Traumatic Finger Amputations: Epidemiology and Mechanism of Injury, 2010-2019

Abstract

Background:

Traumatic finger amputations are a common and well-known hand injury, yet there are few studies addressing long-term epidemiologic data and associated mechanisms of injury. This paper aims to use a large national database to identify the relationship of patient demographics and mechanism of injury in finger amputations.

Methods:

The National Electronic Injury Surveillance System (NEISS) was queried for finger amputations in the United States from 2010 to 2019. Patient demographic information was collected and analyzed by gender, race, age, and further statistical analysis was performed to determine correlations with consumer products.

Results:

Finger amputations accounted for an estimated 234,304 emergency department visits from 2010 to 2019. Most of the patients were male (79%) and identified as white (46.2%). The most commonly implicated products overall were power saws and related power tools, followed by doors and then lawn mowers. A bimodal age incidence was observed with the highest incidence rates occurring in children ages 0 to 4, followed by a second peak incidence rate in the adults ages 65 to 74. The most common mechanisms of injury were found to differ in patients less than 19 and those 20 and over.

Conclusion:

Traumatic finger amputations have a bimodal incidence with changing epidemiology and mechanism of injury with age. The first peak occurs from ages 0 to 4, involves predominantly doors, and has a male to female ratio of 1.30. The second peak occurs from ages 65 to 74, involves mostly power saws, and has a male to female ratio of 6.68.

Level of Evidence:

Prognostic, Level IV

Introduction

Finger injuries are a common reason for emergency department (ED) visits, accounting for an estimated 4.8 million visits per year. ¹ Of these injuries, traumatic finger amputations make up a small, albeit impactful, percentage and are a common orthopedic injury. Such injuries can have significant morbidity to patients in terms of cost, time away from work, body image, function, and quality of life. ² Finger amputations in the United States are most often treated with revision amputation or replantation. Revision amputation provides near normal functional outcomes regarding sensation and range of motion, lower healthcare cost, and quicker return to work. ³ Less frequently, traumatic finger amputations are managed with digit replantation, typically for amputations involving the thumb, multiple digits, or pediatric patients, ⁴ and replantation is far more likely to be carried out at large metropolitan teaching hospitals. ⁵

While there are multiple studies focusing on pediatric and work-related traumatic finger amputations, there is a dearth of literature that discusses long-term epidemiological data and implicated products regarding traumatic finger amputations in the United States. The purpose of this study is to use a national database to examine the incidence and mechanism of injury of finger amputations and their association with patient characteristics. We hypothesize that as patients age, there will be a shift in the incidence and implicated consumer products.

Methods

The National Electronic Injury Surveillance System (NEISS), managed by the Consumer Product Safety Commission, collects data regarding consumer product-related injuries in the United States. ⁶ Data are collected from approximately 100 hospitals that make up a probability sample of all U.S. hospitals with an ED. ⁶ The collected data are coded and assigned a weight so that national estimates can be made based upon location. ⁶ National estimates are considered to be unstable, and therefore unreliable, if the national estimate is less than 1200, the number of cases is less than 20, or if the coefficient of variation is greater than 33%. ⁷

To gather data for this study, the NEISS database was queried for finger amputations during the most recent 10 years (2010-2019) using “finger” (NEISS body part code 92) and “amputation” (NEISS diagnosis code 50). Epidemiologic data were obtained by sorting the data first by 5-year age groups, and then by 5-year age groups and sex. Incidence rates for each age group were calculated using census data as reported by the Centers for Disease Control and Prevention. ⁸ To stratify data by race, the raw data from 2010 to 2019 were analyzed.

To investigate which consumer products are commonly implicated in finger amputations, raw data from various years was sorted and analyzed by product code. The most common products were noted, and the January 2021 NEISS coding manual ⁹ was used to create product groupings that included all relevant product codes as shown in Supplemental Table 1. Additional queries were run to determine national estimate by product grouping. Products that yielded stable data were further broken down by 10-year age groups in additional queries.

Results

Demographics and Epidemiology

There was a national estimate of 234 304 traumatic finger amputations (6 788 raw cases) from 2010 to 2019. Males accounted for approximately 79% of the total cases, with an incidence of 11.81 per 100 000 person-years compared to 3.01 per 100,000 person-years for females. The majority of patients were white, although 37.1% of the cases did not specify race (Figure 1). Amputations occurred in a bimodal age distribution, with the highest incidence found between ages 0 to 4 years, followed by ages 50 to 54 and 55 to 59 as shown in Figure 2 and Supplemental Table 2. When adjusted to age-specific national population, the peaks were ages 0 to 4 (12.48 per 100,000 person-years) and ages 65 to 69 and 70 to 74 (10.41 and 10.89 per 100,000 person-years, respectively) as seen in Figure 3. Additionally, when comparing the distribution of injuries among the 5-year age groups stratified by gender, there was a disproportionately high percentage of young female injuries in the 0 to 4 and 5 to 9 age groups that was statistically significant (P < .0001), as seen in Figure 4 and Supplemental Table 3. Over one-third of the total injuries in females occurred in people aged 19 and younger.

Figure 1.

Distribution of traumatic finger amputations by race.

Note. This figure depicts the percentage of traumatic finger amputations by race.

Figure 2.

National estimate of traumatic finger amputations by gender.

Note. This figure lists the national estimate of traumatic finger amputations, incidence only, for 2010 through 2019. Associated 95% Confidence intervals are listed in Supplemental Table 2.

^aUnstable data for female cases.

Figure 3.

Incident rates of traumatic finger amputations by gender.

Note. This figure reports the national estimate of finger amputations in 100,000 person years based on available population data by 5-year age groups.

Figure 4.

Proportional distribution of traumatic amputations by gender.

Note. This figure shows the overall distribution of traumatic finger amputations by each 5-year age group and compares the percentages between genders. Corresponding p-values shown in Table 3.

Mechanism of Injury

There were 18 products that yielded results with stable national estimates (Supplemental Table 2). Overall, power saws had the highest national estimate of cases at 65 981, followed by doors with a national estimate of 37 181 cases. Of the 18 products listed, the top 9 products yielded national estimates when stratified by 10-year age groups (Table 1). Patients aged 19 and under most commonly sustained amputations due to doors. Doors accounted for nearly 60% of all cases in children under 10 and 15% of cases in the 10 to 19 age group. Chairs or stools and bikes are also commonly involved in traumatic finger amputations in children under 10, making up 5.9% and 5.8% of all cases, respectively. Patients ages 20 and older were most likely to sustain traumatic finger amputations involving power saws, accounting for 55.1% of all cases. This was followed by lawn mowers (13.3%), then knives, and doors (10.4% for each). The percentage of cases that result from power saw steadily increases with age, while the percentage of cases accounted for by doors steadily decreases as shown in Table 2. Table 3 compares the 9 consumer products that yielded stable national estimates stratified by age 19 and younger versus age 20 and older, demonstrating statistically significant difference for all products.

Table 1.

Consumer Products Most Commonly Associated With Traumatic Finger Amputations.

Product name	NE*	95% Confidence interval		# Cases	Est % total
Power saws	65 981	50 521	81 440	1688	28.2
Doors (sliding/hinge; excl garage)	37 181	27 811	46 550	1504	15.9
Lawn mowers	18 127	14 244	22 010	476	7.7
Knives	14 570	10 927	18 212	350	6.2
Blenders/food processors	8618	6675	10 561	198	3.7
Log splitters	7158	4537	9779	180	3.1
Snow throwers, blowers	5776	2745	8807	164	2.5
Bicycles and accessories	4406	2962	5850	169	1.9
Chairs and stools	4016	3015	5017	145	1.7
Garage doors	3700	2571	4828	94	1.6
Hatchets, axes	3411	1847	4974	68	1.5
Fences, fence posts	2421	1441	3402	85	1.0
Manual saws	2159	1367	2951	61	0.9
Fireworks	2145	819	3472	89	0.9
Gym equipment	2145	1285	3006	76	0.9
Floors, flooring materials	1583	918	2248	43	0.7
Door sills or frames	1560	888	2233	56	0.7
Tools, NS**	1465	737	2192	37	0.6

Note. The top 18 products implicated in traumatic finger amputations from 2010 to 2019 are listed above with the 10-year national estimate, reported cases at the surveilling hospitals, and percent of national estimate for each product. The top 9 products, which had stable data and national estimates for each 10-year age group, are highlighted in green.

^*National Estimate.

^**Not specified.

Table 2.

Consumer Products Implicated in Traumatic Finger Amputations by Age Group.

0-9		10-19		20-29
Doors	59.77%	Doors	15.15%	Saws	18.36%
Chairs and stools	5.91%	Saws, power	10.81%	Knives	16.26%
Bikes and accessories	5.79%	Bikes and accessories	9.34%	Doors	12.98%
		Knives	7.69%	Lawn mowers	9.68%
		Log splitters	7.30%	Kitchen appliances	6.26%
30-39		40-49		50-59
Saws	25.83%	Saws	30.79%	Saws	36.37%
Knives	10.98%	Lawn mowers	12.55%	Lawn mowers	10.23%
Lawn mowers	9.20%	Knives	8.08%	Doors	7.70%
Kitchen appliances	5.61%	Doors	7.49%	Kitchen appliances	4.56%
Doors	5.05%	Kitchen appliances	4.59%	Log splitters	4.35%
Log splitters	4.78%			Snow throwers/blowers	4.25%
				Knives	3.96%
60-69		70-79		80 +
Saws	46.50%	Saws	47.0%	Saws	46.12%
Lawn mowers	7.88%	Doors	6.81%
Knives	4.62%
Kitchen appliances	4.47%
Doors	3.68%

Note. This table lists the top products involved in traumatic finger amputations by 10-year age group, as well as the percent of cases the product is involved in.

Table 3.

Mechanism of Injury in Patients Under 19 Versus 20 and Older.

Consumer product category	Age
	19 and younger		20 and older
	Number of cases	%	Number of cases	%	P value
Saws, power only	1835	5.3	63 851	55.1	.0001
Doors	24 137	70.3	12 088	10.4	.0001
Knives	1306	3.8	12 089	10.4	.0001
Snow throwers, blowers	0	0.0	1 698	1.5	.0001
Lawn mowers	0	0.0	15 345	13.3	.0001
Blenders and similar products	0	0.0	7657	6.6	.0001
Log Splitters	1239	3.6	3059	2.6	.0001
Bicycles and accessories	3676	10.7	0	0.0	.0001
Chairs and stools	2133	6.2	0	0.0	.0001
Total	34 326		115 787

Note. This table compares the mechanism of injury in people ages 19 and younger versus ages 20 and older. Percentage of cases reported excludes the results missing due to unstable data and directly compares the top 9 products.

Discussion

Traumatic finger amputations are a common upper extremity injury. These injuries can come with financial, functional, and aesthetic burden on patients. ² Analysis of the NEISS demonstrated 3 key findings in this analysis: (1) traumatic finger amputations have a bimodal age distribution; (2) the mechanism of injury changes with age; and (3) males are far more likely to have a traumatic finger amputation than females are.

Traumatic finger amputations have a bimodal age incidence as shown in Figures 2 and 3. Based solely on incidence, the first peak occurs in the 0 to 4 age group, and the second peak occurs during the sixth decade of life. However, when the data are adjusted to reflect age-specific national population, the second peak occurs in individuals aged 65 to 69 and 70 to 74. Other studies have examined work-related traumatic amputations and reported peak incidences in people ages 25 to 54.^2,10 Largo and Rosenman ¹¹ examined work-related traumatic amputations using state workers’ compensation data and hospital records and found that men in their 20s had the highest rate of work-related traumatic amputations. Of note, each of these studies used raw case numbers rather than population-based incidence in their conclusions. Additionally, these studies focused on work-related traumatic amputations, thus excluding pediatric patients who are too young to work and elderly patients who have either retired or no longer work in the same environments as younger people. Likely, the difference we found is due to a broader catchment in the NEISS database as it relies on ED presentations.

The mechanism of injury and associated consumer product for traumatic finger amputations changes with age. People ages 19 and under had different mechanisms of injury and associated consumer product compared to those 20 years of age and older. Doors, bikes, and chair/stools were more likely to cause amputations in under 20-year-olds versus power saws, lawn mowers, and knives in people 20 and older. This difference in associated consumer products is logical as young children are less likely to have access to products such as power tools and lawn mowers, and they may be lacking in strength and coordination in the use of doors, bikes, and chairs. Our finding that doors are the product most likely to be implicated in traumatic finger amputations in children is consistent with conclusions drawn by other studies and prior literature.^12,13 Furthermore, power saws are previously described as a common product in traumatic amputations in adults. ¹⁴ Pomares et al conducted a single center retrospective study that examined traumatic upper extremity amputations over a 10-year period and found table saws to be the most common cause of traumatic amputations. Although there is a lack of literature commenting on products other than power saws and workplace tools commonly involved in traumatic finger amputations in adults, the common products listed in Table 2 make logical sense. Products like kitchen appliances, snow blowers, lawn mowers, and log splitters are used by adults both at home and in the workplace. These products can be dangerous and easily result in injury due to an accident or inattention. The same logic holds true for all the products listed in Table 1, which account for 80% of the national estimate of all traumatic finger amputations.

Males experience traumatic finger amputations at an overall rate nearly 4 times that of females. The difference between genders is statistically significant with a 95% confidence interval at all age groupings other than the 0 to 4 age group (Supplemental Table 2). The similar incidence rate between males and females in the 0 to 4 age group is likely due to doors accounting for the vast majority of cases in children and a lack of gender predilection regarding interaction with doors. The association of gender and traumatic finger amputations has previously been described in various studies examining traumatic amputations in the workplace.^2,10,11 Additionally, the male predilection to traumatic finger amputations outside of the workplace has been described by Conn et al, ¹⁵ which in accordance with this study, shows that males are significantly more likely to sustain these injuries. Interestingly, females have a higher proportion of amputations in the 0 to 4 and 5 to 9 age groupings compared to men (Figure 4 and Supplemental Table 3). This may reflect that men are more likely to use the previously identified consumer products such as power saws and lawnmowers, which account for the majority of amputations, than women are in their adult years. This difference in product use and amputations later in life may result in a higher proportion of female children sustaining these injuries when compared to male children.

Although a national surveillance registry allows for large-scale reporting on products implicated in traumatic amputations,^{16 -20} this study does have some limitations. Due to the NEISS database’s exclusion of unreliable data, several products that are involved in traumatic finger amputations are not listed in the results. These products include but are not limited to hatches and axes, garage doors, fences, manual saws, fireworks, gym equipment, flooring materials, door frames, and other tools not specified. Approximately 20% of total traumatic finger amputation cases in this study do not have an associated mechanism, and this number can be as high as 55% in some age groups. Additionally, the NEISS captures only those patients who present to one of the included EDs. Therefore, patients who present to a different ED, an urgent care, or primary care office are not included. As with most large databases, the data contained are limited by the accuracy and completeness of input data for each case. The data produced by the NEISS are a national estimate and not a direct nationwide incidence. Despite these limitations, the NEISS database is a reliable method of analyzing various injuries, as well as demographic data and consumer product involvement on a national level.^{16 -20}

Conclusion

Traumatic finger amputations occur in a bimodal age incidence with a changing mechanism of injury, and males are far more likely to experience this injury than females are. There is a difference in the mechanism of injury between people under the age of 20 and people ages 20 and older: doors are the most commonly involved product for traumatic finger amputations in people under 20, and power saws are the most commonly involved product for adults 20 and older. This changing mechanism of injury, combined with the fact that nearly 80% of traumatic amputations are caused by fewer than 20 product categories, allows for both age- and product-targeted interventions aimed at preventing traumatic finger amputations.