Periacetabular bone changes after uncemented total hip arthroplasty evaluated by quantitative computed tomography

As a follow-up of a previously reported three-year study, we analyzed the periprosthetic acetabular cortical and cancellous bone density changes at ten years after implantation of a press-fit cup. Prospective clinical, radiographic, and quantitative computed tomography examinations were performed within ten days and at mean periods of one, three, and ten years after total hip arthroplasty with a press-fit cup, a femoral stem with a tapered design, and alumina-alumina pairing. Periacetabular cortical and cancellous bone density (mg CaHA/mL) in the cranial, ventral, and dorsal regions about the cup were measured for twenty-four hips in vivo. All acetabular cups showed radiographic signs of stable ingrowth, and no acetabular component had to be revised. The loss of periacetabular cancellous bone density about the cup was as much as -37% cranially, -60% ventrally, and -71% dorsally; the decrease was progressive between the one-year and three-year examinations only. In contrast, cortical bone density above the dome of the acetabular cup remained constant throughout the ten-year follow-up. A moderate change in cortical bone density of -5% to -18% was seen at the level of the cup ten years postoperatively. Both periacetabular cortical and cancellous bone density changes were nonprogressive between the three-year and ten-year examinations after press-fit cup fixation.

A Structural Approach to Renal Bone Disease

Beginning with the report in 1994 that an adult male with homozygous loss of estrogen receptor α (ERα) had unfused epiphyses and osteopenia,(1) there is now considerable evidence from observational and interventional studies (summarized in Khosla and colleagues(2)) that estrogen is the dominant regulator of bone metabolism in men. Indeed, a legitimate argument can be made that testosterone is largely a prohormone for the skeleton, with its effects on bone mediated principally via aromatization to estrogen, although it remains likely that testosterone contributes to bone size via effects on periosteal apposition and perhaps indirectly to bone mass by increasing muscle mass.

ObjectiveThe aim of this retrospective study was to evaluate the pre- and postsurgical bone densities at alveolar and extra-alveolar sites following two-jaw orthognathic surgery.MethodsThe sample consisted of 10 patients (mean age, 23.2 years; range, 18.0–27.8 years; 8 males, 2 females) who underwent two-jaw orthognathic surgery. A three-dimensional imaging program (Invivo 5) was used with multidetector computed tomography images taken pre- and postoperatively (obtained 32.3 ± 6.0 days before surgery and 5.8 ± 2.6 days after surgery, respectively) for the measurement of bone densities at the following sites: (1) alveolar bone in the maxilla and mandible, (2) extra-alveolar sites, such as the top of the head, menton (Me), condyle, and the fourth cervical vertebrae (C4).ResultsWhen pre- and postsurgical bone densities were compared, an overall tendency of decrease in bone density was noted. Statistically significant reductions were observed in the densities of cancellous bone at several areas of the maxillary alveolar bone; cortical and cancellous bone in most areas of the mandibular alveolar bone; cortical bone in Me; and cancellous bone in C4. There was no statistically significant difference in bone density in relation to the depth of the alveolar bone. In a comparison of the bone densities between groups with and without genioplasty, there was almost no statistically significant difference.ConclusionsAccelerated tooth movement following orthognathic surgery may be confirmed with reduced bone density. In addition, this study could offer insights into bone metabolism changes following orthognathic surgery, providing direction for further investigations in this field.

Inhibition of cortical and cancellous bone formation in glucocorticoid-treated OVX sheep

We measured bone density (BD) changes to assess adaptive bone remodelling five years after uncemented total hip arthroplasty with taper-design femoral component using quantitative computed-tomography-assisted osteodensitometry (qCT). Nineteen consecutive patients (21 hips) with degenerative joint disease were enrolled in the study. A press-fit cup and a tapered uncemented stem ceramic-ceramic pairing were used in all patients. Serial clinical, radiological and qCT osteodensitometry assessments were performed after the index operation and at the one, two and five year follow-ups. At the latest follow-up, the clinical outcome was rated satisfactory in all hips. The radiological assessment showed signs of osteointegration with stable fixation of all cups and stems. Overall, there was evidence of a BD loss at year five (p = 0.004). We estimate that BD loss was between 2.2% and 12.1% in comparison with baseline postoperative values. Progressive loss of BD in the metaphyseal region was observed in all hips. We found unremarkable BD changes of diaphyseal cortical BD throughout the five year follow-up period. qCT osteodensitometry technology allows differentiation of cortical and cancellous BD changes over time. Periprosthetic BD changes at the five year follow-up are suggestive of stable stem osteointegration with proximal femoral diaphysis load transfer and metaphyseal stress shielding.

Bone loss around uncemented femoral components is suspected to precede implant loosening and contribute to problems in revision surgery. Short-stemmed cementless femoral components are designed to preserve proximal femoral bone stock and ultimately the longevity of the prosthesis. With quantitative computed tomography-assisted osteodensitometry, we prospectively analyzed femoral cortical and cancellous bone density (BD) and contact area changes of an uncemented collum femoris preserving stem (n=38) 10days, 1, 3 and 7years post-operatively. Seven years post-operatively, cancellous BD (mg CaHA/mL) had decreased by as much as -66% and cortical BD by up to -27% at the metaphyseal portion of the femur; the decrease was progressive between the 1- and 3-year examinations and halted thereafter. Contact area (in % out of a possible 100%) decreased proximally between the 1- and 3-year follow-up. Proximal cortical and cancellous bone density loss and decrease of contact area indicate that metaphyseal fixation cannot be achieved. The lack of cortical BD loss and increase of contact area values below the trochanter minor suggest diaphyseal fixation.

Hypoxemia has been recognized as a risk factor for bone loss. The aim of the present study is to investigate the relationship of bone mass and density measures with anemia and hemoglobin levels in a large sample of older community-dwelling persons. The study is based on data from 950 participants enrolled in the "Invecchiare in Chianti" (Aging in the Chianti area, InCHIANTI) study. All the analyses were performed considering continuous hemoglobin levels as well as the dichotomous anemia variable (defined according to WHO criteria as hemoglobin < 12 g/dl in women and < 13 g/dl in men). A peripheral quantitative computerized tomography (pQCT) scan of the right calf was performed in all participants to evaluate total bone density, trabecular bone density, cortical bone density, and the ratio between cortical and total bone area. Linear regression analyses were used to assess the multivariate relationship of pQCT bone measures with anemia and hemoglobin levels after adjustment for demographics, chronic conditions, muscle strength and biological variables. Participants were 75.0 (SD 6.9) years old. In our sample, 101 participants (10.6%) were anemic. In women, coefficients from adjusted linear regression analyses evaluating the association between pQCT bone measures (per SD increase) and hemoglobin levels/anemia showed significant associations of anemia with total bone density (beta = -0.335, SE = 0.163; P = 0.04) and cortical bone density (beta = -0.428, SE = 0.160; P = 0.008). Relationships with borderline significance were found for the associations of anemia with trabecular bone density and the ratio between cortical and total bone area. Significant associations were found between hemoglobin levels and trabecular bone density (beta = 0.112, SE = 0.049; P = 0.02), total bone density (beta = 0.101, SE = 0.046; P = 0.03), cortical bone density (beta = 0.100, SE = 0.046; P = 0.03) and the ratio between cortical bone and total area (beta = 0.092, SE = 0.045; P = 0.04). In men, significant associations were found for hemoglobin levels with total bone density (beta = 0.076, SE = 0.036; P = 0.03) and cortical bone density (beta = 0.095, SE = 0.41; P = 0.02). A borderline significance was reported for the association between anemia and cortical bone density. We concluded that anemia and low hemoglobin levels are negatively and independently associated with bone mass and density. The bone loss associated with hemoglobin levels mainly occurs in the cortical bone. Women with lower hemoglobin levels demonstrate a higher bone loss than male counterparts.

Biomechanical effectiveness of cortical bone thickness on orthodontic microimplant stability: An evaluation based on the load share between cortical and cancellous bone

BackgroundThe anterior-middle superior alveolar (AMSA) anesthetic technique has been reported to be a less traumatic alternative to several conventional nerve blocks and local infiltration for anesthesia of the maxillary teeth, their periodontium, and the palate. However, its anatomic basis remains controversial. The present study aimed to determine if the pattern of cortical and cancellous bone density in the maxillary premolar region can provide a rationale for the success of the AMSA anesthetic technique.MethodsCone-beam computed tomography scans of 66 maxillary quadrants from 34 patients (16 men and 18 women) were evaluated using a volumetric imaging software for cortical and cancellous bone densities in three interdental regions between the canine and first molar. Bone density was measured in Hounsfield units (HU) separately for the buccal cortical, palatal cortical, buccal cancellous, and palatal cancellous bones. Mean HU values were compared using the Mann-Whitney U test and one-way ANOVA with post-hoc analysis.ResultsCancellous bone density was significantly lower (P ≤ 0.001) in the palatal half than in the buccal half across all three interdental regions. However, there was no significant difference (P = 0.106) between the buccal and palatal cortical bone densities at the site of AMSA injection. No significant difference was observed between the two genders for any of the evaluated parameters.ConclusionsThe palatal half of the cancellous bone had a significantly lower density than the buccal half, which could be a reason for the effective diffusion of the anesthetic solution following a palatal injection during the AMSA anesthetic technique.

The goal of this study was to evaluate the effects of chronically-elevated male levels of the potent androgen testosterone on the quality and quantity of both cancellous and cortical bone in a young (mean age 8.0 years), nonhuman female primate model (M. fascicularis). Thirteen intact female monkeys received continuous testosterone supplementation via subcutaneous implants over a 24-month period. A group of 16 untreated, intact, age-matched female monkeys served as controls. At sacrifice, the lumbar vertebrae and femora were recovered in order to analyze the bone mineral quality and quantity of cancellous and cortical bone, respectively, and compared to the control group. Mineralization profiles of the vertebrae and femora were obtained using the density fractionation technique. Chemical analysis of the three largest fractions retrieved by density fractionation was performed to evaluate differences in %Ca, %P, Ca/P ratio, and mineral content (%Ca + %PO4) between the control and experimental groups. In addition, unfractionated bone powder was examined by X-ray diffraction to identify any changes in crystal size. Coronal sections of vertebrae were analyzed for structural parameters using histomorphometry and image analysis. Cross sections taken at the midshaft diaphyseal femora were analyzed for structural macroscopic and intracortical parameters. A nonsignificant shift in the mineralization profile of the vertebrae was observed whereas there was a significant shift in the mineralization profile towards more dense bone in the treated femora as compared with controls (P < 0.05). There was no difference in terms of size/strain of the cortical or cancellous bone crystal as detected by X-ray diffraction. There was a trend towards an increase in cancellous bone area (B.Ar.) in the testosterone-treated vertebrae (P = 0.08) as compared with controls. The architecture of the cancellous bone remained nonsignificantly different between the treatment and control groups as evaluated by image analysis. There was a decrease in osteoid perimeter (P = 0.05) in the experimental group as compared with controls. There was a significant decrease in eroded perimeter measurements in the experimental group as compared with controls (P < 0.03). Although there was a trend towards an increase in cancellous bone area, mineralization was not significantly different in the vertebrae of testosterone-treated female monkeys, indicating that the newly-formed bone tissue became relatively normally mineralized over the two-year period. An increase in bone area, with indices of an overall decreased remodelling pattern as compared with controls, suggests that cancellous bone in the young, nonhuman female primate had been receptive to supraphysiologic levels of testosterone supplementation over the two-year period. There was a trend for an increase in cortical bone area and width with an increased periosteal perimeter in the testosterone-treated group as compare with controls. There was an increase in intracortical remodelling activity with a significant increase in percent porosity (P < 0.05), osteonal bone (P < 0.05), and mean wall width (P < 0.05) in the testosterone-treated group. In conclusion, the cancellous bone from female monkeys appeared to respond to the antiresorptive stimulus of male levels of testosterone with significantly diminished turnover parameters in this compartment. In contrast, the cortical bone compartment responded by displaying significant intracortical remodelling over a two-year period.

To examine changes in radial bone density and biochemical status, with particular reference to calcium, over 18 months in a group of older men. Thirty-six healthy men (aged 66 76 y) were recruited to the study during July and August, 1993. These men were free-living residents of Edmonton who were recruited through local organizations for the retired and semi-retired. Data for the younger group of men (age 29-60 y) were taken from a previous study conducted in our laboratory. using special-purpose computed tomography (gammaCT), trabecular (TBD), cortical (CBD) and integral (IBD) bone densities (gm/cm3) were measured in the ultra-distal radius at 6-month intervals over 18 months. At baseline, and at each subsequent study visit, serum was obtained from each subject for determinations of calcium, phosphate, 25-hydroxyvitamin D, alkaline phosphatase, and immunoreactive parathyroid hormone. A 24-h urine sample was also obtained at each study visit for determination of urinary calcium, phosphate and creatinine. In repeated measures analysis of variance of the data for the older men serum 25-hydroxyvitamin D was significantly decreased (P<0.001) over time, while TBD was increased (+0.60% per year, P<0.01). Longitudinal rates of change for TBD, CBD and IBD were: -0.94%, 0.92% and 0.74% per year respectively when bone density data at baseline for the older men and the historical data for younger men were combined. However, separate analyses of the data for the younger and the older men indicated no significant age-related changes in bone density for men aged 29-60 y, or for men aged 66-76 y. However, differences in TBD, CBD and IBD between the younger and older groups of men were significant (P < 0.001). In a group (n = 36) of older men (mean age 71.7 y) studied longitudinally over 18 months, bone density in the distal radius did not decrease over time. Mean bone density in this group of men was, however, significantly (P < 0.001) lower than in a group of younger men (n = 17, mean age 46.7 y). Regression analysis using cross-sectional bone density data at baseline for the older male group, and historical data for the younger male group, indicates that bone loss occurs with increasing age at a rate of about 1% per year averaged over ages 29-76 y. Bone density variables were not correlated with either height or weight, or with any biochemical or hormonal variable measured in this study.

We measured indices of bone volume (cancellous and cortical) and bone surface (cancellous, endocortical, and intracortical) in intact, full-thickness transiliac bone biopsies obtained from 47 healthy white women (23 premenopausal and 24 postmenopausal) and 82 patients with postmenopausal osteoporosis. In the normal subjects there was the expected loss of cancellous bone with age, best shown by a reduction in bone surface/tissue volume, but no fall in cortical thickness with age despite a significant reduction in forearm bone density measured by single-photon absorptiometry. Bone surface/bone volume was about four times higher in cancellous than in cortical bone, and cancellous bone contributed about one-third of the total bone volume and about two-thirds of the bone surface when related to the core volume referent. In the osteoporotic patients, core width, an index of iliac bone thickness at the biopsy site, was reduced by 10%, but we could not determine whether this was the result of compaction of the core or of bone slenderness. All indices of bone volume, cortical as well as cancellous, were significantly smaller, as were the values for forearm bone densitometry; the relative deficits at different sites depended on whether they were expressed as percentages or as zeta scores. Bone surface/bone volume was increased in both cancellous and cortical bone, but bone surface/tissue volume was reduced in cancellous bone and increased in cortical bone. The proportions of total bone volume and surface contributed by cancellous and cortical bone were almost the same as in normal postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

In order to identify pertinent models of cortical and cancellous bone regeneration, we compared the kinetics and patterns of bone healing in mouse femur using two defect protocols. The first protocol consisted of a 0.9-mm-diameter through-and-through cortical hole drilled in the mid-diaphysis. The second protocol was a 0.9-mm-diameter, 1-mm-deep perforation in the distal epimetaphyseal region, which destroyed part of the growth plate and cancellous bone. Bone healing was analyzed by ex vivo micro-computerized X-ray tomography and histology. In the diaphysis, the cortical gap was bridged with woven bone within 2 weeks. This newly formed bone was rapidly remodeled into compact cortical bone, which showed characteristic parameters of intact cortex 4 weeks after surgery. In the epimetaphysis, bone formation was initiated at the deepest region of the defect and spread slowly toward the cortical gap. In this position, newly formed bone quickly adopted the characteristics of trabecular bone, whereas a thin compact wall was formed at its external border, which reached the density of intact cortical bone but failed to bridge the cortical gap even 13 weeks after surgery. This comparative study indicates that the diaphyseal defect is a model of cortical bone healing and that the epimetaphyseal defect is a model of cancellous bone repair. These models enable experimental genetics studies to investigate the cellular and molecular mechanisms of spontaneous cortical and cancellous bone repair and may be useful for pharmacological studies.

Single-dose pharmacokinetics of vancomycin in porcine cancellous and cortical bone determined by microdialysis