Outcomes After Deep Full-Thickness Hand Burns

Methods 

Results 

Forty-seven percent of the study sample reported working full-time at the time of study participation. Sixty percent of the sample reported being right-handed, 28% being left-handed, and 12% being ambidextrous. The mean TBSA was 58%, and the mean time from injury was 16 years. The reported average length of time spent in intensive care was 81 days and in acute care was 143 days. Eighty-two percent reported having received therapy (inpatient and outpatient therapy) during the stay in the hospital, and 86% rated their compliance with therapy as “excellent” or “good.”

Thirty-nine percent had 1 or more digit amputation(s) of the dominant hand, 46% of the nondominant hand, and 31% had 1 or more digit amputations of both hands. Of the 88 amputations recorded, 19 (22%) were at the MCP joint, 44 (50%) were at the PIP joint, and 25 (28%) were at the DIP joint. Splinting (53%) was the most common treatment reported, followed by pinning (36%) and casting (12.5%). Examination of the burned hand showed that 25% of the sample had joint ankylosis (at the PIP and DIP joints), 22% had a boutonnière deformity, 9% had a Swan-neck deformity, and 9% had joint subluxation (at the PIP and DIP joints). Mallet finger deformity was seen in 3% of this sample.

The total active motion measurements of each digit are shown in table 1. Applying the rating scale as established for tendon injuries of the finger13 (<180° is considered poor, 180°–219° is good, 220°–259° is excellent, 260° is normal) to the total active motion measurements in this study gave the following results: with the exception of 1 measurement, all thumb total active motion measurements were less than 180°. The mean ROM appears to be the worst for the right hand thumb (total active motion, 95°), followed by the little finger (142°) on the left hand. The mean total active motion for the index, middle, and ring fingers on the right hand and the middle finger on the left hand ranged between 182° and 195°, which indicates good functional results. However, about 40% of subjects had total active motion scores of below 180° across all other digits.

Table 1. Mean Total Active Motion of the Right and Left Hands

	Digit	Right Hand	Left Hand
		Mean Total Active Motion	Mean Total Active Motion
	Thumb	95±46	105±43
	Index finger	183±82	164±98
	Middle finger	185±84	195±81
	Ring finger	193±66	167±81
	Little finger	171±108	142±108

NOTE. Values are mean degrees ± SD.

The mean grip and pinch strengths for the sample and normative data16 for the age group are as follows: the mean grip strength for men was 38.8kg (normative, 46.5kg) and 21.6kg (normative, 44.4kg) for the dominant and nondominant hands, respectively. Among women, the mean grip strength was 18.2kg (normative, 26.9kg) and 14.3kg (normative, 26.5kg) for the dominant and nondominant hands, respectively. The mean pinch strength for men was 6.2kg (normative, 10.7kg) and 5.9kg (normative, 11.6kg) for dominant and nondominant hands, respectively, and for women was 3.3kg (normative, 7kg) and 2.6kg (normative, 7kg) for dominant and nondominant hands, respectively.

The time taken to complete the JTHFT and the sex- and age-based norms for the dominant and the nondominant hands are shown in table 2. Complete JTHFT data were not available for 5 subjects and were therefore excluded from the summary reports. When compared with norms in both the dominant and nondominant hand categories, subjects in this sample took longer to complete the test items. Of the 7 items, writing a sentence took the longest time and showed the most difference between the sample and the norm scores. When considering the dominant hand in the 20 to 59 years of age category, women did better in writing, turning cards, picking up small objects, and moving empty large cans, and men did better with simulated feeding, stacking checkers, and moving weighted large cans. With the nondominant hand in the same age group, women did better with all test items except moving heavy large cans.

Table 2. Time to Complete the Test Items on JTHFT by Age and Sex

		Dominant Hand
	Factor	Men				Women
	Age range (y)	20–59	Norms	60–94	Norms	20–59	Norms	60–94	Norms
	Total no. of subjects	11		1		13		2
	Writing	19.6±8.9	12.2	15.0	19.3	17.5±19.8	11.7	13.7±1.7	15.7
	Cards	9.72±7.2	4.0	5.0	5.3	7.38±5.9	4.3	6.0±1.4	4.9
	Small objects	9.36±4.0	5.9	7.0	6.8	8.96±4.7	5.5	8.0±0	6.6
	Simulated feeding	7.86±1.0	6.4	6.0	6.9	11.1±8.5	6.7	13.5±2.1	6.8
	Checkers	6.0±3.5	3.3	4.0	3.8	8.6±10.5	3.3	6.5±.7	3.6
	Large light objects	6.27±4.5	3.0	6.0	3.6	5.2±1.9	3.1	5.0±0	3.5
	Large heavy objects	4.8±1.1	3.0	4.0	3.5	7.7±7.0	3.2	4.7±.35	3.5

		Nondominant Hand
	Factor	Men				Women
	Age range (y)	20–59	Norms	60–94	Norms	20–59	Norms	60–94	Norms
	Total no. of subjects	11		2		12		2
	Writing	33.8±18.4	32.3	39.0	48.2	33.0±7.7	30.2	31.0±5.6	38.9
	Cards	11.7±7.6	4.5	11±1.4	6.1	8.9±5.5	4.8	9.0±2.8	5.5
	Small objects	13.7±8.1	6.2	16±12.7	7.9	12.9±10.9	6.0	11.5±2.1	6.6
	Simulated feeding	13.9±13.8	7.9	13.5±3.5	8.6	12.2±4.0	8.0	15.7±3.8	8.7
	Checkers	17.2±21.5	3.8	5.5±2.1	4.6	7.1±4.8	3.8	6.0±1.4	4.4
	Large light objects	7.2±3.8	3.2	8.5±2.1	3.9	5.5±1.8	3.3	6.5±0.7	3.4
	Large heavy objects	6.2±2.2	3.1	5.0	3.8	10.0±7.8	3.3	6.2±.35	3.8

NOTE. Values are mean seconds ± SD or as indicated.

The mean overall score on the MHQ was 63.48. (A score of 100 indicates better hand performance.) Of the 6 components in the MHQ (table 3), subjects reported the most difficulty in performing ADLs, such as turning a door knob, picking up a coin, holding a glass of water, turning a key in a lock, and holding a frying pan. Spearman correlation coefficients indicate a negative correlation between the JTHFT and MHQ (table 4). The time taken to complete the JTHFT activities decreased as the hand function score on the MHQ increased (P<.01). Significant negative correlations were found between MHQ ADLs and all tasks of the JTHFT. Similar significant correlations were found between the MHQ work performance score and all tasks of JTHFT with the exception of feeding. The MHQ hand function negatively correlated (P<.05) only with the task of picking up small objects and placing them in a small container and none of the other JTHFT tasks. MHQ pain correlated negatively (P<.01) with turning over 3×5-in cards, writing a sentence (P<.05), and picking up small objects. Also, MHQ aesthetics negatively correlated (P<.05) with picking up small objects. There were no significant correlations between MHQ patient satisfaction with hand function and any of the JTHFT tasks. There was a significant negative correlation between MHQ overall score and the task of writing, turning a card, picking up small objects, and moving empty large cans. There was a significant negative correlation between the total score on the JTHFT and the ADLs, pain, and work performance components of the MHQ.

Table 3. Mean Scores of the MHQ

	MHQ Scale	Mean
	Hand function	63±25
	ADLs	56±30
	Work performance	64±32
	Aesthetics	65±27
	Satisfaction	63±27
	Pain	69±26
	MHQ final score	63±23

NOTE. Values are mean ± SD.

Table 4. Correlation Between Time Taken to Complete JTHFT Test Items, Hand Function Measured by MHQ, and Hand Strength

	MHQ	JTHFT Test Items								Strength
		Write	Turn	Pick	Feed	Stack	Light	Heavy	Total	Grip	Pinch
	Hand function	−.209	−.368	−.395⁎	−.212	−.087	−.262	−.349	−.336	.253	.257
	ADLs	−.512†	−.627†	−.572†	−.403⁎	−.419⁎	−.498†	−.503†	−.732†	.319	.229
	Pain	−.425⁎	−.559†	−.437⁎	−.352	−.239	−.276	−.363	−.510†	.440⁎	.054
	Work	−.447⁎	−.669†	−.634†	−.298	−.441⁎	−.440⁎	−.483⁎	−.629†	.491†	.056
	Aesthetics	−.299	−.298	−.400⁎	−.264	−.136	−.333	−.349	−.306	.302	.329
	Satisfaction	−.115	−.279	−.357	−.161	.010	−.238	−.243	−.207	.277	.145
	Overall MHQ score	−.390⁎	−.552†	−.552†	−.365	−.287	−.407⁎	−.478⁎	−.534†	.453⁎	.221
	Grip strength	−.084	−.427⁎	−.462⁎	−.551†	−.363	−.325	−.718†	−.390⁎
	Pinch strength	−.010	−.131	−.148	−.340	−.017	−.291	−.444⁎	−.120

⁎ P=.05. † P=.01.

Discussion 

Burn care providers are aware that hand function is a strong predictor of physical QOL after a massive burn injury.9 This study was specifically designed to assess the impairments of deep full-thickness hand burns and to compare subjective reports and objective assessments of hand function. Although this sample was not random and likely represented a group of people who are highly motivated to maximize function, the data presented are of value because this is among the first reports to compare objective assessments with subjective reports.

Subjects in this sample had large burns (mean, 58% of TBSA), had long length of hospital stay (mean, 224d), and mostly had lived with their injuries for a number of years (mean, 16y). The sample clearly had very severe hand burns, with more than half of them having amputation of 1 or more digits. The most severe involvement was at the level of the PIP joint, with 50% of the amputations at the PIP joint, and 22% of digits with rupture of the extensor mechanism causing a boutonnière deformity. This was not a surprise finding, because the most commonly exposed joint in the burned hand is the PIP joint,17 and a boutonnière deformity at the PIP joint is the most common bone and joint defect.17

Loss of ROM was a clear impairment in these subjects, who had a mean range of loss of 90% total active motion in each digit. Forty percent of subjects had poor functional range with a total active motion of less than 180° (based on the total active motion rating scale). Significant decrease in strength (50% decreases) was seen for measurements of both grip and pinch. This is in contrast to normal pinch and grip strength seen in a study12 of patients with partial- and full-thickness hand burns. Despite these impairments, this patient population was still quite capable of performing most basic ADL skills. This reinforces a previous study,18 that showed that less than 9kg of grip strength is sufficient for functional hand use.

Even with partial amputation or loss of the extensor mechanisms, the intact flexor muscles facilitate function by allowing for a modified grasp. At the time of the study, 47% of subjects in this sample reported working full-time. This percentage did not differ significantly from the percentage of people working before burn injury. Therefore, patients with deep full-thickness hand burns are capable of achieving many functional goals. It is clear that patients have significant impairments and functional limitations, but despite these limitations, they are able to perform most daily activities. This is in contrast to full-thickness burns, which have been shown to have “excellent” outcomes2 and also to the view that deep full-thickness dorsal hand burns do poorly, regardless of the treatment.6

On the JTHFT, as expected, subjects were significantly slower than the general population. Women did better in writing, turning cards, picking up small objects, and moving empty large cans, and men did better with simulated feeding, stacking checkers, and moving heavy large cans. Although not scientifically tested, we observed that the women tended to have longer fingernails, which facilitated the fine motor tasks. A further observation was that men with larger hands were able to generate enough grip to lift heavy large cans, whereas most women had to use the palm to flip cans over and over and on to the test board.

A positive correlation of moderate strength between grip strength, work performance, and overall MHQ score found in this study confirmed the findings of Wahi Michener et al.10 Functionally, subjects reported the most difficulty in performing the MHQ ADL, a subcomponent of the MHQ that includes ADLs such as turning a door knob, picking up a coin, holding a glass of water, turning a key in a lock, and holding a frying pan. This replicates the findings of the JTHFT in this sample, with subjects having much more difficulty than population norms. Although hand function has been shown to predict physical QOL,9 this study did not find a correlation between life satisfaction and hand function. This can be attributed to the fact that satisfaction with life is multifaceted and influenced by the interaction of psychologic and physical variables.19

Several MHQ scales, especially the ADL and work performance subscales, and the overall MHQ score correlated with objective assessments of hand function as measured by the JTHFT. Subjects’ perceptions of hand function in this study corresponded with their abilities to actually perform most everyday activities. Therefore, obtaining subjective feedback from patients in addition to an objective evaluation of hand function can be a valuable resource in planning treatment. Physiologic measures such as total active motion and grip and pinch strengths, used along with standardized outcome measures can provide useful information regarding functional outcomes.

Conclusions 

Although deep full-thickness burn injuries involving the tendons are uncommon and comprise about 5% of hand burns,12 the impairment associated with this injury is the most significant limitation after a major burn injury. It is also true that the burns of the upper extremity need to be considered in the context of the whole patient.17 It is evident that hand burns and hand function cannot be evaluated in isolation. The shoulder, axilla, elbow, and wrist play a significant role in determining hand function. It must also be recognized that burn survivors can amazingly compensate for many aspects of this severe impairment. The burn team must be vigilant to salvage viable digits, protect vulnerable extensor mechanisms, and maximize MCP flexion. The next stage in the evaluation of deep full-thickness hand burns is to evaluate the relationship between treatment alternatives and outcomes. This must include pinning versus casting, new interventions with Integra to salvage tendons, and a variety of rehabilitation interventions. Because these injuries are relatively less common, it is essential that well-designed multicenter studies be appropriately funded to facilitate a better understanding of the limitations caused by deep full-thickness dorsal hand burns.