1 Introduction

In the U.S., over 300,000 individuals sustain hip fractures annually and subsequently present to orthopedic teams for treatment.¹ Hip fractures come with a high healthcare burden costing an estimated $50,000 per patient to treat in the year following the fracture, with a nationwide annual estimate of $5.96 billion per year in the United States.² Perhaps most concerning is the increased mortality risk, with one year mortality rates ranging from 14 % to 36 %0.^3,4 Meanwhile, periprosthetic femoral fractures (PPF) following hip arthroplasty have been shown to have greater than 5 % in-hospital mortality rates and similar one-year mortality rates as native hip fractures.^5–7 Fractures have also been shown to rapidly decline health, as well as quality of life.^8,9 With the aging population, the annual incidence of hip fractures is expected to exceed 600,000 by the year 2050, thereby doubling the burden on patients, providers, and health systems.¹⁰ Meanwhile, the number of Total Hip Arthroplasties (THAs) performed per year in 2050 will be nearly 1.2 million in the US, roughly 4.5 times the number performed in 2020.¹¹

Among those presenting to Emergency Departments (EDs) for hip fractures, recent literature reports up to 88 % are a result of falls.¹² Individuals at highest risk of sustaining serious injury due to falls were more likely to have individual (i.e. female sex and low body weight) and situational (involving stairs and weight-displacing activities) predisposing factors.^13,14 Additionally, the fear of falling bidirectionally contributes to poorer functional status and is a strong predictor of future fall risk.^14–17 This calls for the need to educate and empower individuals at risk to maintain their function and independence and take preventive measures to reduce their risk of falls and restore their confidence.

There are gaps in the current literature addressing the specific mechanisms responsible for falls and other extrinsic contributing factors, particularly in patients suffering hip fracture. Findings are often limited to “fall-related” and are unable to provide contributing environmental factors to the incident.¹² It is important for patients, providers, and insurance companies to understand the mechanism in which people fracture their hips in order to prevent these morbid and financially costly injuries. Public health and medical prevention efforts have been well established to maintain and improve quality of life, improve patient outcomes and reduce economic loss; our study stands to inform prevention efforts through examination of mechanism behind traumatic hip fractures.¹⁸

Managing causative factors of fall-related fractures is paramount to minimizing morbidity, mortality, loss of patient independence, and strain on the healthcare system. However, this can be challenging due to the multifactorial causes of falls and hip fractures.¹⁹ Common preventive measures include regular exercise, pharmacological treatments for osteoporosis, and the use of hip protectors.²⁰ Additionally, hospital systems throughout the US are implementing fall-reduction programs involving patient education, environmental adaptations, assistive devices, and nutrition review to minimize the risk of falls and resulting severe consequences, like hip fractures.²¹ However, current modalities for assessing hip fracture risk have been shown to be insensitive for those at high risk, particularly in terms of bone quality and biomechanical implications in patients with osteoporosis.²² Our study focuses on understanding the environmental and situational causes behind these hip fractures, informing the physician on best practices in counseling patients on safety practices to be applied throughout activities of daily living and beyond. In context of the debilitating effects of a hip fracture, our study aims to identify risk factors to patients and provide information that can inform preventative measures at the provider, community, and national level.

2 Methods

3 Results

3.1

3.1 General

Across all 20,568 injuries, females were more likely to fracture their hip than males (P < .001), comprising 68.4 % (95% CI 67.8%–69.0%) and 31.6% (95 % CI 31.0%–32.2%) of fractures, respectively. Females were on average older at presentation (P < .001) at 80.5 years old (95% CI 80.3–80.7), compared to males at 73.4 years old (95% CI 73.0–73.8). As demonstrated in Fig. 1, more females suffered hip fractures across all age clusters from 60 to 69 through 100+. However, males sustained slightly more fractures in the younger age groups. For both males and females, the greatest number of fractures occurred in their eighties, representing 36.4% (95 % CI 35.8%–37.0%) of all fractures.

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Fig. 1 Flowchart showing study population selection. “Mention of hip fracture” indicates hip fracture-related search criteria located in the narrative of presentation. These search terms include “hip fx”, “hip fracture”, “fx hip”, "fracture hip”, “left hip fx”, “right hip fx”, etc.

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Females and males are most likely to sustain hip fractures in the home when compared to public, unknown, and other locations (P < .001) (Table 1). Of all hip fractures, 62.0% (95% CI 61.4%–62.6%) occur in the home (Table 1).

Table 1 Mechanism of injury incidence across various demographic and circumstantial variables reported as total row percent.

		Falls to Floor	Beds	Stairs	Chairs	Rugs	Toilets	Footwear	Baths & Showers	Ladders	Bicycles	Other
Sex	Male	31.4	10.3	8.0	5.1	2.5	1.7	1.4	2.2	3.0	3.7	30.8
	Female	38.2	11.6	7.8	5.6	4.0	2.8	2.8	1.6	0.3	0.5	24.8
Age Group	0–49	7.5	3.3	6.9	1.1	0.3	0.9	0.5	1.7	3.4	6.6	67.7
	50–59	24.3	8.9	12.4	2.9	2.1	1.9	1.7	2.8	5.1	7.3	30.7
	60–69	30.4	9.8	10.9	4.1	3.0	2.3	2.7	2.5	2.5	3.8	27.9
	70–79	33.7	10.3	10.0	5.1	3.2	2.6	2.9	2.1	1.4	1.5	27.3
	80–89	39.6	11.5	6.9	6.1	4.2	2.5	2.3	1.6	0.5	0.4	24.4
	90–99	43.8	14.0	4.5	6.9	3.9	2.7	2.1	1.4	0.0	0.1	20.6
	100+	40.0	21.6	1.6	3.7	3.2	4.2	1.1	2.1	0.0	0.0	22.6
Location	Public	49.6	16.6	3.0	5.0	2.4	2.2	1.6	1.2	0.0	0.8	17.7
	Home	35.4	11.1	8.0	5.4	4.2	2.7	2.5	2.2	1.4	0.1	27.0
	Unknown	28.5	6.9	15.6	7.3	3.0	2.3	3.0	1.5	2.2	3.4	26.3
	Other	2.0	0.1	1.2	0.0	0.2	0.1	1.2	0.1	0.1	22.9	72.2
Season	Spring	36.2	11.0	8.4	5.2	3.2	2.5	2.3	2.1	1.0	1.7	26.4
	Summer	35.4	11.2	7.8	5.2	3.9	2.2	2.4	1.9	1.2	1.7	27.2
	Fall	36.4	10.7	8.1	5.5	3.5	2.6	2.4	1.7	1.5	1.4	26.2
	Winter	36.1	11.7	7.2	5.8	3.5	2.5	2.3	1.6	0.9	1.4	27.0
Total		36.0	11.2	7.9	5.4	3.5	2.4	2.3	1.8	1.2	1.5	26.7

Products implicated in the mechanism of injury showed similar trends among males and females as shown in Table 1. The 5 most common products (excluding Other) were falls to the floor, and mechanisms involving beds, stairs, chairs, rugs/carpets, and toilets.

4 Dicussion

Based on this nationally representative sample, the majority of all hip fractures presenting to US EDs are elderly and female patients, which is consistent with current literature.^1,3,12,25 This sex difference coincides with life expectancy differences, with females living an average age of 79.3 years and males 73.5 years.²⁶ Thus, elderly patients, particularly women, must be evaluated for their risk of fall and hip fracture, as well as educated on characteristic mechanisms prominent in more specific demographic strata. Our results provide a framework for understanding who is at risk for hip fracture according to various sex, age, location, and season parameters that can be addressed in a patient-specific manner. This data can reinforce patient-centered, personalized care, which has been shown to improve outcomes and is even necessary for certain physician reimbursement models.^27–29

As patients become increasingly bed bound with age, it is not surprising that fractures trend towards fall from bed. However, with nearly 1 out of 5 fractures involving falls from bed, emphasis must be placed on safety measures directed at reducing these controllable injuries. Various safety measures should be considered depending on the broader patient picture, such as minimizing the frequency of moving into and out of bed with measures like urinals, Pure Wicks, other aids for toileting, and improved communication with caregivers/cohabitants. However, some patients are understandably hesitant to surrender their functional independence and presumably less likely to rely on these health aides and other people that limit them to bed.³⁰ It is important for providers to advocate for their safety by providing less-limiting alternatives, like bed posts, bed rails, trapeze bars, etc. Currently, these products and similarly oriented preventive home health products are not included in the Durable Medical Equipment (DME) covered by Medicare Part B.³¹

Medicare Part B coverage includes a variety of DME, including canes, beds, and oxygen tanks, as deemed medically necessary and prescribed by a physician for use at home.³¹ Under this plan, many items require a 20% deductible to be paid by the patient and this coverage is contingent upon patients' physicians and suppliers accepting these products and costs.³¹ To address simple falls to the floor, coverage currently exists for walking and maneuvering aids, such as walkers, crutches, wheelchairs, and scooters. However, significant gaps exist in the current offerings for the remainder of categories evaluated in this study that are responsible for between 60% and 70% of hip fractures among females and males, respectively (Table 1). When searching the Medicare database for “bed” or “bed rail” to find equipment that may prevent bed-related hip fractures, one of the most prevalent mechanisms, there are only 4 relevant results: hospital beds, swing-bed services, air-fluidized beds, and pressure-reducing support surfaces.^32,33 These products, which are largely used for bed-bound at-home health services, fail to address prevention in at-risk individuals not requiring such dramatic at-home interventions. Beyond the current DME covered by Medicare, items that would help with prevention are “not considered ‘primarily medical in nature’...[and] are considered convenience items.”³⁴ This study provides evidence that certain activities and demographics place individuals at risk for hip fracture and related morbidity and mortality.

Unlike other mechanisms, the proportion of fractures attributable to stairs decreases with increasing age. Several factors have been shown to contribute to stair avoidance, such as: age, female gender, obesity, and mobility limitations.³⁵ Individuals that perceive they are at risk when using stairs may opt for single floor units or apartments, living in facilities that have elevators, using wheelchairs and/or ramps, or adopt other stair-avoidant behaviors that may contribute to this trend. For those who cannot make these accommodations, it is important to adopt risk mitigating strategies such as using railings, ramps, or stair lifts whenever possible (Table 5).

In contrast to the elderly population, younger populations appear to experience fractures because of higher height or speed accidents, often as falls from ladders or bicycles. Unsurprisingly, we see these high-risk activities occurring in their respective seasons, with more ladder-related fractures in the Spring and Fall and bicycle-related fractures in the Spring and Summer. For some, delegating house/yard work to professional help may be an important risk mitigating step. These services cost less than $400 on average, and patients should understand their risk and the subsequent cost which comes with a hip fracture to both their well-being and wallets.³⁶ With revision THAs costing approximately $25,000 (before insurance) and native hip fractures with equally high price tags, outsourcing these high-risk activities may be reasonable based on patient-specific demographics and circumstance.³⁷ Bike-riding also poses significant risk with its high-speed injuries, and patients at risk of fracture (osteoporosis, etc.) should be counseled on their increased risk with this activity. This may be an acceptable risk for some patients, but still its risk should be discussed with post-THA patients in which PPF comes with a high cost to mortality and financially. This information illuminates the importance of tailoring educational and advisory efforts to patients based on the time of year and evaluating their risk for specific activities patients are likely to engage in.

Roughly 1 in every 3 patients undergoing Total Joint Arthroplasty (TJA) experience a fall within one year post-operatively.^38–41 Furthermore, patients undergoing THA have been shown to be twice as likely to suffer from falls within 2 years postoperatively compared to TKA patients.⁴² Ultimately, THA is protective, as a functioning hip reduces one's risk of falls; however, postoperative patients remain at significant risk, emphasizing the importance of PPF-related morbidity/mortality and the burden of repeat surgeries.⁴³ With significant morbidity, mortality, and costs associated with native hip fractures and PPF, it is important to utilize information presented in this study to inform TJA patients of their risk and what activities may place them at higher risk of sustaining fractures.

5 Limitations & strength

Our study is not without limitations. As with all registry-based studies, some data may be missing, incomplete, or coded improperly. Specifically, product codes attributed to each ED presentation may be unreliably sourced from patient charts. Missing data may also be a result of incomplete filtering for hip fracture mentioned in patient narratives, potentially leaving patients that would otherwise be included out of analysis. The NEISS registry only provides information on cases and initial encounters and does not provide controls or follow up data. There was also no information regarding medical comorbidities, current medications, or other known risk factor data. Nevertheless, the large population provided by this study provides valuable insight into the common mechanisms in which hip fractures occur.

6 Conclusion

While falls remain the chief cause of hip fractures, many of these injuries stem from overlooked mechanisms. The heightened risk associated with falls from beds and chairs in the elderly, stair-related injuries in middle-aged individuals, and high-force modalities in younger people, highlights the necessity for tailored preventive measures. Providers should counsel their patients on risk reduction measures within the home, while Medicare and other insurers must work to expand coverage for these same measures.

Funding Statement

No external sources of funding were received for this study.

CRediT authorship contribution statement

Benjamin M. Varieur: Conceptualization, Methodology, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Ryan C. White: Writing – review & editing, Methodology, Investigation, Writing – original draft, Writing – review & editing. Daniel R. Schmitt: Writing – review & editing, Supervision. Nicholas M. Brown: Methodology, Writing – review & editing, Supervision.

Guardian patient consent

This study does not warrant explicit guardian/patient consent. The registry utilized for data collection appropriately obtains patient consent.

Ethics statement

This study utilizes data from an anonymized, publicly available data registry and therefore does not warrant explicit regulatory approval.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.