Normal Tibia Research Articles

A histological study of acute hematogenous osteomyelitis following physeal injuries in rabbits.

In young rabbits, the effects of an intravenous injection of Staphylococcus aureus alone, and in combination with a traumatic injury of the proximal tibial physis, were studied by light and electron microscopy. Metaphyseal osteomyelitis and radiographic changes were seen within forty-eight hours after the injury in all rabbits that had a growth-plate disruption and bacteremia. An intravenous injection of bacteria alone produced no morphological or microbiological evidence of infection. In the absence of trauma, normal tibiae were sterile after forty-eight hours. Foreign-body particles have been shown to accumulate in the fine vessels that are adjacent to the growth plate, but we found no similar deposition of bacteria or evidence of phagocytic removal in this area. Phagocytosis of bacteria by neutrophils did not appear to be impaired in the distal third of the metaphysis, but a delayed inflammatory response that allowed proliferation of bacteria and destruction of tissue was observed in the proximal two-thirds of the metaphysis after trauma.

Measurement of tibial torsion by ultrasound.

A method of measuring tibial torsion with ultrasound, using reference lines on the tibia, was developed and tested on dry adult tibiae. This technique was used for evaluation of a group of children with apparently normal tibiae and another group of children with spina bifida, cerebral palsy, or clubfoot. The study showed that it is possible to measure true tibial torsion (rather than tibiofibular torsion) with ultrasound. The technique was found to be reliable and accurate enough for routine clinical use and had advantages over clinical methods and other radiographic imaging techniques. Values obtained by this technique are higher than those obtained by methods using the bimalleolar axis as the distal reference line.

Medial Tibial Pain

In a prospective study of 295 infantry recruits during 14 weeks of basic training, 41% had medial tibial pain. Routine scintigraphic evaluation in cases of medial tibial bone pain showed that 63% had abnormalities. A stress fracture was found in 46%. Only two patients had periostitis. None had ischemic medial compartment syndrome. Physical examination could not differentiate between cases with medial tibial bone pain secondary to stress fractures and those with scintigraphically normal tibias. When both pain and swelling were localized in the middle one-third of the tibia, the lesion most likely proved to be a stress fracture.

The influence of mechanical conditions on the healing of experimental fractures in the rabbit: a microscopical study.

To examine in detail the events that lead to healing under different mechanical conditions, experimental fractures of the rabbit tibia were immobilized with either a metal compression plate or a plastic plate, to produce stable or unstable mechanical conditions respectively. To fracture the bone, a small saw cut is made in the medial cortex and three-point pressure is then applied to fracture the remaining cortical bone. A small amount of bone is removed by the saw cut. This is of no consequence when a plastic plate is used because the plate is designed so that a small gap remains between the fractured surfaces. When a compression plate is used, a gap approximately 100 pm wide remains under the plate. In addition, despite the use of compression, only part of the fractured surfaces are normally in contact, so other narrow fracture gaps may remain. The fractures were examined at experimental times from 4 days to 1 year by both light and electron microscopy. In stable mechanical conditions, a thin layer of periosteal callus starts to form within 4 days and healthy mesenchymal cells and capillaries are adjacent to the fracture. By 7 days the callus is fully developed and is covered by a new periosteum. Over the following weeks it becomes more compact as the cavities are filled by bone. The endosteal callus, if formed, is small. From 9 days onwards the fracture gaps of between 30 and 100 pm are invaded by mesenchymal cells; macrophages remove the debris and fibroblasts lay down a collagenous matrix. Capillaries are numerous. By 2 weeks, these gaps are lined by osteoblasts producing transverse layers of new bone on the fractured surfaces. The gap is rapidly filled by transversely orientated bone to achieve union by 3-4 weeks. Resorption is limited to very small, isolated regions of the fractured surfaces. The gaps between 10 and 30 μm wide appear to be too narrow for cells and capillaries to enter, and they are widened by osteoclastic action. Mesenchymal cells and capillaries then enter and bone is laid down on the surfaces of the newly excavated cavities. After union, the region is recognized as a wide band of irregularly organized bone. In compressed regions, areas of actual contact are very few, and narrow gaps can be seen. Union is achieved by direct Haversian remodelling across gaps up to 9 pm wide. Remodelling starts at about 3 weeks and it is part of the normal process that occurs after union of a fractured cortex. The events in the fractures healing under unstable mechanical conditions diverge immediately. The initial periosteal reaction is similar, but cancellous bone forms only away from the fracture gap. Mesenchymal cells in a fibrous matrix, but with very few, if any, associated capillaries, persist as a thick layer over the fracture gap. At 6 days islands of cartilage begin to develop, and by 12 days the whole central area is filled by a cartilaginous matrix containing thick and thin collagen fibrils and elastic fibres. The cartilage is replaced by bone by 3-4 weeks. At this point, healthy cells and capillaries are found near the fracture gap. A small endosteal callus may form in a similar way. The fracture gaps are now invaded. The debris is removed by macrophages, and fibroblasts produce a collagenous matrix. Osteoclasts cover the fractured surfaces, but the amount of resorption is minimal. Capillaries also enter the gap. Within 1-2 weeks the gap is filled by transverse lamellae of bone. Once the fractured cortex is united, the events are similar in both series of fractures. Resorption of any callus starts. In the periosteal callus, large cavities form particularly along the callus-cortex junction. Over the next 3 months the callus is resorbed and the cortex is extensively remodelled. By 18 weeks no callus remains. The cortical bone is compact, but large cavities filled with fat cells may occur. The overall dimensions of the bone may be larger than that of the contralateral normal tibia, but the layer of cortical bone is thinner. Thus the plate, whether of metal or plastic, affects the structure of the bone. This study serves to emphasize that the mechanical stability of a healing fracture determines the composition and size of the periosteal callus and the time at which union across a fracture gap is achieved. The fracture fragments must be mechanically stable, so that there is no movement at the fracture gap before cells can enter and lay down new bone. This may be achieved immediately, though artificially, by a metal compression plate, or slowly, though naturally, by the formation of a large callus of cancellous bone. The movements and differentiation of the cells involved in healing are discussed. This experimental fracture model will form a basis for future experimental studies of healing fractures.

Porous hydroxyapatite as a bone-graft substitute in metaphyseal defects. A histometric study.

Porous hydroxyapatite (Interpore 500) formed by conversion of the Porites goniopora coral exoskeleton has pores averaging 600 micrometers and pore interconnections averaging 260 micrometers in diameter. In the proximal tibial metaphysis of eight dogs, a defect one cubic centimeter in size was created unilaterally and was fitted with a block of Interpore 500. Both proximal tibial metaphyses were retrieved at two, four, six, and twelve months. Stained undecalcified sections were examined by light microscopy and quantitated by histometric methods. The implant-side specimens contained compact bone along the external surface and trabecular bone interiorly. The interior of these specimens was composed of 51.9 +/- 1.3 per cent soft tissue, 13.0 +/- 1.2 per cent bone, and 35.1 +/- 1.2 per cent Interpore 500 (mean and standard error). The interior of the normal specimens was composed of 79.7 +/- 1.4 per cent soft tissue and 20.2 +/- 1.4 per cent bone. The allocation of implant pore space between bone and soft tissue was proportional to that of bone and soft tissue in the normal tibiae. The stereological distribution of regenerated bone in the porous hydroxyapatite was also the same as in the normal tibiae. The appositional process of incorporation of the implant was confirmed by the finding that 66.5 per cent of the surface of the Interpore 500 was covered with bone ingrowth at twelve months.

The influence of stress and strain in the early development of shaft bones

In chick embryos from stage 23 to stage 27 the whole presumptive zeugopod - or its pre-axial (tibial) portion only - was proximodistally and dorsoventrally inverted by turning it 180 degrees round the anteroposterior axis of the limb bud. Development of the reoriented blastema of the tibia was consistently retarded and variously reduced: this skeletal piece appeared shorter and relatively thicker than the controlateral normal tibia. Chondrification, progress of differentiation of the cartilaginous model, onset and gradual spreading of the ossification processes were considerably delayed. Often the diminutive tibia underwent a degree of bending or angulation of up to 90 degrees - 100 degrees in the sagittal plane. In these bent tibiae - obviously developing under abnormal conditions of intrinsic and extrinsic mechanical stresses - cell hypertrophy appeared greatly retarded or hindered in sites of the diaphysial cartilaginous core which were presumably subjected to strong longitudinal compression. No rigorous temporal and topographical relationships were observed between chondrocyte hypertrophy and onset of perichondral osteogenesis. Apparently, a direct contact between hypertrophic cartilage and perichondrial cells was not strictly required to prompt osteogenesis; this process, in fact, often involved areas of the perichondrium enveloping parvicellular cartilage. Radial pressures exerted by the over-stretched outer layer of the perichondrium, or periosteum, on the subjacent prospective osteogenous layer reduced or prevented the deposition of bone. Conversely, radial stretching of the inner layer of the perichondrium, or periosteum, considerably enhanced cell proliferation, blood vessel formation, differentiation of osteoblasts and formation of bone matrix.

The role of skeletal blood flow in determining the uptake of 99mTc-methylene diphosphonate.

The increased uptake of bone-seeking radionuclides following a fracture has been stated to be due to an increase in bone blood flow, resulting in an increase in capillary surface area available for exchange. This paper examines the relationship between the maximum instantaneous extraction of 99mTc-MDP and blood flow in normal canine tibia. The findings, consistent with the model of capillary action proposed for muscle by Renkin and Crone, are applicable to bone. There is no evidence that in normal bone the surface area available for exchange responds to an increase in bone blood flow.

Iodine-125 labeled phenylphosphonic acid: A new radiopharmaceutical for long-term investigations of the skeleton

A skeletal seeking radiopharmaceutical labeled with a long-lived radionuclide was developed to evaluate regional bone formation and its subsequent resorption. The agent is [phosphonate (phenylmethylene hydroxy) bis] - I-125 or I-125 phi PA. Tissue distribution studies in mice (N = 16) showed approximately 40% of the administered dose to be retained by the skeleton up to 336 hours post IV injection. The percentage of the dose accumulated by the thyroid gland remained at less than 0.5%, indicating minimal deiodination of the I-125 phi PA. Whole body retention studies in the same species revealed a triexponential release pattern with the longest component comprising 33% of the dose with a biologic half-life of 962 days. A fractured rat tibia model was studied with I-125 phi PA and Tc-99m MDP. Chronic loss of the I125 phi PA relative to normal tibia was quantitated: five days (62.8%); 30 days (47.4%). Concomitant increased uptake of the Tc-99m MDP was observed at the fracture site relative to normal: five days (186%); 30 days (1,041%). The above data suggest that I-125 phi PA can be utilized to measure acute bone formation and chronic resorption.

Genetic inhibition of mesenchymal cell death and the development of form and skeletal pattern in the limbs oftalpid3(ta3) mutant chick embryos

ABSTRACTVital staining reveals that in homozygous (ta3/ta3) talpid3 embryos, the areas of mesen-chymal cell death which occur regularly in normal limb development are absent or reduced.The necrotic locus in the central mesenchyme (the ‘opaque patch’) which in the normal chick limb reaches maximum development at stages 24 and 25 is absent or much reduced in talpid3 fore-and hindlimb-buds. Autoradiographic studies, following application of a 2 h pulse of 40 μCi of35SO4 to the vitelline circulation, show that normal tibia and fibula incorporate 35SO4 into chondroitin sulphate at stage 24 and more strongly at stage 26 during the process of chondrogenesis. The mesenchyme in the opaque patch region of normal limbs ceases to incorporate 35SO4 into chondroitin sulphate at stage 24. Talpid3 mesenchyme cells in the equivalent position at stages 24 and 26 continue to incorporate 35SO4, remain viable and become chondrogenic. It is suggested that absence or reduction of this central necrotic locus in talpid3 is causally related to the fusion of radius/ulna and (in some cases) of tibia/fibula characteristic of the later stages (28–35) of talpid3 limb development. This evidence supports the hypothesis that cell death in the opaque patch plays a morphogenetic role in separation of radius/ulna and tibia/fibula.The digital plate of stage 32 normal limbs is characterized by massive necrosis of the interdigital tissue. In talpid3 forelimbs of stages 30–35 interdigital necrosis is absent, and there is no regression of the tissue between the digits (‘soft tissue syndactyly’). In talpid3 hindlimbs of stage 30–35 interdigital necrosis is either absent or much reduced, and there is little or no erosion of the soft tissue between the digits. This evidence supports the hypothesis that the morphogenetic role of interdigital cell death is in causing separation of the digits through shaping and remodelling the contours of the digital plate.

Roentgenographic Measurement of Tibial-Plateau Depression Due to Fracture

Based on a study of true lateral roentgenograms of the proximal ends of fifty normal tibiae, and on roentgenographic and direct measurements of anatomical specimens with experimentally depressed plateaus, it was demonstrated that the plane of the proximal articular surfaces of the tibia normally forms an angle of 76 ± 3.6 degrees with the tibial crest, and that an anteroposterior made with the central ray directed at an angle of 105 degrees to the tibial crest (the approximate complement of the aforementioned 76-degree angle) permits the most accurate roentgenographic measurement of the depression. It was concluded that use of the tibial-plateau view permits more accurate assessment of the initial depression and the effects of treatment.

Identification of neonatal grey lethal mice.

AbstractThe grey lethal mouse is an osteopetrotic mutant which cannot be identified by its external appearance (grey fur) until eight days of age and dies within one month of birth. Techniques for the identification of neonatal mutants would greatly facilitate study of the pathogenesis of osteopetrosis and its early treatment.Under hypothermal anesthesia, the left lower limbs of neonatal mice were amputated just above the knee joint. The external appearance of two day old amputated tibiae could be correlated with the external appearance of the mice at eight days of age. The diaphyses of normal tibiae appeared red under the dissecting microscope due to the presence of hemopoietic tissue occupying the central marrow cavity. Grey lethal tibiae appeared opaque because relatively more unresorbed bone occupied the center of the diaphysis.Histologic examination showed that in normal mice at birth, the mandibular incisor extended posteriorly to the molar region of the jaw, but that in grey lethals dense bone prevented the incisor from growing posteriorly in this fashion.

The Phosphatase Content of Fractured Bone.

In a recent paper Kay states that he observed an increase in plasma phosphatase following fracture, and indirectly he suggests a similar rise in bone phosphatase. In view of our findings on the breaking strength of fractured fibulae of rats, we were of the opinion that a positive correlation existed between the breaking strength and bone phosphatase. This we sought to demonstrate. It was also believed that if the activity of phosphatase in the healing process of fractures is antagonized, after the primary callus has formed on the fifteenth day, by the hormone of the parathyroid gland, as we suggested else where, that subsequent to the fifteenth day the bone phosphatase should be reduced. The method of selecting, feeding and fracturing the right fibulae of the albino rats has been described. The bone phosphatase of the combined unfractured left fibula and tibia, as well as the bone phosphatase of the combined fractured right fibula and its tibia, were estimated by a method personally suggested by Kay, the details of which will be published later. The results are tabulated in Table I. Our findings, incomplete as they are, strongly indicate that the level of bone phosphatase in the fractured fibula rises with the formation of the primary callus and falls as the medullary space is developed. The rapid loss of callus strength during the formation of the medullary space, between the fifteenth and twenty-first days, has been suggested elsewhere as being due to a powerful circulatory decalcifying substance which may possibly be the parathyroid hormone. The sharp reduction in the phosphatase content of the fractured right fibula and its normal tibia, subsequent to the formation of the primary callus on the fifteenth clay, and during the formation of the medullary cavity, suggests that an actual antagonism does exist between phosphatase, and this at present unknown decalcifying substance.