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PubMed2000

Repeatability of tibia lead measurement by X-Ray fluorescence in a battery-making workforce.

The purpose of this study was to remeasure in vivo tibia lead levels in a lead-acid battery manufacturing workforce measured in a previous survey and believed to be unrealistically high. Tibia lead levels were measured by K-shell X-ray fluorescence (XRF) spectroscopy in a stratified random sample (n=40) of the original study group (n=381). The repeat survey showed much lower tibia lead levels (median=54.3 microg lead/g bone mineral, compared to 217.9 microg lead/g bone mineral, n=40). Tibia lead levels were significantly correlated with duration of occupational exposure, zinc protoporphyrin levels, and cumulative blood lead index, but not with current blood lead levels. Thirty-eight of the 40 subjects underwent two consecutive tibia lead measurements to assess the test-retest repeatability of the XRF tibia lead measurement technique. The intraclass correlation coefficient between repeated measurements was 0.926 (P=0.0001). Three measurement pairs differed by more than 20 microg/g. There was no fixed or proportional bias between the two sets of measurements. We conclude that the technique offers a highly repeatable measurement of tibia bone lead. However, care needs to be taken to avoid contamination when performing measurements on active lead workers.

Adult↗
PubMed2001

Effects of lifetime volleyball exercise on bone mineral densities in lumbar spine, calcaneus and tibia for pre-, peri- and postmenopausal women.

To clarify the effects of habitual volleyball exercise on bone in women during the menopausal periods, we measured bone mineral densities (BMDs) of the lumbar spine, calcaneus and tibia every 12 months for 2 years and estimated factors related to the baseline values and annual loss rates. Forty Japanese female volleyball players 42-62 years of age, who had belonged to the district non-professional club for more than 10 years on average, were recruited. Twenty women had regular menstruation at the start, but 7 underwent menopause during the study. Fifty-nine healthy women who did not participate in habitual exercise, but were otherwise comparable with the players, were recruited as the controls. The lumbar and calcaneus BMDs were measured by dual-energy X-ray absorptiometry (DXA), and both the volumetric BMDs and cross-sectional geometry at the diaphysis of the tibia were measured by peripheral quantitative computed tomography. The baseline BMDs of all measured sites and the values of the cortical area and moment of inertia of the tibia in the players were significantly higher than the values in the control women. In the peri- and postmenopausal players, the baseline values of the lumbar and calcaneus BMDs related to total years of participating in regular exercises during adulthood including volleyball (TYE), body mass index (BMI) and years since menopause (YSM). Tibia cortical area and moment of inertia values related to TYE. Annual bone loss rates in the tibia and calcaneus of players were significantly smaller than those values in the controls. However, the bone loss rates in the lumbar spine did not differ significantly between the groups. The bone loss rate in the calcaneus was significantly related to the current number of training hours per week and YSM. The rate of bone loss in the tibia was related to BMI. These data indicated that the total number of years participating in exercise activity during adulthood have positive effects on lumbar and calcaneus BMDs and the cortical structure of the tibia. Habitual volleyball exercise apparently did not alleviate the menopause-related bone loss in the lumbar spine.

Absorptiometry, Photon↗
PubMed2006

Bone mineral density in the proximal tibia and calcaneus before and after arthroscopic reconstruction of the anterior cruciate ligament.

PURPOSE: To monitor changes in bone mineral density (BMD) of the proximal tibia and the calcaneus in patients with anterior cruciate ligament (ACL) rupture before and after arthroscopic reconstruction of the ligament, related to clinical data. TYPE OF STUDY: A 2-year prospective cohort study with assessment of patient evaluation of knee performance, clinical scoring of surgical results, and measurement of BMD in the tibia and calcaneus. METHODS: Eighteen patients with a unilateral ACL rupture underwent an autogenous bone-patellar tendon-bone graft ACL reconstruction. The patients were examined before surgery and after 4, 12, and 24 months. BMD was assessed bilaterally in the proximal tibia and calcaneus using dual-photon absorptiometry and converted to a Z-score by use of BMD values from a group of healthy controls. Clinical evaluation included determination of Lysholm score, quantitative Lachman test, pivot-shift test, and the patients' self-reported highest level of activity and knee performance in sports and daily activities. RESULTS: There were significant declines in Z-score of the proximal tibia of the operated leg during the first year after surgery, whereas there was no change in the calcaneus and contralateral leg. In the lateral tibia, the Z-score was significantly lower at 24 months follow-up, compared with both controls and the noninjured side, whereas BMD of the medial tibia had returned to near normal levels. There were significant improvements in Lysholm score, highest level of activity, and knee performance in daily activities and sports. The patients' evaluation of improvement in knee performance in sports activities at 24 months follow-up was associated with an increase in Z-score of the injured leg. CONCLUSIONS: We found a partially reversible decline in BMD of the proximal tibia after arthroscopic ACL reconstruction. Improvement in knee performance in sports activities was associated with an increase in BMD of the injured leg. BMD of the calcaneus remained unaffected in both legs. LEVEL OF EVIDENCE: Level III, therapeutic case control study.

Activities of Daily Living↗
PubMed2004

Distribution of bone mineral density with age and gender in the proximal tibia.

OBJECTIVE: To investigate both the age and gender related distributions of bone mineral density in the proximal tibia, specifically in aged patients. BACKGROUND: For surgeons to achieve stable long-term fixation of implants in the proximal tibia, the distribution of bone mineral density must first be known. The changes that occur due to age or gender can alter these distributions. METHODS: Quantitative computed tomography and indentation testing were used to investigate 40 human tibiae (27 female, 13 male, average age 63.3 years). RESULTS: A significant reduction in bone mineral density was found in female tibiae between the age groups of < 60 and > or =60. This difference was not found in the male groups and no other significant difference was found between consecutive age groups. A three-dimensional map of the bone mineral density of the proximal tibia is therefore presented for the groups female < 60, female > or =60 and male. Reduced bone mineral density was consistently found in the central regions, whilst the regions of highest bone quality varied from postero-lateral to postero-medial. CONCLUSIONS: Implant fixation for fracture treatment as well as joint replacement of the proximal tibia are now able to take the regions of both high and low bone mineral density into consideration in older patients and those suffering from osteoporosis. RELEVANCE: Knowledge regarding the regional distribution of bone mineral density in the proximal tibia is necessary in order to achieve stable primary and long-term fixation of implants. This manuscript documents the bone mineral density changes that occur with age and gender.

Absorptiometry, Photon↗
PubMed2005

Bone mineral density, chemical composition and biomechanical properties of the tibia of female rats exposed to cadmium since weaning up to skeletal maturity.

The influence of exposure to cadmium (Cd) during skeletal development on the risk of bone fractures at the stage of skeletal maturity was investigated on a female rat model of human exposure. The tibias of rats treated with 1, 5 or 50 mg Cd/l in drinking water for 3, 6, 9 and 12 months (since weaning) were used. The exposure to Cd dose- and time-dependently influenced the tibia bone mineral density (BMD) and chemical composition. In skeletally matured animals, at each level of the exposure to Cd, the BMD at the whole tibia and its diaphysis as well as the percentage of minerals content in the bone, including the content of zinc, copper and iron, were decreased compared to control. Moreover, in the 50 mg Cd/l group, the percentage of organic components content increased. The Cd-induced changes, at all levels of exposure, resulted in weakening in the yield strength and fracture strength of the tibia (a three-point bending test of the diaphysis and compression test with vertical loading) of the skeletally matured females. A very important and clinically useful finding of this study is that a decrease (even by several percent) in the tibia BMD results in weakness in the bone biomechanical properties and that the BMD may predict the risk of its fracture at the exposure to Cd. Moreover, the results together with our previous findings seem to suggest that tibia, due to higher vulnerability of its diaphysis, compared to the femoral diaphysis, to damage by Cd may be more useful than femur to investigate the effect of Cd on the cortical bone. The present study revealed that a low exposure to Cd (1 mg Cd/l), corresponding to low human environmental exposure, during the skeletal development affects the tibia mineral status leading to weakening in its mechanical properties at the skeletal maturity. The findings allow for the conclusion that environmental exposure to Cd during childhood and adolescence may enhance the risk of low BMD and fractures at adulthood.

Animals↗
PubMed2006

Ultrasonometric evaluation of bone healing: Experimental study using a model of diaphyseal transverse osteotomy of sheep tibiae.

Noninvasive ionizing-radiation-free methods of evaluation, such as ultrasonometry, are desirable in any medical situation. An in vitro ultrasonometric study was undertaken to evaluate the bone healing process of sheep tibiae submitted to a diaphyseal transverse osteotomy at different times after the procedure. Fifteen sheep weighing an average of 37 kg had surgery for a transverse mid-diaphyseal osteotomy of the right tibia; they were divided postoperatively into three groups of five for periods of observation at 30, 45 and 60 days. The intact left tibiae of the 15 animals were used for control. The healing process was monitored with conventional radiographs taken at two-week intervals, and the animals were killed at the end of the period of observation of each group. Both surgical and intact tibiae were removed, their diameters were measured and they were submitted to measurement of underwater ultrasound propagation velocities (USPV) at the osteotomy sites in both the sagittal and frontal planes. The diameters of the surgical tibiae decreased with time in both planes (from 26.9 mm to 22.0 mm and to 20.9 mm in the sagittal plane, and from 29.3 mm to 23.9 mm and to 23 mm in the frontal plane), with significant differences between the periods of observation (p < or = 0.018 and p < or = 0.003 between 30 and 45 days and 30 and 60 days, respectively, for the sagittal plane and p < or = 0.006 and p < or = 0.003 between 30 and 45 days and 30 and 60 days, respectively, for the frontal plane) and between surgical and intact tibiae at all time points (p < or = 0.0005 for each comparison). USPV increased with time from 2290 m/s to 2399 m/s and to 2382 m/s in the sagittal plane, and from 2376 m/s to 2472 m/s and to 2466 m/s in the frontal plane, accounting for an approximate 5% difference between 30 and 60 days Differences between the surgical and intact tibiae were significant at all time points (p < or = 0.0005 for both sagittal and frontal planes) but not between periods for either plane. There was a strong negative correlation between diameter and USPV (Pearson's correlation coefficient of -0.8998 for the sagittal plane and -0.9192 for the frontal plane). It was concluded that ultrasonometric evaluation of the bone healing process is feasible, yielding precise and reliable results, with a potential for clinical application.

Animals↗
PubMed2000

Mechanical validation of whole bone composite tibia models.

Composite synthetic models of the human tibia have recently become commercially available as substitutes for cadaveric specimens. Their use is justified by the advantages they offer as a substitute for real tibias. The present investigation concentrated on an extensive experimental validation of the mechanical behaviour of the whole bone composite model, compared to human specimens for different loading conditions. The stiffness of the tibias was measured with a torsional load applied along the long axis, and with a bending load applied both in the latero-medial and in the antero-posterior direction. The bending stiffness of the composite tibias matched well with that of the cadaveric specimens. This was not true for the torsional stiffness. In fact, the composite tibias were much stiffer than the cadaveric specimens, possibly due to the structure of the reinforcement material. The inter-specimen variability for the composite tibias was much lower than that for the cadaveric specimens. Thus, it seems that the composite tibias are suitable to replace cadaveric specimens for certain types of test, whereas they might be unsuitable for others, depending on the loading regimen.

Biomechanical Phenomena↗
PubMed2001

Trabecular bone strain changes associated with cartilage defects in the proximal and distal tibia.

Intraarticular fractures with cartilage defects can lead to post-traumatic arthritis (PTA). The purpose of this study was to determine how cartilage defects affect load transmission through subchondral trabecular bone in human cadaveric knees and ankles to further understand the pathomechanics of PTA. We created full-thickness cartilage defects in the meniscectomized proximal tibia and distal tibia and measured changes in trabecular bone strain using Texture Correlation. Texture Correlation compares high quality digital images made from contact radiographs of unloaded samples to images of the same sample under load to measure trabecular bone strain. Cartilage defects caused trabecular bone strain to decrease in the proximal tibia and increase in the distal tibia. The column of bone directly beneath the defect in the tibial plateau had the most significant reduction in strain. In the distal tibia, strain near the jointline and in the anterior third had the most significant increases in strain. The distal tibia had greater strain changes with small defects. The clinical course of intraarticular fractures of the proximal and distal tibia are markedly different. We postulate that disturbances in load transmission through the subchondral bone caused by cartilage defects may be important mechanical determinants of PTA.

Aged↗
PubMed1999

Prediction of the strength of the elderly proximal femur by bone mineral density and quantitative ultrasound measurements of the heel and tibia.

Quantitative ultrasound (QUS) of the heel and tibia have recently been approved in the United States for diagnostic evaluation of low bone mass. The goal of this study was to use human cadaveric specimens to compare correlations among: a) strength of the proximal femur; b) bone mineral density of the femur, tibia, and heel; and c) QUS of the tibia and heel. We obtained 26 proximal femurs and intact lower limbs from 16 female and 10 male cadavers, with a mean age of 81+/-12 years. Bone mineral density (BMD, g/cm2) of the proximal femur and tibia were assessed using dual-energy x-ray absorptiometry, and BMD (g/cm) of the heel was measured using single-energy x-ray absorptiometry. Ultrasound velocity at the mid-tibia was determined using a contact, gel-coupled ultrasound device. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) of the heel were determined using a transmission ultrasound device with water-based coupling. The femurs were tested to failure in a configuration designed to simulate a fall to the side with impact to the greater trochanter. As in previous studies, the strength of the proximal femur was very strongly correlated with femoral BMD and heel BMD (r2 = 0.78-0.92, p < .0001 for all). BUA and SOS of the heel were also strongly correlated to femoral strength (r2 = 0.70 and 0.67, respectively, p < 0.0001 for both), whereas tibia SOS was only weakly correlated (r2 = 0.19, p = 0.03). The average coefficient of variation for triplicate tibial SOS measurements was 0.50%. This study indicates that, although tibial SOS measurements are precise, they are not strongly correlated with femoral BMD or strength. In contrast, heel QUS measurements are strongly correlated with the strength of the proximal femur. These findings imply that tibial SOS may be of limited use for assessing hip fracture risk. Prospective fracture risk data are needed to define further the clinical utility of tibia ultrasound measurements.

Absorptiometry, Photon↗
PubMed2004

Possible involvement of MIP-1alpha in the recruitment of osteoclast progenitors to the distal tibia in rats with adjuvant-induced arthritis.

In the rat model of rheumatoid arthritis, a marked formation of osteoclasts is found in the distal tibia and the metatarsal bone. It was therefore postulated that osteoclast progenitors would be increased in the bone marrow cavities of rats with adjuvant-induced arthritis (AA rats). Bone marrow cells obtained from tibia of AA rats were cultured to form cells in the osteoclast lineage to access the number of osteoclast progenitors. Unexpectedly, only a suppressed level of osteoclast progenitors was detected in the diaphyseal bone marrow of tibia in AA rats. Distribution of osteoclast progenitors in the bone marrow cavity was examined, and it was shown that osteoclast progenitors accumulated in the distal tibia. Macrophage inflammatory protein (MIP)-1alpha, an osteoclastogenic CC chemokine, was expressed in ED-1-positive macrophages localizing in the distal tibia with marked bone destruction. Chemotaxis studies showed that MIP-1alpha expressed significant activity towards bone marrow cells. The suppressed level of osteoclastogenesis in bone marrow cells of AA rats was restored to a normal level by the addition of MIP-1alpha. It was suggested that MIP-1alpha is involved in the migration of osteoclast progenitors to the distal tibia as well as in osteoclastogenesis in AA rats. In these rats, in situ hybridization of the distal tibia with a high level of bone destruction showed significant expression of Receptor activator nuclear factor kappaB ligand (RANKL) messenger RNA in aggregates of multinucleated osteoclast-like cells present in the bone marrow cavity, a unique pathological feature for these rats. Migrated osteoclast progenitors are thought to be efficiently differentiated into osteoclasts in response to RANKL expressed by the aggregates of osteoclast-like cells under the influence of the MIP-1alpha. Such positive-feedback regulation of osteoclastogenesis could result in the highest recruitment of active osteoclasts in the area of marked bone destruction.

Animals↗
PubMed1996

Oblique proximal tibial osteotomy for the correction of tibia vara in the young.

Proximal tibial osteotomy in the growing patient historically has been associated with a high rate of neurovascular complications and malunion. Here is reported a technique of valgus proximal tibial osteotomy, of the incomplete closing wedge type, that has avoided neurovascular compromise while achieving reliable correction and rapid bony union. Oblique proximal tibial valgus osteotomies with lateral tension plate fixation were performed on 18 tibiae in 14 patients (age range, 5-25 years) with tibia vara. The primary diagnosis was Blount's disease in 13 tibiae, achondroplasia in 2 tibiae, multiple epiphyseal dysplasia in 2 tibiae, and hypochondroplasia in 1 tibia. No postoperative plaster immobilization was necessary. All patients were able to bear weight fully by 8 weeks after surgery. Average angular correction was 18 degrees. One patient had overcorrection because of an unrecognized intraoperative fracture of the media] tibial cortex. There were no neurovascular complications. No growth disturbance of the proximal tibial physis was noted. Oblique proximal tibial osteotomy with tension plate fixation successfully corrected varus deformity of the proximal tibia in the growing patient without damage to the proximal tibial physis or neurovascular compromise.

Adolescent↗
PubMedDate not supplied

Accuracy of correction of tibia vara: acute versus gradual correction.

The purpose was to assess the accuracy of deformity correction achieved in patients with tibia vara using acute intraoperative correction compared with gradual postoperative correction. Acute correction (AC) group consisted of 14 patients (14 tibiae) with a mean age of 11.4 years and whose tibia vara was corrected acutely and held using an EBI external fixator. Gradual correction (GC) group consisted of 18 patients (18 tibiae) with a mean age of 10.2 years and whose tibia vara was corrected gradually using 6-axis deformity analysis and Taylor Spatial Frame. Deformity measurements were compared preoperatively, postoperatively, and at latest follow-up. At latest follow-up, medial proximal tibial angle deviation from normal was similar for the 2 groups; posterior proximal tibial angle was significantly greater in the AC group (5.6 degrees) than in the GC group (1.9 degrees). Mechanical axis deviation was significantly greater in the AC group (17.1 mm) than in the GC group (3.1 mm). Postoperatively, frequency of accurate translation corrections (achieved translation within 5 mm of preoperative required translation) was significantly greater in the GC group (18/18) than in the AC group (7/14). Frequency of accurate angulation corrections (medial proximal tibial angle within 3 degrees of normal and posterior proximal tibial angle within 5 degrees of normal) was significantly greater in the GC group (17/18) than in the AC group (7/14). For both groups, all tibiae with preoperative internal rotation deformity had accurate rotation correction. Correction of preoperative limb-length inequality was achieved in 5 of the 7 patients in the AC group and 11 of the 11 patients in the GC group. Gradual deformity correction is a more accurate treatment method of tibia vara than acute correction.

Adolescent↗
PubMedDate not supplied

Tibia valga after proximal metaphyseal fractures in childhood: a normal biologic response.

Seventeen children with 19 proximal tibial metaphyseal fractures were followed-up between 2 and 7 years after injury. Detailed measurements of the metaphyseal/diaphyseal/metaphyseal distances medially and laterally on the injured and noninjured sides demonstrated overgrowth. In four patients, the medial distance of the injured tibia was longer than the lateral distance, which was the same distance as the uninjured tibia. In 11 patients, there was an overgrowth of both the medial and lateral sides of the injured tibia, compared to the unijured tibia, and in each instance, the medial distance of the injured tibia was always longer than the lateral. In a patient with bilateral metaphyseal fractures, the medial length exceeded the lateral length in both tibias. In the child with metaphyseal and diaphyseal fractures, the medial side of the tibia with the metaphyseal fracture was the longest of the four measurements. In five of six patients with Harris lines, there was distal as well as proximal tibial metaphyseal overgrowth, but the distal line was always parallel to the physis and did not contribute to the valgus angulation. Thus there was not only a generalized increased growth proximally and distally, but there also was an eccentric proximal medial overgrowth in every patient.

Adolescent↗
PubMed2000

Quantitative radiographic changes in the mandible and the tibia in systemically loaded rats fed a low-calcium diet.

The combined effect of the duration of loaded physical exercise and the percentage of calcium intake on the mandible and tibia were studied in developing male rats. For the loaded exercise, rats ran on a treadmill at a rate of 12 m per min for either 1 or 2 h per day. A total of 54 4-week-old male Wistar rats were randomly assigned to one of six groups. After 4 weeks of the diet and loaded exercise, the rats were killed and their mandibles and tibia were removed. Each individual bone was assessed by radiography and the radiographs were then used for measurements of cortical thickness, bone length and bone width. All radiographic images were analyzed using a computer-based scanner image analysis system. In addition, we measured the dry weight both of the tibia and mandible. The results demonstrated that significant differences in cortical thickness, bone length, bone width, and bone weight, both of the tibia and the mandible, were detectable between the normal diet group and the low-calcium diet group. Among the normal diet groups, significant differences were found in cortical thickness, bone length, bone width, and bone weight of the tibia, whereas no significant differences in either cortical bone thickness, bone length or bone weight of the mandible were detected. In contrast, among the low-calcium diet groups, no significant differences were detected in cortical thickness, bone length, bone width or bone weight for either the tibia or the mandible. Our results suggested that systemic exercise, such as running, promote the linear dimensions and the cortical thickness of the tibia in response to local stimuli. Furthermore, sufficient calcium intake appears to be necessary to allow the effect of systemic exercise on tibial bone growth to occur. In contrast, systemic loaded exercise does not promote either bone growth or development of the mandible even under conditions of sufficient calcium intake.

Animals↗
PubMed2001

Physical and mechanical characteristics of tibias from transgenic mice expressing mutant bovine growth hormone genes.

Physical and mechanical characteristics of tibia from mice expressing either the M4, M11, or G119K mutant bovine growth hormone (bGH) gene and displaying large, near-normal, or small-size phenotypes, respectively, were compared to those of non-transgenic, control mice (NTC). Three animals of each strain were euthanized at 28, 38, 48, 58, and 68 days of age. Variables were regressed against age to establish the pattern of change throughout the experiment, and the regression results are presented. Tibias from G119K were shorter (13.1 mm) and lighter (37.3 mg) than those from other strains, and M4 tibias were heavier (87.9 mg) and longer (16.6 mm) at 70 days of age. The ratio of tibia length to body weight suggests longitudinal bone growth was not reduced as much as overall growth in G119K mice. The external and internal dimensions of the G119K tibias were smaller than the other strains whereas the M4 tibias were somewhat larger. Differences in physical dimensions between the NTC and M11 mice did not greatly affect bone mechanical characteristics. Tibias from M4 mice resisted more load at both flexure and breaking compared to the other strains. At 50 days of age, stress at flexure was greater at all ages for G119K mice (12.4 kg/mm2) and was decreased in M4 mice (8.5 kg/mm2). The bGH mutations produce different effects on bone growth and its mechanical characteristics. There also may be differential tissue responsiveness to the mutant bGH analogs, as longitudinal growth was not as affected as empty body growth in the G119K mice. These transgenic mouse strains provide valuable models to study bone growth, formation, and reformation in response to GH regulation, and more importantly, the M4 and G119K mice may serve as a model in which the priorities for GH action on bone vs muscle may be determined.

Animals↗
PubMed2004

Precision of bone mineral density scans at the proximal tibia in osteoarthritic subjects.

This study was conducted to assess the precision of dual-energy X-ray absorptiometry (DXA) measurements at the proximal tibia and compare it with precision at other skeletal sites. Precision at the proximal tibia was determined in two groups: 14 subjects with knee osteoarthritis (OA) and 14 normal subjects who were scanned bilaterally four times each, with repositioning. Precision of femoral neck, trochanter, and total hip was also determined in both groups. Group mean bone mineral density (BMD), standard deviation (SD), and root mean squared coefficient of variation (%CV) were determined for both tibias and hips, lumbar spine (L2-L4) and total body. The %CV of the proximal tibia ranged from 1.01% to 1.24% and did not differ significantly in the two groups. The %CV of the hips, spine, and total body ranged from 0.79% to 2.28%. We conclude that DXA scans at the proximal tibia are highly reproducible and that precision at the proximal tibia is comparable to that of the hip, spine, and total body. A larger study is needed to determine whether proximal tibia BMD measurements have research or clinical application for osteoarthritis or other conditions.

Absorptiometry, Photon↗
PubMed1983

Mechanical effects of metal plate fixation. In vitro investigation on intact and osteotomized human and rabbit tibiae.

In order to study the in vitro stress-protecting effect on intact bone, and the rigidity of plate fixation on osteotomized bone, human and rabbit tibiae were tested in three-point bending in an Instron testing machine. Intact tibiae were loaded in the elastic range before and after metal plate application. The deformation was measured with a linear voltage differential transformer. In the human specimens a median stiffness increase of 31 per cent was obtained in the plated bone segment after application of a tibial plate (140 x 12 x 4 mm) and of 43.8 per cent after application of a femoral plate (140 x 16 x 5 mm). In the rabbit specimens a median stiffness increase of 31.9 per cent was obtained after application of a thin plate (45 x 5 x 1 mm). In osteotomized human tibiae with tibial plate fixation, a median elastic stiffness of 51.4 per cent of the intact bone was found, compared to 40.4 per cent in osteotomized rabbit tibiae plated with the thin plate. There was good agreement between the results in human tibiae plated with a tibial plate, and rabbit tibiae with the small plate. In previous studies of the stress-protecting effect of internal plate fixation on rabbit tibiae more rigid plates have been used. These plates seem to have been overdimensioned. In further studies in rabbits plates of similar size as the one tested in this study should be applied.

Animals↗
PubMed1991

Influence of age, sex, and method of rearing on tibia length and mineral deposition in broilers.

Two experiments were conducted to determine linear growth and mineral deposition in the tibiae of Vantress x Arbor Acres broilers. In Experiment 1, birds were maintained in battery brooders for 21 days then housed in floor pens from Day 22 to 70. In the second experiment, birds were reared either in battery brooders and grow-out cages or floor pens from Day 1 to 63. Males and females were maintained separately. Birds in both trials were weighted at weekly intervals and three birds of each sex per treatment were euthanatized weekly to obtain tibia samples. Tibiae were cleaned of muscle and connective tissues, dried, extracted with diethyl ether, measured for length in centimeters, weighed, and ashed. Results from both experiments show a curvilinear response for weight gain, bone length, and bone ash weight. In some cases, sex by week or week by rearing interactions (P less than .001) were observed. As expected, males had greater weight gain and bone length than females. In Experiment 2, birds grown in floor pens had greater (P less than .05) bone length, tibia weight, and tibia ash weight than cage-reared birds, but percentage tibia ash was not different between the two rearing systems. Tibia growth and mineral deposition were influenced by gender and rearing systems. Bone ash weight data for females in both trials had a response curve that approached a sigmoidal shape. Response curve for males tended to be more quadratic, indicating a significant (P less than .003) week by week by sex interaction. Thus, there was evidence for bone growth differences not only between rearing systems, but also between sexes, the latter not unexpected.

Age Factors↗