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Comparison of three-point bending test and peripheral quantitative computed tomography analysis in the evaluation of the strength of mouse femur and tibia.

We compared the mechanical and densitometric testing methods in evaluating the mechanical strength of mouse cortical bones. The femora and tibiae of 10 male mice (weight 32.8 +/- 4.0 g) were utilized. Volumetric cortical bone mineral density (vCtBMD), cross-sectional cortical area at midshaft (CSA), cross-sectional moment of inertia (CSMI), and strength strain index (SSI) were measured by peripheral quantitative computed tomography (pQCT). The precision of pQCT expressed as a coefficient of variation (CV) was 1.1%, 2.7%, and 6.4% for vCtBMD, CSA, and CSMI, respectively. The mechanical properties were measured by a three-point bending test. The method error measured from paired bones was 7.3%-10.1% for breaking bending force, 15.0%-15.2% for stiffness, 2.0%-2.4% for vCtBMD, 5.2%-6.4% for CSA, 13.5%-17.6% for CSMI, and 8.9%-18.1% for SSI. CSMI and CSA were found to be the best explanatory variables for the breaking force of femur and tibia, respectively, while CSA and CSMI were the best predictors for the elastic modulus of femur and tibia, respectively. CSA had a higher correlation with mechanical parameters than vCtBMD. On the basis of this study, the mechanical tests and the pQCT measurements are relevant in biomechanical studies on mouse bones and justify the use of the murine model. High-resolution pQCT gives better precision than the three-point bending test in studies of mouse bones.

Animals↗

Immunohistochemical localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias in rats.

Type I collagen, fibronectin and tenascin C play an important role in regulating early osteoblast differentiation, but the temporal and spatial relationship of their localization during embryonic osteogenesis in vivo is notknown. The present study was designed to localize these three molecules in the dentary of mandibles and tibias in rat embryos using immunohistochemistry. Serial paraffin sections were cut and adjacent sections were processed for von Kossa staining or immunohistochemistry for type I collagen, fibronectin and tenascin C. In the dentary, tenascin C was localized within and around the mesenchymal cell condensation in embryos at 14 days in utero. The bone matrix at 15 days showed immunoreactivity for both type I collagen and fibronectin. The immunoreactivity of type I collagen was persistent, whereas that of fibronectin decreased with age of embryos. In tibias, tenascin C was localized in the perichondral mesenchymal tissue at 17 days. Immunoreactivity for type I collagen was persistent in the bone matrix, whereas the tibial bone showed little immunoreactivity for fibronectin at any embryonic age examined. The present study demonstrated characteristic localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias.

Animals↗

The application of resonance frequency measurements to study the stability of titanium implants during healing in the rabbit tibia.

The aim of this investigation was to measure the resonance frequency of a number of implants placed in the rabbit tibia at insertion and at predetermined periods thereafter and to correlate the results with histomorphometric measurements made when the animals were sacrificed. Ten mature New Zealand White rabbits were used in the study. Two c.p. threaded titanium implants were placed in the right tibia of each animal. Resonance frequency measurements were made by screwing a small transducer onto a standard abutment mounted on each fixture. Measurements were repeated with the transducer oriented perpendicular and parallel to the long axis of the tibia for all proximal implants 14 and 28 days after placement and in 6 implants additionally at 42, 56, 93, 122 and 168 days after which all animals were sacrificed. Histomorphometric analysis comprised 2 parts; measurement of bone-implant contact area and height. A significant increase in resonance frequency was observed after 14 (405 Hz, +/- 234 Hz) and 28 (658 Hz, +/- 332 Hz) days. The increase in resonance frequency levelled after approximately 40 days and little further change was observed. The variation in bone-implant contact area was relatively small (1.8-4.9 mm2) and the range of bone-implant contact heights was also narrow (-1.5 (-)+ 1.5 mm). Values for resonance frequencies plotted against contact area and height were grouped around 10 kHz. In conclusion, it was shown that resonance frequency measurements can be made at placement and during healing in vivo and changes may be related to the increase in stiffness of an implant in the surrounding tissues.

Animals↗

Reconstruction of the extensor mechanism after proximal tibia endoprosthetic replacement.

The proximal tibia is a difficult area in which to perform a wide resection of a bone tumor. This difficulty is due to the intimate relationship of tumor in this location to the nerves and blood vessels of the leg, inadequate soft tissue coverage after endoprosthetic reconstruction, and the need to reconstruct the extensor mechanism. Competence of the extensor mechanism is the major determinant of functional outcome of these patients. Between 1980 and 1997, 55 patients underwent proximal tibia resection with endoprosthetic reconstruction for a variety of malignant and benign-aggressive tumors. Reconstruction of the extensor mechanism included reattachment of the patellar tendon to the prosthesis with a Dacron tape, reinforcement with autologous bone-graft, and attachment of an overlying gastrocnemius flap. All patients were followed for a minimum of 2 years; 6 patients (11%) had a transient peroneal nerve palsy, 4 patients (7.2%) had a fasciocutaneous flap necrosis, and 2 patients (3.6%) had a deep wound infection. Full extension to extension lag of 20 degrees was achieved in 44 patients, and 8 patients required secondary reinforcement of the patellar tendon. Function was estimated to be good to excellent in 48 patients (87%). Reattachment of the patellar tendon to the prosthesis and reinforcement with an autologous bone-graft and a gastrocnemius flap are reliable means to restore extension after proximal tibia endoprosthetic reconstruction.

Adolescent↗

[Congenital bowing of the tibia in neurofibromatosis von Recklinghausen (author's transl)].

There is a close, but not constant, relationship between congenital bowing of the tibia or infantile pseudo-arthrosis of the tibia and von Recklinghausen's neurofibromatosis. In about 40% it is possible to confirm the diagnosis by examining relatives, but the radiological findings and the course of the disease, as well as by histological examination. Anterior bowing with dysplastic-sclerotic bone changes results in the "high risk tibia". This may lead to a pathological fracture. Treatment depends on the clinical findings and radiological changes. It should be aimed at preventing pathological fractures and pseudarthrosis.

Adolescent↗

[Minimally Invasive Stryker-Osteonics unicondylar knee prosthesis with metal-backed tibia component: a 5-year follow-up].

INTRODUCTION: The aim of this study was to evaluate the medium-term results of minimally invasive unicompartmental knee joint arthroplasty with a metal-backed tibia component. MATERIAL AND METHODS: Ninety-one unicompartmental knee replacements with a metal-backed tibia component, type SCR-Stryker Osteonics, were implanted in a minimally invasive technique in 91 patients between 1997 and 1999. The evaluation of medium-term results was based on The Knee Society Clinical Rating System by Insall and Scott and was done at 6 weeks, 1, 3 and 5 years after surgery. This rating system is based on the clinical and symptoms of the patient (maximum score 100). RESULTS: Preoperatively, the average knee score was 57.6 (44-66), the function score 63.3 (48-71). Throughout the period of investigation all patients had an increased knee and function score. One year after surgery the knee and function scores increased to 94.8 (39-100) and 93.6 (75-100). Five years post-implantation only 64 patients could be re-evaluated but they also had a knee and function score corresponding to the 3-year results [knee score: 98.2 (94-100); function score: 98.9 (85-100)]. Revision surgery using a total knee prosthesis was performed in 3 cases. DISCUSSION: The unicompartmental knee arthroplasty was a good surgical method for managing medial, unicompartmental arthritis of the knee joint. The results presented by the authors and corroborated by many literature data provide evidence that unicompartmental arthroplasty is of great importance in the treatment of unicompartmental knee arthritis. The results achieved by the minimally invasive technique of a unicompartmental knee arthroplasty with a metal-backed tibia component of the type Stryker-Osteonics were equal to the conventional surgical technique in literature. Good indications were patients older than 60 years with normal weight and normal sports activity. Well-functioning collateral and cruciate ligaments were mandatory. Moreover, the minimally invasive technique may lead to a shorter time of rehabilitation because of the reduced soft tissue damage.

Adult↗

Growth disturbance following metaphyseal bending fractures of the proximal tibia--an experimental study in the mini pig.

Based on our clinical experience, we postulate that the unilateral "posttraumatic genu valgum" develops on the grounds of an unreduced primary valgus deformity. This induces a disturbance of the consolidation on the medial aspect of the fracture. Subsequently, a partial medial stimulation of the epiphyseal plate develops resulting in a secondary valgus deformity. We succeeded in proving experimentally this postulate using the Mini Pig as an experimental model. We investigated 33 tibiae of 17 Mini Pigs. With radiological follow-up studies we were able to show that the operatively created primary valgus deformity induces an increased valgus deformity of functional significance. This is a model of the unreduced fracture in men. However, the transection of the pes anserinus and the periost per se did not provoke a significant valgus formation. Based on these experimental results and our clinical findings we postulate the following treatment for the metaphyseal bending fractures of the proximal tibia in men: 1. Accurate, usually conservative, reduction of any primary valgus malposition of the fracture. 2. Retention of the corrected position of the tibia in a plaster cast. 3. Compression of the medial aspect of the fracture to prevent disturbance of consolidation and subsequent development of valgus deformity.

Animals↗

[Aplasia of the tibia - a case report with observation for 38 years (author's transl)].

The paper reports the result of operative treatment in a case of total congenital absence of the tibia. The boy was treated conservatively by plaster casts and apparative supports until he was six years old. Then the upper end of the fibula was set into the intercondylic fossa of the femur and two months later a talofibular fusion correcting the clubfoot deformity was performed. 32 years after this procedure the leg is now 28 cm shorter. The knee joint is absolutely stable in extended position and active flexion is possible to 45 degrees. The fibula shows a remarkable hypertrophy and has changed its form into a tibia-like bone. The patient is able to walk 15 km without any pain using a supporting apparatus. In congenital absence of the tibia or fibula we prefer orthopedic - surgical devices which preserve the dysplastic part of the limb instead of primary amputation.

Braces↗

Proximal tibia--extensor mechanism composite allograft for revision TKA with chronic patellar tendon rupture.

Rupture of the patellar tendon following TKA is fortunately an uncommon complication with an incidence of 0.2-4% (Abril et al. 1995). Numerous options have been reported for treating this complication, including primary suture into a bone trough (Abril et al. 1995), autogenous tendon transfer (Cadambi and Engh 1992), and use of an artificial ligament (Fujikawa et al. 1994). Allograft patellar tendon has also been utilized either retaining the host patella and using a bone-tendon-bone graft or excising the host patella and using a quadriceps tendon-patella-patellar tendon-tibial tubercle graft (Emerson et al. 1990, Emerson et al. 1994, Zanotti et al. 1995, Booth et al. 1999). All of these techniques require structural integrity of the proximal tibia in the area of the tibial tubercle in order to attach the repair or graft to restore continuity of the extensor mechanism. When there is massive osteolysis and bone loss involving the proximal tibia, the situation becomes more complex and the previously described techniques are not advisable. In such cases, function can be obtained with a composite allograft of proximal tibia-patellar tendon-patella-quadriceps tendon. We describe a technique for dealing with this difficult clinical situation.

Arthroplasty, Replacement, Knee↗

Tibia as donor site for alveolar bone grafting in patients with cleft lip and palate: long-term experience.

Tibial bone grafts were studied in 137 patients with clefts of the lip and palate. Twenty-one had clefts of the lip and primary palate and 116 had complete unilateral clefts of the lip and palate. Bone grafting was performed secondarily or late secondarily. Bone was harvested from the proximal part of the tibia distal to the tuberosity through an incision about 15 mm long. The mean follow-up time after bone grafting was 5.5 years (range 2-11). There were no operative, or early or late postoperative complications reported (such as haematoma, fracture, or shortening of the limb). Harvesting time was about 15 minutes. The possibility of operating with two teams makes the total operating time shorter. Bleeding was negligible (less than 15 ml) and the amount of bone obtained was always sufficient. Patients were mobilised the next day and were back to full physical activity by one month. Indications for tibial bone grafting included facilitation of tooth eruption into the graft, giving bony support to the neighbouring teeth, making it possible to insert a titanium fixture, raising the alar base of the nose, and closing an oronasal fistula. Compared with iliac, cranial, mandibular, and costal donor sites, using the tibia took less time, gave less bleeding, made it possible for two teams to operate simultaneously, gave a smaller scar, and there were minimal complications and satisfactory quantity and quality of bone in all cases. The results suggested that the tibia is an excellent choice of graft for residual alveolar clefts in patients with cleft lip and palate.

Alveolar Process↗

Quantification of tartrate resistant acid phosphatase distribution in mouse tibiae using image analysis.

Tartrate resistant acid phosphatase (TRAP) activity of bone is a suitable biochemical marker for osteoclastic bone resorption. Qualitatively, the histochemical distribution of TRAP has been used to identify osteoclasts responsible for bone resorption; however, there have been few attempts to quantify TRAP localization. We describe a method for evaluating bone resorption by quantifying area percentages of positive TRAP localization using image analysis. Mouse tibiae were paraffin embedded following demineralization in disodium ethylenediamine tetraacetic acid. Longitudinal sections of tibia were cut from 15 levels in the left and the right limbs of six mice (180 sections total) and stained for TRAP distribution. Positive TRAP localization was quantified by pixel area count and reported as a percentage of the total tissue area specified. The 1.85 mm2 region of interest was placed at the midpoint of the epiphyseal growth plate containing the provisional calcification layer and the primary spongiosa, while excluding cortical bone of each mouse tibia. The percentage of TRAP localization ranged from 0.95 to 1.31% and was not significantly different from level to level or limb to limb in each mouse (p > 0.100). Within the same region of interest, an osteoclast count along the bone perimeter also was performed. We demonstrated a strong correlation (r2 = 0.903) between the conventional histomorphometric osteoclast index and positive TRAP localization, validating the latter as an alternative method to assess bone resorption. Quantitative analysis of TRAP is significant because it allows statistical comparisons between treatment groups, promotes precise pathological diagnoses and facilitates a reference data base that may aid the study of bone related diseases involving increased bone resorption.

Acid Phosphatase↗

Associations of blood lead, dimercaptosuccinic acid-chelatable lead, and tibia lead with neurobehavioral test scores in South Korean lead workers.

The authors performed a cross-sectional study to evaluate associations between blood lead, tibia lead, and dimercaptosuccinic acid (DMSA)-chelatable lead and measures of neurobehavioral and peripheral nervous system function among 803 lead-exposed workers and 135 unexposed controls in South Korea. The workers and controls were enrolled in the study between October 1997 and August 1999. Central nervous system function was assessed with a modified version of the World Health Organization Neurobehavioral Core Test Battery. Peripheral nervous system function was assessed by measuring pinch and grip strength and peripheral vibration thresholds. After adjustment for covariates, the signs of the beta coefficients for blood lead were negative for 16 of the 19 tests and blood lead was a significant predictor of worse performance on eight tests. On average, for the eight tests that were significantly associated with blood lead levels, an increase in blood lead of 5 microg/dl was equivalent to an increase of 1.05 years in age. In contrast, after adjustment for covariates, tibia lead level was not associated with neurobehavioral test scores. Associations with DMSA-chelatable lead were similar to those for blood lead. In these currently exposed workers, blood lead was a better predictor of neurobehavioral performance than was tibia or DMSA-chelatable lead, mainly in the domains of executive abilities, manual dexterity, and peripheral motor strength.

Adult↗

Association of blood lead and tibia lead with blood pressure and hypertension in a community sample of older adults.

Few studies have compared associations of blood lead and tibia lead with blood pressure and hypertension, and associations have differed in samples with occupational exposure compared with those with mainly environmental lead exposure. African Americans have been underrepresented in prior studies. The authors performed a cross-sectional analysis of 2001-2002 data from a community-based cohort in Baltimore, Maryland, of 964 men and women aged 50-70 years (40% African American, 55% White, 5% other race/ethnicity) to evaluate associations of blood lead and tibia lead with systolic and diastolic blood pressure and hypertension while adjusting for a large set of potential confounding variables. Blood lead was a strong and consistent predictor of both systolic and diastolic blood pressure in models adjusted and not adjusted for race/ethnicity and socioeconomic status. Tibia lead was associated with hypertension status before adjustment for race/ethnicity and socioeconomic status (p = 0.01); after such adjustment, the association was borderline significant (p = 0.09). Propensity score analysis suggested that standard regression analysis may have exaggerated the attenuation. These findings are discussed in the context of complex causal pathways. The data suggest that lead has an acute effect on blood pressure via recent dose and a chronic effect on hypertension risk via cumulative dose.

Black or African American↗

Unicortical critical size defect of rabbit tibia is larger than 8 mm.

The critical-size defect is important as an experimental model to test bone repair materials. Guided tissue regeneration is an established method for tissue regeneration within periodontal surgery. Bony defects covered by a membrane are allowed to be filled by bony tissue. Healing of 8-mm unicortical trephine defects was tested in Copenhagen White rabbit tibia using 3 different membranes. The critical-size defect in Copenhagen White rabbit tibia is larger than 8 mm, because control defects 8 mm in diameter healed spontaneously. However, it is anatomically not possible to create defects larger than 8 mm in an adult Copenhagen White rabbit tibia.

Animals↗

Observations of the proximal tibia in total knee arthroplasty.

Relatively little has been written concerning the proximal tibia in total knee arthroplasty. Few authors have looked at landmarks and guidelines for tibial tray preparation and tibial tray orientation. The current study showed that a line drawn 1 mm medial to the medial border of the tibial tubercle and going through the midsulcus of the tibial spines (the midsulcus line) provided a reproducible landmark for the tibia, and when a perpendicular cut was made relative to this line, 46 of 50 knees were cut in appropriate alignment. In addition, it has been said that the tibial tray should be rotated externally to approximately the medial 1/3 of the tubercle to maximize function. The current study showed that when the tibia is allowed to float in a functional position relative to the femoral implant, the tibial external rotation was only 2 mm lateral from the medial age of the tibial tubercle; this is far less than the medial 1/3 of the tubercle and close to the starting point of the midsulcus line.

Aged↗

Transtibial amputation with plantar flap for congenital deficiency of the tibia.

Disarticulation of the knee has been the preferred treatment for the severe type (Type Ia and Type Ib classification of Jones et al) of congenital deficiency of the tibia because of marked flexion contracture of the knee and loss of quadriceps function. In such cases, the disarticulated stump is often small and poorly covered by soft tissues because of dysplastic femoral condyles and calf muscles. Therefore, stump complications after disarticulation may prevent early aggressive walking exercises and delay independent ambulation. To overcome this problem, a greater weightbearing surface was created by a transtibial amputation with a short stump of the fibula using the flexed knee. By this method, the distal femoral condyle and the anterior surface of the fibula were used for weightbearing. In addition, coverage of the new weightbearing area by a neurovascular pedicled sensate plantar flap provided a more tolerable weightbearing site. The purpose of the current study was to report a 5-year-old boy with bilateral congenital total deficiency of both tibias, who was treated using this technique. The patient was ambulating independently 15 weeks after surgery. A transtibial amputation with a plantar flap is an alternative procedure to knee disarticulation for the severe type of congenital deficiency of the tibia.

Amputation, Surgical↗

Medial torsion of the tibia in Japanese patients with osteoarthritis of the knee.

To assess the reliability of the landmarks for the rotationally neutral alignment of the tibial component in total knee arthroplasty for Japanese patients, the rotational position of the medial (1/3) of the tibial tuberosity relative to the femoral epicondylar line (Angle TT) and that relative to the center of the ankle (Angle TT-AA) were measured in 24 knees with medial femorotibial osteoarthritis and in 28 normal knees by computed tomography. Angle TT-AA shows the degree of medial torsion of the tibia. The range of Angle TT and that of Angle TT-AA each was greater than 40 degrees. The position of the tibial tuberosity and degree of medial torsion of the tibia varied by individual. In patients with severe medial torsion, the internal rotation of the foot is extreme if the medial (1/3) of the tibial tuberosity is used for the rotationally neutral alignment of the partially constrained tibial component. In the treatment specifically of patients from East Asian countries, medial torsion of the tibia should be taken into account in total knee arthroplasty to ensure proper patellar tracking and proper rotation of the foot in knees with medial femorotibial osteoarthritis.

Adult↗

A dynamic biomechanical analysis of the etiology of adolescent tibia vara.

Biomechanical overload of the proximal tibial physis due to static varus alignment and excessive body weight has been implicated in the etiology of infantile tibia vara. Whether a similar pathophysiologic process applies to adolescent tibia vara is controversial, with poor consensus concerning the nature and significance of static knee alignment early in the course of the disease. This study examines the hypothesis that dynamic gait deviations to compensate for increased thigh girth associated with obesity (fat-thigh gait) could result in increased loading of the medial compartment of the knee during the gait cycle. Three-dimensional motion analysis was used to identify the kinematic/kinetic profile associated with fat-thigh gait. Gait deviations identified were dynamic stance-limb knee varus, increased stance-limb knee rotation, and swing-limb circumduction. Pathologic compressive forces were generated in an anthropometric model by using recorded fat-thigh gait deviations and clinically appropriate excessive body weight. This analysis supports the clinical observation that underlying static varus malalignment of the knee is not a prerequisite for the development of adolescent tibia vara and illustrates the significance of dynamic gait deviations when considering knee-joint loading.

Adolescent↗