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PubMed1992

Repetitive loading, in vivo, of the tibia and femora of rats: effects of a single bout of treadmill running.

The presence of microdamage in the tibiae and femora of rats following repetitive loading in vivo was investigated by subjecting 48 male rats, aged 12 weeks, to treadmill running (26.8 m.min-1 on 10% grade) for 0.56 hours (5,000 cycles, E1), 1.13 hours, (10,000 cycles, E2), 2.27 hours (20,000 cycles, E3), and 3.4 hours (30,000 cycles, E4) with Group C as control. Following exercise, tibiae and femora were excised and the right limbs were tested in torsion at 180 degrees.sec-1. Transverse sections were cut from the proximal, mid- and distal diaphysis of left tibiae and femora, bulk stained in basic fuchsin, cut to 50 microns thick, and examined for the presence of microdamage. Following these periods of loading, tibiae and femora showed no evidence of microdamage initiation, as evidenced by light microscopy, or corresponding alterations in mechanical properties. It was concluded that the magnitude of loading produced by single bouts of intensive exercise, which encompassed up to 30,000 loading cycles, was insufficient to initiate fatigue microdamage in tibiae or femora of rats.

Animals↗

PubMed1977

Magnesium and the mineral metabolism of chick embryo tibiae in organ culture.

Using bone organ culture techniques, three concentrations of magnesium were evaluated for their effects on the mineral mass of embryonic chick tibiae incubated for 3 days with or without a metabolic inhibitor (1 mM iodoacetic acid) added to the media. Varying the medium Mg level from 0.3 to 3.0 mM had little effect on the net increase in mineral in live bones (without the inhibitor), but in dead tibiae (with the inhibitor) there was a marked net decrease in mineral deposition with increasing Mg concentration. Bone Mg mass varied directly with the level of Mg in the medium regardless of whether or not the tibiae were inhibited. Responsiveness to parathyroid hormone (PTH) with regard to mineral loss and increased lactate production was not affected by Mg even in tibiae incubated in Mg-free media. However, PTH-treated bones cultured in Mg-free media had a significantly elevated Mg mass, suggesting that the hormone may have a Mg-conserving effect on bone during severe Mg deficiency. The findings of this study support the hypothesis that bone cells regulate the level of Mg to which newly forming mineral is exposed and that PTH-responsiveness in embryonic chick tibiae is not dependent on the ambient Mg concentration.

Animals↗

PubMed1992

Characterization of in vivo strain in the rat tibia during external application of a four-point bending load.

This paper describes a technique for characterizing strains and stresses induced in vivo in the rat tibia during application of an external four-point bending load. An external load was applied through the muscle and soft tissue with a four-point bending device, to induce strain in a 11 mm section of the right tibiae of ten adult female Sprague-Dawley rats. Induced strains were measured in vivo on the lateral surface of the tibia. Inter-rat difference, leg positioning and strain gage placement were evaluated as sources of variability of applied strains. Beam bending theory was used to predict externally induced in vivo strains. Finite element analysis was used to quantify the magnitude of shear stresses induced by this type of loading. There was a linear relationship between applied load and induced in vivo strains. In vivo strains induced by external loading were linearly correlated (R2 = 0.87) with the strains calculated using beam bending theory. The finite element analysis predicted shear stresses at less than 10% of the longitudinal stresses resulting from four-point bending. Strains predicted along the tibia by finite element analysis and beam bending theory were well-correlated. Inter-rat variability due to tibia size and shape difference was the most important source of variation in induced strain (CV = 21.6%). Leg positioning was less important (CV = 9.5%).

Animals↗

PubMed1991

Repetitive loading, in vivo, of the tibiae and femora of rats: effects of repeated bouts of treadmill-running.

Twenty-four male rats, aged 12 weeks, were subjected to approximately 20,000 loading cycles per day of treadmill running (2 h/day, 26.8 m/min and 10% gradient) for 5 (group A) and 10 days (group B); with corresponding controls (C5) and (C10). Rats in groups B and C10 were given weekly doses of tetracycline from 4 days prior to training. Following training, right tibiae and femora were tested to failure in torsion at 180 degrees/s. Sections were cut from the distal, mid and proximal diaphysis of left bones, bulk-stained in basic fuchsin and two transverse sections (50 microns) were cut and examined for the presence of microdamage and fluorescence. Results for mechanical testing showed a significant reduction in stiffness of tibiae (P less than 0.01) for groups A and B and a significant increase in twist angle (P less than 0.01) for group A when compared with controls. No evidence of microdamage was observed from histological analysis. But, labelling demonstrated reduced appositional growth of the periosteal and endosteal surface at the mid-diaphysis of exercised tibiae (P less than 0.01). These tibiae also showed fewer regions of, measurable, appositional growth than controls (P less than 0.05). Exercised femora showed increased appositional growth at the endocortical surface of the mid-diaphysis (P less than 0.05). Reductions in stiffness of exercised tibiae were significantly correlated with cross-sectional area.

Animals↗

PubMed1987

Static measurement of tibia vara. Reliability and effect of lower extremity position.

The purpose of this study was to examine the reliability of tibia vara measurements and to determine the effects of lower extremity position on such measurements. A manual goniometer was used to measure tibia vara in both lower extremities of 20 healthy subjects while they assumed three different positions: double-limb stance (DLS) with subtalar joint position uncontrolled (Condition 1), DLS with subtalar joint positioned in neutral (Condition 2), and single-limb stance with subtalar joint position uncontrolled (Condition 3). Intraclass correlation coefficients (p less than .05) revealed that tibia vara measurements were reliable both within and between raters with mean absolute differences between repeated measures of 2 to 3 degrees. An analysis of variance and a Newman-Keuls post-hoc test (p less than .05) showed that Condition 3 produced the greatest value of tibia vara followed by Conditions 1 and 2, respectively. The results of this study suggest that lower extremity position is an important consideration when measuring tibia vara and determining whether treatment intervention is indicated.

Adult↗

PubMed1986

A three-dimensional finite element analysis of the upper tibia.

A three-dimensional finite element model of the proximal tibia has been developed to provide a base line for further modeling of prosthetic resurfaced tibiae. The geometry for the model was developed by digitizing coronal and transverse sections made with the milling machine, from one fresh tibia of average size. The load is equally distributed between the medial and lateral compartments over contact areas that were reported in the literature. An indentation test has been used to measure the stiffness and the ultimate strength of cancellous bone in four cadaver tibiae. These values provided the statistical basis for characterising the inhomogeneous distribution of the cancellous bone properties in the proximal tibia. All materials in the model were assumed to be linearly elastic and isotropic. Mechanical properties for the cortical bone and cartilage have been taken from the literature. Results have been compared with strain gage tests and with a two-dimensional axisymmetric finite element model both from the literature. Qualitative comparison between trabecular alignment, and the direction of the principal compressive stresses in the cancellous bone, showed a good relationship. Maximum stresses in the cancellous bone and cortical bone, under a load which occurs near stance phase during normal gait, show safety factors of approximately eight and twelve, respectively. The load sharing between the cancellous bone and the cortical bone has been plotted for the first 40 mm distally from the tibial eminence.

Aged↗

PubMed1992

Sectorial angioarchitecture of the human tibia.

The blood supply of the periosteum of the human tibia was investigated by anatomical dissection of 12 lower extremities which were filled with injection mass. By division of the tibia into 4 segments (proximal and distal fifths; proximal and distal diaphysis) a general supplying system of the periosteum was found. The proximal fifth of the tibial periosteum is nourished by branches of the arteriae recurrentes tibiales anterior et posterior and the aa. inferiores medialis et lateralis genus. At the proximal diaphysis (next three tenths of the tibia) periosteal branches arise from the aa. tibialis anterior and posterior, whereas the distal diaphysis is nourished exclusively by semicircular vessels of the a. tibialis anterior which twine around the bone and merge with each other at the facies medialis. Concerning the periosteal blood supply of the distal fifth of the tibia, two different types were found. In two thirds of the cases the lateral side was nourished by branches of the a. tibialis anterior, which are supported by vessels from the a. fibularis. In one third the latter branch was absent so that the rami periostales arising from the a. tibialis anterior nourished the lateral aspect of the distal tibia alone. The dorsal region was supplied in all cases by rami of the a. fibularis and a. tibialis posterior. On the medial side the periosteal nourishment is ensured only by anastomosis. Branches of the a. tibialis anterior supply the facies lateralis and facies posterior where it is supported by vessels of the a. tibialis posterior and in a minor region of rami of the a. fibularis (distal) and a. poplitea (proximal).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMedDate not supplied

Anterior-posterior and rotational displacement of the tibia elicited by quadriceps contraction.

The anterior-posterior displacement and rotation of the tibia elicited by isolated loading of the quadriceps muscle was determined as a function of joint angle and muscle load using a computerized radiographic technique. Data collected from 12 fresh-frozen cadaveric knees demonstrated that quadriceps contraction can result in significant (less than 7 mm) anterior displacement of the tibia in the range of 0 degrees to 80 degrees of flexion, and a mild (less than 2 mm) posterior displacement in the range of 80 degrees to 120 degrees of flexion. Peak anterior displacement of 6.3 mm was observed at 30 degrees of flexion under a 12 kg load in the quadriceps, while a constant 1.5 mm posterior displacement was observed throughout flexion angles exceeding 80 degrees. It was further shown that the magnitude of the anterior displacement increased nonlinearly as the quadriceps force increased. Loading of the quadriceps also resulted in internal rotation of the tibia in the range of 0 degrees to 90 degrees of flexion, and in external rotation of the tibia in the range of 90 degrees to 120 degrees. Peak internal rotation of 7 degrees was observed at 15 degrees of flexion and a peak external rotation of 1 degrees was detected at 120 degrees of flexion. Larger quadriceps load resulted in larger rotation. We concluded that quadriceps contraction during knee extension has direct impact on anterior displacement and rotation of the tibia and therefore on anterior cruciate ligament stress, increasing it as the muscle's force is increased during knee extension.(ABSTRACT TRUNCATED AT 250 WORDS)

Anterior Cruciate Ligament↗

PubMed1992

Use of an intramedullary rod for the treatment of congenital pseudarthrosis of the tibia.

The use of an intramedullary rod as described by Williams, combined with implantation of an autogenous bone graft, resulted in union of an established congenital pseudarthrosis of the tibia in nine of ten patients. One patient needed additional bone-grafting before union occurred. The average age at the time of the operation was five years and three months. A rod of the appropriate length was inserted at the site of the non-union, antegrade through the distal part of the tibia and the hindfoot and then retrograde through the proximal fragment. This resulted in splinting of the tibia, ankle, and subtalar joints. Solid osseous union occurred an average of six months after the procedure in all ten patients. Five patients had a refracture of the tibia after the initial consolidation. Three of the five needed one or more additional operative procedures; one was managed with a cast; and one patient, who had been followed for four years before the refracture, did not return for treatment of the refracture. As is the plan with this method of treatment, the distal part of the tibia grew off the rod and the distal tip of the rod was located proximal to the foot and ankle, or it was located more proximally than it had been at the operation, in six patients. The rod was removed from three patients. At an average of six years, all ten patients were able to walk without pain.

Amputation, Surgical↗

PubMed1987

Longitudinal growth of the femur and tibia after diaphyseal lengthening.

Growth of the femur and tibia after lengthening of their diaphyses, which had been performed several years before skeletal maturity, was assessed in eighteen patients by serial orthoroentgenograms. The rate of growth of the lengthened femora, which had been congenitally short, increased after each of seven lengthening procedures, from an average preoperative rate of 82 per cent of the normal side to 90 per cent of the normal side. The amount of surgical lengthening was similar for the femora and the tibiae, averaging 18 per cent of the preoperative length of the bone in the femora and 20 per cent of the preoperative length of the bone in the tibiae. However, the rate of growth of the lengthened tibiae decreased after each of eleven lengthening procedures (six performed for a congenital short tibia; three, for patients who had Ollier's disease; one, for a patient who had poliomyelitis; and one, for a patient who had hemangiomas), from an average preoperative rate of 88 per cent of normal to an average of 64 per cent of normal.

Bone Lengthening↗

PubMed1988

In vivo tibia lead measurements as an index of cumulative exposure in occupationally exposed subjects.

In vivo tibia lead measurements of 20 non-occupationally exposed and 190 occupationally exposed people drawn from three factories were made using a non-invasive x ray fluorescence technique in which characteristic x rays from lead are excited by gamma rays from a cadmium-109 source. The maximum skin dose to a small region of the shin was 0.45 mSv. The relation between tibia lead and blood lead was weak in workers from one factory (r = 0.11, p greater than 0.6) and among the non-occupationally exposed subjects (r = 0.07, p greater than 0.7); however, a stronger relation was observed in the other two factories (r = 0.45, p less than 0.0001 and r = 0.53, p less than 0.0001). Correlation coefficients between tibia lead and duration of employment were consistently higher at all three factories respectively (r = 0.86, p less than 0.0001; r = 0.61, p less than 0.0001; r = 0.80, p less than 0.0001). A strong relation was observed between tibia lead and a simple, time integrated, blood lead index among workers from the two factories from which blood lead histories were available. The regression equation from two groups of workers (n = 88, 79) did not significantly differ despite different exposure conditions. The correlation coefficient for the combined data set (n = 167) was 0.84 (p less than 0.0001). This shows clearly that tibia lead, measured in vivo by x-ray fluorescence, provides a good indicator of long term exposure to lead as assessed by a cumulative blood lead index.

Adolescent↗

PubMed1988

Fatigue fractures of the proximal tibia simulating malignancy.

The clinical and radiological features of nine fatigue fractures developing along the soleal line of the posteromedial cortex of the proximal tibia are described. Seven patients were referred with the diagnosis of a probable malignant sarcoma of bone. All nine patients were male and all but one were 18 years of age or less. Only two gave a history of a recent increase in physical activity. The plain radiographic findings consisted of an uninterrupted, lamellar, periosteal reaction arising medially and posteriorly in the proximal tibia with the fracture seen through the thickened posterior cortex. Bone scan revealed a fusiform focus of increased uptake in the posteromedial cortex of the tibia with varying degrees of activity in the adjacent metaphysis. Computed tomography, on a soft-tissue window, showed perifracture oedema and the absence of a soft-tissue mass. The attenuation of the underlying medulla was increased as a result of fibrosis and hyperaemia. On an extended window setting, both periosteal and endosteal callus was identified, maximal in the posteromedial tibia, and the fractures, multiple in two cases, were best demonstrated on a cortical window. Clinical and radiological features that differentiate a fatigue fracture of the tibia from a sarcoma are discussed.

Adolescent↗

PubMed1992

Posterolateral bone grafting for nonunion of the tibia.

Sixty-two tibial diaphyseal nonunions in 60 patients were treated with a posterolateral bone graft over an 18-year period (1969-1987). The majority were complicated by severe soft tissue damage or segmental bone loss. Thirty-four had a deep infection. Primary healing was achieved in 92%. Three types of bone grafts have been used: from 1969 to 1978 either a whole iliac bone graft (10 tibiae) or a nonvascularized fibular graft (11 tibiae) was used. Since 1978 small iliac cancellous bone chips (41 remaining tibiae) were applied to the posterior surfaces of tibia and interosseous membrane. In three tibiae with major bone defects, cancellous allografts were added to the autogenous bone. The use of cortico-cancellous bone chips resulted in a shorter healing time, compared to a nonvascularized fibular graft or a massive corticocancellous bone block.

Adolescent↗

PubMed1992

Intramedullary interlocked tibia nailing: a new technique (preliminary report).

This paper presents a modified surgical technique for interlocked intramedullary stabilization of tibia fractures. An external distractor is used to achieve an indirect fracture reduction on a fluoroscopy table. This method avoids the potential traction complications associated with conventional fracture tables. The fluoroscopy unit remains in one position during the entire operation. This technique decreases set-up time, provides complete control over the involved extremity, facilitates an accurate reduction, allows for compression at the fracture site, and simplifies the interlocking procedure. Twenty patients with 20 tibia shaft fractures were treated with this technique. No complications occurred during acute fracture care. Alignment was anatomic or near anatomic in all cases and physician satisfaction was 100%. At follow-up, averaging 5.2 months, there has been no change in fracture alignment, and most tibias are demonstrating clinical and radiographic healing. Distraction at the fracture site with a statically locked tibia nail may impede healing. The external distractor can be used to compress the fracture site prior to static interlocking, and this may facilitate healing. Dynamization of the nail should be considered when early signs of healing are absent. This technique is simple, accurate, and safe, and should be considered when treating an unstable tibia shaft fracture with a locked intramedullary nail.

Adolescent↗

PubMed1987

Carbon fiber reinforced plastic (CFRP) plates versus stainless steel dynamic compression plates in the treatment of fractures of the tibiae in dogs.

In a series of 14 dogs, fractures of both tibiae were caused by a "bone-breaker" designed in the authors' department and observed to produce a consistent and realistic canine fracture. One tibia was plated with a carbon fiber reinforced plastic (CFRP) plate and the other with a dynamic compression (DC) plate. Roentgenographic examination demonstrated healing of the CFRP-plated tibiae with abundant callus, and almost total remodeling of the fracture callus between ten and 20 weeks. Biomechanical testing by three-point bending revealed little difference between the strength of union of the fractures at 12-16 weeks. At 20 weeks, although the numbers were too small for statistical confirmation, the CFRP-plated tibiae were consistently stronger than the DC-plated tibiae.

Animals↗

PubMed1986

Treatment of infected pseudarthrosis of the femur and tibia with an interlocking nail.

Between 1970 and 1977, 64 patients with infected pseudarthrosis of the femur and tibia were treated with an interlocking nail. The type of primary treatment prior to the development of the infected pseudarthrosis was plate fixation in 21 femurs and seven tibias and conventional intramedullary nails in 16 femurs and 20 tibias. Fracture union was obtained in 34 of the 38 femoral infected pseudarthrosis (89.5%) and 19 of 27 tibial infected nonunions (62.5%) following interlocking nailing. Seven of the eight failures (87.5%) in the tibial group were the result of reoperation with interlocking nails following infected plate fixation. Following removal of the interlocking nail and treatment of residual infection, osteomyelitis was considered quiescent in 59 patients (35 femurs and 24 tibias) and active in five patients (two femurs and three tibias). Today, external fixation in combination with gentamicin-PMMA chains for local antibiotic treatment is used in the majority of such cases, because fracture instability and the chronic osteomyelitis can be treated simultaneously.

Adult↗

PubMed1975

Anatomical differences in the femur and tibia between Negroids and Caucasoids antheir effects upon locomotion.

Nine variables of length, width and circumference of the femur and tibia were measured on post-cranial remains of 28 Caucasoids and 45 Negroids. The distance from the point of tibial attachment of the patellar ligament to the head of the tibia (PLID) was also determined. It was found that the Negroid has a significantly longer and narrower femur and tibia than the Caucasoid, although PLID did not vary between the two groups. Thus PLID, relative to the length of the tibia, was less in Negroids than Caucasoids. A factor analysis was carried out in order to examine the relation between PLID and the other variables. It appeared that the same three factors governed the ten variables in both races. In Caucasoids, PLID did not load on either the "length" or "width" factors and appeared unique. In Negroids, PLID loaded on Factor III with two width measures, and this factor correlated positively with the "width" factor. It is suggested that in Caucasoids PLID does not relate to length or width dimensions of the leg but in Negroids it is related to width rather than length.

Anthropometry↗

PubMed1990

The histological effects of the implantation of different sizes of polyethylene particles in the rabbit tibia.

This study examines the histological effects of different sizes of polyethylene particles implanted into the rabbit tibia. Seventeen mature New Zealand white female rabbits were allocated into three groups. Group 1 (5 rabbits) received polyethylene particles averaging approximately 16 microns in diameter, implanted into the right proximal tibia through a drill hole. Group 2 (5 animals) received particles averaging 26 microns, and Group 3 (7 rabbits) received particles averaging 67 microns. The left tibia was drilled but not implanted. Animals were sacrificed after 16 weeks. Histological analysis disclosed decreased hematopoietic activity within the left tibial drill hole. In all groups, the right tibia demonstrated positively birefringent polyethylene particles surrounded by, and within (smaller particles), histiocytes and giant cells in a fibrous tissue stroma. Statistical analysis disclosed more fibrocytes and less marrow cells at the interface of Group 3 (largest particles) compared to Group 1 and 2. Larger polyethylene particles, being less readily phagocytosed, appear to produce more fibrous encapsulation, compared to particles of a smaller size. The histological reaction stimulated by the different sizes of polyethylene particles resembled the membrane surrounding loose joint arthroplasties in humans.

Animals↗