Bone loss at the os calcis compared with bone loss at the knee in individuals with spinal cord injury

BACKGROUND/OBJECTIVE: The objective of this study was to document acute bone loss at the os calcis and compare it with bone loss at the knee following spinal cord injury (SCI) as a potential proxy for bone loss in individuals with SCI. METHODS: Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DEXA) at the knee and os calcis, which also was assessed by ultrasound in 6 individuals--5 with complete SCI and 1 with incomplete SCI--at means of 33.5 and 523 days following injury. RESULTS: Bone mineral was progressively greater as measured from proximal to distal sites. The net average BMD of the knee declined 24% (P = 0.017). The distal femur lost 27% (P = 0.038) and the proximal tibia lost 32% (P = 0.015), whereas the os calcis lost 38% (P = 0.001) as measured by DEXA and 49% (P < 0.001) as estimated from ultrasound. The mean loss of 24% at the knee was significantly different from the loss percentages at the os calcis as measured by both techniques: DEXA (P = 0.036) and ultrasound (P = 0.043). Differences between annualized loss rates at the knee and the os calcis measured by both techniques also were significant: DEXA (P = 0.032) vs ultrasound (P = 0.038). However, annualized loss rates demonstrated the same trend for differential loss at the sites examined in the 5 individuals with complete injuries but not for the 1 participant with an incomplete injury. The loss rates were similar for the complete and incomplete participants at the os calcis, but not at the knee. CONCLUSION: The BMD of the os calcis declined 38% by DEXA and 49% by ultrasound compared with 24% at the knee when measured 1 to 1.5 years after injury. BMD of the os calcis and distal femur measured by DEXA in persons with complete SCI were highly correlated (r = 0.84, P < 0.0001).     

Risk Factors For Osteoporosis at the Knee in the Spinal Cord Injury Population

Abstract

Background: The objective of this study was to determine modifiable and nonmodifiable risk factors for bone loss at the knee in individuals with spinal cord injury (SCI) by examining known risk factors for osteoporosis in the general population and additional, unique nonmodifiable SCI elements including age at injury onset, injury duration, and extent of neurologic injury (Ievei and completeness).

Methods: Risk factors were examined by logistic regression in 152 individuals with chronic SCI. Knees were classified as osteoporoticbased on whether bone mineral density (BMD) of the knee as assessed by dual-energy x-ray absorptiometry feil within the 95%confidence interval of the BMD of the knee of individuals who had experienced fractures at the knee.

Results: Accuracy for predicted membership in the osteoporotic group and nonosteoporotic group were 79.22'7o and 69.33%,respectively. Of all variables included in the analysis, 3 had a significant effect on predicted group membership: completeness ofinjury (P < 0.0001), body mass index (BMI) (P=0.0035), and age (P=0.0394). lndividuals with complete injuries were 6.17times (617'7o) more likely to have BMD of the knee low enough to place them in the osteoporotic category. The odds ratio for BMIindicated that every unit increase in BMIIowered the odds of being in the osteoporotic group by 11.29%. The odds ratio for ageindicated that every 1 -year increase in age increased the odds of being in the osteoporotic group by 3.54%. No other modifiableor nonmodifiable risk factors were significant predictors.

Conclusion: Completeness of injury dictates and overrides most modifiable and nonmodifiable risk factors for bone loss at the kneeleading to pathologic fractures in SCI. SCI osteoporosis may be classifi ed more appropriately as neuragenie in origin.     

Evaluation of bone mineral loss in patients with chronic traumatic spinal cord injury in Iran

Abstract

Objectives

We described the associations between demographic and injury-related factors on bone mineral density (BMD) of the spine and the hip among adult patients with chronic spinal cord injury (SCI).

Design

BMD in spinal and femoral bone sites were assessed. Multivariate analysis was performed to evaluate the relationship between anthropometric and injury-related factors with BMD. Serum level and amount of dietary intake of calcium, phosphor, and 25-hydroxy vitamin D were measured.

Setting

A referral tertiary rehabilitation center in Iran.

Participants

Patients with SCI who had no previous history of endocrine disorders and were not on specific medications entered the investigation. Those with non-traumatic SCI, pregnant, or with substance dependency were excluded as well.

Interventions

No interventions were applied.

Main study outcome measures

Dual X-ray absorptiometry was performed to estimate BMD. Body mass index was positively associated with higher femoral (P < 0.01, r = 0.56) and hip (P < 0.0001, r = 0.82) BMD only in female participants. The high prevalence of vitamin D deficiency (60%) was noticeable.

Results

Older male patients revealed lower BMD only in spinal vertebrae (P < 0.02, r = ?0.21). A significant higher BMD loss in lumbar vertebras in male patients with complete spinal cord lesion (P < 0.009) was detected. Spinal reduction of BMD was more severe when the level of injury was above T6 (P < 0.02).

Conclusion

Along with the clarification of age, gender, post injury duration, and the other factors' effect on the BMD in the SCI patients, here we have also shown the noticeable prevalence of the 25-hydoxy vitamin D deficiency in these patients which needs attention.     

Five-Year Longitudinal Bone Evaluations In Individuals With Chronic Complete Spinal Cord Injury

Background/Objectives:Knowledge of spinal cord injury (SCI) bone changes has been derived primarilythrough cross-sectional studies, many of which are controvertible. Longitudinal studies are sparse, and longtermlongitudinal chronic studies are unavailable. The objective of this study was to provide a clearerperception of chronic longitudinal bone variations in people with complete SCI.

Methods:Bone status of 31 individuals with chronic, complete SCI was assessed twice using dual-energy xrayabsorptiometry at an average interval of 5.06 ± 0.9 years. Because the sample of women was small (4),the primary analyses of change and comparisons of those with paraplegia vs tetraplegia were confined to themale participants.

Results: Spine Z-scores showed a significant increase (P < 0.0001 ). The average Z-scores, initial and followup,were within the normal range. Hip Z-scores also showed a significant increase (P < 0.0001 ), and hipbone mineral density (BMD) increased in 48% of the participants. Knee BMD and lower extremity total bonemineral showed significant decreases (P < 0.003 and P < 0.02, respectively), but increases were seen in 33% and 26% at the respective sites. Individuals with tetraplegia had significantly lower values across all regions(P < 0.0001 ), and changes were significantly different compared with paraplegia (P < 0.0001 ). Bone valuesand changes in men vs women, despite the small sample of women, showed highly significant differences(P < 0.003?0.002).

Conclusion:Chronic effects of complete SCI do not exclusively result in continued loss of BMD or a staticstate of lowered BMD; gain in BMD may occur. The nature and magnitude of the effects of complete SCI on BMD vary by site, with sex and level of injury, which has implications for treatment and its assessment.     

Identification of Women with Reduced Bone Density at the Lumbar Spine and Femoral Neck using BMD at the Os Calcis

We assessed the clinical usefulness of bone density measurements at the os calcis as a screening tool to identify patients with low bone density at the lumbar spine and femoral neck. Bone mineral density (BMD) was recorded in 443 women (mean age 60 years) referred to a bone densitometry service. Measurements were made at the lumbar spine and femoral neck using a Lunar DPXL and at the right os calcis using a Peripheral Instantaneous X-ray Imaging (PIXI) dual-energy X-ray absorptiometry system. Average T-scores derived using the manufacturer”s data were: 1.59 for the lumbar spine, −1.41 for the femoral neck and −0.87 for the os calcis. The prevalence of osteoporosis using WHO criteria (T-scores of −2.5 or less) was 36% for the lumbar spine or femoral neck but only 9.7% for the os calcis. BMD of the os calcis correlated with that at the lumbar spine (r= 0.69, p<0.001) and femoral neck (r= 0.67, p<0.001). The area under the receiver operator characteristics curve was 0.836 (standard error 0.020) for the os calcis related to osteoporosis at the lumbar spine or femoral neck. Optimal accuracy was obtained at a T-score of ≤−1.3 (BMD 0.39 g/cm²) when the sensitivity was 69.6% (95% confidence interval 65.3, 73.9%) and specificity 82.6% (95% confidence interval 79.1, 86.1%). However, the probability of diagnosing low bone density from a given BMD at the os calcis varied by age and site scanned. Accordingly, for informing management strategies, the choice of a single cutoff BMD at the os calcis may not be appropriate and several thresholds may be adopted based on age, the site of interest (lumbar spine or femoral neck) and consideration of associated clinical features. Thus, the use of heel bone density scanners could reduce the number of axial bone density measurements required. The advantages of portability, low cost and shorter scan times should reduce the cost of detection and provide a greater opportunity for identification of women at risk of fracture. Received: 18 June 1999 / Accepted: 30 March 2000     

Risk factors for osteoporosis at the knee in the spinal cord injury population

BACKGROUND: The objective of this study was to determine modifiable and nonmodifiable risk factors for bone loss at the knee in individuals with spinal cord injury (SCI) by examining known risk factors for osteoporosis in the general population and additional, unique nonmodifiable SCI elements including age at injury onset, injury duration, and extent of neurologic injury (level and completeness). METHODS: Risk factors were examined by logistic regression in 152 individuals with chronic SCI. Knees were classified as osteoporotic based on whether bone mineral density (BMD) of the knee as assessed by dual-energy x-ray absorptiometry fell within the 95% confidence interval of the BMD of the knee of individuals who had experienced fractures at the knee. RESULTS: Accuracy for predicted membership in the osteoporotic group and nonosteoporotic group were 79.22% and 69.33%, respectively. Of all variables included in the analysis, 3 had a significant effect on predicted group membership: completeness of injury (P < 0.0001), body mass index (BMI) (P = 0.0035), and age (P = 0.0394). Individuals with complete injuries were 6.17 times (617%) more likely to have BMD of the knee low enough to place them in the osteoporotic category. The odds ratio for BMI indicated that every unit increase in BMI lowered the odds of being in the osteoporotic group by 11.29%. The odds ratio for age indicated that every 1-year increase in age increased the odds of being in the osteoporotic group by 3.54%. No other modifiable or nonmodifiable risk factors were significant predictors. CONCLUSION: Completeness of injury dictates and overrides most modifiable and nonmodifiable risk factors for bone loss at the knee leading to pathologic fractures in SCI. SCI osteoporosis may be classified more appropriately as neurogenic in origin.     

Neuromotor and Musculoskeletal Responses to Locomotor Training for an Individual With Chronic Motor Complete AIS-B Spinal Cord Injury

Background/objective: To determine the effects of locomotor training (LT)using body weight support(BWS), treadmill, and manual assistance on muscle activation, bone mineral density (BMD), and body composition changes for an individual with motor complete spinal cord injury (AIS B), 1 year after injury.

Methods: A man with chronic C6 AIS B (motor complete and sensory incomplete) spinal cord injury (SCI),1 year after injury, completed 2 blocks of LT over a 9-monthtraining period (35-session block followed by8.6 weeks of no training and then a 62-session block).

Results: Before training, muscle activation was minimal for any muscle examined, whereas after the 2 blocksof LT (97 sessions), hip and knee muscle activation patterns for the bilateral rectus femoris, biceps femoris,and gastrocnemius were in phase with the kinematics. Mean EMG amplitude increased for all bilateral muscles and burst duration increased for rectus femoris and gastrocnemius muscles, whereas burst duration decreased for the biceps femoris after 62 LT sessions. Before LT, left biceps femoris had a pattern that reflected muscle stretch, whereas after training, muscle stretch of the left biceps femoris could not totally account for mean EMG amplitude or burst duration. After the62 training sessions, total BMD decreased (1.54%), and regional BMD decreased (legs: 6.72%). Total weight increased, lean mass decreased (6.6%), and fat mass increased (7.4%) in the arms, whereas fat mass decreased (3.5%) and lean mass increased (4%) in the legs.

Conclusions: LT can induce positive neural and body composition changes in a nonambulatory personwith chronic SCI, indicating that neuromuscular plasticity can beinduced by repetitive locomotor trainingafter a motor complete SCI.     

Bone changes in the lower limbs from participation in an FES rowing exercise program implemented within two years after traumatic spinal cord injury

Objective: To determine the effect of a functional electrical stimulation (FES) rowing program on bone mineral density (BMD) when implemented within two years after SCI.

Design: Prospective.

Setting: Health Care Facility.

Participants: Convenience sample; four adults with recent (<2 years) traumatic, motor complete SCI (C7-T12 AIS A-B).

Intervention: A 90-session FES rowing exercise program; participants attended 30-minute FES training sessions approximately three times each week for the duration of their participation.

Outcome Measures: BMD in the distal femur and tibia were measured using peripheral Quantitative Computed Tomography (pQCT) at enrollment (T₀) and after 30 (T₁), 60 (T₂), and 90 (T₃) sessions. Bone stimulus was calculated for each rower at each time point using the average number of weekly loading cycles, peak foot reaction force, and bone mineral content from the previous time point. A regression analysis was used to determine the relationship between calculated bone stimulus and change in femoral trabecular BMD between time points.

Results: Trabecular BMD in the femur and tibia decreased for all participants in T_0-1, but the rate of loss slowed or reversed between T_1-2, with little-to-no bone loss for most participants during T_2-3. The calculated bone stimulus was significantly correlated with change in femoral trabecular BMD (P?=?0.016; R^2?=?0.458).

Conclusion: Consistent participation in an FES rowing program provides sufficient forces and loading cycles to reduce or reverse expected bone loss at the distal femur and tibia, at least temporarily, in some individuals within two years after SCI.

Trial Registration: NCT02008149.     

Trabecular Bone Score at the Distal Femur and Proximal Tibia in Individuals With Spinal Cord Injury

Rapid declines in bone mineral density (BMD) at the knee after spinal cord injury (SCI) are associated with an increased risk of fracture. Evaluation of bone quality using the trabecular bone score (TBS) may provide a complimentary measure to BMD assessment to examine bone health and fracture risk after SCI. The purpose of this study was to assess bone mineral density (BMD) and trabecular bone score (TBS) at the knee in individuals with and without SCI. Nine individuals with complete SCI (mean time since SCI 2.9?±?3.8?yr) and 9 non-SCI controls received dual-energy X-ray absorptiometry scans of the right knee using the lumbar spine protocol. BMD and TBS were quantified at epiphyseal, metaphyseal, diaphyseal, and total bone regions of the distal femur and proximal tibia. Individuals with SCI illustrated significantly lower total BMD at the distal femur (23%; p?=?0.029) and proximal tibia (19%; p?=?0.02) when compared with non-SCI controls. Despite these marked differences in BMD from both locations, significant differences in total TBS were observed at the distal femur only (6%; p?=?0.023). The observed differences in total BMD and TBS could be attributed to reductions in epiphyseal rather than metaphyseal or diaphysis measurements. The relationship between TBS and duration of SCI was well explained by a logarithmic trend at the distal femoral epiphysis (r²?=?0.54, p?=?0.025). The logarithmic trend would predict that after 3?yr of SCI, TBS would be approximately 6% lower than the non-SCI controls. Further evaluation is needed to determine if TBS measures at the knee provide important information about bone quality that is not captured by traditional BMD.     

Age-Related Changes in Serum Undercarboxylated Osteocalcin and its Relationships with Bone Density, Bone Quality, and Hip Fracture

The effect of the degree of carboxylation of osteocalcin (OC) on the properties of bone is unclear. The aim of this study was to relate serum concentrations of total OC (tOC) and undercarboxylated OC (ucOC), measured with a two-site immunoassay, to bone mineral density (BMD) at the femoral neck and ultrasonic transmitted velocity (UTV) at the os calcis in 257 women aged 60–99 years, 22 of whom had sustained a hip fracture. There was an increase in tOC (r = 0.19, P= 0.003) and ucOC (r = 0.20, P= 0.002) with age. No significant difference in tOC or ucOC between subjects with and without hip fracture was found. Serum tOC was negatively correlated with femoral neck BMD (r =−0.23, P= 0.0001) and os calcis UTV (r =−0.29, P= 0.0001) and partial correlations indicated that these relationships were independent of age. Serum ucOC also correlated negatively with os calcis UTV (r =−0.21, P= 0.001) and less strongly with femoral neck BMD (r =−0.13, P= 0.052). After adjusting for age, only the relationship between ucOC and os calcis UTV remained significant (r =−0.16, P= 0.017). It is concluded that in women over 60 years, the increase in tOC reflects an age-related rise in bone remodeling, whereas the increase in ucOC reflects an age-related fall in vitamin K status. The stronger relationship of ucOC with UTV than BMD suggests that the rise in ucOC may perhaps relate more to changes in bone quality than mineral content. Higher serum ucOC concentrations in subjects with a history of hip fracture could not be confirmed. Received: 8 January 1997 / Accepted: 29 September 1997     

Evaluation of Bone Mineral Density in Patients With Spinal Cord Injury

Abstract

Background/Objective: This study was performed to evaluate the bone mineral density (BMD) values in patients with spinal cord injury (SCI) and determine the effects of the level, severity, and duration of the neurological lesion and spasticity on BMD values.

Methods: A total of 75 patients with traumatic SCI and a healthy control group of 39 people were included in the study. The BMD values of the lumbar spine and 4 different regions of the hip (femoral neck, Ward's triangle, trochanter, and femoral shaft) of all cases were measured using dual energy x-ray absorptiometry. The biochemical markers were also analyzed.

Results: The BMD values in all measured regions were found to be decreased in patients compared with that of controls. The level and seventy of the lesion and the spasticity did not significantly affect BMD values in the regions analyzed. The BMD values of the hip decreased as the duration of SCI increased. The levels of plasma phosphorus and alkaline phosphatase, calcium in 24-hour urine samples, and the calcium/creatinine ratio in spot urines were found to be significantly higher in the patient group.

Conclusion: All patients with SCI had lower BMD values than controls. The level and severity of SCI and spasticity did not significantly affect BMD values. The BMD values of the hip decreased as the duration of SCI increased.     

Assessment of Bone Mineral Density at the Distal Femur and the Proximal Tibia by Dual-Energy X-ray Absorptiometry in Individuals With Spinal Cord Injury: Precision of Protocol and Relation to Injury Duration

Spinal cord injury (SCI) is characterized by marked bone loss at the knee, and there is a need for established dual-energy X-ray absorptiometry (DXA) protocols to examine bone mineral density (BMD) at this location to track therapeutic progress and to monitor fracture risk. The purpose of this study was to quantify the precision and reliability of a DXA protocol for BMD assessment at the distal femur and the proximal tibia in individuals with SCI. The protocol was subsequently used to investigate the relationship between BMD and duration of SCI. Nine individuals with complete SCI and 9 able-bodied controls underwent 3 repeat DXA scans in accordance with the short-term precision methodology recommended by the International Society of Clinical Densitometry. The DXA protocol demonstrated a high degree of precision with the root-mean-square standard deviation ranging from 0.004 to 0.052?g/cm² and the root-mean-square coefficient of variation ranging from 0.6% to 4.4%, depending on the bone, the region of interest, and the rater. All measurements of intra- and inter-rater reliability were excellent with an intraclass correlation of ≥0.950. The relationship between the BMD and the duration of SCI was well described by a logarithmic trend (r²?=?0.68–0.92). Depending on the region of interest, the logarithmic trends would predict that, after 3?yr of SCI, BMD at the knee would be 43%–19% lower than that in the able-bodied reference group. We believe the DXA protocol has the level of precision and reliability required for short-term assessments of BMD at the distal femur and the proximal tibia in people with SCI. However, further work is required to determine the degree to which this protocol may be used to assess longitudinal changes in BMD after SCI to examine clinical interventions and to monitor fracture risk.     

Measurement of bone in the os calcis: a clinical evaluation

Bone mineral content (BMC) was measured in the os calcis of 232 normal subjects aged 17-82 years. The mean reproducibility (coefficient of variation) of the measurement was 1.8%. Substantial bone loss occurred between the ages of 20 and 50 years, and in females the menopause was associated with additional bone loss. There was no significant difference in the rate of bone loss in females and males, but the mean BMC was greater at all ages in males than in females. We also compared os calcis BMC with spinal bone mineral density (BMD), measured by quantitative computed tomographic (CT) scanning, in 85 subjects: 33 were normal controls, 19 had osteoporosis defined by the presence of one or more pathological fractures, and in the remainder the CT examination was performed at the patient's request. Os calcis BMC correlated with spinal BMD in both females (r = 0.69, p less than 0.001) and males (r = 0.84, p less than 0.001). However, the os calcis BMC did not reliably predict spine values around the CT "fracture threshold" of 90-100 mg/cm3 and did not correlate with osteoporotic fracture as well as did spinal BMD. It is concluded that measurement of the os calcis BMC is of limited clinical usefulness for the early diagnosis of osteoporosis.     

Relationships between T-scores at the hip and bone mineral density at the distal femur and proximal tibia in persons with spinal cord injury

Objective: To identify T-score values at the total hip (TH) and femoral neck (FN) that correspond to the cutoff value of <0.60?g/cm² for heightened risk of fracture at the distal femur (DF) and proximal tibia (PT).

Design: Retrospective analysis of data in a research center’s database.

Setting: Community-based individuals with spinal cord injury (SCI).

Participants: 105 unique individuals with SCI.

Outcome Measurements: DXA derived areal BMD (aBMD) and T-score of the DF, PT, TH, and FN.

Results: The aBMD at the DF and PT regions were predictors of T-scores at the TH (R ²?=?0.63, P?<?0.001 and R ²?=?0.65, P?<?0.001) and FN (R ²?=?0.55, P?<?0.001 and R ²?=?0.58, P?<?0.001). Using the DF and PT aBMD of 0.60?g/cm² as a value below which fractures were more likely to occur, the predicted T-score was ?3.1 and ?3.5 at the TH and ?2.6 and ?2.9 at the FN, respectively. However, when the predicted and observed T-score values disagree outside the 95% limit of agreement, the predicted T-score values are lower than the measured T-score values, overestimating the measured values between ?2.0 and ?4.0 SD.

Conclusion: The DF and PT cutoff value for aBMD of 0.60?g/cm² was a moderate predictor of T-score values at the TH and FN, with considerable inaccuracies outside the clinically acceptable limits of agreement. As such, the direct measurement of knee aBMD in persons with SCI should be performed, whenever possible, prior to prescribing weight bearing upright activities, such as robotic exoskeletal-assisted walking.     

Preliminary evaluation of a new ultrasound bone densitometer

Summary A new ultrasound bone densitometer has been developed that measures ultrasonic properties of the os calcis, namely, the speed of sound (SOS), broadband ultrasound attenuation (BUA), and a proprietary factor derived from SOS and BUA, termed stiffness. Short-term precision of ultrasound measurements was 1.4% for BUA, 0.2% for SOS, and 1.5% for stiffness in healthy women, and 1.1% for BUA, 0.1% for SOS, and 1.5% for stiffness in osteopenic women. One hundred seven women underwent measurements by ultrasound, together with dual energy X-ray absorptiometry (DXA) bone mineral density (BMD) measurements of the lumbar spine and proximal femur. Correlations between SOS, BUA, and stiffness measurements and DXA BMD measurements were all highly significant (P < 0.001) with r values varying from 0.54 to 0.67. BUA, SOS, and stiffness measurements were all significantly different between normal and osteopenic women even after adjusting for age, height, and weight (P < 0.05,P < 0.001, andP < 0.01, respectively). These results demonstrate that this ultrasound system measures ultrasonic properties of the os calcis with good precision, the measurements correlate moderately well with DXA BMD measurements and they can differentiate between normals and those with osteopenia.     

Bisphosphonate Use in Acute and Chronic Spinal Cord Injury: A Systematic Review

Background/Objective: Bone density loss occurs rapidly after traumatic spinal cord injury (SCI) and is associated with low-energy fractures below the level of injury, commonly occurring around the knee. Bisphosphonates have been tested as potential agents to prevent bone loss after SCI, but no guidelines exist for clinical use of bisphosphonates in these patients. The objective of this study was to systematically review and evaluate evidence quality in studies of bisphosphonate use in patients with post-treatment follow-up of sublesional bone mineral density.

Methods: Literature search in MEDLINE/PubMed and ISI database using key words bisphosphonates, spinal cord injury, quadriplegia, paraplegia, and tetraplegia.

Results: The search identified 6 experimental studies and 1 quasi-experimental study of bisphosphonate therapy in patients with acute and chronic SCI. The studies were small and of fair or poor quality, and none included fracture outcomes. Mild attenuation of bone density loss with acute administration of bisphosphonates after SCI was found at some measurement sites but was not always maintained during follow-up.

Conclusions: Data were insufficient to recommend routine use of bisphosphonates for fracture prevention in these patients. Current studies are limited by heterogeneity of patient populations and outcome measures. Uniform bone density measurement sites with rigorous quality control and compliance monitoring are needed to improve reliability of outcomes. Future studies should address specific populations (acute or chronic SCI) and should assess fracture outcomes.     

Ultrasound and dual X-ray absorptiometry densitometry in women with hip fracture

To assess the usefulness of the measurement of the os calcis by ultrasound, a method that probably reflects bone quality as well as density, we have studied 54 women with hip fracture of the proximal femur and a control group. Ultrasound evaluation of the os calcis [broadband ultrasound attenuation (BUA), speed of the sound (SOS), and a combined index (stiffness)], and bone mineral density (BMD) determination over the proximal femur by dual X-ray absorptiometry (DXA) were performed. Weight, BMD, and ultrasound values in the hip fracture patients were significantly lower than controls (P<0.001). The Z-scores for BUA and stiffness were not different than that for femoral neck. Ward's triangle or trochanteric BMD (between-1.7 and -1.5). The odds ratios determined by receiver-operating characteristics (ROC) analysis were greater at the femoral neck (25.1) and BUA (24.4). Intermediate values were found at stiffness (16.9), Ward's triangle (12.8), and trochanter (11.1), and lower values were obtained at SOS (4.2). In turn, patients with trochanteric hip fractures had a significantly lower femoral neck and Ward's triangle BMD, stiffness, and BUA than patients with cervical hip fractures. Comparing a subgroup of 30 women with hip fractures without vertebral fractures with an age-matched group of 87 women with osteoporotic vertebral fractures, both groups were of similar weight and BMD but all ultrasound values were significantly lower in the hip fractures compared with vertebral fracture patients (P<0.05-P<0.01). Our findings suggest that in women with hip fractures, ultrasound evaluation of the os calcis has diagnostic sensitivity comparable to DXA of the femur and could be useful to predict hip fracture risk. Ultrasound values are lower in hip fractures compared with vertebral fracture, age-matched women and in older compared with younger hip fracture patients.     

Factors Influencing Bladder Stone Formation in Patients With Spinal Cord Injury

Abstract

Objective: Bladder stones that form in patients with spinal cord injury (SCI) can cause significant morbidity. This study sought dto analyze factors associated withbladder stone formation to determine which patients might be at increased risk to developbladder stones.

Methods: A review of 56 SCI patients treated for bladder calculi over a 10-year period at a single institution was performed. These patients were compared with a control population of general SCI patients known tobe stone free. The factors compared were patient age, duration of injury, Ievei of injury, completeness of injury, method of bladder management, and the presence of documentedurinary tract infections with urease -producing organisms.

Results: All patients with stones were male and had a median age of 5 8.5years. The median Ievei of injury was C6, the median time since injury was 21 years, 66% had complete injuries, 68% managed their bladders with in dwelling cathetersor suprapubic tubes,and 83% had a history of infections with urease-producing organisms. When compared with the control group, patients forming bladder stones were older (P = 0 .03), were more likely to have in dwelling catheters (P < 0.0001 ), had a history of infections with urease-producing organisms (P = 0 .04), and had complete injuries(P= 0 .018).

Conclusion: This information can be used to identify patients who have anincreased risk of bladder stones and measures can betaken to reduce their incidence and morbidity.     

Changes of basic bone turnover parameters in short-term and long-term patients with spinal cord injury

The bone mineral density (BMD), the cross- links (PYD, DPD and NTx) and the bone specific alcaline phosphatase (BAP) was investigated in a cross-sectional study in 62 male patients with spinal cord injury (SCI), n = 28 short-term (0–1 year after SCI) and n = 34 long-term SCI patients (> 5 years after SCI). Knowledge about this parameters are necessary to find an adequate therapy for this special kind of osteoporosis. Immobilisation osteoporosis in SCI patients is a well-known problem that may lead to pathological fractures. Little is known regarding the extend of the osteoporosis as well as the causative factors. Measurements of the BMD in the proximal femur and the lumbar spine were performed with dual-energy-X-ray-absorptiometry (DEXA), of the osteoblast marker BAP (bone specific alkaline phosphatase) from serum and the osteoclast markers PYD (pyridinoline), DPD (desoxy-pyridinoline) and NTx (N-telopeptide of collagen type I) from urine. We found a significant decrease of BMD in the proximal femur and no relevant change in the lumbar spine compared to an age- and sex correlated control group (Z-score) in short-term and long-term SCI patients. There was a significant bone loss at the proximal femur between short and long-term SCI patients, whereas at the lumbar spine the BMD even slightly increases. Bone resorption (cross-links) was increased in both groups, though in long-term SCI patients it is significantly decreased compared to short-term SCI patients (DPD from 211.7 u/g creatinine to 118.1 u/g creatinine; NTx from 215.1 nmol/mmol creatinine to 83,6 nmol/mmol creatinine). The bone formation marker BAP is slightly below normal range in both groups (12.3 U/l in short-term, 9.7 U/l in long- term SCI patients). Only the proximal femur is affected by the immobilisation osteoporosis of SCI patients, therefore the BMD measurements in these patients should be performed at the lower limb. The problem of the immobilisation osteoporosis in SCI patients is the striking increase of bone resorption and the missing reaction of the bone formation.     

Metabolic rate and cardiorespiratory response during hybrid cycling versus handcycling at equal subjective exercise intensity levels in people with spinal cord injury

Abstract

Objective

To compare the metabolic rate and cardiorespiratory response during hybrid cycling versus handcycling at equal subjective exercise intensity levels in people with spinal cord injury (SCI).

Design

Cross-sectional study.

Setting

Amsterdam Rehabilitation Research Centre | Reade, Amsterdam, The Netherlands.

Methods

On separate days, nine individuals with a motor complete paraplegia or tetraplegia (eight men, age 40 ± 13 years, time since injury 12 ± 10 years) performed 5-minute bouts of hybrid cycling (day 1) and handcycling (day 2) at moderate (level 3 on a 10-point rating of perceived exertion (RPE) scale) and vigorous (RPE level 6) subjective exercise intensity, while respiratory gas exchange was measured by open-circuit spirometry and heart rate was monitored using radiotelemetry.

Outcome measures

Metabolic rate (calculated with the Weir equation) and cardiorespiratory response (heart rate, oxygen pulse, and ventilation).

Results

Overall, the metabolic rate during hybrid cycling was 3.4 kJ (16%) higher (P = 0.006) than during handcycling. Furthermore, compared with handcycling, the overall heart rate and ventilation during hybrid cycling was 11 bpm (11%) and 5.3 l/minute (18%) higher (P = 0.004 and 0.024), respectively, while the oxygen pulse was the same (P = 0.26).

Conclusion

Hybrid cycling induces a higher metabolic rate and cardiorespiratory response at equal RPE levels than handcycling, suggesting that hybrid cycling is more suitable for fighting obesity and increasing cardiorespiratory fitness in individuals with SCI.