Impaired geometric properties of tibia in older women with hip fracture history

Thigh Muscle Composition and Its Relationship to Functional Recovery Post Hip Fracture Over Time and Between Sexes

BACKGROUND

Computed tomography (CT)-scan measures of muscle composition may be associated with recovery post hip fracture.

METHODS

In an ancillary study to Baltimore Hip Studies Seventh cohort, older adults were evaluated at 2 and 6 months post hip fracture. CT-scan measures of muscle were acquired at 2 months. Short Physical Performance Battery (SPPB) was measured at 2 and 6 months. Generalized estimating equations were used to model the association of muscle measures and physical function, adjusting for age, sex, body mass index, and time postfracture.

RESULTS

Seventy-one older adults (52% males, age 79.6 ± 7.3 years) were included. At 2-months, males had greater thigh cross-sectional area (CSA, p < .0001) and less low-density muscle (p = .047), and intermuscular adipose tissue (p = .007) than females on the side of the fracture, while females performed better on the SPPB (p = .05). Muscle measures on the fractured side were associated with function at 2 months in both sexes. Participants with the lowest tertile of muscle CSA difference at 2-months, indicating greater symmetry in CSA between limbs, performed better than the other 2 tertiles at 6-months. Males performed worse in functional measures at baseline and did not recover as well as females (p = .02).

CONCLUSION

CT-scan measures of muscle CSA and fatty infiltration were associated with function at 2-months post hip fracture and with improvement in function by 6 months. Observed sex differences in these associations suggest that rehabilitation strategies may need to be adapted by sex after hip fracture.

Acute Sarcopenia after Elective and Emergency Surgery

Sarcopenia is an increasingly recognised condition of loss of muscle mass and function. The European Working Group on Sarcopenia in Older People 2 (EWSOP2) updated their definition in 2018, emphasising the importance of low muscle strength in diagnosis. Acute sarcopenia has been arbitrarily defined as sarcopenia lasting less than 6 months. This review highlights the pathophysiology involved in muscle wasting following surgery, focussing on hormonal factors, inflammation, microRNAs, and oxidative stress. Biomarkers such as GDF-15, IGF-1 and various microRNAs may predict post-surgical muscle loss. The impact of existing sarcopenia on various types of surgery and incident muscle wasting following surgery is also described. The gaps in research found include the need for longitudinal studies looking in changes in muscle strength and quantity following surgery. Further work is needed to examine if biomarkers are replicated in other surgery to consolidate existing theories on the pathophysiology of muscle wasting.

Tibial cortical and trabecular variables together can pinpoint the timing of impact loading relative to menarche in premenopausal females

OBJECTIVES

Though relationships between limb bone structure and mechanical loading have provided fantastic opportunities for understanding the lives of prehistoric adults, the lives of children remain poorly understood. Our aim was to determine whether or not adult tibial skeletal variables retain information about childhood/adolescent loading, through assessing relationships between cortical and trabecular bone variables and the timing of impact loading relative to menarche in premenopausal adult females.

METHODS

Peripheral quantitative computed tomography was used to quantify geometric and densitometric variables from the proximal tibial diaphysis (66% location) and distal epiphysis (4% location) among 81 nulliparous young adult female controls and athletes aged 19-33 years grouped according to intensity of impact loading both pre- and post-menarche: (1) Low:Low (Controls); (2) High:Low; (3) High:High; (4) Moderate:Moderate; (5) Low:Moderate. ANCOVA was used to compare properties among the groups adjusted for age, stature, and body mass.

RESULTS

Significant increases in diaphyseal total cross-sectional area and strength-strain index were documented among groups with any pre-menarcheal impact loading relative to groups with none, regardless of post-menarcheal loading history (p < .01). In contrast, significantly elevated distal trabecular volumetric bone mineral density was only documented among groups with recent post-menarcheal loading relative to groups with none, regardless of pre-menarcheal impact loading history (p < .01).

CONCLUSIONS

The consideration of diaphyseal cortical bone geometric and epiphyseal trabecular bone densitometric variables together within the tibia can identify variation in pre-menarcheal and post-menarcheal impact loading histories among premenopausal adult females.

Physical function and lean body mass as predictors of bone loss after hip fracture: a prospective follow-up study

Background

Predictors of bone deterioration after hip fracture have not been well characterized. The aim of this study was to examine the associations of physical function and lean body mass (LBM) with loss of bone density and strength in older people recovering from a hip fracture.

Methods

A total of 81 over 60-year-old, community-dwelling men and women operated for a hip fracture participated in this 1-year prospective follow-up study. Distal tibia total volumetric bone mineral density (vBMD_TOT, mg/cm³) and compressive strength index (BSI, g²/cm⁴) and mid-tibia cortical vBMD (vBMD_CO, mg/cm³) and bending strength index (SSI, mm³) were assessed in both legs by peripheral quantitative computed tomography (pQCT) at baseline (on average 10 weeks after fracture) and at 12 months. At baseline, LBM was measured with a bioimpedance device and physical function with the Short Physical Performance Battery (SPPB) and perceived difficulty in walking outdoors. Robust multivariable linear regression models were used to estimate the associations of physical function and LBM with the change in bone parameters at 12-months.

Results

The mean change in distal tibia vBMD_TOT and BSI in both legs ranged from − 0.9 to − 2.5%. The change in mid-tibia vBMD_CO and SSI ranged from − 0.5 to − 2.1%. A lower SPPB score, difficulty in walking outdoors and lower LBM predicted greater decline in distal tibia vBMD_TOT in both legs. A lower SPPB score and difficulty in walking outdoors were also associated with a greater decline in distal tibia BSI in both legs. At the midshaft site, a lower SPPB score and lower LBM were associated with greater decline in SSI on the fractured side.

Conclusions

Older hip fracture patients with low physical function and lower LBM may be at risk for greater decline in tibia bone properties during the first post-fracture year. Acknowledgement of the risk factors could assist in developing interventions and care to promote bone health and overall recovery.

Trial registration

ISRCTN, ISRCTN53680197. The trial was registered retrospectively but before the recruitment was completed. Registered March 3, 2010.

Effects of a Home-Based Physical Rehabilitation Program on Tibial Bone Structure, Density, and Strength After Hip Fracture: A Secondary Analysis of a Randomized Controlled Trial

Weight‐bearing physical activity may decrease or prevent bone deterioration after hip fracture. This study investigated the effects of a home‐based physical rehabilitation program on tibial bone traits in older hip fracture patients. A population‐based clinical sample of men and women operated for hip fracture (mean age 80 years, 78% women) was randomly assigned into an intervention (n = 40) and a standard care control group (n = 41) on average 10 weeks postfracture. The intervention group participated in a 12‐month home‐based rehabilitation intervention, including evaluation and modification of environmental hazards, guidance for safe walking, nonpharmacological pain management, motivational physical activity counseling, and a progressive, weight‐bearing home exercise program comprising strengthening exercises for the lower legs, balance training, functional exercises, and stretching. All participants received standard care. Distal tibia (5% proximal to the distal end plate) compressive bone strength index (BSI; g²/cm⁴), total volumetric BMD (vBMD_TOT; mg/cm³), and total area (CSA_TOT; mm²), as well as midtibia (55%) strength–strain index (SSI; mm³), cortical vBMD (vBMD_CO; mg/cm³), and ratio of cortical to total area (CSA_CO/CSA_TOT) were assessed in both legs by pQCT at baseline and at 3, 6, and 12 months. The intervention had no effect (group × time) on either the distal or midtibial bone traits. At the distal site, BSI of both legs, vBMD_TOT of the fractured side, and CSA_TOT of the nonfractured side decreased significantly over time in both groups 0.7% to 3.1% (12 months, p < 0.05). At the midshaft site, CSA_CO/CSA_TOT and SSI of both legs, and vBMD_CO of the fractured leg, decreased significantly over time in both groups 1.1% to 1.9% (12 months, p < 0.05). Trabecular and cortical bone traits of the tibia on the fractured and the nonfractured side deteriorated throughout follow‐up. The home‐based physical rehabilitation intervention aimed at promoting mobility recovery was unable to prevent bone deterioration in older people after hip fracture. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Decreased postoperative gluteus medius muscle cross-sectional area measured by computed tomography scan in patients with intertrochanteric fractures nailing

BACKGROUND

In patients with femoral intertrochanteric fractures treated by cephalomedullary (CM) nailing, abduction force reportedly decreased by 25-30% during the postoperative follow-up period. The purpose of the current study is to evaluate the cross-sectional area (CSA) and adipose tissue ratio (ATR) of the gluteus medius muscle on the postoperative computed tomography (CT) view, expecting this graphic study will support clinical results.

MATERIALS AND METHODS

A total of 27 patients with femoral intertrochanteric fractures treated by CM femoral nail implants completed the study. The mean age at osteosynthesis was 83 years (range: 72-94 years). The mean postoperative follow-up period was 23 months. The three CT axial slice views were defined as slices A, B, and C corresponding to proximal, midway, and distal part of gluteus medius, respectively. The CSA and ATR were assessed bilaterally.

RESULTS

The mean and standard deviation of CSA values (mm²) between the nonoperated/ operated side were as follows: slice A: 2225.8 ± 621.2/1984.5 ± 425.8; slice B: 2145.1 ± 538.3/1854.9 ± 383.9; and slice C: 1711.0 ± 459.0/1434.5 ± 396.9 ( p < 0.01 in slices A, B, and C). The mean and standard deviation of ATR values (%) from the nonoperative/ operative side were as follows: slice A: 2.8 ± 1.7/5.2 ± 3.5; slice B: 2.7 ± 1.9/4.6 ± 3.2; and slice C: 3.6 ± 3.0/4.8 ± 3.2 ( p < 0.01 in slices A and B and p < 0.05 in slice C).

CONCLUSION

Our image findings documented that gluteus medius is significantly changed in CSA and ATR. The damage possibly triggers decrease in muscular strength of hip abduction in the postoperative follow-up period. This measurement is objective, and needed no patient's endurance and cooperation.

Non-invasive Assessment of Lower Limb Geometry and Strength Using Hip Structural Analysis and Peripheral Quantitative Computed Tomography: A Population-Based Comparison

Hip fracture is the most significant complication of osteoporosis in terms of mortality, long-term disability and decreased quality of life. In the recent years, different techniques have been developed to assess lower limb strength and ultimately fracture risk. Here we examine relationships between two measures of lower limb bone geometry and strength; proximal femoral geometry and tibial peripheral quantitative computed tomography. We studied a sample of 431 women and 488 men aged in the range 59-71 years. The hip structural analysis (HSA) programme was employed to measure the structural geometry of the left hip for each DXA scan obtained using a Hologic QDR 4500 instrument while pQCT measurements of the tibia were obtained using a Stratec 2000 instrument in the same population. We observed strong sex differences in proximal femoral geometry at the narrow neck, intertrochanteric and femoral shaft regions. There were significant (p < 0.001) associations between pQCT-derived measures of bone geometry (tibial width; endocortical diameter and cortical thickness) and bone strength (strength strain index) with each corresponding HSA variable (all p < 0.001) in both men and women. These results demonstrate strong correlations between two different methods of assessment of lower limb bone strength: HSA and pQCT. Validation in prospective cohorts to study associations of each with incident fracture is now indicated.

Asymmetry in CT Scan Measures of Thigh Muscle 2 Months After Hip Fracture: The Baltimore Hip Studies

BACKGROUND

Hip fracture is an important problem for older adults with significant functional consequences. After hip fracture, reduced muscle loading can result in muscle atrophy.

METHODS

We compared thigh muscle characteristics in the fractured leg with those in the nonfractured leg in participants from the Baltimore Hip Studies 7th cohort using computed tomography (CT) scan imaging.

RESULTS

At 2 months postfracture, a single 10-mm axial CT scan was obtained at the midthigh level in 47 participants (26 men and 21 women) with a mean age of 80.4 years (range 65-96), and thigh muscle cross-sectional area (CSA), CSA of intermuscular adipose tissue (IMAT), as well as mean radiological attenuation were measured. Total thigh muscle CSA was less on the side of the fracture by 9.2 cm(2) (95% CI: 5.9, 12.4 cm(2)), whereas the CSA of IMAT was greater by 2.8 cm(2) (95% CI: 1.9, 3.8 cm(2)) on the fractured side. Mean muscle attenuation was lower on the side of the fracture by 3.61 HU (95% CI: 2.99, 4.24 HU).

CONCLUSIONS

The observed asymmetry is consistent with the effect of disuse and inflammation in the affected limb along with training effects in the unaffected limb due to the favoring of this leg with ambulation during the postfracture period.

Type of surgery is associated with pain and walking difficulties among older people with previous hip fracture

AIM

The aim was to assess the level of lower body pain among people with previous femoral neck fracture, and whether the type of surgery was associated with pain and physical function a mean of 2 years after surgery.

METHODS

The study included 115 community-dwelling older adults aged 60 years and older with previous femoral neck fracture, and 31 reference subjects without previous lower limb injuries. A total of 30 patients had internal fixation surgery, 70 had hemiarthroplasty and 15 had total hip replacement. All patients had surgery in the same hospital and received typical inpatient rehabilitation. From 1.6 months to 7.5 years after the fracture, the patients underwent examination including clinical evaluation, measurements of pain in the lower body (visual analog scale), physical function (maximal walking speed, Timed Up & Go, Berg Balance Scale) and self-reported walking difficulties.

RESULTS

Hip fracture patients reported more pain (81 ± 88 mm) compared with the reference group (25 ± 39 mm, P = 0.004). Patients with internal fixation reported significantly more pain than the other study groups. Significantly more patients with internal fixation (53%) reported walking difficulties compared with patients who had hemiarthroplasty (29%, P = 0.028) or total hip replacement (13%, P = 0.018). No significant difference was observed in performance-based physical function between the fracture groups, but participants in the reference group had better physical function than any of the fracture groups.

CONCLUSIONS

Hip fracture patients treated with internal fixation experienced more pain and walking difficulties than the hemiarthroplasty and total hip replacement groups. Different types of surgical fixation might require different rehabilitation and pain management strategies after hip fracture. Geriatr Gerontol Int 2015; ●●: ●●-●●.

Asymmetry in CT Scan Measures of Thigh Muscle 2 Months After Hip Fracture: The Baltimore Hip Studies

BACKGROUND

Hip fracture is an important problem for older adults with significant functional consequences. After hip fracture, reduced muscle loading can result in muscle atrophy.

METHODS

We compared thigh muscle characteristics in the fractured leg to those in the nonfractured leg in participants from the Baltimore Hip Studies 7th cohort using computed tomography scan imaging.

RESULTS

At 2 months postfracture, a single 10mm axial computed tomography scan was obtained at the midthigh level in 43 participants (23 men, 20 women) with a mean age of 79.9 years (range: 65-96 years), and thigh muscle cross-sectional area, cross-sectional area of intermuscular adipose tissue, and mean radiologic attenuation were measured. Total thigh muscle cross-sectional area was less on the side of the fracture by 9.46cm(2) (95% CI: 5.97cm(2), 12.95cm(2)) while the cross-sectional area of intermuscular adipose tissue was greater by 2.97cm(2) (95% CI: 1.94cm(2), 4.01cm(2)) on the fractured side. Mean muscle attenuation was lower on the side of the fracture by 3.66 Hounsfield Units (95% CI: 2.98 Hounsfield Units, 4.34 Hounsfield Units).

CONCLUSIONS

The observed asymmetry is consistent with the effect of disuse and inflammation in the affected limb along with training effects in the unaffected limb due to the favoring of this leg with ambulation during the postfracture period.

Volumetric bone mineral density and bone geometry assessed by peripheral quantitative computed tomography in women with differentiated thyroid cancer under TSH suppression

OBJECTIVE

TSH suppression therapy in patients with differentiated thyroid cancer (DTC) has been associated with adverse effects on areal bone mineral density (aBMD) only in postmenopausal women. The purpose of study was to examine the effect of TSH suppression therapy on skeletal integrity using peripheral quantitative computed tomography (pQCT) at the radius and tibia in pre- and postmenopausal women with DTC and controls.

STUDY DESIGN AND PATIENTS

Subjects included 80 women with DTC (40 pre- and 40 postmenopausal) and 89 (29 and 60, respectively) controls. pQCT was performed at the radius and tibia, Dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine, while samples were taken for calciotropic hormones and bone markers.

RESULTS

No differences were observed concerning aBMD by DXA. In premenopausal women, there were no significant differences concerning vBMD, while cortical thickness was higher at the radius in patients with DTC (P < 0·01) compared with controls. In postmenopausal women with DTC trabecular bone mineral content (BMC), area and vBMD were lower at the radius (all P < 0·05), while at the tibia trabecular BMC and vBMD were lower at the mixed transition zone (14% from the distal end, P < 0·05) compared with controls. Cortical thickness was lower at the radius (P < 0·01) in postmenopausal patients compared with controls. Serum CTX was higher in postmenopausal women with DCT (P < 0·01), while in premenopausal patients, parathyroid hormone (PTH) was lower (P = 0·01) compared with controls.

CONCLUSIONS

TSH suppression therapy is associated with higher bone resorption only in postmenopausal women; this adversely affects trabecular and cortical bone properties especially at nonweight-bearing sites such as the radius.

Dependency in activities of daily living following limb trauma in elderly referred to shahid beheshti hospital, kashan-iran in 2013

Background:

Activities of daily living (ADL) are an important indicator of health and independence in elderly. It provides useful information for proper planning in the field of elderly care. Trauma in elderly population is frequent and can negatively affect the independence in ADL.

Objectives:

The purpose of the present study was to evaluate elderly independence in activities of daily living (ADL) following limb trauma and its related factors in patients referred to trauma emergency ward of Shahid Beheshti Hospital, Kashan, Iran, in 2013.

Patients and Methods:

This descriptive study was conducted on 200 traumatic patients admitted to trauma emergency ward of Shahid Beheshti Hospital in 2013. The questionnaire used in this study had three parts as demographic data, information related to trauma and ISADL (independency scale of activities of daily living). ISADL was completed in emergency ward to declare pretraumatic status; it was also completed 1 and 3 months after trauma. Statistical analysis was conducted by Chi-square test, One-way and two-factor ANOVA, and Multiple regression analysis. Data analysis was conducted using SPSS software, version 16.

Results:

The average age of participants was 70.57 ± 9.05 years. In total, 80.5% of the elderly were completely independent in ISADL before trauma; this decreased to 13.5% one month after trauma. Besides, 32% of the elderly were completely or relatively dependent three months after trauma. Two-factor ANOVA showed a significant association between the scores of ISADL, the time interval and the type and location of an injured organ, and having the surgery as a treatment.

Conclusions:

More than three-quarters of the elderly were independent in ISADL before the trauma, but trauma in elderly patients had a substantial negative effect on patients' ability and ADL function.

Peripheral quantitative computed tomography measures are associated with adult fracture risk: the Hertfordshire Cohort Study

Peripheral quantitative computed tomography (pQCT) captures novel aspects of bone geometry that may contribute to fracture risk and offers the ability to measure both volumetric bone mineral density (vBMD) and a separation of trabecular and cortical compartments of bone, but longitudinal data relating measures obtained from this technique to incident fractures are lacking. Here we report an analysis from the Hertfordshire Cohort Study, where we were able to study associations between measures obtained from pQCT and DXA in 182 men and 202 women aged 60-75 years at baseline with incident fractures over 6 years later. Among women, radial cortical thickness (HR 1.72, 95% CI 1.16, 2.54, p=0.007) and cortical area (HR 1.91, 95% CI 1.27, 2.85, p=0.002) at the 66% slice were both associated with incident fractures; these results remained significant after adjustment for confounders (age, BMI, social class, cigarette smoking and alcohol consumption, physical activity, dietary calcium, HRT and years since menopause). Further adjustment for aBMD made a little difference to the results. At the tibia, cortical area (HR 1.58, 95% CI 1.10, 2.28, p=0.01), thickness (HR 1.49, 95% CI 1.08, 2.07, p=0.02) and density (HR 1.64, 95% CI 1.18, 2.26, p=0.003) at the 38% site were all associated with incident fractures with the cortical area and density relationships remaining robust to adjustment for the confounders listed above. Further adjustment for aBMD at this site did lead to attenuation of relationships. Among men, tibial stress-strain index (SSI) was predictive of incident fractures (HR 2.30, 95% CI 1.28, 4.13, p=0.005). Adjustment for confounding variables and aBMD did not render this association non-significant. In conclusion, we have demonstrated relationships between measures of bone size, density and strength obtained by pQCT and incident fracture. These relationships were attenuated but in some cases remained significant after adjustment for BMD measures obtained by DXA, suggesting that some additional information may be conferred by this assessment.

Age and sex differences in estimated tibia strength: influence of measurement site

Variability in peripheral quantitative computed tomography (pQCT) measurement sites and outcome variables limit direct comparisons of results between studies. Furthermore, it is unclear what estimates of bone strength are most indicative of changes due to aging, disease, or interventions. The purpose of this study was to examine age and sex differences in estimates of tibia strength. An additional purpose of this study was to determine which tibia site or sites are most sensitive for detecting age and sex differences in tibia strength. Self-identifying Caucasian men (n=55) and women (n=59) aged 20-59yr had their tibias measured with pQCT from 5% to 85% of limb length in 10% increments distal to proximal. Bone strength index, strength strain index (SSI), moments of inertia (Ip, Imax, and Imin), and strength-to-mass ratios (polar moment of inertia to total bone mineral content [BMC] ratio [Ip:Tot.BMC] and strength strain index to total BMC ratio [SSI:Tot.BMC]) were quantified. There were significant (p<0.01) site effects for all strength variables and strength-to-mass ratios. Site×sex interaction effects were significant (p<0.05) for all strength variables. Men had greater (p<0.01) values than women for all strength variables. Sex differences in Ip, Imax, Ip:Tot.BMC, SSI, and SSI:Tot.BMC ratios were the smallest at the 15% site and peaked at various sites, depending on variable. Site×age interactions existed for Imax, Ip:Tot.BMC, and SSI:Tot.BMC. There were significant age effects, Imax, Ip:Tot.BMC, and SSI:Tot.BMC, as values were the lowest in the 20-29 age group. Age and sex differences varied by measurement site and variable, and larger sex differences existed for moments of inertia than SSI. Strength-to-mass ratios may reflect efficiency of the whole bone architecture.

Promoting mobility after hip fracture (ProMo): study protocol and selected baseline results of a year-long randomized controlled trial among community-dwelling older people

Background

To cope at their homes, community-dwelling older people surviving a hip fracture need a sufficient amount of functional ability and mobility. There is a lack of evidence on the best practices supporting recovery after hip fracture. The purpose of this article is to describe the design, intervention and demographic baseline results of a study investigating the effects of a rehabilitation program aiming to restore mobility and functional capacity among community-dwelling participants after hip fracture.

Methods/Design

Population-based sample of over 60-year-old community-dwelling men and women operated for hip fracture (n = 81, mean age 79 years, 78% were women) participated in this study and were randomly allocated into control (Standard Care) and ProMo intervention groups on average 10 weeks post fracture and 6 weeks after discharged to home. Standard Care included written home exercise program with 5-7 exercises for lower limbs. Of all participants, 12 got a referral to physiotherapy. After discharged to home, only 50% adhered to Standard Care. None of the participants were followed-up for Standard Care or mobility recovery. ProMo-intervention included Standard Care and a year-long program including evaluation/modification of environmental hazards, guidance for safe walking, pain management, progressive home exercise program and physical activity counseling. Measurements included a comprehensive battery of laboratory tests and self-report on mobility limitation, disability, physical functional capacity and health as well as assessments for the key prerequisites for mobility, disability and functional capacity. All assessments were performed blinded at the research laboratory. No significant differences were observed between intervention and control groups in any of the demographic variables.

Discussion

Ten weeks post hip fracture only half of the participants were compliant to Standard Care. No follow-up for Standard Care or mobility recovery occurred. There is a need for rehabilitation and follow-up for mobility recovery after hip fracture. However, the effectiveness of the ProMo program can only be assessed at the end of the study.

Trial registration

Current Controlled Trials ISRCTN53680197

Analysis of plastic deformation in cortical bone after insertion of coated and non-coated self-tapping orthopaedic screws

Insertion of internal fracture fixation devices, such as screws, mechanically weakens the bone. Diamond-like carbon has outstanding tribology properties which may decrease the amount of damage in tissue. The purpose of this study was to investigate methods for quantification of cortical bone damage after orthopaedic bone screw insertion and to evaluate the effect of surface modification on tissue damage. In total, 48 stainless steel screws were inserted into cadaver bones. Half of the screws were coated with a smooth amorphous diamond coating. Geometrical data of the bones was determined by peripheral quantitative computed tomography. Thin sections of the bone samples were prepared after screw insertion, and histomorphometric evaluation of damage was performed on images obtained using light microscopy. Micro-computed tomography and scanning electron microscopy were also used to examine tissue damage. A positive correlation was found between tissue damage and the geometric properties of the bone. The age of the cadaver significantly affected the bone mineral density, as well as the damage perimeter and diameter of the screw hole. However, the expected positive effect of surface modification was probably obscured by large variations in the results and, thus, statistically significant differences were not found in this study. This can be explained by natural variability in bone tissue, which also made automated image analysis difficult.

Bone strength measured by peripheral quantitative computed tomography and the risk of nonvertebral fractures: the osteoporotic fractures in men (MrOS) study

Many fractures occur in individuals without osteoporosis defined by areal bone mineral density (aBMD). Inclusion of other aspects of skeletal strength may be useful in identifying at-risk subjects. We used surrogate measures of bone strength at the radius and tibia measured by peripheral quantitative computed tomography (pQCT) to evaluate their relationships with nonvertebral fracture risk. Femoral neck (FN) aBMD, measured by dual-energy X-ray absorptiometry (DXA), also was included. The study population consisted of 1143 white men aged 69+ years with pQCT measures at the radius and tibia from the Minneapolis and Pittsburgh centers of the Osteoporotic Fractures in Men (MrOS) study. Principal-components analysis and Cox proportional-hazards modeling were used to identify 21 of 58 pQCT variables with a major contribution to nonvertebral incident fractures. After a mean 2.9 years of follow-up, 39 fractures occurred. Men without incident fractures had significantly greater bone mineral content, cross-sectional area, and indices of bone strength than those with fractures by pQCT. Every SD decrease in the 18 of 21 pQCT parameters was significantly associated with increased fracture risk (hazard ration ranged from 1.4 to 2.2) independent of age, study site, body mass index (BMI), and FN aBMD. Using area under the receiver operation characteristics curve (AUC), the combination of FN aBMD and three radius strength parameters individually increased fracture prediction over FN aBMD alone (AUC increased from 0.73 to 0.80). Peripheral bone strength measures are associated with fracture risk and may improve our ability to identify older men at high risk of fracture.

Denosumab improves density and strength parameters as measured by QCT of the radius in postmenopausal women with low bone mineral density

BACKGROUND

Bone strength is determined by both cortical and trabecular bone compartments and can be evaluated radiologically through measurement of bone density and geometry. Quantitative computed tomography (QCT) separately assesses cortical and trabecular bone reliably at various sites, including the distal radius where there is a gradation of cortical and trabecular bone. We evaluated the effect of denosumab, a fully human monoclonal antibody that inhibits RANK ligand, on distal radius QCT in women with low bone mass to assess the impact of this novel therapy separately on trabecular and cortical bone.

METHODS

Postmenopausal women (n=332) with spine areal bone mineral density (BMD) T-scores between -1.0 and -2.5 received denosumab 60 mg or placebo every 6 months during the 24-month study. QCT measurements along the distal radius were made using a whole-body computed tomography scanner and were used to determine the percentage change from baseline in volumetric BMD; volumetric bone mineral content (BMC); cortical thickness; volume; circumference; and density-weighted polar moment of inertia (PMI), a derived index of bone strength.

RESULTS

Denosumab treatment significantly increased total BMD and BMC along the radius (proximal, distal, and ultradistal sections). At 24 months, the ultradistal region had the greatest percentage increase in total BMD (4.7% [95% CI, 3.6-5.7]; P<0.001) and total BMC (5.7% [95% CI, 4.8-6.6]; P<0.001) over placebo. When cortical and trabecular bone at the proximal and distal regions were separately assessed, cortical bone had significant (P<0.001) increases in BMD, BMC, and thickness, and trabecular bone had a significant increase in BMD relative to placebo (P<0.05). Bone strength, estimated by density-weighted PMI, significantly increased compared with placebo after 6 months of treatment, with the largest percentage increase occurring at 24 months in the ultradistal region (6.6% [95% CI, 5.6-7.6]; P<0.0001).

CONCLUSIONS

QCT measurements demonstrated that denosumab significantly increased BMD, BMC, and PMI along the radius over 24 months. Additionally, denosumab prevented the decrease in QCT-measured cortical thickness observed in the placebo group. These data extend the evidence from previous dual-energy X-ray absorptiometry studies for a positive effect of denosumab on both the cortical and trabecular bone compartments and propose a possible mechanism for the reduction in fracture risk achieved with denosumab therapy.

Women with hip fracture experience greater loss of geometric strength in the contralateral hip during the year following fracture than age-matched controls

This study examined femur geometry underlying previously observed decline in BMD of the contralateral hip in older women the year following hip fracture compared to non-fractured controls. Compared to controls, these women experienced a greater decline in indices of bone structural strength, potentially increasing the risk of a second fracture.

INTRODUCTION

This study examined the femur geometry underlying previously observed decline in BMD of the contralateral hip in the year following hip fracture compared to non-fractured controls.

METHODS

Geometry was derived from dual-energy X-ray absorptiometry scan images using hip structural analysis from women in the third cohort of the Baltimore Hip Studies and from women in the Study of Osteoporotic Fractures. Change in BMD, section modulus (SM), cross-sectional area (CSA), outer diameter, and buckling ratio (BR) at the narrow neck (NN), intertrochanteric (IT), and shaft (S) regions of the hip were compared.

RESULTS

Wider bones and reduced CSA underlie the significantly lower BMD observed in women who fractured their hip resulting in more fragile bones expressed by a lower SM and higher BR. Compared to controls, these women experienced a significantly greater decline in CSA (-2.3% vs. -0.2%NN, -3.2% vs. -0.5%IT), SM (-2.1% vs. -0.2%NN, -3.9% vs. -0.6%IT), and BMD (-3.0% vs. -0.8%NN, -3.3% vs. -0.6%IT, -2.3% vs. -0.2%S) and a greater increase in BR (5.0% vs. 2.1%NN, 6.0% vs. 1.3%IT, 4.4% vs. 1.0%S) and shaft outer diameter (0.9% vs. 0.1%).

CONCLUSION

The contralateral femur continued to weaken during the year following fracture, potentially increasing the risk of a second fracture.