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[Pronation from the viewpoint of the transfer of movement between the calcaneus and the tibia].

Excessive foot eversion and abnormal tibial rotation have been associated with knee injuries. Why and whether or not overpronation in athletes leads to overuse injuries at the knee joint, however, is still not understood. It could be that this is related to the mechanical coupling at the ankle joint complex. The purpose of this study was to quantify the movement transferred from calcaneal eversion-inversion into tibial rotation, and vice-versa from tibial rotation into calcaneal eversion-inversion. Fourteen foot-leg specimens were used for investigation. A holding device with six degrees of freedom was constructed which allowed to rotate the calcaneus and to determine the resulting tibial rotation, and vice-versa. The movement transfer between calcaneus and tibia varied substantially, and it was not the same for both input modes. In the case of applied internal tibial rotation no calcaneal eversion was found. Apparently, the movement transfer depends from the individual mechanical coupling at the ankle joint complex. Excessive calcaneal eversion does only result in excessive rotational loading of the knee joint when coupled with a high movement transfer at the ankle joint complex. Finally, the results imply that, during gait, pronation results from ground reaction forces acting on the calcaneus, since internal tibial rotation is not transferred into calcaneal eversion.

Biomechanical Phenomena↗

[Evaluation of reproducibility and precision of ultrasonic measurements of the calcaneus for diagnosing osteopenia].

The study aimed at evaluating precision of ultrasound measurements of mineral bone density of the calcaneus, and evaluating correlation between the obtained results with those measured with single photon absorptiometry (SPA) and DEXA in different skeletal sites. In 24 healthy individuals and 44 patients with osteoporosis SOS, BUA, calcaneus stiffness index, spine bone mineral density (L2-L4), femoral neck and calcaneal bone mineral densities were measured with DEXA technique whereas BMD in distal radial bone was measured with SPA. Very good precision of ultrasound measurements--better for SOS (CV = 0.12%), worse for BUA (CV = 1.64%) due to repositioning--was achieved. Statistically significant correlation between ultrasound and DEXA measurements of BMD in calcaneus bone (r = 0.90), and significant but worse correlations with BMD measurements for the spine (r = 0.43), femoral bone neck (r = 0.53), and 1/3 radius, (r = 0.51) were achieved. Ultrasound measurements of bone mineral density have low error of repeatability and good accuracy, enabling to discriminate healthy individuals from osteoporosis patients.

Adult↗

Advances in the treatment of calcaneus fracture.

The calcaneus is the largest of the tarsal bones and the most commonly fractured, being involved in more than half of all major tarsal injuries. Intraarticular fractures of the calcaneus are seriously disabling and of significant economic consequences. Ninety percent of these injuries occur in working age men, most commonly industrial workers. Many of these workers will never return to their jobs, and of those who do, 20% will be out for up to 3 years. The optimal treatment for intra-articular fractures is controversial. However, in the past few years, progress has been made in understanding the nature of calcaneus fracture. The availability of computed tomographic scanning and improved surgical techniques has improved the outlook for many of these patients to return to productive activity.

Calcaneus↗

Achilles tenodesis for calcaneus deformity in the myelodysplastic child.

Calcaneus deformity in patients with neurologic disorders leads to gait disturbances, a high incidence of osteomyelitis, cellulitis, and skin breakdown, and a major problem in the fitting of shoes of orthoses. Correction of this deformity remains a difficult challenge for the orthopedic surgeon. Twelve tenodeses of the tendo Achillis to the fibula or tibia were performed in eight patients with myelodysplasia in an attempt to control calcaneus deformity. The average age of the patients at the time of surgery was 7.4 years (range, 3.1-13.5 years) with an average follow-up period of 6.3 years (range, two to 10.9 years). The clinical examination demonstrated definite improvement in the ability to brace, prevent skin breakdown, and improve gait in all but one patient who had progressive hindfoot valgus. Roentgenographically, there was improvement in the tibiocalcaneal angle in 67%, fibular station in 58%, talar tilt in 25%, and growth of the posterior aspect of the calcaneus in 58%.

Achilles Tendon↗

[Experiment studies on fractures of the human calcaneus under vertical pressure (author's transl)].

In 60 cases typical compression fractures of the calcaneus were achieved by means of static compression of the test preparation. Afterwards the load bearing capacity of the fractured calcaneus was studied. In case of pure vertical compression the calcaneus does not loose much stability. The load bearing capacity of the studied bones after fracture achieved on an average still 63% of the initial value. In adequate cases of compression fractures, not only the early mobilization but the early weight bearing has to be discussed.

Biomechanical Phenomena↗

[Distal intra-articular resection of the calcaneus in the treatment of severe or recurrent congenital clubfoot].

INTRODUCTION: Secondary adaptive bone changes and joint distorsions in clubfoot may present a barrier to adequate correction of the deformity. The purpose of our study is to show how the lateral excision of the calcaneus distal part as described by Lichtblau, in combination with an appropriate medial release allows better correction of forefoot deformity, with less recurrence rate. MATERIAL AND METHODS: Between 1974 and 1982, 43 feet in 38 patients underwent this type of surgery. Lateral excision o the calcaneus was decided preoperatively in 34 feet, for recurrence of the forefoot deformity following previous surgery. In the remaining 9 feet, this lateral excision was decided intraoperatively, because of an uncomplete correction of the fore part of the foot, despite an adequate posteromedial release. The resected angle from the distal intra-articular part of the calcaneus varied from 10 to 30 degrees with an average of 15 degrees. RESULTS: All our results were evaluated at end of growth. Mean age at follow-up was 15 years and 4 months, with an average period of 10 years and 7 months following surgery. The average forefoot adduction moved from 21 degrees preoperatively to 1 degree at last follow-up. The clinical calcaneocuboid mobility was preserved in 37 cases. Four types of complications were encountered in 7 patients: pain in 5 cases, calcaneocuboid fusion in 6 cases, recurrence of deformity in 2 cases, and overcorrection in 5 cases; this last complication was related to intraoperative overcorrection rather than a progressive deterioration of the result, and had no clinical significance. No overcorrection was seen after calcaneocuboid fusion. We have found no relation between age at surgery, and the incidence of calcaneocuboid fusion, but the two cases operated on children under one year old, ended up with a bad result. DISCUSSION: The resection of a single side of a joint may permit normal joint function to be retained. The resected cartilage is replaced by a fibrocartilage that resembles the original articular cartilage, provided the resected defect is deep enough to allow vascularization from the underlying bone. CONCLUSION: The success of this method depends on an accurate surgical technique, as described by its promoter. It can be of great help in severe and complicated clubfeet. It achieves the goal with a calcaneocuboid function often preserved.

Calcaneus↗

[Ultrasound assessment of the calcaneus: for the time being a conservative approach in clinical use; the ERGO study (Erasmus Rotterdam Health and the Elderly)].

OBJECTIVE: To examine whether ultrasound measurements of the calcaneus can help to identify subjects with a risk for non-vertebral fractures. DESIGN: Cross-sectional survey. SETTING: The suburb of Ommoord in Rotterdam, the Netherlands. METHODS: 1421 subjects (631 men, 790 women) underwent both ultrasound measurements of the calcaneus and bone mineral density measurement of the femoral neck by dual energy X-ray absorptiometry (DXA). At the calcaneus speed of sound (SOS in m/s) and broadband ultrasound attenuation (BUA in dB/MHz) were measured. In addition, all subjects were asked about fractures in the preceding 5 years. The frequency of non-vertebral fractures was examined per tertile of SOS and BUA. In addition, we examined whether there was a trend in the number of fractures per tertile of SOS or BUA, within tertiles of femoral neck bone mineral density. RESULTS: The measures of SOS, BUA and bone mineral density (DXA-measured) are comparable as predictors of fractures. Subjects with values of SOS, BUA or bone mineral density in the lowest tertiles were all found to report two to three times as many fractures as subjects with values for these variables in the highest tertiles. Within tertiles of bone mineral density, subjects with a low SOS reported more fractures than subjects with a high SOS. For BUA a similar but less pronounced pattern was visible. Nevertheless, the area under the receiver operating characteristic (ROC) curve was 0.63 for SOS and 0.64 for BUA, comparable to 0.62 for bone mineral density of the proximal femur. Combining ultrasound and bone mineral density measurements had limited effect on the area under the ROC curve (0.65). CONCLUSIONS: Subjects with lower values of ultrasound parameters are at increasing risk of fracture, especially if low ultrasound values are accompanied by a lower bone mineral density. It remains to be seen whether ultrasound parameters are useful for screening.

Absorptiometry, Photon↗

Broadband ultrasound attenuation at the calcaneus measured using a new contact ultrasound unit.

We evaluated a new contact ultrasound device, developed and manufactured in France, for measuring broadband ultrasound attenuation at the calcaneus. We first studied the influence on measurement results of a number of parameters including the nature of the coupling agent, heel position, transducer temperature, and foot vasodilation. We then determined the reproducibility of the measurements (2.14 +/- 1.07% in the medium-term) and established reference values in women (n = 612) and men (n = 106). Broadband ultrasound attenuation decreased between 25 and 85 years of age by 34% in women and 17% in men. Sensitivity and specificity for detection of decreased bone mass at the calcaneus were 85.5% and 81.5%, respectively. Sensitivity and specificity of the measurement at the calcaneus as compared to the lumbar spine were 90.7% and 89.1%, respectively. This unit intended for screening purposes is very easy to use, and the measurements it provides are immediately available. It can be expected to help determine the optimal strategy for use of ultrasound in the management of osteoporosis.

Adult↗

[Essential bone cyst of the calcaneus in children. Report of three cases].

OBJECTIVE: The purpose of this study was to analyze the properties of essential bone cyst of the calcaneus in childhood, as well as its evolution, and differences with regard to adults. PATIENTS AND METHODS: The cases of children with a diagnosis of essential bone cyst of calcaneus in last sixteen years in the pediatric orthopedic unit of San Carlos Clinic have been reviewed. We evaluated the information regarding the clinical history and the radiological and histological date as well as the therapy result with esteroid intracavity therapy and curettage and bone grafting. The radiologic score was done following Södergard criteria and the posttreatment follow-up with Neer's score. RESULTS: The mean age of the patients was 10.3 years. Two of the patients had recurrent heel pain for more than six months. Treatment consisted in intracavitary esteroid in two cases and curettage and bone grafting in all three cases, in two of the cases because of failure of esteroid therapy and in the other because of an atypical X-ray image. In all cases the histological stady identified the existence of a characteristic membrane conective tissue. The postsurgery follow-up a period of half four years has been satisfactory. CONCLUSIONS: The essential bone cyst of the calcaneous is exceptional localization in children, frequently symptomatic and resistant to the esteroid intracavitaria contrary to what happens with the essential bone cyst of other localizations and with the essential bone cyst of the calcaneus in the adults. The recurrent heel pain and atipical X-ray image are surgery indications.

Adolescent↗

Diagnostic performance of quantitative ultrasound calcaneus measurement in case finding for osteoporosis in Thai postmenopausal women.

AIM: Dual-energy X-ray absorptiometry (DXA) is currently considered the gold standard for the diagnosis of osteoporosis. Quantitative ultrasound (QUS) can be an alternative method that is less expensive, portable, and can be used at a primary care level to indicate osteoporosis in women. The present study aimed to assess the diagnostic performance of QUS calcaneus measurement in a case finding for osteoporosis in Thai postmenopausal women using DXA as a gold standard. METHODS: Three hundred postmenopausal women, who had not menstruated normally for at least 1 year, were included in the study. To determine the accuracy and reliability of QUS of the calcaneus, calcaneus bone density measurement was carried out using the QUS and left femoral neck bone density was measured using DXA. Bone mass density (BMD) was interpreted as osteoporotic or normal using WHO criteria for determining the performance of QUS. Optimal cut-off values were determined using a receiver operating characteristic (ROC) curve for diagnosing the osteoporosis cases. RESULTS: The number of osteoporosis cases in this study was 107 (35.67%). The sensitivity, specificity, positive and negative predictive values were 39.25%, 91.71%, 72.41%, 73.14%, respectively, when using the T-score of the WHO criteria as a reference. The positive and negative likelihood ratios were 4.73 and 0.66. When using the ROC curve to determine the optimal cut-off values, using the stiffness index of the QUS and categorizing age (<65 years and >or=65 years) before conducting the test, sensitivity and specificity were 77.6% and 59.6%, respectively. CONCLUSIONS: Bone mass density measurement for predicting osteoporosis using QUS had a very low sensitivity and was not good enough to replace the standard tool (DXA).

Absorptiometry, Photon↗

Age-related changes in human tendo calcaneus collagen fibrils.

OBJECTIVE: The ruptures of tendo calcaneus often occur between the age of 30-45 years as described by several textbooks. It is also described that some diseases and drugs are said to be responsible in the etiology; however, there are no studies related with the detailed histological structure of collagen fibrils found in the tendon in the age groups of humans. In view thereof, this study was aimed to obtain further information on the etiology and to find an answer regarding the frequency of the ruptures occurring between the age of 30-45 years in humans. METHODS: In the study, the biopsy specimens taken from 28 patients (ages 1-68 year) who had undergone surgery due to tendo calcaneus ruptures or achilloplasty operation were examined by transmission electron microscope. All the specimens were prepared according to routine electron microscopic tissue preparation technique. The patients were divided into 7 age groups (1-9, 10-19, 20-29, 30-39, 40-49, 50-59, >60 years) and there were 4 patients in each group. The transverse diameters of collagen fibers were measured from the ultra thin sections and statistical analysis of the results were performed. The study was carried out in the electron microscopy laboratory of the Anatomy Department of Hacettepe University, Ankara, Turkey between January 2004 and September 2004. RESULTS: The diameters of the collagen fibers were higher in the 20-29 year-old group compared to other groups and it showed a statistically significant difference. In patients who were in the 30-39 year-old group or older, the diameters of the collagen fibers were lesser than the 20-29 year-old group. However, an increase was observed in the collagen fibril concentration of these groups. In examination of the specimens of patients who were under 20-year-old, the diameter of the collagen fibers were less than the 20-29 year-old group. The electron microscopic appearance of the tissue sample of a one-year-old patient had a specific organization and in this patient, both the diameters and concentration of collagen fibers were less. CONCLUSION: We believe that the decrease in the diameters of collagen fibers of 30-45 year-old patients who are in the active period of their life, can play a role in the etiology of the frequency of tendo calcaneus ruptures similar to other etiologic factors.

Achilles Tendon↗

The estimation of sex on the basis of the talus and calcaneus.

The present report records and describes sexual dimorphism of the talus and calcaneus in American Blacks and Whites from the Terry Collection housed in the Smithsonian Institution, Washington, D.C. The greater amount of sexual dimorphism was observed in the talus, where 81 percent of the study sample could be accurately sexed. Four discriminant functions based on measurements from the talus and/or the calcaneus allowed sexing 79 to 89% of the study sample accurately. The techniques developed were then applied to two North American Indian samples, and sex of the individuals in these samples was assessed with the same degree of accuracy.

Black People↗

Modeling and remodeling in a developing artiodactyl calcaneus: a model for evaluating Frost's Mechanostat hypothesis and its corollaries.

The artiodactyl (mule deer) calcaneus was examined for structural and material features that represent regional differences in cortical bone modeling and remodeling activities. Cortical thickness, resorption and formation surfaces, mineral content (percent ash), and microstructure were quantified between and within skeletally immature and mature bones. These features were examined to see if they are consistent with predictions of Frost's Mechanostat paradigm of mechanically induced bone adaptation in a maturing "tension/compression" bone (Frost, 1990a,b, Anat Rec 226:403-413, 414-422). Consistent with Frost's hypothesis that surface modeling activities differ between the "compression" (cranial) and "tension" (caudal) cortices, the elliptical cross-section of the calcaneal diaphysis becomes more elongated in the direction of bending as a result of preferential (> 95%) increase in thickness of the compression cortex. Regional differences in mineral content and population densities of new remodeling events (NREs = resorption spaces plus newly forming secondary osteons) support Frost's hypothesis that intracortical remodeling activities differ between the opposing cortices: 1.) in immature and mature bones, the compression cortex had attained a level of mineralization averaging 8.9 and 6.8% greater (P < 0.001), respectively, than that of the tension cortex, and 2.) there are on average 350 to 400% greater population densities of NREs in the tension cortices of both age groups (P < 0.0003). No significant differences in cortical thickness, mineral content, porosity, or NREs were found between medial and lateral cortices of the skeletally mature bones, suggesting that no modeling or remodeling differences exist along a theoretical neutral axis. However, in mature bones these cortices differed considerably in secondary osteon cross-sectional area and population density. Consistent with Frost's hypothesis, remodeling in the compression cortex produced bone with microstructural organization that differs from the tension cortex. However, the increased remodeling activity of the tension cortex does not appear to be related to a postulated low-strain environment. Although most findings are consistent with predictions of Frost's Mechanostat paradigm, there are several notable inconsistencies. Additional studies are needed to elucidate the nature of the mechanisms that govern the modeling and remodeling activities that produce and maintain normal bone. It is proposed that the artiodactyl calcaneus will provide a useful experimental model for these studies.

Animals↗

Anatomical consideration of vascularized bone graft transfer from the medial calcaneus to the talus.

To investigate the possibility of use of the calcaneal branches of the posterior tibial artery as the pedicle for the vascularized bone graft to the talus, a detailed anatomical study was carried out on 30 fresh cadaver feet. Although there are several branches from the posterior tibial artery to the calcaneus, the largest posterior branch was defined as the main calcaneal branch. We recognized frequently a large branch nourishing the superior part of the calcaneus and named it the superior calcaneal branch. Twenty feet had the superior calcaneal branches. Pedicled bone grafts using the superior calcaneal branch to the postero-medial portion of the talar body were possible in 18 of 20 feet. Pedicled bone grafts using the main calcaneal branches were possible in 9 of 12 feet in which the superior calcaneal branches were not available. Finally, vascularized bone grafts were judged to be feasible in 27 feet (90%).

Adult↗

The heritability of bone mineral density, ultrasound of the calcaneus and hip axis length: a study of postmenopausal twins.

Population based studies have demonstrated that having a first degree relative with a hip fracture is predictive of future hip fractures. Postmenopausal bone mineral density (BMD), ultrasound of calcaneus and hip axis length are associated with hip fracture, with the association for ultrasound and hip axis length being independent of BMD. The aim of this study was to determine the genetic component of these three important risk factors. We performed a classical twin study using 500 normal female twins, 128 identical and 122 non-identical pairs, aged 50 to 70 years. We measured bone mineral density at multiple sites, hip axis length (distance from the inner rim of the acetabulum to the greater trochanter), broadband ultrasound attenuation and velocity of sound of the calcaneus. Bone density had a strong genetic component at all sites with estimates of heritability ranging from 0.46 to 0.84. Hip axis length and velocity of sound had major genetic components with estimates of 0.62 and 0.61 respectively, which remained virtually unchanged after adjustment for bone mineral density. Broadband ultrasound attenuation had a moderate genetic component with an estimate of 0.53, which was reduced further to 0.45 after adjustment for BMD. In summary, all three bone measurements, which are independently associated with hip fracture, are independently heritable. This study suggests that a combination of different genetic factors acting on the structure, dimensions and density of bone may explain the importance of family history as a risk factor for hip fracture.

Aged↗

Field strength and angle dependence of trabecular bone marrow transverse relaxation in the calcaneus.

The contribution from reversible dephasing, R2', to the effective transverse relaxation rate, R2*, in trabecular bone marrow, is governed by the magnetic field inhomogeneity induced by the difference in diamagnetic susceptibility between bone and bone marrow and should, therefore, scale linearly with field strength. Measurement of R2' in the calcaneus at 1.5 and 4 T by means of the GESFIDE (gradient-echo sampling of free induction decay and echo) pulse sequence showed R2' to increase by a factor of 2.73 at the higher field, which is close to the ratio of the field strengths (2.67). At both field strengths, R2' dominates R2*, contributing more than 90% to the total relaxation rate at 4 T. The data further indicate large regional variations within the calcaneus and a notable dependence of R2' on the angle of the foot relative to the direction of the static field. The findings have implications on the choice of the calcaneal site for assessment of trabecular density.

Adult↗

Comparison of broadband ultrasound attenuation to single X-ray absorptiometry measurements at the calcaneus in postmenopausal women.

Broadband ultrasound attenuation (BUA), a radiation-free and portable technology, may be useful in assessing bone density and fracture risk. In this study, we compared cross-sectional BUA measurements to the more established single energy X-ray absorptiometry measurements of bone mineral density (BMD) at the calcaneus in 259 healthy postmenopausal women, aged 45-76 years. Paired measurements with repositioning of the subject's dominant heel were made consecutively by each method. A coefficient of variation (CV) for each method was calculated for each individual from the paired scans. BUA and BMD of the heel were also compared with BMD of the lumbar spine and femoral neck, as measured by dual energy X-ray absorptiometry. BUA was significantly correlated with BMD at the calcaneus (r = 0.66, P < 0.01). Heel BUA was also correlated with lumbar spine BMD (r = 0.43, P < 0.01) and femoral neck BMD (r = 0.43, P < 0.01) but the correlations were lower than those between heel BMD and spine (r = 0.63, P < 0.01) or femoral neck BMD (r = 0.62, P < 0.01). The mean CV for heel BUA (3.60 +/- 3.50%) was significantly greater than that for heel BMD (1.06 +/- 0.99%, P < 0.01). The moderate correlation of calcaneal BUA and BMD, the lower correlations of BUA than heel BMD with both spine and hip BMD, and lower precision of BUA indicate BUA does not predict bone density as effectively as absorptiometry, the current standard methodology.

Absorptiometry, Photon↗

Prognostic significance of posterior subtalar joint arthrography following fractures of the calcaneus.

Nineteen patients with 22 intra-articular fractures of the calcaneus were investigated by posterior subtalar joint arthrography after 6 (2-15) months following injury, and their clinical symptoms were compared with the arthrographic findings. The arthrograms were classified into four types based on the findings of the joint space of the posterior subtalar joint in Anthonsen's view. The classification correlated significantly (P = 0.03) with the clinical results which were assessed after 23 (9-41) months following injury. We conclude that posterior subtalar joint arthrography has prognostic value in assessing patients with fractures of the calcaneus.

Adolescent↗