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PubMed2004

Accuracy of 3D MR microscopy for trabecular bone assessment: a comparative study on calcaneus samples using 3D synchrotron radiation microtomography.

Magnetic resonance (MR) imaging is attractive for a noninvasive and radiation-free assessment of in vivo trabecular bone architecture. However the quantitative evaluation of architectural parameters could be biased by the limited sensitivity of MR. The aim of this study was to determine the accuracy of trabecular bone architectural parameters obtained from 3D high-resolution MR images, by comparison to reference images obtained by high-resolution X-ray microtomography using synchrotron radiation, from 29 samples of human calcaneus. MR images were obtained with a 66 microm x 66 microm x 66 microm voxel size, using a 8.5 T MR microscope. Microtomography images were acquired with a 10 microm x 10 microm x 10 mum voxel size, from the same samples. 3D architectural parameters characterizing the morphometry, topology, anisotropy, and orientation were computed from both modalities and carefully compared. To avoid errors, an identical region of interest was selected in the two corresponding images, and the same algorithms were run at identical spatial resolution. Our results establish that network connectivity, orientation and anisotropy are reliable from the MR data. The bone volume fraction, and morphometric parameters measured from the MR data, were found to be biased with respect to their values from the microtomography data, although there was a significant correlation between the two modalities.

Aged↗
PubMed1989

Trabecular structure compared to stress trajectories in the proximal femur and the calcaneus.

The theory that the trabecular structure within bones follows the principal stress trajectories, is investigated by two-dimensional finite element models of increasing complexity. This is done for the proximal femur of the human and for the calcaneus of the horse. In both cases, a simple model with well-chosen loading and boundary conditions gives good agreement between the observed trabecular structure and the calculated stress trajectories. It is shown that this stress trajectory theory has a mechanically founded explanation.

Adaptation, Biological↗
PubMed1986

Fractures of the talus and calcaneus: evaluation by computed tomography.

Fractures of the talus and calcaneus may be difficult to evaluate using conventional imaging modalities. Failure to recognize these fractures or to appreciate their extent may result in severe deformity or disability. Patients with talar and calcaneal fractures had computed tomography to assess its role in the management of these fractures. Computed tomography is superior to other imaging modalities in showing the position of the fracture fragments, the number of fragments, the relation of the fracture to the articular surfaces, residual articular changes, and evidence of healing.

Calcaneus↗
PubMed1996

Estimation of sex on the basis of radiographs of the calcaneus.

Lateral and anteroposterior radiographs of the ankles of 800 Central Europeans aged 20 to 79 were analyzed with regard to sexual dimorphism. All the distances, but not the angles, of the calcaneus were much larger in males than in females. Approximately 80% of the study sample could be sexed correctly by classifying all specimens greater than 86.0 mm in length as male and those less than 86.0 mm as female. The prevalence of os tibiale externum was 8.0 and 2.6% and the prevalence of plantar heel spur was 16.3 and 6.5% (increasing with age) for males and females, respectively, being significantly more frequent in females. On the other hand, the bone island frequencies were 9.1% in males and 4.8% in females. Our study suggests that radiographs of the ankle are a convenient, rapid, cheap and non-invasive means for estimating sex.

Adult↗
PubMed2005

Conditions of the calcaneus in skeletally immature patients.

Most conditions of the calcaneus in children, including calcaneal apophysitis, calcaneal fractures, and even intra-articular displaced fractures can be treated successfully with nonoperative methods. Calcaneal bone cysts require surgery only if symptomatic or at risk for pathologic fracture. Calcaneal osteomyelitis must be recognized and treated promptly to prevent severe complications.

Adolescent↗
PubMed2005

Calcaneus fractures: a review article.

Calcaneus fractures are a significant burden to society. Assessment and treatment of these injuries has improved significantly. The use of CT scanning has allowed a greater understanding of the pathologic anatomy of these fractures, and has provided for prognostic classification systems with respect to outcome. The treatment options are diverse and are reviewed.

Calcaneus↗
PubMed2005

The anatomy of the calcaneus and surrounding structures.

Appreciation of the normal anatomy of the calcaneus is significant for various reasons. Restoration of normal anatomy has been of particular interest for fracture care. In addition, knowledge of surrounding structures is important when planning surgical approaches and vital when performing percutaneous procedures. Understanding of anatomic relationships allows discernment of the pathophysiology that is related to chronic conditions. The biomechanics of normal structures provides a theoretic basis for reconstruction and rehabilitation, and individual variations in calcaneal anatomy can be a predisposition for pathology.

Calcaneus↗
PubMed2006

Quantitative ultrasound of the calcaneus in long-term liver or cardiac transplantation patients.

Bone loss is one of the most common complications after solid-organ transplantation, but it is frequently under-diagnosed. Our purpose was to evaluate quantitative ultrasound of calcaneus (QUS) in comparison with dual-energy X-ray absorptiometry (DXA) to identify transplant recipients with osteoporosis. We have cross-sectionally evaluated 140 transplant recipients (85 liver and 55 cardiac transplantations; mean age: 53.6 years, time since transplantation: 67.9 months). Devices used were Hologic 4500 QDR for DXA measurements and Sahara Clinical Sonometer (Hologic Inc, Bedford, MA) for calcaneal QUS. Quantitative ultrasound index (QUI) was calculated from speed of sound (m/s) and broadband ultrasonic attenuation (dB/MHz). QUI T-score and bone mineral density (BMD) T-score (spine and hip) were obtained from Spanish normative data. According to World Health Organization criteria, defined either at lumbar spine or femoral neck, 61% of the females had osteopenia and 32% had osteoporosis, whereas 52% of the males had osteopenia and 11% had osteoporosis. Calcaneal QUS parameters (speed of sound, broadband ultrasonic attenuation, and QUI) were positively correlated with lumbar and femoral BMD (p<0.001). In receiver operator characteristic analysis, a T-score QUI<or=-1.4 standard deviation (SD) had 68% sensitivity and 72% specificity for osteoporosis diagnosis by DXA criteria. However, to obtain maximal sensitivity (5% of false-negative), QUI T-score cutoff should be -0.6 SD, but specificity drops to 42%. In conclusion, a positive correlation exists between lumbar and femoral BMD and QUS parameters in long-term liver or cardiac transplant recipients. QUS could be recommended for screening of osteoporosis in long-term transplanted patients.

Absorptiometry, Photon↗
PubMed2004

2D arrays device for calcaneus bone transmission: an alternative technological solution using crossed beam forming.

In the context of manned space flight with the European Space Agency, a quantitative ultrasound device for transmission imaging through the calcaneus bone has been developed. It includes two matrix transducers of 576 elements each in order to electronically perform the scanning and the focusing of the 500 kHz ultrasonic beam. This device called the BEAM scanner, provides two parametric images of attenuation (BUA, broadband ultrasonic attenuation) and velocity (SOS, speed of sound) of the investigated skeletal site. The cost and complexity of such a device has motivated the study of an alternative solution, less demanding in terms of technology, based on a crossed beam former [H. Ermert et al., A new concept for a real-time ultrasound transmission camera, in: IEEE Ultrasonics Symposium Proceedings, 2000, pp. 1611-1614]. It consists in forming two perpendicular cylindrically focused planes, one in emission, one in reception, instead of two spherically focused apertures. The crossing line of the two planes replaces the focused beam. The 2D beam forming technological challenge is moved to a 1D simpler and cheaper architecture. In this work the two solutions have been compared for in vivo measurements. Data sets have been acquired using all spatial combinations of emission and reception single elements of the matrix. Then signals have been processed using either the cylindrical or the spherical focussing mode. For cylindrical focussing, the increased level of the side lobes caused severe artefacts. Several apodization techniques have been implemented to reduce these artefacts, resulting in encouraging results. After a brief description of this new ultrasonic method for bone quantitative assessment, several reconstructed images using both processing schemes are presented. Corresponding statistical results obtained in 29 subjects are also provided.

Algorithms↗
PubMed2001

Fractures of the calcaneus.

Fractures of the calcaneus (os calcis) are the most common of tarsal bone fractures, with an overall prevalence of approximately 2%. Despite increased experience with these types of fractures, however, there is considerable debate regarding their treatment and overall management. Controversies remain regarding the most appropriate classification system, treatment options, indications for surgery, surgical approaches, and post-operative management. This article presents a rational approach to the treatment of os calcis fractures based on current and past literature and the authors' preferred methods of treatment.

Calcaneus↗
PubMed2004

[Percutaneous fluoroscopic and arthroscopic controlled screw fixation of posterior facet fractures of the calcaneus].

We describe a new technique for reduction and percutaneous osteosynthesis of displaced posterior facet fractures of the calcaneus which appears to overcome the problems encountered with other percutaneous methods described for this type of surgery. The method relies on the use of traction which allows automatic reduction of the greater tubersosity. The patient is installed on an orthopedic traction table. Pin traction provides anatomic reduction of the posterior articular surface and restitution of Böhler's angle under fluoroscopic and arthroscopic control. We used this technique in thirteen patients with fifteen displaced posterior facet fractures of the calcaneum. Mean patient age was 50.4 Years. Mean follow-up was twenty Months. We did not have any cutaneous or infectious complications in this short series. In the majority of the cases, the overall functional and physical results were excellent or good. The mean Böhler's angle was 27 degrees, corresponding to 83% correction compared with the healthy side. These preliminary results are encouraging. We were able to restitute calcaneum anatomy, shorten hospital stay, and avoid all skin complications. Indications for this percutaneous technique could be widened. It is a valid alternative to open treatment of posterior facet fractures of the calcaneum.

Adult↗
PubMed2001

Acceleration of the calcaneus at heel strike in neutrally aligned and pes planus feet.

OBJECTIVE: The purpose of this research was twofold: (1) to study the impulsive acceleration of the calcaneus at heel strike in subjects with neutrally aligned (i.e., normal) feet and (2) to explore how the acceleration may differ in subjects with pes planus (i.e., flat) feet. The component of the acceleration vector aligned with the long axis of the tibia was quantified. DESIGN: Subjects with either foot type were instrumented and calcaneal acceleration was quantified during comfortable cadence locomotion. BACKGROUND: Aberrant peak acceleration has been associated with osteoarthritis. While tibial acceleration has been quantified, calcaneal acceleration has not. Additionally, foot morphology, or foot type, has demonstrated an effect on foot function and thus there may be differences in calcaneal acceleration between foot types. METHODS: Six subjects with neutrally aligned feet and six with pes planus feet were selected via a clinical exam. Accelerometers were attached to the posterior aspect of the medial surface of the calcanei bilaterally and 10 walking trials were collected.Results. The average baseline-to-peak acceleration for the neutrally aligned and pes planus feet was 4.79 g (SD, 2.14 g) and 5.24 g (SD, 3.28 g), respectively; the peak-to-peak acceleration was 5.03 g (SD, 2.74 g) and 6.75 g (SD, 3.89 g). There were no significant differences (P>0.05) between foot types. CONCLUSIONS: The calcaneal acceleration at heel strike for neutrally aligned and pes planus feet was not sensitive to foot type. RELEVANCE: Aberrant acceleration has been associated with the development of osteoarthritis [J. Biomech. 5 (3) (1972) 267; J. Biomech. 6 (1) (1973) 51; J. Biomech. 15 (7) (1982) 487]. Osteoarthritis at the subtalar joint, as well as the ankle and midtarsal joints, may be initiated and/or perpetuated by excessive calcaneal acceleration at heel strike.

Acceleration↗
PubMedDate not supplied

The ability of quantitative ultrasound at the calcaneus to identify postmenopausal women with different types of nontraumatic fractures.

The aim of the cross-sectional study was to determine if ultrasound (US) measurements of the calcaneus have the ability to predict the risk for fractures and to discriminate between postmenopausal women with and without different types of nontraumatic fractures. All women (n = 1,129, age range 40 to 87 years) were divided into group 1, created by 656 women with 956 nontraumatic past fractures, and group 2, consisting of 473 women without fractures. Group 1 was divided into subgroups: with hip fractures, with vertebral (nonhip) fractures, with wrist (nonhip and nonspine) fractures and with other (nonhip, nonspine and nonwrist) fractures. The speed of sound (SOS; m/s) and broadband ultrasound attenuation (BUA; dB/MHz) were measured with the Achilles system (Lunar), which also calculates stiffness index (SI; %). US values were significantly lower in group 1 (1,481.4 +/- 20.2 m/s, 98.7 +/- 9.4 dB/MHz, 61.1 +/- 11.0%; p < 0.000001) and in subgroups (p < 0.000001), and these women had a higher mean age and longer postmenopausal period than women without fractures (1508.2 +/- 26.5 m/s, 107.7 +/- 9.9 dB/MHz, 74.2 +/- 13.0%). Women with hip fractures had the lowest US values (1464.6 +/- 18.6 m/s, 89.9 +/- 8.7 dB/MHz, 50.6 +/- 10.5%), women with vertebral fractures had intermediate values (1473.6 +/- 17.4 m/s, 94.8 +/- 8.9 dB/MHz, 56.4 +/- 10.0%), and women with wrist (1,484.3 +/- 19.8 m/s, 99.9 +/- 9.3 dB/MHz, 62.7 +/- 10.7%) and other fractures (1,483.3 +/- 21.0 m/s, 100.4 +/- 8.6 dB/MHz, 62.7 +/- 10.6%) had the highest values. The US values differed significantly between subgroups with fractures (p < 0.05), with no significant differences between women with wrist and other fractures. ROC analysis showed SOS to have the best sensitivity and specificity in detecting fracture cases. All US parameters revealed the greatest areas under the ROC curve (AUCs) for hip fracture (0.92 to 0.93) in comparison to smaller AUCs for vertebral fractures (ranging from 0.84 to 0.87), and the smallest AUCs for wrist and other fractures (ranging from 0.72 to 0.77 and 0.72 to 0.78, respectively). Generally, the SOS measurement presented greater odds ratio (OR) than BUA and SI: 4.1 (3.09 to 5.43) for any fracture, 11.66 (3.09 to 43.96) for hip fracture, 6.51 (3.61 to 11.73) for vertebral fracture, 3.32 (2.41 to 4.58) for wrist fracture and 4.2 (2.7 to 6.54) for other fracture. The present study demonstrates the ability of calcaneal QUS to discriminate between healthy individuals and subjects with different types of nontraumatic fractures. Calcaneal US parameters show the best sensitivity and specificity in discriminating the hip fracture patients from the controls. Generally, the SOS parameter is a better discriminator than SI and BUA and estimates the highest OR for fractures.

Adult↗
PubMed1997

Bone status after long-term anticonvulsant therapy in epileptic patients: evaluation using quantitative ultrasound of calcaneus and phalanges.

The bone status of 25 epileptic female patients on long-term (mean 19 y) anticonvulsant therapy was investigated using quantitative ultrasound of the calcaneus (Lunar Achilles) and phalanges (Igea DBM Sonic 1200). Comparisons were made with a control group of 43 normal healthy women. Radiogrammetric measurements of the second metacarpal bone were also made in the epileptic patients. While all of the ultrasonic parameters were reduced in the epileptic group, differences only achieved statistical significance for speed of sound (SOS) at the phalanges. Phalangeal SOS correlated significantly with cortical thickness of the second metacarpal bone (r = 0.44, p < 0.05). The data suggest that long-term anticonvulsant therapy is associated with significant cortical bone loss. Quantitative ultrasound may have a role in monitoring bone loss in epileptic patients and in guiding suitable preventive therapy.

Adult↗
PubMed2000

Temperature dependence of ultrasonic attenuation in human calcaneus.

Ultrasonic attenuation in calcaneus has been shown to be a useful measurement for the diagnosis of osteoporosis. Several studies indicate that this measurement is affected by temperature fluctuations, although the fundamental causes for this are currently not well understood. To investigate this phenomenon, six defatted human calcanei were interrogated in vitro at six temperatures ranging from 10 degrees C to 40 degrees C. The temperature-related variation was -0.18 dB/cm MHz degrees C (95% confidence interval: -0.27 dB/cm MHz degrees C, -0.10 dB/cm MHz degrees C). This study reinforces the notion, advanced by other investigators, that temperature-related effects need to be taken into account when performing diagnostic measurements that require high precision (such as monitoring responses to drug intervention), will aid in the interpretation of in vivo experiments designed to investigate temperature-dependent precision limitations, will facilitate comparisons between in vitro studies normally carried out at room temperature with in vivo studies carried out at body temperature, and fills a gap in the compendium of measurements of temperature-dependences of acoustic properties of biologic tissues.

Bone Density↗
PubMed1998

The use of spiral computed tomography in musculoskeletal radiology of the lower limb: the calcaneus as an example.

The advent of spiral (helical) computed tomography (CT) has markedly increased the speed of modern CT systems and has found a use in a variety of musculoskeletal applications. However, the limitations of the technique must be understood if examinations are to be tailored and optimised. This review puts the limitations and advantages into context by outlining how spiral CT can be applied to musculoskeletal imaging of the lower limb. Imaging of intra-articular fractures of the calcaneus serves as a timely example of how the imaging parameters can be optimised and where the technique can offer potential advantages over conventional CT.

Ankle Joint↗
PubMedDate not supplied

Hematogenous osteomyelitis of the calcaneus in children: surgical treatment and use of implanted antibiotic beads.

Hematogenous osteomyelitis is a relatively uncommon disorder that may prove elusive to early diagnosis and treatment. Metaphyseal long bones are commonly involved and the calcaneus is rarely affected. A high index of suspicion should be maintained regarding the pediatric patient with pain out of proportion to a minor injury. Delay in the diagnosis of hematogenous osteomyelitis in the pediatric patient can result in irreversible growth disturbances and devastating sequelae. The authors present a typical case history with an unusual postoperative course and a review of the clinical aspects and surgical treatment of hematogenous calcaneal osteomyelitis in a child.

Anti-Bacterial Agents↗