Characteristics of falls and risk of hip fracture in elderly men

A method for simulating forward falls and controlling impact velocity

Assessment of protective arm reactions associated with forward falls are typically performed by dropping research participants from a height onto a landing surface. The impact velocity is generally modulated by controlling the total height of the fall. This contrasts with an actual fall where the fall velocity is dependent on several factors in addition to fall height and not likely predictable at the onset of the fall. A counterweight and pulley system can be used to modulate the fall velocity in simulated forward falls in a manner that is not predictable to study participants, enhancing experimental validity. However, predicting the fall velocity based on participant height and weight and counterweight mass is not straightforward. In this article, the design of the FALL simulator For Injury prevention Training and assessment (FALL FIT) system is described. A dynamic model of the FALL FIT and counterweight system is developed and model parameters are fit using nonlinear optimization and experimental data. The fitted model enables prediction of fall velocity as a function of participant height and weight and counterweight load. The method can be used to provide controllable perturbations thereby elucidating the control strategy used when protecting the body from injury in a forward fall, how the control strategy changes because of aging or dysfunction or as a method for progressive protective arm reaction training.•Construction of device to simulate forward falls with controllable impact velocity using material that are commercially available is described•A dynamic model of the FALL FIT is developed to estimate the impact velocity of a simulated forward fall using participant height and counterweight load•The dynamic model is validated using data from 3 previous studies.

Upright trunk and lateral or slight anterior rotation of the pelvis cause the highest proximal femur forces during sideways falls

Whole-body models are historically developed for traffic injury prevention, and they are positioned accordingly in the standing or sitting configuration representing pedestrian or occupant postures. Those configurations are appropriate for vehicle accidents or pedestrian-vehicle accidents; however, they are uncommon body posture during a fall accident to the ground. This study aims to investigate the influence of trunk and pelvis angles on the proximal femur forces during sideways falls. For this purpose, a previously developed whole-body model was positioned into different fall configurations varying the trunk and pelvis angles. The trunk angle was varied in steps of 10° from 10 to 80°, and the pelvis rotation was changed every 5° from -20° (rotation toward posterior) to +20° (rotation toward anterior). The simulations were performed on a medium-size male (177 cm, 76 kg) and a small-size female (156 cm, 55 kg), representative for elderly men and women, respectively. The results demonstrated that the highest proximal femur force measured on the femoral head was reached when either male or female model had a 10-degree trunk angle and +10° anterior pelvis rotation.

Characteristics of step responses following varying magnitudes of unexpected lateral perturbations during standing among older people - a cross-sectional laboratory-based study

INTRODUCTION

The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falling.

AIM

We aimed to explore whether different kinematic patterns and strategies occur in the first recovery step in single-step trials in which a single step was required to recover from a fall, and in multiple-step trials in which more than one step was required to recover from a fall. In addition, in the multiple-step trials, we examined kinematic patterns of balance recovery where extra steps were needed to recover balance.

METHODS

Eighty-four older adults (79.3 ± 5.2 years) were exposed to unannounced right/left perturbations in standing that were gradually increased to trigger a recovery stepping response. We performed a kinematic analysis of the first recovery step of all single-step and multiple-step trials for each participant and of total balance recovery in the multiple-step trial.

RESULTS

Kinematic patterns and strategies of the first recovery step in the single-step trials were significantly dependent on the perturbation magnitude. It took a small, yet significantly longer time to initiate a recovery step and a significantly longer time to complete the recovery step as the magnitude increased. However, the first recovery step in the multiple-step trials showed no significant differences between different perturbation magnitudes; while, in total balance recovery of these trials, we observed a small, yet significant difference as the magnitude increased.

CONCLUSIONS

At relatively low perturbation magnitudes, i.e., single-step trials, older adults selected different first stepping strategies and kinematics as perturbation magnitudes increased, suggesting that this population activated pre-planned programs based on the perturbation magnitude. However, in the first recovery step of the multiple-step trials, i.e., high perturbation magnitudes, similar kinematic movement patterns were used at different magnitudes, suggesting a more rigid, automatic behavior, while the extra-steps were scaled to the perturbation magnitude. This suggest that older adults activate pre-planned programs based on the magnitude of the perturbation, even before the first step is completed..

Test-retest reliability of the FALL FIT system for assessing and training protective arm reactions in response to a forward fall

The use of the hands and arms is an important protective mechanism in avoiding fall-related injury. The aim of this study was to evaluate the test-retest reliability of fall dynamics and evokd protective arm response kinematics and kinetics in forward falls simulated using the FALL simulator For Injury prevention Training and assessment system (FALL FIT). Fall FIT allows experimental control of the fall height and acceleration of the body during a forward fall. Two falls were simulated starting from 4 initial lean angles in Experiment 1 and with 4 different fall accelerations in Experiment 2. Fourteen younger adults (25.1±3.5 years) and 13 older adults (71.3±3.7 years) participated in Experiment 1 and 13 younger adults (31.8±5.7 years) participated in Experiment 2. Intraclass correlation coefficients (ICC) were used to the evaluate absolute agreement of single measures at each condition and averages across conditions. Average measures of fall dynamics and evoked kinematics and kinetics exhibited excellent reliability (ICC(A,4)>0.86). The reliability of single measures (ICC(A,1) > 0.59) was good to excellent, although 18% of single measures had a reliability (ICC(A,1)) between 0.00 and 0.57. The FALL FIT was shown to have good to excellent reliability for most measures. FALL FIT can produce a wide range of fall dynamics through modulation of initial lean angle and body acceleration. Additionally, the range of fall velocities and evoked kinematics and kinetics are consistent with previous fall research.•

The FALL FIT can be used to gain further insight into the control of protective arm reactions and may provide a therapeutic tool to assess and train protective arm reactions.

The relation between kinematic synergy to stabilize the center of mass during walking and future fall risks: a 1-year longitudinal study

BACKGROUND

Incorrect body weight shifting is a frequent cause of falls, and the control of the whole-body center of mass (CoM) by segmental coordination is essential during walking. Uncontrolled manifold (UCM) analysis is a method of examining the relation between variance in segmental coordination and CoM stability. However, no prospective cohort study has thoroughly investigated how variance in segmental configurations to stabilize the CoM relates to future falls. This study explored whether variance to stabilize the CoM was related to future falls.

METHODS

At the baseline visit, 30 community-dwelling older adults walked 20 times on a 6-m walkway. Using kinematic data collected during walking by a three-dimensional motion capture system, UCM analysis was performed to investigate how segmental configuration contributes to CoM stability in the frontal plane. One year after the baseline visit, we evaluated whether the subjects experienced falls. Twelve subjects had experienced falls, and 16 had not. Comparisons of variance between older adults with and without falls were conducted by covariate analysis.

RESULTS

No significant differences in variance were found in the mediolateral direction, whereas in the vertical direction, older adults with fall experiences had a greater variance, reflecting an unstable CoM, than those with no fall experiences.

CONCLUSIONS

We verified that the high variance in segmental configurations that destabilize the CoM in the vertical direction was related to future falls. The variables of UCM analysis can be useful for evaluating fall risk.

Association between falling direction and age in older patients with hip fractures

BACKGROUND

The incidence of fall-related hip fractures in old patients aged over 85 years was reported to be higher than that in old patients aged between 65 and 84 years; however, there are no known studies that reported differences of these age groups with respect to the falling situation.

OBJECTIVE

This study investigated the association between age and falling direction in patients with hip fractures.

MATERIAL AND METHODS

This study analyzed the medical records of older patients with fall-related hip fractures who were hospitalized in 2011-2018. Demographic (sex, age, and body mass index, BMI), medical and clinical (body mineral density, type of fracture, and cognitive function), and lifestyle variables (use of assistive device for locomotion and place of residence) and characteristics of falling (direction and location) were extracted. These were compared between the patients aged between 65 and 84 years (65-84 group) and over 85 years (85+ group). Multivariable logistic regression analysis was conducted to investigate associations with each falling direction (forward, sideways, and backward) with other variables.

RESULTS

Compared with the 65-84 group, the proportion of hip fractures due to sideways falls was lower in the 85+ group (P < 0.05) while the proportion of hip fractures due to backward falls was higher in the 85+ group. The multivariable logistic regression analysis showed the sideways and backward falling were only associated with the age group.

CONCLUSION

These results suggested that the falling direction was associated with age but not with other variables investigated in this study in older patients with hip fractures.

The Effect of Fall Biomechanics on Risk for Hip Fracture in Older Adults: A Cohort Study of Video-Captured Falls in Long-Term Care

Over 95% of hip fractures in older adults are caused by falls, yet only 1% to 2% of falls result in hip fracture. Our current understanding of the types of falls that lead to hip fracture is based on reports by the faller or witness. We analyzed videos of real-life falls in long-term care to provide objective evidence on the factors that separate falls that result in hip fracture from falls that do not. Between 2007 and 2018, we video-captured 2377 falls by 646 residents in two long-term care facilities. Hip fracture was documented in 30 falls. We analyzed each video with a structured questionnaire, and used generalized estimating equations (GEEs) to determine relative risk ratios (RRs) for hip fracture associated with various fall characteristics. All hip fractures involved falls from standing height, and pelvis impact with the ground. After excluding falls from lower than standing height, risk for hip fracture was higher for sideways landing configurations (RR = 5.50; 95% CI, 2.36-12.78) than forward or backward, and for falls causing hip impact (3.38; 95% CI, 1.49-7.67). However, hip fracture risk was just as high in falls initially directed sideways as forward (1.14; 95% CI, 0.49-2.67), due to the tendency for rotation during descent. Falling while using a mobility aid was associated with lower fracture risk (0.30; 95% CI, 0.09-1.00). Seventy percent of hip fractures involved impact to the posterolateral aspect of the pelvis. Hip protectors were worn in 73% of falls, and hip fracture risk was lower in falls where hip protectors were worn (0.45; 95% CI, 0.21-0.99). Age and sex were not associated with fracture risk. There was no evidence of spontaneous fractures. In this first study of video-captured falls causing hip fracture, we show that the biomechanics of falls involving hip fracture were different than nonfracture falls for fall height, fall direction, impact locations, and use of hip protectors. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Effect of fall characteristics on the severity of hip impact during a fall on the ground from standing height

The magnitude of hip impact force during a fall on the ground (i.e., concrete surface) from standing height was determined. We found that this force decreases up to 59%, depending on how they land on the ground.

INTRODUCTION

We determined the magnitude of hip impact force that humans may experience in the event of a fall from standing height on the ground, in order to examine how the hip impact force was affected by characteristics of a fall.

METHODS

Twenty subjects mimicked a typical older adults' falls on a mat. Trials were acquired with three initial fall directions: forward, sideways, and backward. Trials were also acquired with three knee positions at the time of hip impact: knee together, knee on the mat, and free knee. During falls, attenuated vertical hip impact forces and corresponding depression of the mat were measured via a force plate placed under the mat and motion capture system, respectively. Using a mass-spring model, actual hip impact force and body stiffness during a fall on the ground were estimated.

RESULTS

Hip impact force averaged 4.0 kN (SD = 1.7). The hip impact force was associated with knee condition (F = 25.6, p < 0.005), but not with fall direction (F = 0.4, p = 0.599). Compared with "knee on the mat," hip impact force averaged 59% and 45% greater in "free knee" and "knee together," respectively (4.6 versus 2.9 kN, p < 0.005; 4.3 versus 2.9 kN, p < 0.005). However, the hip impact force did not differ between "free knee" and "knee together (4.6 versus 4.3 kN, p = 0.554).

CONCLUSION

Our results suggest that hip fracture risk during a fall decreases substantially, depending on how they land on the ground, informing the development of safe landing strategies to prevent fall-related hip fractures in older adults.

Mechanistic complexities of bone loss in Alzheimer's disease: a review

Purpose/Aim: Alzheimer's disease (AD), the primary cause of dementia in the elderly, is one of the leading age-related neurodegenerative diseases worldwide. While AD is notorious for destroying memory and cognition, dementia patients also experience greater incidence of bone loss and skeletal fracture than age-matched neurotypical individuals, greatly impacting their quality of life. Despite the significance of this comorbidity, there is no solid understanding of the mechanisms driving early bone loss in AD. Here, we review studies that have evaluated many of the obvious risk factors shared by dementia and osteoporosis, and illuminate emerging work investigating covert pathophysiological mechanisms shared between the disorders that may have potential as new risk biomarkers or therapeutic targets in AD.Conclusions: Skeletal deficits emerge very early in clinical Alzheimer's progression, and cannot be explained by coincident factors such as aging, female sex, mobility status, falls, or genetics. While research in this area is still in its infancy, studies implicate several potential mechanisms in disrupting skeletal homeostasis that include direct effects of amyloid-beta pathology on bone cells, neurofibrillary tau-induced damage to neural centers regulating skeletal remodeling, and/or systemic Wnt/Beta-catenin signaling deficits. Data from an increasing number of studies substantiate a role for the newly discovered "exercise hormone" irisin and its protein precursor FNDC5 in bone loss and AD-associated neurodegeneration. We conclude that the current status of research on bone loss in AD is insufficient and merits critical attention because this work could uncover novel diagnostic and therapeutic opportunities desperately needed to address AD.

Previous Damage Accumulation Can Influence Femoral Fracture Strength: A Finite Element Study

To manage osteoporotic hip fracture risk, it is necessary to understand failure mechanisms of bone at both the material and organ level. The structural response of bone is dependent on load history. Repeated loading causes progressive microstructural cracking, resulting in reduced apparent-level stiffness and, if damage is significant, reductions to peak load bearing capability. However, the effect of previous damage accumulation has not been well explored at the organ level. It was hypothesized that femoral fracture load and fracture pattern may be sensitive to damage accumulation from previous loading events. Six cadaveric specimens were used to develop patient specific finite element (FE) models from quantitative tomographic (qCT) scans. Material properties were assigned from qCT intensity at each element location, and damage evolution was predicted using a previously validated quasi-brittle FE model. Three scenarios were investigated: stumble followed by another stumble (S-S), fall followed by another fall (F-F), and stumble followed by a fall (S-F). Fracture load and pattern were compared to FE predictions for a single stumble (S) or single fall (F) loading event. Most specimens were resilient to accumulated damage, showing little (<5%) change in fracture load from the multiple-load scenarios (S-S, F-F, and S-F) compared to an equivalent single load scenario (S or F). Only one specimen demonstrated moderate (5-15%) reductions in strength from all three multiple-load scenarios. However, two specimens experienced moderate (20-30%) increase in fracture load in some load cases. In these cases, initial damage caused the load to be more evenly distributed upon subsequent loading events. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2197-2203, 2019.

Exploring the role of applied force eccentricity after foot-contact in managing anterior instability among older adults during compensatory stepping responses

BACKGROUND

The specific mechanisms responsible for age-related decline in forward stability control remain unclear. Previous work has suggested reactive control of net ground reaction force (GRF_net) eccentricity may be responsible for age-related challenges in mediolateral stability control during the restabilisation phase of forward compensatory stepping responses.

RESEARCH QUESTIONS

Does reactive control of GRF_net eccentricity play a role in managing forward stability control during the restabilisation phase of a forward stepping response to external balance perturbation?

METHODS

Healthy younger (YA) (n = 20) and older adults (OA) (n = 20) were tethered to a rigid frame, via adjustable cable. Participants were released from a standardised initial forward lean and regained their balance using a single step. Whole-body motion analysis and four force platforms were utilised for data acquisition. Forward instability was quantified as centre of mass (COM) incongruity - the difference between the first local peak and final stable anterior COM positions. The extent of GRF_net eccentricity was quantified as the sagittal-plane angle of divergence of the line of action of the GRF_net relative to the COM. Two discrete points during restabilisation were examined (P1 and P2), which have been suggested to be indicative of proactive and reactive COM control, respectively. Age-related differences in magnitude, timing and trial-to-trial variability of kinematic and kinetic outcome variables were analysed using two-factor ANOVAs with repeated-measures.

RESULTS

OA exhibited greater COM incongruity magnitude and variability - both were reduced with trial-repetition. There were no age-related differences in the magnitude or timing of P2. Instead, OA exhibited a reduced magnitude of GRF_net eccentricity at P1. There was a positive correlation between AP COM incongruity magnitude and P1 magnitude.

SIGNIFICANCE

Different from mediolateral stability control, the present results suggest that OA may experience forward stability control challenges as a function of insufficient preparatory lower limb muscle activation prior to foot-contact.

Incidence, risk factors and economic burden of fall-related injuries in older Chinese people: a systematic review

OBJECTIVE

China's population is ageing and fall-related injury in older Chinese people is a growing public health concern. This review aims to synthesise existing evidence on the incidence, risk factors and economic burden of fall-related injury among older Chinese people to inform health service planning.

METHODS

A systematic search of literature on falls and injury among older people living in China was performed in six electronic databases including both English and Chinese databases. Results were combined using narrative synthesis due to the heterogeneity of included studies.

RESULTS

A total of 93 studies from Mainland China, Taiwan and Hong Kong were included in this review. Most of these studies were descriptive; 82 reported the incidence of fall-related injury among older Chinese people, 7 studies examined the risk factors for fall-related injury and 22 studies described the economic burden of fall-related injury. The incidence of fall-related injury reported among older Chinese people ranged from 0.6% to 19.5%. Risk factors significantly associated with fall-related injury among older Chinese included older age, female sex, walking aid use, living environments, chronic disease, medication usage, visual impairment and a fall direction other than forward. The cost of fall-related injury among older Chinese people ranged from US$16 to US$3812 per person per fall.

CONCLUSION

Falls-related injuries are a significant public health issue for older Chinese people. Further studies using prospective design to identify risk factors and the economic burden of fall-related injuries are needed.

The Association Between Fall Frequency, Injury Risk, and Characteristics of Falls in Older Residents of Long-Term Care: Do Recurrent Fallers Fall More Safely?

Background

Although a fall is a necessary prerequisite to a fall-related injury, previous studies suggest that frequent fallers are at lower injury risk for a given fall. We tested the hypotheses that differences in protective responses or the circumstances of falls underlie differences in injury risk with fall frequency.

Methods

We analyzed video footage of 897 falls experienced by 220 long-term care residents (mean age 82 ± 9 years) to identify the cause of imbalance, activity leading to falling, direction of fall initiation, balance recovery and fall protective responses, and occurrence of impact to the head or hip. We further obtained injury information from the facilities' fall registration. We used generalized estimating equation models to examine the association between quartiles of fall frequency, injury risk, and fall characteristics.

Results

Residents with the highest fall frequency group (Q4; ≥5.6 falls/year) were less likely to sustain an injury per fall. They were less likely to fall during walking and more likely to fall during stand-to-sit transfers. Residents in the lowest fall frequency group (Q1; <1.15 falls/year) were more likely to fall during walking, and walking was associated with an increased risk for injury.

Conclusion

When compared to less frequent fallers, more frequent fallers had a lower risk for injury per fall. This appeared to be explained by differences in the circumstances of falls, and not by protective responses. Injury prevention strategies in long-term care should target both frequent and infrequent fallers, as the latter are more mobile and apt to sustain injury.

The circumstances, orientations, and impact locations of falls in community-dwelling older women

OBJECTIVE

We sought to characterize the circumstances, orientations, and impact locations of falls in community-dwelling, ambulatory, older women.

METHODS

For this longitudinal, observational study, 125 community-dwelling women age≥65years were recruited. Over 12-months of follow-up, fall details were recorded using twice-monthly questionnaires.

RESULTS

More than half (59%) of participants fell, with 30% of participants falling more than once (fall rate=1.3 falls per person-year). Slips (22%) and trips (33%) accounted for the majority of falls. Approximately 44% of falls were forward in direction, while backward falls accounted for 41% of falls. About a third of all falls were reported to have lateral (sideways) motion. Subjects reported taking a protective step in response to 82% of forward falls and 37% of backward falls. Of falls reporting lateral motion, a protective step was attempted in 70% of accounts. Common impact locations included the hip/pelvis (47% of falls) and the hand/wrist (27%). Backwards falls were most commonly reported with slips and when changing direction, and increased the risk of hip/pelvis impact (OR=12.6; 95% CI: 4.7-33.8). Forward falls were most commonly reported with trips and while hurrying, and increased the risk of impact to the hand/wrist (OR=2.6; 95% CI: 1.2-5.9).

CONCLUSION

Falls in older ambulatory women occur more frequently than previously reported, with the fall circumstance and direction dictating impact to common fracture locations. Stepping was a common protective recovery strategy and that may serve as an appropriate focus of interventions to reduce falls in this high risk population.

Physical Activity for Strengthening Fracture Prone Regions of the Proximal Femur

PURPOSE OF REVIEW

Physical activity improves proximal femoral bone health; however, it remains unclear whether changes translate into a reduction in fracture risk. To enhance any fracture-protective effects of physical activity, fracture prone regions within the proximal femur need to be targeted.

RECENT FINDINGS

The proximal femur is designed to withstand forces in the weight-bearing direction, but less so forces associated with falls in a sideways direction. Sideways falls heighten femoral neck fracture risk by loading the relatively weak superolateral region of femoral neck. Recent studies exploring regional adaptation of the femoral neck to physical activity have identified heterogeneous adaptation, with adaptation principally occurring within inferomedial weight-bearing regions and little to no adaptation occurring in the superolateral femoral neck. There is a need to develop novel physical activities that better target and strengthen the superolateral femoral neck within the proximal femur. Design of these activities may be guided by subject-specific musculoskeletal modeling and finite-element modeling approaches.

Risk Factors for Hip Fracture in Older Men: The Osteoporotic Fractures in Men Study (MrOS)

Almost 30% of hip fractures occur in men; the mortality, morbidity, and loss of independence after hip fractures are greater in men than in women. To comprehensively evaluate risk factors for hip fracture in older men, we performed a prospective study of 5994 men, primarily white, age 65+ years recruited at six US clinical centers. During a mean of 8.6 years of 97% complete follow-up, 178 men experienced incident hip fractures. Information on risk factors including femoral neck bone mineral density (FNBMD) was obtained at the baseline visit. Cox proportional hazards models were used to calculate the hazard ratio (HR) with 95% confidence intervals; Fine and Gray models adjusted for competing mortality risk. Older age (≥75 years), low FNBMD, currently smoking, greater height and height loss since age 25 years, history of fracture, use of tricyclic antidepressants, history of myocardial infarction or angina, hyperthyroidism or Parkinson's disease, lower protein intake, and lower executive function were all associated with an increased hip fracture risk. Further adjustment for competing mortality attenuated HR for smoking, hyperthyroidism, and Parkinson's disease. The incidence rate of hip fracture per 1000 person-years (PY) was greatest in men with FNBMD T-scores <-2.5 (white women reference database) who also had 4+ risk factors, 33.4. Men age ≥80 years with 3+ major comorbidities experienced hip fracture at rates of 14.52 versus 0.88 per 1000 PY in men age <70 years with zero comorbidities. Older men with low FNBMD, multiple risk factors, and multimorbidity have a high risk of hip fracture. Many of these assessments can easily be incorporated into routine clinical practice and may lead to improved risk stratification. © 2016 American Society for Bone and Mineral Research.

Body mass index, waist-hip ratio and risk of chronic medical condition in the elderly population: results from the Well-being of the Singapore Elderly (WiSE) Study

BACKGROUND

The aim of the current study was to establish the prevalence and relationship of Body Mass Index (BMI) and Waist-Hip Ratio (WHR) with chronic health conditions and their associated socio-demographic correlates in the elderly population of Singapore.

METHODS

The data was extracted from the Well-being of the Singapore Elderly (WiSE) study, a comprehensive single phase, cross-sectional, population-based, epidemiological study conducted in 2013 among Singaporean residents (n = 2565) aged 60 years and above with a mean age of 72.7 years (range 60 to 105, SD = 9.53). The respondents were assessed with anthropometric measurements including height, weight, BMI, waist circumference, hip circumference and WHR. Participants provided information on their socio-demographic details and chronic health conditions.

RESULTS

Prevalence of those who were obese, overweight, normal and underweight based on BMI was 8.7 %, 33.4 %, 52.5 % and 5.5 % respectively. Malays were more likely to be overweight compared to Chinese and Indians, while Malays and Indians were more likely to be obese compared to Chinese. Participants who were never married were less likely to be overweight compared to married. Participants aged 85 years and above were more likely to be underweight compared to those aged 60-75 years. Prevalence of high WHR (above 0.90 for men and 0.80 for women) was 79.8 % and this was more pervasive amongst Indians. Participants who were homemakers were more likely to have high WHR while those with tertiary education tended to have low WHR. Being overweight was associated with hypertension and heart problems, while obesity was associated with hypertension and diabetes, and a high WHR was associated with hypertension and diabetes. There were no significant differences in the other chronic conditions in this elderly population.

CONCLUSIONS

This study demonstrates the importance of anthropometric measurements in the elderly and its association with certain chronic physical conditions, indicating their utility in the clinical management of these conditions in the elderly.

Rationale for Strengthening Muscle to Prevent Falls and Fractures: A Review of the Evidence

Falls represent a major public health problem in older people, predominantly due to the resulting injuries which lead to progressive disability, immobilization and resulting comorbidities, dependency, institutionalization, and death. Reduced muscle strength and power have been consistently identified as risk factors for falls and related injuries, and it is likely these associations result from the central role played by reduced muscle strength and power in poor balance recovery. In addition, muscle strength and power are involved with protective responses that reduce the risk of an injury if a fall occurs. Progressive resistance training (PRT) is the standard way to increase muscle strength and power, and this training forms one of the main components of fall prevention exercise interventions. However, PRT has rarely been implemented in routine practice due to multiple challenges inherent to frail older people. The ongoing development of drugs expected to increase muscle power offers a new opportunity to reduce the risk of falls and fall-related injuries. The intent here is not to replace exercise training with drugs but rather to offer a pharmacologic alternative when exercise is not possible or contraindicated. The target population would be those most likely to benefit from this mechanism of action, i.e., weak older people without major causes for falls independent of muscle weakness. Provided such a tailored strategy was followed, a muscle anabolic may address this major unmet need.

Risk factors for hip impact during real-life falls captured on video in long-term care

Hip fracture risk is increased by landing on the hip. We examined factors that contribute to hip impact during real-life falls in long-term care facilities. Our results indicate that hip impact is equally likely in falls initially directed forward as sideways and more common among individuals with dependent Activities of Daily Living (ADL) performance.

INTRODUCTION

The risk for hip fracture in older adults increases 30-fold by impacting the hip during a fall. This study examined biomechanical and health status factors that contribute to hip impact through the analysis of real-life falls captured on video in long-term care (LTC) facilities.

METHODS

Over a 7-year period, we captured 520 falls experienced by 160 residents who provided consent for releasing their health records. Each video was analyzed by a three-member team using a validated questionnaire to determine whether impact occurred to the hip or hand, the initial fall direction and landing configuration, attempts of stepping responses, and use of mobility aids. We also collected information related to resident physical and cognitive function, disease diagnoses, and use of medications from the Minimum Data Set.

RESULTS

Hip impact occurred in 40 % of falls. Falling forward or sideways was significantly associated with higher odds of hip impact, compared to falling backward (OR 4.2, 95 % CI 2.4-7.1) and straight down (7.9, 4.1-15.6). In 32 % of sideways falls, individuals rotated to land backward. This substantially reduced the odds for hip impact (0.1, 0.03-0.4). Tendency for body rotation was decreased for individuals with dependent ADL performance (0.43, 0.2-1.0).

CONCLUSIONS

Hip impact was equally likely in falls initially directed forward as sideways, due to the tendency for axial body rotation during descent. A rotation from sideways to backward decreased the odds of hip impact 10-fold. Our results may contribute to improvements in risk assessment and strategies to reduce risk for hip fracture in older adults.

Fall incidents unraveled: a series of 26 video-based real-life fall events in three frail older persons

Background

For prevention and detection of falls, it is essential to unravel the way in which older people fall. This study aims to provide a description of video-based real-life fall events and to examine real-life falls using the classification system by Noury and colleagues, which divides a fall into four phases (the prefall, critical, postfall and recovery phase).

Methods

Observational study of three older persons at high risk for falls, residing in assisted living or residential care facilities: a camera system was installed in each participant’s room covering all areas, using a centralized PC platform in combination with standard Internet Protocol (IP) cameras. After a fall, two independent researchers analyzed recorded images using the camera position with the clearest viewpoint.

Results

A total of 30 falls occurred of which 26 were recorded on camera over 17 months. Most falls happened in the morning or evening (62%), when no other persons were present (88%). Participants mainly fell backward (initial fall direction and landing configuration) on the pelvis or torso and none could get up unaided. In cases where a call alarm was used (54%), an average of 70 seconds (SD=64; range 15–224) was needed to call for help. Staff responded to the call after an average of eight minutes (SD=8.4; range 2–33). Mean time on the ground was 28 minutes (SD=25.4; range 2–59) without using a call alarm compared to 11 minutes (SD=9.2; range 3–38) when using a call alarm (p=0.445).

The real life falls were comparable with the prefall and recovery phase of Noury’s classification system. The critical phase, however, showed a prolonged duration in all falls. We suggest distinguishing two separate phases: a prolonged loss of balance phase and the actual descending phase after failure to recover balance, resulting in the impact of the body on the ground. In contrast to the theoretical description, the postfall phase was not typically characterized by inactivity; this depended on the individual.

Conclusions

This study contributes to a better understanding of the fall process in private areas of assisted living and residential care settings in older persons at high risk for falls.

Effects of age and lean direction on the threshold of single-step balance recovery in younger, middle-aged and older adults

Several studies have quantified and compared balance recovery between healthy younger and older adults, using a variety of large postural perturbations and loss of balance directions. However, to the best of our knowledge, no studies at the threshold of balance recovery, where avoiding a fall is not always possible, have included middle-aged adults. We thus determined the maximum lean angle from which 20 younger, 16 middle-aged and 16 older healthy adults could be suddenly released and still recover balance using a single step for forward, sideways and backward leans. Results showed that the maximum lean angles of younger adults were 23% greater than middle-aged adults and 48% greater than older adults. The maximum lean angles for forward leans were 23% greater than sideways leans and 22% greater than backward leans. These declines with age and lean direction were associated with declines in response initiation, execution and geometry. Finally exponential regressions showed that the critical ages at which the ability to recover balance and avoid a fall significantly decreases were 51.0, 60.6 and 69.9 yrs for forward, sideways and backward leans, respectively. Therefore, we have demonstrated that age affects the ability to recover balance nearly a decade earlier than the rate of falls. Future studies should thus not only include older adults over 65 yrs, but also middle-aged adults under 65 yrs, or recruit all ages from 18 to 85 yrs. Finally, the critical ages identified in this study may justify an earlier screening of aging adults to prevent future falls, especially the first fall.

Dementia and hip fractures: development of a pathogenic framework for understanding and studying risk

Dementia and hip fractures are 2 conditions that are seen primarily in older adults, and both are associated with substantial morbidity and mortality. An individual with dementia is up to 3 times more likely than a cognitively intact older adult to sustain a hip fracture. This may occur via several mechanisms, including (1) risk factors that are common to both outcomes; (2) the presence of dementia increasing hip fracture incidence via intermediate risk factors, such as falls, osteoporosis, and vitamin D; and (3) treatment of dementia causing side effects that increase hip fracture risk. We describe a model that applies these 3 mechanisms to explain the relationship between dementia and hip fractures. Comprehensive understanding of these pathways and their relative influence on the outcome of hip fracture will guide the development of effective interventions and potentially improve prevention efforts.

A nonlinear QCT-based finite element model validation study for the human femur tested in two configurations in vitro

PURPOSE

Femoral fracture is a common medical problem in osteoporotic individuals. Bone mineral density (BMD) is the gold standard measure to evaluate fracture risk in vivo. Quantitative computed tomography (QCT)-based homogenized voxel finite element (hvFE) models have been proved to be more accurate predictors of femoral strength than BMD by adding geometrical and material properties. The aim of this study was to evaluate the ability of hvFE models in predicting femoral stiffness, strength and failure location for a large number of pairs of human femora tested in two different loading scenarios.

METHODS

Thirty-six pairs of femora were scanned with QCT and total proximal BMD and BMC were evaluated. For each pair, one femur was positioned in one-legged stance configuration (STANCE) and the other in a sideways configuration (SIDE). Nonlinear hvFE models were generated from QCT images by reproducing the same loading configurations imposed in the experiments. For experiments and models, the structural properties (stiffness and ultimate load), the failure location and the motion of the femoral head were computed and compared.

RESULTS

In both configurations, hvFE models predicted both stiffness (R(2)=0.82 for STANCE and R(2)=0.74 for SIDE) and femoral ultimate load (R(2)=0.80 for STANCE and R(2)=0.85 for SIDE) better than BMD and BMC. Moreover, the models predicted qualitatively well the failure location (66% of cases) and the motion of the femoral head.

CONCLUSIONS

The subject specific QCT-based nonlinear hvFE model cannot only predict femoral apparent mechanical properties better than densitometric measures, but can additionally provide useful qualitative information about failure location.

Preventing Patient Falls

Patients are at a higher risk of falling in the hospital than at home because of their acute illness, medications, other treatments, or unfamiliarity with the hospital environment. Despite numerous efforts, inpatient falls remain a leading adverse event in hospitals and other inpatient settings, resulting in loss of function, death, and higher health costs. This article explores the factors in hospital settings that can reduce and prevent inpatient falls.

A novel diagnostic sign of hip fracture mechanism in ground level falls: two case reports and review of the literature

Introduction

Most elderly hip fractures are the result of a ground level fall. Defining high risk falls and fracture mechanisms are important to develop successful hip fracture prevention programs. This case series presents a previously unreported diagnostic sign and for the first time documents a hip fracture mechanism for a knee impact injury from a ground level fall in two elderly patients.

Case presentation

Case 1 was a 65-year-old Caucasian woman who fell forward with initial contact to her left knee, sustaining an impacted femoral neck fracture of her ipsilateral left hip. Case 2 was a 92-year-old Caucasian woman who fell bending forward, impacting her left knee and sustaining a comminuted intertrochanteric fracture of her ipsilateral left hip. The fractures occurred as a result of unprotected ground level falls in a forward direction with initial impact to the knee. The knee contusions were located near Gerdy’s tubercle and appear characteristic of a direct impact injury.

Conclusion

The physical finding of a small localized site of impact and/or contusion in the anterior aspect of the knee in both of these patients with radiographic evidence of an ipsilateral hip fracture would strongly suggest that a knee impact injury can transmit enough energy to the proximal femur by axial loading to result in the hip fracture. The physical finding described is a reliable indicator of this hip fracture mechanism.

[Diagnosis and treatment of osteoporosis in persons aged more than 75 years]

Osteoporosis is a progressive skeletal disease characterized by a decrease in bone strength and an increase in the number of fractures. This disease is considered by the World Health Organization to be the second most important health problem in the world after cardiovascular disease. The prevalence of osteoporosis is increasing due to population aging. With age, the loss of bone mass in the spine and hip, which starts at menopause in women and around the age of 60 years in men, continues. Old age is when most fragility fractures occur and the incidence of these fractures is increasing exponentially in persons aged more than 75 years. Several treatments with demonstrated effectiveness in decreasing fracture risk and increasing bone mineral density are currently available for osteoporosis. Nevertheless, the scientific evidence on the safety and efficacy of these treatments is much more scarce in older people than in young populations. There are few reports on the efficacy of these treatments in non-vertebral--specifically hip--fractures in the elderly. Consequently, the present review aims to analyze the scientific evidence on the diagnosis and treatment of osteoporosis, and particularly the evidence on the antifracture efficacy of distinct antiresorptive agents and anabolic drugs in people older than 75 years.

Follow-up for Alzheimer patients: European Alzheimer Disease Consortium position paper

BACKGROUND AND PURPOSE

Alzheimer disease (AD) is one of the leading causes of dependence in the elderly. Providing care for patients with AD is complex and the type of care required depends on the stage of the disease and varies over time. The aim of this article is to discuss available care strategies once the AD diagnosis has been made and to propose a follow-up plan as standard of care at a European level.

METHODS

The proposals developed in this article stem from the collaborative work of a panel of multidisciplinary experts involved in the care of AD patients (European Alzheimer Disease Consortium) based on the results of published scientific studies and on their experience from clinical practice.

CONCLUSION

Suggestions for follow-up frequency and easily administered and scored assessment tools are provided, thereby increasing efficiency and quality of care for patients with Alzheimer disease.

Variation in risk factors for fractures at different sites

Fractures in older people are important medical problems. Knowledge of risk factors is essential for successful preventive measures, but when fracture sites of diverse etiology are combined, risk factors for any one site are difficult to identify and may be missed entirely. Among older people, incidence rates of hip, proximal humerus, and vertebral fractures increase with age, but not rates of distal forearm and foot fractures. Low bone mineral density is strongly associated with hip, distal forearm, vertebral, and proximal humerus fractures, but not foot fracture. Most fractures of the hip, distal forearm, and proximal humerus result from a fall, whereas smaller proportions of fractures of the foot and vertebrae follow a fall. Frail people are likely to fracture their hip or proximal humerus, while healthy, active people tend to fracture their distal forearm. We strongly recommend that studies identify risk factors on a site-specific basis.

Age differences in energy absorption in the upper extremity during a descent movement: implications for arresting a fall

BACKGROUND

Falls are the number one cause of unintentional injury in older adults. The protective response of "breaking the fall" with the outstretched hand is often essential for avoiding injury to the hip and head. In this study, we compared the ability of young and older women to absorb the impact energy of a fall in the outstretched arms.

METHODS

Twenty young (mean age = 21 years) and 20 older (M = 78 years) women were instructed to slowly lower their body weight, similar to the descent phase of a push-up, from body lean angles ranging from 15 degrees to 90 degrees . Measures were acquired of peak upper extremity energy absorption, arm deflection, and hand contact force.

RESULTS

On average, older women were able to absorb 45% less energy in the dominant arm than young women (1.7 +/- 0.5% vs 3.1 +/- 0.4% of their body weight x body height; p < .001). These results suggest that, even when both arms participate equally, the average energy content of a forward fall exceeds by 5-fold the average energy that our older participants could absorb and exceeds by 2.7-fold the average energy that young participants could absorb.

CONCLUSIONS

During a descent movement that simulates fall arrest, the energy-absorbing capacity of the upper extremities in older women is nearly half that of young women. Absorbing the full energy of a fall in the upper extremities is a challenging task even for healthy young women. Strengthening of upper extremity muscles should enhance this ability and presumably reduce the risk for injury to the hip and head during a fall.

Falls: epidemiology, pathophysiology, and relationship to fracture

Falls are common in the elderly, and frequently result in injury and disability. Most falls result from an interaction between individual characteristics that increase an individual's propensity to fall and acute mediating risk factors that provide the opportunity to fall. Predisposing risk factors include age-associated changes in strength and balance, comorbidities such as osteoarthritis, visual impairment and dementia, psychotropic medications, and certain types of footwear. Fewer studies have focused on acute precipitating factors, but environmental and situational factors are clearly important to fall risk. Approximately 30% of falls result in an injury that requires medical attention, with fractures occurring in approximately 10%. In addition to the risk factors for falls, the fall descent, fall impact, and bone strength are all important determinants of whether a fall will result in a fracture. In recent years, numerous studies have been directed toward the development of effective fall and fall-related fracture prevention interventions.

A matched case-control study of circumstances of occupational same-level falls and risk of wrist, ankle and hip fracture in women over 45 years of age

This study examined the association between circumstances of occupational same-level falls and the risk of wrist, ankle and hip fracture in women over 45 years of age. Cases of fractures and matched controls who suffered non-fracture injuries, all from same-level falls, were selected from workers' compensation claims data. Cases and controls were matched on age, season of fall, industry and state. Information was obtained about manual material handling, fall hazard, initiating event and fall location. Falls during pushing/pulling were associated with increased wrist fracture risk. Falls due to tripping were associated with increased wrist fracture risk, but decreased risk of ankle fracture. Falling outdoors was associated with increased wrist and ankle fracture risk. Increasing age was associated with increased injury risk from tripping-initiated vs. slipping-initiated falls. Few circumstances increased risk of fracture at multiple sites, indicating that they affect risk of fracture by primarily affecting point of impact. The proportion of female workers over 45 years of age, who are at increased risk of fracture, is increasing in developed countries. This study examined the associations between circumstances of falls and wrist, ankle and hip fracture risks among these workers and found that the associations differed by fracture sites.

Preventing fall-related vertebral fractures: effect of floor stiffness on peak impact forces during backward falls

STUDY DESIGN

In vivo biomechanical study of 11 male volunteers.

OBJECTIVE

To measure the peak forces applied to the buttocks in a backward fall from standing, and to determine whether this force is lowered by reductions in floor stiffness.

SUMMARY OF BACKGROUND DATA

Fall-related vertebral fractures are common and backward falls result in impact to the buttocks. Compliant flooring may reduce impact force and risk for vertebral fracture during a fall. However, we have little knowledge of the peak forces applied to the body during a backward fall, or how floor stiffness affects this force.

METHODS

Eleven males, mean age 25 +/- 5 (SD) years, were suddenly released from a backward lean of 15 degrees , falling backward onto the ground which was covered with 4.5, 7.5, or 10.5 cm of ethylene vinyl acetate foam rubber. We measured 3-dimensional impact forces applied to the buttocks at 960 Hz with a force plate. We used repeated measures analysis of variance and post hoc t tests to compare peak forces between conditions. We also modeled peak vertical force for falls onto a bare floor. RESULTS.: There was a significant difference in peak vertical force between falls onto the 10.5 cm foam condition compared with the 7.5 cm (P = 0.002) and 4.5 cm (P < 0.001) conditions. Peak vertical force (N) was (mean +/- SD) 5099 +/- 868, 4788 +/- 702, and 4544 +/- 672 for the 4.5, 7.5, and 10.5 cm foam conditions, respectively, and estimated at 6027 +/- 988 for the rigid (bare floor) condition. Compared with the bare floor, these foam floors provided, on average, 24, 20, and 15% force attenuation respectively.

CONCLUSION

In a backward fall onto the buttocks, peak impact forces are 6.4 to 9.0 times body weight in a fall onto a bare floor. Reducing floor stiffness using even a thin (4.5 cm) layer of foam may provide 15% vertical force attenuation during a fall onto the buttocks.

Effect of combined exercise training on bone, body balance, and gait ability: a randomized controlled study in community-dwelling elderly women

The purpose of this study was to investigate whether a 48-week multicomponent exercise program could improve the risk factors for fall and hip fracture. Fifty elderly women 65-70 years of age participated. These participants were divided into an exercise group (25 subjects) that attended an exercise program and a control group (25 subjects) that did not. The exercise program included stretching for 9 min, strength training for 10 min followed by 23 min of weight-bearing exercise at an intensity above 65%-75% of the maximal heart rate, and 18 min of balance and posture correction training. The program was conducted three times per week for 48 weeks. The 10-m maximal walk time, maximal step length, and eyes-open-one-legged-stand time in the exercise group improved significantly (P < 0.05). Concerning deoxypyridinoline, the exercise group achieved a significant improvement (P < 0.05) after the 48 weeks. Bone mineral density (BMD) of the femoral neck and trochanter in the exercise group was significantly increased after the exercise program; also body sway was significantly improved (P < 0.05). In conclusion, a multi-component exercise program with weight-bearing exercise at a moderate intensity and gait training may be effective in offsetting a decline in BMD and improving aggravation of bone resorption in this population. In addition, this program has a positive effect on postural stability and gait ability.

Determining fall direction and impact location for various disturbances and gait speeds using the articulated total body model

Because fall experiments with volunteers can be both challenging and risky, especially with older volunteers, we wished to develop computer simulations of falls to provide a theoretical framework for understanding and extending experimental results. To perform a preliminary validation of the articulated total body (ATB) model for passive falls, we compared the model predictions of fall direction, impact location, and impact velocity as a function of disturbance type (faint, slip, step down, trip) and gait speed (fast, normal, slow) to experimental results with young adult volunteers. The three-dimensional ATB model had 17 segments and 16 joints. Its physical characteristics, environment definitions, contact functions, and initial conditions were representative of our experiment. For each combination of disturbance and gait speed, the ATB model was left to fall passively under gravity once disturbed, i.e., no joint torques were applied, until impact with the floor occurred. Finally, we also determined the sensitivity of the model predictions to changes in the model's parameters. Our model predictions of fall angles and impact angles were qualitatively in agreement with those observed experimentally for ten and seven of the 12 original simulations, respectively. Quantitatively, the model predictions of fall angles, impact angles, and impact velocities were within one experimental standard deviation for seven, three, and nine of the 12 original simulations, respectively, and within two experimental standard deviations for ten, nine, and 11 of the 12 original simulations, respectively. Finally, the fall angle and impact angle region did not change for 92% and 95% of the 74 input variation simulations, respectively, and the impact velocities were within the experimental standard deviations for 78% of the 74 input variation simulations. Based on our simulations and a sensitivity analysis, we conclude that our preliminary validation of the ATB model for passive falls was successful. In fact, these ATB model simulations represent a significant step forward in fall simulations. We believe that with additional work, the ATB model could be used to accurately simulate a variety of human falls and may be useful in further understanding the etiology and mechanisms of fall injuries such as hip fractures.

Stride width discriminates gait of side-fallers compared to other-directed fallers during overground walking

PURPOSE

The purpose was to identify differences in gait characteristics between older fallers with a tendency to fall sideways compared to those who do not fall to the side.

METHOD

The authors conducted a prospective, case control study of ambulatory adults older than 70 residing in retirement communities. Measurements included spatial and temporal gait parameters and prospective fall surveillance.

RESULTS

In all, 29 participants fell to the side, and 64 fell in other directions (forward, backward, straight down); 46 participants experienced no falls. Side-fallers exhibited narrower stride widths compared to other-directed fallers, and stepwise and discriminant analysis correctly classified 67% of side-fallers and other-directed fallers using only stride width.

DISCUSSION

This study suggests that side-fallers, who have narrower stride widths compared to those who fall in other directions, may not be adapting their gait to compensate for lateral instability. More research is needed to determine whether narrow gait contributes to unstable walking patterns.

Are distal radius fractures due to fragility or to falls? A consecutive case-control study of bone mineral density, tendency to fall, risk factors for osteoporosis, and health-related quality of life

BACKGROUND

A fracture of the distal radius is considered to indicate an increased risk of future fractures, especially a hip fracture. The main causes may be osteoporosis or a tendency to fall, separately or in combination.

METHODS

93 women and 5 men with a recent radius fracture and the same number of controls were measured with a heel-DXL and asked to complete one questionnaire on their quality of life (SF-36), and one on risk factors.

RESULTS

The mean T-score of the patients was -2.1, and for the controls it was -1.9 (p = 0.3). The patients aged over 64 years had a history of falling more often than the corresponding controls (p = 0.01), but there was no difference in T-score. By contrast, patients 45-64 years of age showed a non-significant, lower T-score (p = 0.09), but there was no difference concerning their history of falling. For all other risk factors, no differences were found between the patients and the controls. There were significant differences between the patients and the controls in some of the functions in the SF-36, due to the radius fracture.

INTERPRETATION

This study indicates that the underlying cause of a distal radius fracture may be different in patients aged 45-64 years and those who are more than 64 years old.

Maximum Potential Preventive Effect of Hip Protectors

OBJECTIVES

To estimate the maximum potential preventive effect of hip protectors in older persons living in the community or homes for the elderly.

DESIGN

Observational cohort study.

SETTING

Emergency departments in the Netherlands.

PARTICIPANTS

Hip fracture patients aged 70 and older who visited the emergency departments of five hospitals in the Netherlands (n=520).

MEASUREMENTS

Using the risk score of the Dutch Guidelines for Osteoporosis, how many patients had a high risk for fractures was retrospectively assessed. In addition, the circumstances of the hip fracture were assessed (n=299). Four factors were specified that might influence the maximum potential preventive effect of hip protectors: (1) hip fracture occurred in persons having a low risk, (2) hip fracture was not the consequence of a fall, (3) hip fracture occurred during circumstances that preclude the use of hip protectors, and (4) hip fracture occurred during the night.

RESULTS

When providing hip protectors to women at high risk of fractures, 48.2% of all hip fractures could have been prevented.

CONCLUSION

Many hip fractures occur in persons with a low risk for hip fracture or under circumstances that preclude the use of hip protectors. It was estimated that the maximum potential preventive effect of hip protectors is approximately 50% in older women living in the community or homes for the elderly. The actual preventive effect will be lower and depends on the acceptance and effectiveness of hip protectors and adherence to wearing them.

Reducing hip fracture risk during sideways falls: Evidence in young adults of the protective effects of impact to the hands and stepping

Hip fracture is rare in young adults, despite evidence that the energy available in a fall is sufficient to fracture the young proximal femur. This might be explained by protective responses that allow young individuals to avoid hip impact during sideways falls. To test this hypothesis, we conducted experiments with 44 individuals (31 women and 13 men) aged 19-26 years, who were instructed to try to maintain balance after a sudden unpredictable sideways translation was applied to the platform they stood upon. While the surface adjacent to the platform was formed of gymnasium mats, we provided no information on surface compliance, or the direction and speed of the perturbation. Ninety percent of participants fell and impacted the pelvis, and 98% of those cases involved direct impact to the hip region. Impact occurred to the hand in 98% of falls, and preceded impact to the pelvis by 50 ms on average (SD=40, range=-12-175 ms). The impact velocity of the pelvis decreased 3.6% for every 10 ms increase in the interval between hand and pelvis impact, and was reduced by 22% on average by stepping prior to impact. Our results suggest that the lack of hip fractures in young adults cannot be explained by avoidance of hip impact during sideways falls. Rather, it probably relates to use of the hands and stepping, and by simply possessing sufficient bone strength to withstand the direct blow to the greater trochanter that tends to accompany sideways falls.

Musculoskeletal disorders associated with obesity: a biomechanical perspective

Despite the multifactorial nature of musculoskeletal disease, obesity consistently emerges as a key and potentially modifiable risk factor in the onset and progression of musculoskeletal conditions of the hip, knee, ankle, foot and shoulder. To date, the majority of research has focused on the impact of obesity on bone and joint disorders, such as the risk of fracture and osteoarthritis. However, emerging evidence indicates that obesity may also have a profound effect on soft-tissue structures, such as tendon, fascia and cartilage. Although the mechanism remains unclear, the functional and structural limitations imposed by the additional loading of the locomotor system in obesity have been almost universally accepted to produce aberrant mechanics during locomotor tasks, thereby unduly raising stress within connective-tissue structures and the potential for musculoskeletal injury. While such mechanical theories abound, there is surprisingly little scientific evidence directly linking musculoskeletal injury to altered biomechanics in the obese. For the most part, even the biomechanical effects of obesity on the locomotor system remain unknown. Given the global increase in obesity and the rapid rise in musculoskeletal disorders, there is a need to determine the physical consequences of continued repetitive loading of major structures of the locomotor system in the obese and to establish how obesity may interact with other factors to potentially increase the risk of musculoskeletal disease.

Incidence and characteristics of falls leading to hip fracture in Iranian population

An estimated one in three adults aged 65 years or older falls each year, making falls a major health concern. Hip fractures are the most serious consequences of falls in elderly people. Identifying the characteristics of falls leading to hip fracture may provide information about high risk individuals, environment, and activities useful for the development of intervention strategies. Little is known, however, about the incidence and characteristics of falls leading to hip fracture in Middle Eastern countries. Therefore, the authors presented data from the Iranian Multicenter Study on Accidental Injuries, a prospective population-based study conducted in 9 provinces of Iran in 2003. All the hospitals serving about 9.5 million people in the study area were prospectively surveyed for any incident injury resulting from accidental events. A total of 2,186 patients (1,372 male, 814 female) were admitted due to any injurious fall events, where 572 (26.2%) of them suffered a hip fracture. Annual incidence rates of injurious fall events and related hip fractures were 116.3 and 30.4 per 100,000 person-years, respectively. These figures were 237.1 and 93.6 per 100,000 person-years for people over the age of 50 years, respectively. 71% of fall injuries and 76% of hip fractures occurred indoors. Among 450 patients with hip fractures >or=50 years of age, 61.8% arose from a fall from standing height or less. Only 1 in these 450 hip fractures occurred at the time of recreational activity. In multivariate logistic regression analysis, no factor was an independent predictor of hip fractures comparing to other fall-related injuries among younger participants (>or=20 and <50 years). For older patients, falls from standing height or loss (odds ratio (OR) = 2.67), falls during walking (OR = 1.71), and falls on stairs (OR = 1.73) were detected as risk factors of hip fracture. Married persons and those falling from a ladder or other elevations were less likely to fracture their hip in this age group. Our data suggest that modification of the factors external to the homes is less likely to prevent more than a small proportion of fall-related hip fractures in Iran. Further studies on this topic have potential applications for developing preventive strategies.

Association between level of frailty and bone mineral density in community-dwelling men

The goal of this study is to determine the associations between the components of a frailty definition and bone mineral density (BMD) in older men. A total of 392 community dwelling men (age range: 58-95 yr) with a mean age of 73+/-8 yr were evaluated. Femoral neck BMD T-scores ranged from -5.78 to +2.50, with 48.7% who had T-scores between -1 and -2.5 (low bone mass) and 8.7% who had T scores < or = -2.5 (osteoporosis). Participants were characterized as normal (39%), intermediate (55%), or frail (6%). Hand grip strength was 31.5+/-9.1 kg in those with normal BMD compared with 26.5+/-7.9 kg in those with osteoporotic BMD (p=0.0026). Walk speed (8 ft) was 2.32+/-0.49 s in those with normal BMD compared with 2.87+/-1.30 s with osteoporotic BMD (p=0.0015). Femoral neck T-score declined significantly with increasing level of frailty (p=0.014), but significance of decline was lost when corrected for age. Increasing frailty was associated with lower femoral neck BMD, although the association was not independent of age. Two components of the frailty model (i.e., hand grip strength and walking speed) were independently associated with lower femoral neck BMD, a finding that has not previously been reported in men.

Circunstancias asociadas a las caídas responsables de fractura de fémur en pacientes ancianos. Diferencias por grupo de edad y género

BACKGROUND

The majority of hip fractures are produced because of a fall. We examined the characteristics associated with falls causing hip fracture in elderly patients.

MATERIAL AND METHODS

Characteristics of falls owing to hip fracture were analyzed in 410 consecutive patients admitted in 6 hospitals during the 2004. We evaluated the location, time and the possible cause of fall: intrinsic risk factor, extrinsic or combined.

RESULTS

We evaluated 316 women (77%) and 94 men, mean age 81.9 years. Previous to the hip fracture, the mean BI was 77.5. The mean value of falls during the last year was 1.9. Previously to the fall that caused hip fracture, we found that 24% of the patients had fallen repeatedly (more than two falls). Usually falls were at home (68%) and during daytime (80%). In 45% of patients an intrinsic risk factor was considered the most likely cause, in 33% an extrinsic risk factor and in 22% a combination.

CONCLUSIONS

The majority of falls owing to hip fracture in elderly people happen in daytime, at home and due to intrinsic risk factors. Efforts to identify elderly people at risk of fall should be stressed in order to establish preventive measures.