Abstract
Background:
Hip fracture is a common cause of morbidity and mortality in the elderly. As the risk factors for hip fracture often persist after the original injury, patients remain at risk for sequential fractures. Our aim was to report the incidence, epidemiology, and outcome of sequential hip fracture in the elderly.
Methods:
Data were collected during the acute hospital stay and at 120 days after admission from twenty-two acute orthopaedic units across Scotland between January 1998 and December 2005. These data were analyzed according to two separate time periods: by six-month intervals up to eight years after the primary fracture and by twenty-day intervals for the first two years after the primary fracture.
Results:
The risk of sequential fracture was highest in the first twelve months, affecting 3% of surviving patients and decreasing to 2% per survival year thereafter. Survival to twelve months after sequential fracture was 63% compared with 68% for those with a single fracture (p = 0.03). Sequential hip fracture was also associated with greater loss of independent mobility and changes in residential status compared with single fractures.
Conclusions:
Sequential hip fracture is a relatively rare injury. Individuals who sustain this injury combination have poorer outcomes both in terms of survival and functional status.
Level of Evidence:
Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
Fragility fractures are an increasing cause of morbidity and mortality in the elderly population1. Each year in the United Kingdom, approximately 70,000 patients are admitted for treatment of a hip fracture1-3. It is predicted that this number may increase by as much as 75% over the next two decades as a consequence of changes in population demographics2. Patients who sustain a single fragility fracture are at increased risk of sustaining additional injuries4-6, as the risk factors that predispose an individual to sustain a hip fracture often persist after treatment of the original injury1,3. The aim of this study was to report the incidence, epidemiology, and outcomes of sequential hip fracture in the elderly.
Data Collection
The Scottish Hip Fracture Audit is a national, prospective audit that collects data from patients over fifty years of age who are admitted to Scottish hospitals after sustaining a hip fracture. Dedicated local coordinators use a standard core dataset to collect case-mix, process, and outcome data during patients’ acute hospital stay and at 120 days after acute admission. During the period 1998 to 2005, data were collected from all twenty-two Scottish acute-care mainland orthopaedic hospitals that treated hip fracture patients. During this period, participation in the Scottish Hip Fracture Audit depended on the availability of local resources to fund data collection. As a consequence, continuous periods of data collection in individual hospital units varied between one and eight years, with a mean period of data collection of 3.9 years (including five hospitals that had two runs of data collection). During continuous periods of data collection, data on all hip fractures in patients admitted to that hospital were included in the database.
To match patients’ records between fractures and to identify patient deaths outside the 120-day audit collection period, we used data linkage techniques to match the Scottish Hip Fracture Audit database to the National Health Service Scotland Information Services Division’s routine SMR01 (Scottish Morbidity Records 01) database. The SMR01 database records and links all patient admissions across Scotland, including linkage to the General Register Office for death dates.
Analysis of Sequential Fracture Incidence
Records of patients who sustained single, unilateral fractures and those who sustained sequential fractures were initially analyzed within single periods of continuous data collection from each hospital (even if a hospital had two periods of data collection). This was done because we could not ascertain that the patient did not have a second fracture between periods of data collection when or if there was a break in audit participation by a particular hospital. As the length of time available to detect second fractures was the interval between the time when the first fracture occurred and when the hospital stopped a continuous period of audit collection, the number of patients contributing to the analysis of second fractures decreased over time from the date of the first fracture (see Appendix). Patients were excluded on the day when the hospital where they presented with the original fracture stopped continuous collection of fracture data.
Data were analyzed according to two separate time periods. In the initial analysis, we analyzed each patient’s second fracture and survival status by six-month intervals up to eight years after admission for the primary fracture. We subsequently analyzed these data in more detail by twenty-day intervals for the first two years after the primary fracture as it allowed us to observe any early patterns in sequential fracture incidence in the period immediately after the index injury. Individuals were included in the analysis for a particular time period following the primary fracture only if the admitting hospital continued to collect audit data for that time period (e.g., from 2.5 to three years). If that hospital ceased data collection during this time period (e.g., in the ninth month following the first fracture), then the patient’s data for the incomplete period (the six to twelve-month period) and subsequent periods were excluded from the analysis. Although some patients were known to have sustained second fractures or died in these partial half-year periods, their data were again excluded to avoid overestimation of second fracture incidence.
Analysis of Sequential Fracture Incidence After Gaps
Five hospitals had gaps in their data collection, ranging from periods of two months to more than two years. During these gaps, we could not determine whether patients had sustained second fractures, but we did know whether these patients had or had not sustained a second fracture during the subsequent second period of data collection. We therefore analyzed second fracture rates obtained from periods after such gaps separately as an independent source of estimation of second fracture rates. This second analysis is especially useful because it allows us to include a higher proportion of patient data more than three years after the original fracture, when patterns were becoming obscure in the first dataset because of smaller sample sizes.
Statistical Analysis
Statistical analysis was performed with use of SPSS software (version 13.0; SPSS, Chicago, Illinois). We examined, using a logistic regression model, the predictive value of demographic variables associated with a higher probability of sustaining a second fracture within one year after the first fracture. Six predictor variables (age, sex, status according to the American Society of Anesthesiologists [ASA] score7, prefracture residence, prefracture mobility, and type of fracture) were offered to the model, together with their fifteen first-order interaction groups, with use of a forward stepwise method. Other reported outcome measures include 120-day mortality, duration of hospital stay, residence, and mobility at 120 days.
Source of Funding
No external funding was received for this study.
Incidence of Sequential Hip Fracture
A total of 28,392 patients with a hip fracture were initially included in the analysis of continuous hospital participation data between January 1998 and December 2005. Of those, 3963 patients presented within the last six months of a hospital’s data collection and an additional 214 were not matched to the SMR01 database. Data on these patients are excluded from the first six-month bar (see Appendix), although they were still eligible for inclusion for up to six months when the analysis was broken down into smaller twenty-day periods. The number of eligible patients decreased to 14,917 (53%) after two years and to 7188 (25%) by four years (see Appendix). Patients who presented with simultaneous, bilateral hip fractures or with second injuries to the same side as the original hip fracture were excluded. As mortality after the initial hip fracture was substantial compared with the risk of sustaining a second fracture, the cumulative proportion of patients in the population who sustained sequential fractures remained low throughout the eight-year period (see Appendix). If patients who died were not excluded from the analysis, new second fractures occurring within a six-month period were always too rare to be a distinguishable proportion of the original number of eligible patients. However, when we excluded patients who had either died or sustained a second fracture prior to the start of a given six-month time period, the percentage of patients who sustained a sequential fracture in the subsequent six-month period varied between 1.0% and 1.5%, at least up to three years (see Appendix). The risk of sequential fracture was highest in the first twelve months, affecting 3% of surviving patients and decreasing to 2% per survival year thereafter.
When we analyzed the period of up to two years after the primary fracture in greater detail (Fig. 1), the percentage of surviving patients who sustained a second fracture in a given twenty-day period decreased throughout the first twelve months (Pearson correlation, r = −0.68, p = 0.002). No further subsequent decrease was evident during the second twelve-month period following the primary fracture (r = 0.01, p = 0.95).
As described previously, additional data on second fractures were also available from patients whose initial admitting hospital had a temporary gap in continuous data collection. Although the overall number of eligible patients in each six-month period was lower than that for the previous analysis of second fractures within periods of continuous hospital participation, sample sizes of eligible patients for periods after gaps approached and exceeded the previous analysis from the fifth to seventh years after the original fracture. This provides a useful comparison with the earlier analysis (see Appendix).
The observed sequential fracture incidence estimated from the two methods did not differ markedly or consistently (Fig. 2). This suggests that our inability to identify and exclude patients who had a second fracture during the gap period was not a major source of underestimation, so we therefore combined data from the two methods. With use of the combined data, the probability of a surviving patient sustaining a second fracture in the next six months remained at approximately 1% from one to seven years after the primary fracture (Fig. 2).
Case-Mix Variables Associated with Risk of Sequential Hip Fracture
To determine which patients are most at risk of sustaining a second hip fracture within twelve months of the original fracture, we analyzed the demographic factors most frequently associated with this injury. After excluding the thirty-five patients who presented with simultaneous bilateral hip fractures and patients whose second fracture data were not available at twelve months, 2.3% (473) of the remaining 20,267 patients had sustained a second fracture by twelve months. However, 6393 (32%) of 20,267 patients had also died by twelve months, and, as factors associated with death could potentially confound the analysis of factors associated with sustaining a second fracture, we restricted the analysis to the 13,874 patients who survived for the entire twelve-month period. Three hundred and fifty (2.5%) of the 13,874 patients who survived to twelve months sustained a second fracture during that period.
Table I documents differences in patient case-mix variables between those who sustained a single or a sequential fracture. On univariate analysis, female sex, increasing age, and medical comorbidity were found to have an association with increased risk of sequential hip fracture. No other case-mix variable was significantly different between cohorts. However, as the case-mix variables are themselves highly intercorrelated, a more sophisticated approach was required. We therefore included each of the six predictor case-mix variables together with all of their first-order interactions in a logistic regression analysis model. The first parameter to enter the logistic regression model was the interaction between prefracture residence and mobility (Table II, Fig. 3). Patients who were least likely to sustain a second hip fracture were those who walked unaided at home. The patients who required walking aids and/or assistance to walk had similar rates of second fractures whether they lived at home or in a nursing home or hospital ward. The patients most likely to sustain a second fracture were those who could walk unaided and resided in a nursing home or hospital ward (Fig. 3). Age was the only other parameter to enter the logistic regression model as a significant predictor (p < 0.001), with older patients having a higher risk of sustaining a second fracture (Table II).
Mortality After Sequential Fracture
To determine the additional mortality effect associated with sequential hip fracture, we compared survival between patients who sustained an early second fracture (within twelve months of the original injury) and those who had not. Survival to twelve months after the second fracture was 63% (300 of 473) compared with 68% (13,495 of 19,794) for those who sustained a single fracture (chi-square test, p = 0.03).
Functional Outcome After Sequential Hip Fracture
Sixty-six percent of patients who sustained a single hip fracture resided in their own home before the fracture. Patients who sustained a second fracture were less likely to reside in their own homes at the time of the second fracture. Fifty-one percent of patients who sustained a second fracture more than twelve months after the primary injury were residing in their own home compared with only 34% of those who sustained the injury within four months of the primary fracture. Similarly, place of residence at 120 days after the fracture varied substantially, depending on both if and when a second hip fracture occurred (see Appendix). Sixty percent of patients who sustained a single hip fracture were residing in their own home by 120 days after fracture. This figure decreased to 45% for those who sustained a second fracture more than twelve months after the primary injury and to only 32% for those who sustained the second fracture within four months. However, the subset of patients who sustained sequential fractures and were admitted from their own home prior to both fractures were almost as likely to be residing in their own home by 120 days if the interval between fractures was more than one year (84% [385] of 461 patients who had a primary fracture versus 81% [172] of 213 patients with sequential fractures; p = 0.44).
These residential changes largely mirror the decline in mobility after successive hip fractures (see Appendix). Forty-five percent of patients who sustained a single hip fracture had walked without aids and unaccompanied at the time of injury. Mobility at the time of the second fracture again depended on the time interval between the first and second fractures. Eighteen percent of patients who sustained a second fracture more than twelve months after the primary injury were walking without aids and unaccompanied compared with only 6% of those who sustained their second fracture within four months.
Mobility at 120 days after injury followed a similar pattern. Fourteen percent of patients who sustained a single hip fracture walked without aids and unaccompanied at 120 days after the fracture. This figure decreased to 9% for those who sustained the second fracture more than twelve months after the primary injury and to only 6% of those who sustained the second fracture within four months.
Length of hospital admission is a major factor affecting the overall cost of hip fracture treatment. Length of stay in an acute orthopaedic hospital was slightly shorter after the second fracture (see Appendix), reflecting the greater proportion of patients with a second fracture discharged directly to a nursing home or institutional care from the acute orthopaedic ward.
Osteoporosis, falls, and associated fragility fractures represent a major public health issue. Each year, approximately one-third of people who are sixty-five years or older and half of people over eighty years old have at least one fall8,9. Approximately 10% to 15% of falls by the elderly result in a fracture8,9. It is known that individuals who sustain one fragility fracture are at considerable risk of sustaining future, often more serious injuries10. As such, public health interventions have been introduced to lessen the major impact of fragility fractures on patients and health-care providers11,12.
Decreased bone mineral density, advanced age, previous fragility fracture, cognitive impairment, functional impairment, visual impairment, and sedative medications all increase an individual’s risk of sustaining a hip fracture13. As many of these risk factors are difficult to modify, patients who survive a primary hip fracture continue to be at risk of sustaining a second, contralateral hip fracture14. As such, the relatively low incidence of sequential hip fracture reported in this study is surprising. In a number of previous studies, the annual incidence of sequential hip fracture has been reported to range from 2% to 10%, with a lifetime risk of up to 20%14-23. In the present study, approximately 3% of surviving patients sustained a contralateral hip fracture in the first year after the primary injury and this rate decreased to approximately 2% of those surviving per annum thereafter. The cumulative incidence of a second hip fracture in patients surviving to five years after the first fracture was 8.3% (6.9% when those who died were not excluded).
Reider et al. reported a decline in bone mineral density of the contralateral hip in the twelve-month period following a hip fracture compared with control subjects without a fracture24. As such, one would expect the risk of contralateral hip fracture to be highest in the first year after the primary fracture. We found that the percentage of surviving patients who sustained a second fracture in a given twenty-day period was highest during the first twelve months after the primary fracture and decreased throughout this period (Fig. 1). No further subsequent decrease was evident during the second twelve-month period following the original fracture. In orthopaedic units that had a second period of participation in the audit (using six-month periods of follow-up), annual fracture incidence was also approximately 2% of surviving patients per annum.
The mortality in patients after sustaining a hip fracture is high compared with that for age and sex-matched individuals in the general population1,25. Johnston et al. recently reported that mortality in patients who were eighty-five years of age or older with a fracture of the hip exceeded the level of the general population for two to five years after the fracture26. In the patients who were less than eighty-five years old, excess mortality associated with hip fracture persisted beyond eight years. It is therefore logical to expect that mortality after sustaining a second hip fracture would be substantially higher. However, survival after a second fracture sustained within twelve months of the primary injury was 63% compared with 68% in the control cohort (chi-square test, p = 0.03). This difference, although significant, is perhaps much less than we might have expected if second fractures have a substantial additive effect on mortality.
Hip fracture is known to have a significant impact on the functional capacity of a patient both in terms of independent living and mobility. Function and residential status are also important outcome measures as principal determinants of cost of care in the community. Place of residence both before fracture and at 120 days after fracture varied significantly between patient groups. Patients who sustained a single fracture were more likely to be residing in their own home at the time of fracture (66%) and more likely to return home by 120 days after injury (60%). For the patients who sustained sequential fractures, the time interval between injuries was the primary determinant of residence before and after injury. If the injury occurred more than twelve months after the primary fracture, loss of independent living was much less (51% at home before fracture and 45% at 120 days) than if the injury occurred within four months (only 34% at home before fracture and 32% at 120 days). However, patients who sustained hip fractures contralaterally and were admitted from their own home prior to both the primary and the second fracture were just as likely to be back home 120 days following either event (84% compared with 81%).
Hip fracture had a substantial negative effect on independent mobility. Forty-five percent of patients who sustained a single fracture were independently walking at the time of injury, but this decreased to just 14% of surviving patients by 120 days after injury. Patients who sustained sequential fractures were less likely to be independently mobile at the time of second fracture, and this was again primarily dependent on the time interval between injuries. Only 21% of those who sustained a sequential fracture more than twelve months after primary injury were independently mobile at the time of the second fracture compared with only 12% in the group who sustained a second injury within four months. At 120 days, only 9% and 6% of these respective groups were independently mobile. Thus, sequential hip fracture had a particularly devastating effect on independent mobility, more so than on mortality or independent living.
As hip fracture has such a substantial effect on mortality, mobility, independent living, and health-care costs, it would be useful to identify patients who are at risk of developing second fractures1-3. We investigated the demographic factors in the most immediately vulnerable group, defined as those who sustained a second fracture within twelve months of the original injury. The patients who were most likely to sustain a second fracture were those who walked independently in the nursing home or hospital setting. Patients who walk unsupervised would presumably be more likely to fall than those who are supported by walking aids or directly assisted by nursing home or hospital staff. This finding is important as it suggests that although a patient may be able to walk independently without aids or assistance, this places them at a higher risk of sustaining additional hip fractures, and closer supervision of such patients may be warranted. As expected, old age increased the risk of sustaining a second fracture, likely because the factors that predispose an individual to sustain a hip fracture tend to be more prevalent with increasing age. No other case-mix variable entered our predictive model at a level of significance (p < 0.05), emphasizing the relative scarcity and unpredictability of this second hip fracture.
In the present study, demographic data were used to predict individuals at risk of sequential hip fracture. However, other risk factors have been associated with a risk of falls and sequential hip fracture, but we were unable to analyze them because of the retrospective design of this study and the feasibility of collecting such data on a national basis. In a study of 193 patients in the year after sustaining a hip fracture, Lloyd et al. reported that 56% of participants fell at least once, 28% had recurrent falls, 30% were injured, 12% sustained a new fracture, and 5% sustained a new hip fracture27. Multivariate analyses identified older age, congestive heart failure, poorer quality of life, and nutritional status as independent risk factors for recurrent and injurious falls. Bone density measurements were not routinely available to us, but they could also provide an additional patient variable to help to identify patients at higher risk of sustaining a second hip fracture.
A recent study by Faucett et al. investigated the theoretical cost-effectiveness of prophylactic fixation to prevent contralateral hip fractures28. In view of the low incidence, high mortality after primary injury, and the difficulty in predicting those who are likely to sustain a second fracture, such interventions are unlikely to be effective either from a cost or patient perspective.
In conclusion, sequential hip fracture is a relatively rare injury that affects approximately 3% of surviving patients in the first year subsequent to the initial fracture, and 2% of survivors per annum thereafter. Sequential hip fracture is associated with higher mortality and further loss of independent mobility and residential status compared with single hip fractures, with the time interval between fractures being of critical importance to patient outcome. However, although outcome after sequential hip fracture was less favorable, the impact was not as great as might be expected. Analysis of case-mix variables identified independent mobility in a nursing home or hospital setting and advancing age as significant risk factors for sequential hip fracture. These findings may prove useful for cost-effective targeting of at-risk individuals for prevention of this injury.
Tables showing data on place of residence and indoor mobility at 120 days according to when and whether a second hip fracture occurred and data on the length of stay in acute orthopaedic care as well as figures showing the number of patients included and outcomes in years 0 to 7 and the percentage of surviving patients after a second fracture are available with the online version of this article as a data supplement at jbjs.org.
Holt
G;
Smith
R;
Duncan
K;
Finlayson
DF;
Gregori
A. Early mortality after surgical fixation of hip fractures in the elderly: an analysis of data from the scottish hip fracture audit. J Bone Joint Surg Br.
2008 Oct;90(
10):1357-63.[CrossRef]
Holt
G;
Smith
R;
Duncan
K;
Hutchison
JD;
Reid
D. Changes in population demographics and the future incidence of hip fracture. Injury.
2009 Jul;40(
7):722-6. .[CrossRef]
Rozental
TD;
Makhni
EC;
Day
CS;
Bouxsein
ML. Improving evaluation and treatment for osteoporosis following distal radial fractures. A prospective randomized intervention. J Bone Joint Surg Am.
2008 May;90(
5):953-61.[CrossRef]
Silman
AJ. The patient with fracture: the risk of subsequent fractures. Am J Med.
1995 Feb 27;98(
2A):12S-16S.[CrossRef]
Owens
WD;
Felts
JA;
Spitznagel
EL
Jr. ASA physical status classifications: a study of consistency of ratings. Anesthesiology
.1978;49:239-43.[PubMed][CrossRef]
Tinetti
ME. Clinical practice. Preventing falls in elderly persons. N Engl J Med.
2003 Jan 2;348(
1):42-9.[CrossRef]
Nevitt
MC;
Cummings
SR;
Hudes
ES. Risk factors for injurious falls: a prospective study. J Gerontol.
1991 Sep;46(
5):M164-70.
Kanis
JA;
Johnell
O;
De Laet
C;
Johansson
H;
Oden
A;
Delmas
P;
Eisman
J;
Fujiwara
S;
Garnero
P;
Kroger
H;
McCloskey
EV;
Mellstrom
D;
Melton
LJ;
Pols
H;
Reeve
J;
Silman
A;
Tenenhouse
A. A meta-analysis of previous fracture and subsequent fracture risk. Bone.
2004 Aug;35(
2):375-82.[CrossRef]
Bischoff-Ferrari
HA;
Willett
WC;
Wong
JB;
Giovannucci
E;
Dietrich
T;
Dawson-Hughes
B. Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials. JAMA.
2005 May 11;293(
18):2257-64.[CrossRef]
Cranney
A;
Waldegger
L;
Zytaruk
N;
Shea
B;
Weaver
B;
Papaioannou
A;
Robinson
V;
Wells
G;
Tugwell
P;
Adachi
JD;
Guyatt
G. Risedronate for the prevention and treatment of postmenopausal osteoporosis. Cochrane Database Syst Rev.
2003;.
Osteoporosis: review of the evidence for prevention, diagnosis and treatment and cost-effectiveness analysis. Osteoporos Int.
1998;8
Suppl 4:S1-80.
Egan
M;
Jaglal
S;
Byrne
K;
Wells
J;
Stolee
P. Factors associated with a second hip fracture: a systematic review. Clin Rehabil.
2008 Mar;22(
3):272-82. .[CrossRef]
Ryg
J;
Rejnmark
L;
Overgaard
S;
Brixen
K;
Vestergaard
P. Hip fracture patients at risk of second hip fracture: a nationwide population-based cohort study of 169,145 cases during 1977-2001. J Bone Miner Res.
2009 Jul;24(
7):1299-307.[CrossRef]
Lawrence
TM;
Wenn
R;
Boulton
CT;
Moran
CG. Age-specific incidence of first and second fractures of the hip. J Bone Joint Surg Br.
2010 Feb;92(
2):258-61.
Oliver
D. Development of services for older patients with falls and fractures in England: successes, failures, lessons and controversies. Arch Gerontol Geriatr.
2009 Dec;49
Suppl 2:S7-12.[CrossRef]
Lönnroos
E;
Kautiainen
H;
Karppi
P;
Hartikainen
S;
Kiviranta
I;
Sulkava
R. Incidence of second hip fractures. A population-based study. Osteoporos Int.
2007 Sep;18(
9):1279-85. .[CrossRef]
Melton
LJ
3rd;
Kearns
AE;
Atkinson
EJ;
Bolander
ME;
Achenbach
SJ;
Huddleston
JM;
Therneau
TM;
Leibson
CL. Secular trends in hip fracture incidence and recurrence. Osteoporos Int.
2009 May;20(
5):687-94. .[CrossRef]
Chapurlat
RD;
Bauer
DC;
Nevitt
M;
Stone
K;
Cummings
SR. Incidence and risk factors for a second hip fracture in elderly women. The Study of Osteoporotic Fractures. Osteoporos Int.
2003 Apr;14(
2):130-6. .
Chiu
KY;
Pun
WK;
Luk
KD;
Chow
SP. Sequential fractures of both hips in elderly patients—a prospective study. J Trauma.
1992 May;32(
5):584-7.[CrossRef]
Wolinsky
FD;
Fitzgerald
JF. Subsequent hip fracture among older adults. Am J Public Health.
1994 Aug;84(
8):1316-8.[CrossRef]
Yamanashi
A;
Yamazaki
K;
Kanamori
M;
Mochizuki
K;
Okamoto
S;
Koide
Y;
Kin
K;
Nagano
A. Assessment of risk factors for second hip fractures in Japanese elderly. Osteoporos Int.
2005 Oct;16(
10):1239-46. .[CrossRef]
Reider
L;
Beck
TJ;
Hochberg
MC;
Hawkes
WG;
Orwig
D;
YuYahiro
JA;
Hebel
JR;
Magaziner
J; Study of Osteoporotic Fractures Research Group. Women with hip fracture experience greater loss of geometric strength in the contralateral hip during the year following fracture than age-matched controls. Osteoporos Int.
2010 May;21(
5):741-50. .[CrossRef]
Johnston
AT;
Barnsdale
L;
Smith
R;
Duncan
K;
Hutchison
JD. Change in long-term mortality associated with fractures of the hip: evidence from the scottish hip fracture audit. J Bone Joint Surg Br.
2010 Jul;92(
7):989-93.[CrossRef]
Lloyd
BD;
Williamson
DA;
Singh
NA;
Hansen
RD;
Diamond
TH;
Finnegan
TP;
Allen
BJ;
Grady
JN;
Stavrinos
TM;
Smith
EU;
Diwan
AD;
Fiatarone Singh
MA. Recurrent and injurious falls in the year following hip fracture: a prospective study of incidence and risk factors from the Sarcopenia and Hip Fracture study. J Gerontol A Biol Sci Med Sci.
2009 May;64(
5):599-609. .[CrossRef]
Faucett
SC;
Genuario
JW;
Tosteson
AN;
Koval
KJ. Is prophylactic fixation a cost-effective method to prevent a future contralateral fragility hip fracture?J Orthop Trauma.
2010 Feb;24(
2):65-74.[CrossRef]
Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. In addition, one or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.