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At least 127 records · Page 7Linked to original sources
PubMed2000

Quantitative ultrasound imaging of the calcaneus: precision and variations during a 120-Day bed rest.

This study reports on the precision and variation of quantitative ultrasound (US) parameters [broadband ultrasonic attenuation (BUA) or slope of the frequency-dependent attenuation in dB/MHz and speed of sound (SOS m/second)] after 120 days of continuous bed rest in six normal male volunteers. Quantitative US was measured at the calcaneus using a new US bone imaging scanner. The measurements were carried out on both heels at approximately 2-week intervals. The short-term precision was 0.31% for SOS and 2.8% for BUA. The long-term precision was 0.58% for SOS, 4.7% for BUA. A significant decrease of SOS values of -26 m/second (P < 0.0001) for the right heel and -17 m/second (P < 0.05) for the left heel was found at the group level. In terms of percentage change this represents -1.7% for the right heel and -1.1% for the left heel. These percentage decrements were 3.5-5.5 times that of the short-term precision and 2-3 times that of the long-term precision of the technique. At the individual level, the decrease of SOS was statistically significant (P < 0.05) or marginally significant (P < 0.1) for four out of 6 subjects. For 2 other subjects, similar trends were observed, but without reaching statistical significance. BUA did not change significantly during follow-up. These results are consistent with previous findings on changes of ultrasonic properties from the calcaneus during aging, pregnancy, or therapy, showing that calcaneus SOS is a valuable index of bone loss. These preliminary data suggest that prolonged exposure to simulated weightlessness may lead to a lower SOS, which then could be used for the follow-up of bone demineralization occurring during long-term space flights.

Adult↗
PubMed1998

Plantar flexion force is related to calcaneus bone ultrasonic parameters in postmenopausal women.

The aim of this report was to study the relationship between the plantar flexion strength produced by contraction of the triceps surae (gastrocnemii-soleus) muscle and the calcaneus bone parameters assessed by quantitative ultrasound in 45 healthy postmenopausal women. Plantar flexion strength was related to calcaneus broadband ultrasound attenuation (BUA) (r = 0.43, P = 0.003) and to speed of sound (SOS) (r = 0.3, P = 0.04). Plantar flexion appeared to predict ultrasonic properties, independently of body weight (R2 = 19% and 9% for BUA and SOS, respectively). These results suggest that the stresses related to locomotion locally enhance bone remodeling but further studies are needed to identify the respective role of the compressive strains related to ground reaction forces at heel-strike and the muscular tensile strains applied on the calcaneus where the calcaneal tendon is inserted.

Calcaneus↗
PubMed1998

Discordance between ultrasound of the calcaneus and bone mineral density in black and white women.

Black women have 40% of the incidence rate for hip fracture and have a higher bone mineral density (BMD) than white women. The possibility was raised that bone quality may be disproportionately greater than the advantage in bone density in protection against osteoporotic fractures in black versus white women. Ultrasound (US) of the calcaneus is believed to measure properties of bone in addition to its density. We performed bone density measurements and US of the calcaneus in 108 black and 177 healthy white women, aged 20-70 years. The highest correlation was seen between total body bone density and speed of sound (r = 0.75). The interracial differences in BMD were all statistically significant and varied from 3.4 to 7.6%. The US measurements had lesser interracial differences than the bone density measurements, with velocity barely different between races. These findings suggest that US of the calcaneus measures properties of bone different from density. Fracture prediction data using US from prospective data in white women should not be extrapolated to black women because of the discordance between bone density and US measurements. Prospective studies are needed comparing US measurements in black women to the occurrence of osteoporotic fractures.

Adult↗
PubMed1998

Acute and subacute changes in the ultrasound measurements of the calcaneus following intense exercise.

The amount of exercise necessary to cause bone structural change in humans is unknown. We examined whether a single bout of intense exercise in vivo leads to acute and subacute changes in the physical properties of bone as measured by ultrasound. It was hypothesized that structural changes such as accumulation of fatigue microdamage would result in a decrease in velocity of sound (VOS) and broadband ultrasound attenuation (BUA) across the calcaneus. We performed a prospective cohort study in 111 (97 M, 14 F) entrants of the 1996 Melbourne marathon (42.3 km) and 28 (10 M, 18 F) nonrunning controls. Runners had a mean (SD) age of 45.3 +/- 11.4 years (range 20-75), had completed 15.2 +/- 17.3 prior marathons (0-88), and had been running regularly for 14.2 +/- 9.2 years (0.25-50). An ultrasound densitometer (Cuba Clinical, McCue) was used to measure VOS and BUA across the right calcaneus. Runners were tested on three occasions: 1-3 days prior to, immediately after (<2 hours), and 5-6 days following the marathon. Seventy-three (66%) runners presented for all three measurements. Controls were tested on three occasions with the same time intervals as the runners. BUA values in the runners were significantly elevated by 5.0% immediately after the marathon but returned to baseline levels by the third test session (P = 0. 0001). Changes in BUA values in the controls were not significant and all were less than 0.7% (P = 0.88). Age was a significant independent predictor of the BUA change between test 1 and test 2 in the runners (beta = 0.2094; SE = 0.0917; P = 0.03). VOS measurements were not significantly different across the three testing sessions in both the runners (P = 0.07) and the controls (P = 0.33). Therefore, ultrasound measurements of BUA and VOS did not detect evidence of lasting structural change in the calcaneus following a marathon.

Adult↗
PubMed1999

Relationships between static histomorphometry and ultrasound in the human calcaneus.

The aim of this study was to explore the relationship(s) between histomorphometric measurements of cancellous bone structure and ultrasound. Ultrasonic measurements were made using a CUBA research system consisting of a pair of 1 Mhz unfocused transducers. Speed of sound (SOS) and broadband ultrasonic attenuation (BUA) were determined in 15 human cadaveric heels, with mean precision for all measurements coefficients of variation (CV) = 0.6% and 12%, respectively. The calcaneus was dissected and a 7.5 mm transcortical cylinder was removed from the path of ultrasound (US) transmission. The cortices were removed and the remaining cancellous core was sectioned into approximately 5 mm blocks, numbered from 1 to 6 (medial-lateral). Histomorphometric measurements were performed on decalcified, 5 microm-thick sections from blocks 1-6 using an automatic color image analysis system. There were significant differences between blocks 1 and 3-6 for BS/TV, BV/TV, Tb.N, and Tb. Sp (all P < 0.001), all decreasing in a medial-lateral direction (except Tb.Sp), implying that the medial portion of the calcaneus had more trabeculae with less spacing between them than the lateral portion. Furthermore, Tb.Th and BS/BV variables were uniform across the calcaneus, suggesting that individual trabeculae were of similar dimension. We found no significant correlations between US and histomorphometric parameters either averaged over all blocks or by using each block region separately. In conclusion, this study does not support the notion that US measurements of SOS and BUA through the heel reflect calcaneal cancellous bone structure, however, further studies using larger sample sizes may be warranted.

Aged↗
PubMed2001

"Duplicate calcaneus": a rare developmental defect observed in several skeletal dysplasias.

Duplication of the calcaneus is a rarely observed radiographic finding that probably results from delayed coalescence of two primary calcaneal centers of ossification. We performed a review of 2,500 computerized cases of skeletal dysplasias and syndromes with bone involvement in the International Skeletal Dysplasia Registry, searching for those cases in which a duplicate calcaneus had been recorded. We found that it was a non-random feature of three skeletal dysplasias and groups comprising thanatophoric dysplasia and the chondrodysplasia punctata and short rib (polydactyly) groups. We conclude that duplication of the calcaneus should be considered a consistent feature of these entities and may reflect a more generalized developmental defect.

Bone Diseases, Developmental↗
PubMed2001

Intraosseous lipoma of the calcaneus.

BACKGROUND AND AIMS: Intraosseous lipoma of the calcaneus is thought to be a rare tumour. As most of the articles have been single case reports, we performed a meta-analysis to evaluate diagnostic and therapeutic procedures. METHODS: Based on 54 cases located at the calcaneus, typical features and treatment were studied. RESULTS: A predilection was seen for adults between 30 and 60 years of age. Males were affected in two of three cases. The lesions were found incidentally in 33%. Symptomatic cases presented with pain, and some patients showed additional tenderness or swelling. All calcaneal lipomas were located at the base of the neck of the calcaneus (Ward's triangle). Radiological appearance depends on the stage due to evolutionary changes of the tumour. Diagnosis can be established with CT or MRI, as both methods show fat-equivalent densities in the lesion. Pathological fracture has not been reported. CONCLUSION: Continued observation in asymptomatic cases is a reasonable clinical approach. We propose surgical treatment with curettage and bone grafting only in symptomatic cases.

Adult↗
PubMed1993

The forces acting on the human calcaneus.

The forces acting on the human calcaneus are analysed for a static standing posture. An optimization procedure is invoked to solve the statically indeterminate set of forces which could arise from muscles, ligaments and reactions between the calcaneus and other bones and also the ground. Two alternative objective functions are investigated; that which returns no active muscle force is considered the more realistic, since electromyographic studies show that in static standing only minor muscle activity occurs to counteract body sway. This set of forces is then applied to the bone for finite element stress analysis to produce stress trajectories, which are then validated against both the trabecular configuration of the cancellous bone of the calcaneus and also the distribution of the orientations of the hydroxyapatite crystal major and minor axes.

Biomechanical Phenomena↗
PubMed1995

Predicting vertebral deformity using bone densitometry at various skeletal sites and calcaneus ultrasound.

We investigated the usefulness of bone density measurements from multiple skeletal sites and calcaneus ultrasound for evaluating the probability of vertebral deformation. Bone mineral density (BMD) was measured at the second metacarpal and middle phalanges using radiographic absorptiometry of hand radiographs, and at the lumbar spine using dual-energy x-ray absorptiometry. Distal radius and proximal radius were measured using single-energy x-ray absorptiometry (SXA), expressed as bone mineral content (BMC, grams per centimeter), and as BMD (grams per square centimeter). The calcaneus was measured using both SXA (BMD) and broadband ultrasound attenuation (BUA). Among the women in this study (mean age 74, SD = 5), 84 women developed new vertebral deformations (57 cases with one and 27 cases with two or more deformations), which were identified on serial radiographs during an average of 9 years prior to the measurements of bone density. Logistic regression analysis was used to calculate odds ratios for risk of deformation corresponding to a 1-SD difference in density or ultrasound, adjusted for age. All bone measurements were significantly associated with vertebral deformation, with odds ratios (95% confidence intervals) ranging from 1.40 (1.10, 1.78) for proximal radius BMD to 1.88 (1.45, 2.44) for calcaneus BMD measurements. Measurements of calcaneal BUA, calcaneal BMD, and hand BMD generally remained significant when included simultaneously with another measurement in the same model, suggesting that spine or radius BMD may not provide much additional information about risk of deformation. It appears that all of the measurements of bone density and ultrasound provide useful information regarding the probability of deformation. These findings await confirmation in a prospective study.

Absorptiometry, Photon↗
PubMed2006

Charcot of the calcaneus.

Charcot of the calcaneus, although not as prolific as midfoot deformation, still results in significant morbidity. Current treatment centers on methods proven effective for other joints in the foot. Most neuropathic conditions of the calcaneus can be managed reasonably nonoperatively. In cases of severe deformity or ulceration, surgical management may be the more conservative approach. The surgical principles of proper soft tissue balancing and handling are critical. As the diabetic population continues to increase, the incidence of Charcot of the calcaneus will concomitantly increase. Further research into methods of arthrodesis and osteotomy with external fixation seem to be the direction of the future.

Arthrodesis↗
PubMed2006

Adult stature reconstruction from the calcaneus of South Africans of European descent.

The reconstruction of adult stature from length of limb bones is not a new concept. Population specific regression equations for stature estimation have been derived from these bones in most part of the world. Due to increased violence in major cities of the world resulting in dismemberment of the human body and skeleton, there was a need for derivation of regression equations from fragments of long bones of limbs and segments of the vertebral column. This was achieved with lower accuracies compared to intact limb bones. The calcaneus, the largest of the foot bones, has been used for sex determination in Americans, Europeans and South Africans. Its usefulness in the estimation of stature is not well documented. In this study, Fully's anatomical method was utilized in the estimation of stature of 85 complete skeletons of South Africans of European descent of known sex and age, obtained from the Raymond A Dart Collection of Human skeletons. Univariate and multivariate regression equations were derived from nine measurements of the calcaneus. Most measurements presented with significantly positive correlation with stature. The resulting standard error of estimate, which is a measure of the accuracy of the equations, compared well with the values that have been recorded for fragments of long bones; thereby making the calcaneus a reliable skeletal element in the estimation of adult stature of South Africans of European descent.

Adult↗
PubMed2006

Assessment of low quantitative ultrasound values of calcaneus in Chinese mainland women.

Calcaneus quantitative ultrasound (QUS) assessment is a safe and reliable method for evaluating skeletal status. Until now, considerable data have been accumulated on the distribution of QUS in Caucasian populations, whereas such data are still insufficient in Asian populations, especially in Chinese mainland. The present study aimed to obtain the distribution characteristic of calcaneus QUS in healthy Chinese women, and to further investigate the distribution of low bone mass by QUS stiffness index (SI). This study included 2,498 healthy Chinese females aged 10-87 yr. The QUS exhibited a characteristic mild rise and then fall pattern with increasing age. Age, body height, and weight were significant influencing factors on SI, especially age and weight. The prevalence of osteoporosis detected using instrument-derived T-score or internal T-score was different from that calculated according to calcaneus bone mass density (BMD) previously reported. Furthermore, between instrument-derived T-scores and internal T-scores, there were also significant differences. We concluded that the World Health Organization criteria from BMD may not be appropriate for QUS, and the instrument-derived T-score may also not be appropriate for the studied population. The results will be useful for predicting fracture risk of Chinese women and determining diagnostic criteria of osteoporosis by QUS.

Adolescent↗
PubMed2004

Intraosseous infusions via the calcaneus.

OBJECTIVES: To demonstrate that intraosseous infusions via the calcaneus could deliver fluids to systemic veins and that intraosseous infusions do not require bones with medullary cavities. To demonstrate that intraosseous infusions could be successful in adults. DESIGN: Ten adult cadavers were injected with 16 gauge intraosseous needles and infused with 10 ml of methyl green dye at a concentration of 10 mg/ml. MAIN OUTCOME MEASURES: Observation of methyl green dye in the great saphenous, medial malleolar and dorsal veins of the foot recorded by digital photography on injection and at 1 min post-injection. RESULTS: Immediate entry of methyl green dye into the superficial veins of the leg was seen in 14 out of the 20 legs trialled and delayed entry was noted in the two legs of another cadaver. No venous entry was seen in one cadaver and intraosseous access failed in one cadaver. CONCLUSIONS: Successful intraosseous infusions can be performed via the calcaneus. Intraosseous infusions can be successful in adult populations. While not a substitute for intraosseous infusions in other sites, the calcaneus provides an easily accessible site free of overlying vital structures.

Adult↗
PubMed2000

Measurements of phase velocity and group velocity in human calcaneus.

Ultrasonic velocity in calcaneus correlates highly with bone mineral density, which is a good predictor of osteoporotic fracture risk. Several commercial bone sonometers perform a velocity measurement based on the transit time of a broadband pulse to assess skeletal status. This approach is somewhat problematic, however, because several authors have reported ambiguities in measurements in calcaneus. Phase velocity is an alternative that may be less dependent on device spectral characteristics. In addition, dispersion (the frequency-dependence of phase velocity) is a fundamental property worth investigating to increase understanding of interaction between ultrasound and bone. To compare two group-velocity measurement methods and one phase-velocity measurement method, a polycarbonate sample (for method validation) and 24 human calcanei were investigated in vitro. Phase velocity in calcaneus at 500 kHz was 1511 m/s +/- 30 m/s (mean +/- standard deviation). Average phase velocity decreased approximately linearly with frequency (-18 m/s MHz). The two group velocity measurements were comparable and tended to be slightly lower than phase velocity. The magnitude of dispersion showed little correlation with bone mineral density.

Bone Density↗
PubMed2000

Quantitative ultrasound and dual X-ray absorptiometry measurements of the calcaneus in patients on maintenance hemodialysis.

It has been suggested that quantitative ultrasound measurements (QUS), which reflect mainly bone density, could be influenced by bone micro-architecture. The aim of the study was to assess whether the relationship of QUS to dual X-ray absorptiometry (DXA) would reflect abnormalities of bone structure observed in renal osteodystrophy. QUS and bone mineral density of the calcaneus (BMDc) were measured by DXA in 30 patients on maintenance hemodialysis and 34 age- and gender-matched controls. QUS parameters and BMDc were significantly lower in hemodialysis patients than in controls (speed of sound [SOS] and broadband ultrasound attenuation [BUA], p = 0. 030; stiffness, p = 0.003; BMDc, p = 0.006). Bone measurements were not correlated with serum parathyroid hormone (PTH). The regression lines of SOS, BUA, and stiffness to BMDc were not significantly different from that of the controls. When dividing the patients into two subgroups according to their median PTH (203 pg/mL), the slopes of the regression lines of BUA to BMDc were significantly different between these two subgroups (p = 0.052). The slope of the subgroup with PTH </= 203 pg/mL was significantly different from that of the controls (p = 0.030). In conclusion, QUS of the calcaneus can be used for bone assessment in patients on maintenance hemodialysis. The differences in the slopes of patients with a less pronounced degree of hyperparathyroidism compared with patients with a higher degree of hyperparathyroidism and to controls suggest that BUA of the calcaneus contains information on bone complementary to DXA measured at the same site. The clinical relevance of this finding is presently unclear.

Absorptiometry, Photon↗
PubMed1997

In vitro assessment of the relationship between acoustic properties and bone mass density of the calcaneus by comparison of ultrasound parametric imaging and quantitative computed tomography.

This in vitro study aimed to add new experimental evidence to clarify the relation between acoustic properties of bone and bone mineral density (BMD) of the human calcaneus. Parametric images of normalized broadband ultrasonic attenuation (nBUA) and ultrasound bone velocity (UBV) were compared with quantitative computed tomography (QCT) images of the calcaneus. The experimental protocol was designed to control the different potential sources of error in acoustic measurements, including the shape and thickness of the samples, intervening soft tissues and cortical bone, boundary effects, and variation in location of the regions of interest (ROIs) analyzed by ultrasound and X-ray. The present study was based on bone specimens from calcaneus removed from 15 cadavers (six male and nine female donors ranging from 69 to 89 years of age). Immersion ultrasonic measurements were performed in the through-thickness direction at normal incidence using a pair of focused broad-band 0.5-MHz transducers. QCT of the specimens was performed using standard 10-mm-thick slices with the Cann-Genant calibration standard. Identical, site-matched ROIs were selected for quantitative analysis on the three images. The pattern of acoustic parameters was similar to that of BMD with QCT. The relationships between nBUA and BMD (r2 = 0.75), between UBV and BMD (r2 = 0.88) and between nBUA and UBV (r2 = 0.84) were highly significant (p < 10(-4). From this study, it appears that ultrasound parameters as measured with current transmission techniques reflect mainly bone quantity and only reflect microarchitecture to a small extent and that BUA and UBV reflect the same bone property.

Acoustic Stimulation↗
PubMed1997

Assessment of the strength of the proximal femur in vitro: relationship with ultrasonic measurements of the calcaneus.

Matched pairs of the right proximal femur and right calcaneus were obtained from 64 cadavers (28 female, 36 male). Ultrasonic velocity and broadband ultrasonic attenuation were measured in the calcaneus using a laboratory ultrasound system. Bone mineral density (BMD) was measured at the calcaneus and at the trochanteric and neck regions of the femur using dual-energy X-ray absorptiometry. Femoral strength was determined in a mechanical test simulating a fall onto the greater trochanter. Femoral BMD was more strongly correlated with femoral strength (r2 = 0.71, 0.88 for neck BMD and trochanteric BMD, respectively) than were any of the other predictive variables investigated (p < 0.05). Calcaneal ultrasonic measurements alone produced correlations with femoral strength of r2 = 0.40-0.47, with no significant differences observed in predictive ability between the various ultrasonic parameters. In multiple regression analysis, ultrasound was, in general, not a significant additional independent predictor of femoral strength when combined with either femoral or calcaneal BMD, and combining ultrasonic parameters did not improve the ability to predict femoral strength. Calcaneal width was found to be significantly correlated with both femoral strength and femoral BMD, and this explained the slightly better correlations with femoral strength found for those ultrasonic parameters which were not effectively normalized for calcaneal width. In summary, calcaneal ultrasound did not significantly enhance the prediction of femoral strength compared to femoral BMD measurements alone. Given the substantial differences between the in vitro and in vivo situations, this finding does not necessarily contradict emerging clinical data indicating that ultrasound and BMD have comparable and independent predictive ability for hip fracture risk. Reasons for the apparent discrepancy are discussed, including the enhanced accuracy of DXA in vitro. Nevertheless, it is suggested that further fundamental investigations into the efficacy of current ultrasonic techniques are warranted.

Biomechanical Phenomena↗
PubMedDate not supplied

Calcaneus secundarius presenting as calcaneonavicular coalition: a case report.

Calcaneus secundarius is an accessory ossicle of the anterior calcaneal facet identified in up to 5% of the population. Calcaneus secundarius rarely leads to symptoms, but its presence may generate pain around the ankle. The purpose of this case report is to describe this atypical accessory ossicle, which can mimic a calcaneonavicular coalition, and to explain the clinical approach to reach a diagnosis and determine treatment. The authors report the case of a 13-year-old girl who sustained several lateral sprains of the right ankle and had local chronic pain. Clinical findings were consistent with calcaneonavicular coalition but radiographic examinations revealed a calcaneus secundarius. The location of this ossicle may limit the range of motion of the subtalar joint, mimicking a calcaneonavicular coalition. Surgical excision of this bulky accessory ossicle was performed, and this treatment fully resolved the pain and improved subtalar motion.

Adolescent↗