar laminectomy at the age of 26 years. One patient had hip dysplasia requiring orthopedic surgical intervention. All patients had recurrent patella dislocation. Sterol and very long chain fatty acid profiles, FISH analysis for SHOX gene deletions, blood lymphocyte karyotype, and phytanic acid levels were normal in those tested, and no mutations in arylsulfatase D and E genes were detected. These data suggest that the longterm clinical and functional prognosis in this condition appears to be better than that expected based on initial clinical and radiological findings.
The strain environment of the tibial midshaft of two female macaques was evaluated through in vivo bone strain experiments using three rosette gauges around the circumference of the bones. Strains were collected for a total of 123 walking and galloping steps as well as several climbing cycles. Principal strains and the angle of the maximum (tensile) principal strain with the long axis of the bone were calculated for each gauge site. In addition, the normal strain distribution throughout the cross section was determined from the longitudinal normal strains (strains in the direction of the long axis of the bone) at each of the three gauge sites, and at the corresponding cross-sectional geometry of the bone. This strain distribution was compared with the cross-sectional properties (area moments) of the midshaft. For both animals, the predominant loading regime was found to be bending about an oblique axis running from anterolateral to posteromedial. The anterior and part of the medial cortex are in tension; the posterior and part of the lateral cortex are in compression. The axis of bending does not coincide with the maximum principal axis of the cross section, which runs mediolaterally. The bones are not especially buttressed in the plane of bending, but offer the greatest strength anteroposteriorly. The cross-sectional geometry therefore does not minimize strain or bone tissue. Peak tibial strains are slightly higher than the peak ulnar strains reported earlier for the same animals (Demes et al. [1998] Am J Phys Anthropol 106:87-100). Peak strains for both the tibia and the ulna are moderate in comparison to strains recorded during walking and galloping activities in nonprimate mammals.
Allometric equations relating length and cross-sectional geometric properties of the femur and tibia are generated using skeletal remains from three recent human population samples. Approximate isometry, or geometric similarity, is found both within and between samples. Cross-sectional areas scale to approximately length2, while second moments of area scale to approximately length4. It is shown that this is consistent with the maintenance of equivalent mechanical stress in long bones of different length under dynamic loadings in vivo. Other evidence indicates that bending and torsional loadings are more critical than axial loadings in the determination of lower limb bone cross-sectional dimensions.
The relationship between advancing age in adults and patterns of cortical bone maintenance has been extensively documented for archaeological populations (Dewey, et al., 1969; Van Gerven et al., 1969; Perzigian, 1973). Most recently, this research has been expanded to include a more thorough consideration of the geometric properties of bone in relationship to adult age changes (Martin and Atkinsin, 1977; Ruff and Hayes, 1983). To date, however, few studies have documented subadult patterns of cortical bone maintenance in archaeological populations and none have incorporated the relationship between patterns of cortical bone loss and gain and the changing geometric properties of growing bone. Using a sample of 172 tibias from children excavated from the Medieval Christian site of Kulubnarti, located in Nubia's Batn el Hajar, the present research examines the relationship between percent cortical area, bone mineral content, and cross-sectional moments of inertia. Among these children, bone mineral content increases steadily from birth in spite of a reduction in percent cortical area during early and late childhood. It appears, therefore, that tissue quality of the bone is not adversely affected by the reduction. Furthermore, the reduction in percent cortical area in later childhood corresponds to a dramatic increase in bending strength measured by cross-sectional moments of inertia. Thus, whether this cortical reduction is due entirely or in part to either normal modeling or nutritional stress, the tissue and organ quality of the bone is not adversely affected.
A distal right tibia described by G.S. Miller in 1929 (Smithsonian Misc. Coll. 82[5]:1-16) on the island of Hispaniola is shown to be that of a heretofore unknown extinct platyrrhine and is informally referred to as Ceboid M. Its affinities appear to be with the dwarfed callitrichids, especially Saguinus. It is suggested that Ceboid M represents yet another case of gigantism in the Antilles, in response to a lack of both competitors and predators. A reconsideration of the affinities of Xenothrix mcgregori from Jamaica is suggested.
A method for inducing paralysis in embryonic chicks is described. This involves single injections of the neuromuscular blocking agents, D-tubocurrarine Chloride or decamethonium iodide, into 10-day embryos. The dose which optimises survival and paralysis is determined along with the effect of the drugs on embryonic growth. Decamethonium iodide at a dose of 1 mg per embryo gave maximum survival and paralysis to 18 days of incubation. Paralysis was assessed by observation of treated embryos in ovo and by examination of embryos removed from their shells between 11 and 18 days of incubation. Embryos were completely paralysed 24 hours post-injection and remained paralysed until 18 days of incubation. Paralysed embryos failed to hatch. Development of the leg musculature was severely retarded in paralysed embryos. This method of inducing paralysis has considerable advantages over previous continuous infusion methods. The growth and collagen content of the tibia in the paralysed embryos was reduced and these results, and other applications of the method, are discussed.
The cartilaginous matrix in the growth plate of the proximal tibia of rats is subdivided into various compartments according to criteria established by electron microscopic examination. In conventionally fixed specimens, the arrangement of collagen fibrils was analyzed by transmission and scanning electron microscopy. Distribution of proteoglycans and relations between matrix and cells were studied after fixation in media containing cationic dyes. Matrix compartments are best characterized by the density and arrangement of their collagen fibrils. On the other hand, proteoglycans are distributed almost homogenously all over the matrix. Each chondrocyte is surrounded by a thin envelope of proteoglycans, the pericellular matrix. Adjacent to this is a layer dominated by the content and order of its collagen fibrils, the territorial matrix. Its inner part covers the pericellular matrix with a thin net of intersecting fibrils. The outer part unites the cells of each column by a sheath of tightly packed longitudinal fibrils. This distinction is only possible in the longitudinal parts of the territorial matrix, whereas in the transverse septa both layers fuse into a common network. The interterritorial matrix is interposed between the columnar units and thus represents the central part of the longitudinal septa. Mineralization is restricted to the interterritorial matrix and matrix vesicles are coincidentally found in the same compartment. During growth, this structural organization undergoes a permanent and relatively fast remodeling, a process that is discussed in view of possible cell matrix interactions.
The ultrastructural distribution of two noncollagenous proteins, osteopontin (OPN) and osteocalcin (OC), originally extracted from bone matrix and proposed to play an important role in bone formation, was examined in the matrices of bone and cartilage from embryonic and postnatal chicken tibial growth plates by high-resolution immunocytochemistry using the colloidal gold technique. In bone, immunolabeling patterns using polyclonal antibodies against chicken OPN and OC were generally similar in that both showed an intense, but regionally variable, labeling of mineralized bone matrix and small mineralization loci dispersed throughout the osteoid and containing prominent condensed organic material. Unmineralized osteoid showed weak-to-moderate labeling. In the mineralized bone matrix proper, labeling was predominantly associated with amorphous, electron-dense patches of organic material among the collagen fibrils. In growth plate cartilage, both proteins first appeared related to calcified cartilage in the hypertrophic zone, although the labeling patterns were somewhat different. For OPN, gold particles were mostly associated with an organic lamina limitans-like density containing condensed, filamentous organic matrix at the periphery of small nodules and large masses of calcified cartilage, with additional moderate labeling throughout the interior of the calcified cartilage. For OC, labeling was observed over filamentous structures throughout the calcified cartilage matrix, with some, but less, labeling at the periphery. In the lowermost zones of the growth plate, the major reaction using both antibodies was found over a layer of dense, amorphous organic material at the periphery of the calcified cartilage at the future bone/calcified cartilage interface, a labeling pattern that persisted following bone deposition at these sites. OPN and to a lesser extent OC were also concentrated in cement (resting, reversal) lines. Throughout the bone and cartilage of the tibia, cells of both the osteoblastic and the osteoclastic lineages were found directly apposed to labeled surfaces and lamina limitans of organic matrix containing OPN and OC. In summary, it is concluded from the immunocytochemical data presented here that the association of OPN and OC with mineralized regions of the extracellular matrices of bone and cartilage and the accumulation of these proteins at tissue surfaces and interfaces are consistent with the hypotheses that they play a role in the extracellular mineralization process per se and/or that they may mediate cell adhesion and dynamics.
A high coefficient of variation is characteristic of the bioelectric potentials recorded from living long bones. As a consequence, the data collected from animal and human experiments are difficult to use in practical ways. A distribution curve for bone bioelectric potentials has been calculated using polynomial regression analysis to process the voltage values recorded on the whole length of rabbit tibiae, with reference electrodes positioned in three different points of the bone. The distribution curve so obtained is presented to fulfill the need for a reference curve for the bioelectric potentials recorded from rabbit tibial surfaces.
The formation of a secondary ossification center in the cartilaginous epiphysis of long bones requires the excavation of canals and marrow space and, therefore, the resorption of cartilage. On the assumption that its resorption requires the lysis of the major cartilage component aggrecan, it was noted that the core protein may be cleaved in vitro by proteinases from two subfamilies: matrix metalloproteinases (MMPs) and aggrecanases. Such cleavage results in aggrecan being replaced by a fragment of itself referred to as a "G1-fragment." To find out if this cleavage occurs in the developing epiphysis of the rat tibia, the approach has been to localize the G1 fragments. For this purpose two neoepitope antisera were applied, one capable of recognizing the MMP-generated G1-fragment that bears the C-terminus ...FVDIPEN341 and the other capable of recognizing the aggrecanase-generated G1-fragment that carries the C-terminus ...NITEGE373. With the aid of these antisera, we report here that aggrecan cleavage is localized to newly developed sites of erosion. Thus, at 6 days of age, canals allowing the entry of capillaries are dug out from the surface of the epiphysis in a radial direction (stage I), whereas immunostaining indicative of aggrecan cleavage by MMPs appears at the blind end of each canal. The next day, the canal blind ends fuse to create a marrow space in the epiphysis (stage II), whereas immunostaining produced by MMPs occurs along the walls of this space. By 9 days, clusters of hypertrophic chondrocytes are scattered along the marrow space wall to initiate the formation of the secondary ossification center (stage III), where the resorption sites are unreactive to either antiserum. From the 9th to the 21st day, the center keeps on enlarging and, as the distal wall of the marrow space recedes, it is intensely immunostained with both antisera indicating that both MMPs and aggrecanases are involved in this resorption. We conclude, that both enzyme subfamilies contribute to the lysis of aggrecan. However, the results suggest that the respective subfamilies target different sites and even stages of development in the tissue, suggesting some diversity in the mode of aggrecan lysis during the excavation of a secondary ossification center.
A comparative study of stress distributions in the component materials of a number of models of a prosthetically resurfaced tibia is presented. Although the geometry is idealized to be axisymmetric, the loadings for which the finite element analyses are performed are considered to be nonaxisymmetric, simulating more realistically the loading conditions in vivo. The different models are chosen with the view of determining the influence of changes in the prosthesis design on the induced stress distribution in the component materials. The changes considered are in the thickness of the cement and the cement-bone composite layers, and in the shape of the prosthesis. Experimentally measured values of strains are compared with the analytically predicted values to check the validity of the assumptions used in the finite element modeling. The comparison of induced stresses in the different materials reveals the desirability, from a mechanical behavior point of view, of introducing a cement-bone composite layer and using a prosthesis with domed subsurface in the fixation system. It is shown that for a model incorporating these features, considerable reduction of stresses in the cement, in its bulk and at its interface with the prosthesis plate, is achieved. The reduced stresses can be expected to have beneficial effects on the long-term behavior of the cement and its interfaces in the fixation system.
We examined the tissue reaction to three alumina implants--single-crystal alumina (SA), dense polycrystal alumina (DPA), and porous polycrystal alumina (PPA)--inserted transcortically, extending into the medullary canal of rat tibiae, and assessed the quantitative differences in bone reaction using an image processing system. There was no difference in the degree of maturation of newly formed bone around the three kinds of alumina. SA and DPA were encapsulated with a continuous bone layer, but some bone tissue was attached focally around PPA. Bone trabeculae in the control site diminished in size and number chronologically. Multinucleated giant cells were observed on the surface of DPA and PPA, but not on SA. Tabulation of the quantitative evaluation indicated that SA showed the highest, DPA a lower, and PPA the lowest in bone contact rate, bone contact thickness, and bone contact area. These data suggest that SA is superior to the other two as an implant material.