Intramedullary Fixation Does Not Cause a Large Amount of Hidden Blood Loss in Elderly Patients with Intertrochanteric Fractures

Figures & data

Table 1 Demographic and Injury-Related Data of the Study Participants

Characteristics	Non-Operative Group (Group A) (n=133)	Delayed Surgery Group (Group B) (n=250)	Acute Surgery Group (Group C) (n=634)	Total (n=1017)	p-value^a
Demographic
Gender, n (%)					0.119
Male	50 (37.6%)	95 (38.0%)	200 (31.5%)	345 (33.9%)
Female	83 (62.4%)	155 (62.0%)	434 (68.5%)	672 (66.1%)
Age,years	79.5±8.0	78.3±8.4	78.3±8.5	78.4±8.4	0.275
BMI, n (%)					0.458
Normal (BMI<24 kg/m^2)	89 (66.9%)	148 (59.2%)	368 (58.0%)	605 (59.5%)
Overweight (24≤BMI<28 kg/m^2)	34 (25.6%)	79 (31.6%)	204 (32.2%)	317 (31.2%)
Obesity (BMI≥28 kg/m^2)	10 (7.5%)	23 (9.2%)	62 (9.8%)	95 (9.3%)
Injury-related data
Fracture type, n (%)					0.283
Stable (A1.1–A2.1)	91 (68.4%)	152 (60.8%)	390 (61.5%)	633 (62.2%)
Unstable (A2.2–A3.3)	42 (31.6%)	98 (39.2%)	244 (38.5%)	384 (37.8%)
Injury mechanism, n (%)					0.484
Fall injury	130 (97.7%)	241 (96.4%)	620 (97.8%)	991 (97.4%)
Violent injury	3 (2.3%)	9 (3.6%)	14 (2.2%)	26 (2.6%)

Notes: Plus–minus values are means±SD; ^aIn gender, fracture type, injury mechanism, and BMI, p-values are the results of pearson chi-square tests. In age, p-value is the result of ANOVA test on mean.

Abbreviations: NA, not available; BMI, body mass index; IQR, interquartile range.

Figure 1 Flow diagram of included patients.

Table 2 Comorbidities of the Study Participants

Comorbidities	Non-Operative Group (Group A) (n=133)	Delayed Surgery Group (Group B) (n=250)	Acute Surgery Group (Group C) (n=634)	Total (n=1,017)	p-value ^a
Hypertension					0.274
Yes	62 (46.6%)	135 (54.0%)	309 (48.7%)	506 (49.8%)
No	71 (53.4%)	115 (46.0%)	325 (51.3%)	511 (50.2%)
Diabetes					0.002*
Yes	36 (27.1%)	81 (32.4%)	134 (21.1%)	251 (24.7%)
No	97 (72.9%)	169 (67.6%)	500 (78.9%)	766 (75.3%)
Coronary heart disease					0.001*
Yes	43 (32.3%)	82 (32.8%)	139 (21.9%)	264 (26.0%)
No	90 (67.7%)	168 (67.2%)	495 (78.1%)	753 (74.0%)
Carotid plaque/atherosclerosis					0.963
Yes	41 (30.8%)	78 (31.2%)	192 (30.3%)	311 (30.6%)
No	92 (69.2%)	172 (68.8%)	442 (69.7%)	706 (69.4%)
Cerebrovascular disease					0.022*
Yes	53 (39.8%)	91 (36.4%)	187 (29.5%)	331 (32.5%)
No	80 (60.2%)	159 (63.6%)	447 (70.5%)	686 (67.5%)
Delirium					0.580
Yes	9 (6.8%)	11 (4.4%)	37 (5.8%)	57 (5.6%)
No	124 (93.2%)	239 (95.6%)	597 (94.2%)	960 (94.4%)
Arrhythmia					0.001*
Yes	30 (22.6%)	34 (13.6%)	69 (10.9%)	133 (13.1%)
No	103 (77.4%)	216 (86.4%)	565 (89.1%)	884 (86.9%)
Myocardial infarction					0.248
Yes	6 (4.5%)	11 (4.4%)	16 (2.5%)	33 (3.2%)
No	127 (95.5%)	239 (95.6%)	618 (97.5%)	984 (96.8%)
Heart failure					<0.001*
Yes	16 (12.0%)	12 (4.8%)	12 (1.9%)	40 (3.9%)
No	117 (88.0%)	238 (95.2%)	622 (98.1%)	977 (96.1%)
Valvular heart disease					0.307
Yes	3 (2.3%)	8 (3.2%)	10 (1.6%)	21 (2.1%)
No	130 (97.7%)	242 (96.8%)	624 (98.4%)	996 (97.9%)
Lung disease					<0.001*
Yes	42 (31.6%)	53 (21.2%)	92 (14.5%)	187 (18.4%)
No	91 (68.4%)	197 (78.8%)	542 (85.5%)	830 (81.6%)
Respiratory failure					0.021*
Yes	5 (3.8%)	9 (3.6%)	7 (1.1%)	21 (2.1%)
No	128 (96.2%)	241 (96.4%)	627 (98.9%)	996 (97.9%)
Hepatobiliary disease					0.659
Yes	4 (3.0%)	8 (3.2%)	14 (2.2%)	26 (2.6%)
No	129 (97.0%)	242 (96.8%)	620 (97.8%)	991 (97.4%)
Digestive system disease					0.624
Yes	4 (3.0%)	4 (1.6%)	16 (2.5%)	24 (2.4%)
No	129 (97.0%)	246 (98.4%)	618 (97.5%)	993 (97.6%)
Renal dysfunction					0.918
Yes	6 (4.5%)	13 (5.2%)	29 (4.6%)	48 (4.7%)
No	127 (95.5%)	237 (94.8%)	605 (95.4%)	969 (95.3%)
Tumor					0.616
Yes	2 (1.5%)	7 (2.8%)	12 (1.9%)	21 (2.1%)
No	131 (98.5%)	243 (97.2%)	622 (98.1%)	996 (97.9%)
Hypoproteinemia					0.165
Yes	22 (16.5%)	58 (23.2%)	153 (24.1%)	233 (22.9%)
No	111 (83.5%)	19 2(76.8%)	481 (75.9%)	78 4(77.1%)

Notes: Values are presented as number (%). *p<0.05, statistical significance. ^ap- values are the results of Pearson chi-square tests.

Table 3 The Maximum Hidden Blood Loss Calculated During Hospitalization, Perioperative Hemoglobin Values, Operation-Related Data, and Transfusion Data of 1,017 Patients with Intertrochanteric Fractures^a

Variables	Non-Operative Group (Group A) (n=133)	Delayed Surgery Group (Group B) (n=250)	Acute Surgery Group (Group C) (n=634)	Total (n=1,017)	p-value^b
HBLmax, mL IQR	584.1 (407.1, 875.7)	780.8 (510.7, 1,131.8)	649.2 (453.3, 972.1)	662.3 (457.5, 1,010.6)	<0.001*
Hb values, g/L
Hbadm	105.3±20.8^c	106.6±21.4^c	110.8±17.9	109.0±19.3	0.001*
Hblow	93.8±18.2	90.9±16.8	94.8±15.2^d	93.7±16.1	0.005*
Hbdis	106.7±14.7	104.0±13.2	104.2±12.4	104.5±12.9	0.112
Hb decrease between Hbadm and Hblow	11.7 (0, 61.7)	15.7 (0, 65.1)^e	16.0 (0, 71.6)^e	15.4 (0, 71.6)	0.002*
Hb decrease between Hbadm and Hbdis	−1.4 (−86.1, 61.7)^c	2.6 (−60.7, 62.7)^c	6.5 (−61.2, 54.0)	4.5 (−86.1, 62.7)	<0.001*
Operation-related data
ASA grade, n (%)					<0.001*
I	8 (6.0%)	22 (8.8%)	103 (16.2%)	133 (13.1%)
II	35 (26.3%)	88 (35.2%)	274 (43.2%)	397 (39.0%)
III	46 (34.6%)	108 (43.2%)	191 (30.1%)	345 (33.9%)
IV	41 (30.8%)	25 (10.0%)	60 (9.5%)	126 (12.4%)
V	3 (2.3%)	7 (2.8%)	6 (0.9%)	16 (1.6%)
Bone traction before surgery, n (%)					<0.001*
No	100 (75.2%)	179 (71.6%)	529 (83.4%)	808 (79.4%)
Yes	33 (24.8%)	71 (28.4%)	105 (16.6%)	209 (20.6%)
Duration of operation, min	NA	105.4±35.6	99.6±34.0	101.2±34.5	0.025*
Method of anesthesia, n (%)					0.116
General anesthesia	NA	98 (39.2%)	296 (46.7%)	394 (44.6%)
Spinal anesthesia	NA	25 (10.0%)	50 (7.9%)	75 (8.5%)
Combined spinal-epidural anesthesia	NA	127 (50.8%)	288 (45.4%)	415 (46.9%)
Intra-operative blood loss, mL IQR	NA	200 (150, 400)	100 (200, 300)	100 (200, 300)	0.001*
Red blood cell transfusion
Yes	93 (69.9%)	195 (78%)	455 (71.8%)	743 (73.1%)	0.116
No	40 (30.1%)	55 (22%)	179 (28.2%)	274 (26.9%)
Blood transfusion volume, units IQR	2 (0, 4)^d	4 (2, 6)	2 (0, 4)^d	2 (0, 6)	0.001*

Notes: Plus–minus values are means±SD. *p<0.05, statistical significance. ^aValues are presented as the means±SD for normally distributed data; HBL_max and blood transfusion volume are presented as the median (interquartile range); Two variables of perioperative hemoglobin decreased values and intra-operative blood loss are presented as the median (range); ASA grade, bone traction before surgery, method of anesthesia, and red blood cell transfusion is presented as the number (%). All the red blood cells transfusions are assumed to contain the same number of cells and a unit of red blood cells is approximately 200 mL. ^bIn Hb_adm, Hb_low, and Hb_dis, p-values are the results of ANOVA tests on mean. In HBL_max, Hb drop between admission and the lowest recorded, Hb drop between admission and discharge and blood transfusion volume, p-values are the results of Kruskal–Wallis H-tests on median. In ASA grade, bone traction before surgery, method of anesthesia, and red blood cell transfusion, p-value are the results of Pearson chi-square tests. In duration of operation, p-value is the result of two independent sample t-test on mean. In intra-operative blood loss, p-value is the result of Wilcoxon rank-sum test on median. ^cSignificant differences in statistics compared with group C. ^dSignificant differences in statistics compared with group B. ^eSignificant differences in statistics compared with group A.

Abbreviations: HBL, hidden blood loss; ASA, American Society of Anesthesiologists; Hb, hemoglobin; IQR, interquartile range.

Table 4 Multiple Linear Regression Analysis of Association Between Risk Factors and the Maximum Hidden Blood Loss Calculated During Hospitalization in 1017 Patients

Variables^a	β	Β^’	95% CI	p-value
Constant	386.237		(288.221, 484.253)	<0.001*
Male	198.139	0.229	(141.215, 238.974)	<0.001*
Age	−1.760	−0.036	(−4.870, 1.350)	0.267
Unstable fracture	197.314	0.233	(149.561, 245.068)	<0.001*
ASA-grade
2	32.547	0.039	(−41.013, 106.106)	0.385
3	72.321	0.084	(−3.498, 148.140)	0.062
4	18.435	0.015	(−75.828, 112.699)	0.701
5	144.980	0.044	(−50.241, 340.201)	0.145
Violent injury	−4.204	−0.002	(−152.713, 144.304)	0.956
Bone traction before surgery	30.871	0.030	(−28.447, 90.189)	0.307
BMI
Overweight (24≤BMI<28 kg/m^2)	57.685	0.065	(6.515, 108.854)	0.027*
Obesity (BMI≥28 kg/m^2)	97.989	0.070	(16.261, 179.716)	0.019*
Grouping
Group B	122.312	0.128	(41.786, 202.838)	0.003*
Group C	68.708	0.081	(−3.201, 140.617)	0.061
Method of anesthesia
Spinal anesthesia	−5.885	−0.004	(−114.631, 102.862)	0.915
Combined spinal-epidural anesthesia	16.027	0.020	(−42.609, 74.663)	0.592
Duration of operation	−0.336	−0.029	(−1.262, 0.591)	0.477
Intra-operative blood loss	−0.087	−0.034	(−0.294, 0.120)	0.411
Blood transfusion volume	21.822	0.228	(16.327, 27.317)	<0.001*
Comorbidities
Hypertension	16.172	0.020	(−35.212, 67.557)	0.537
Diabetes	36.972	0.039	(−18.301, 92.244)	0.190
Coronary heart disease	2.546	0.003	(−54.131, 59.224)	0.930
Carotid plaque/atherosclerosis	−2.553	−0.003	(−59.916, 54.811)	0.930
Cerebrovascular disease	−34.057	−0.039	(−88.779, 20.665)	0.222
Delirium	−36.920	−0.021	(−140.276, 66.437)	0.483
Arrhythmia	−28.046	−0.023	(−99.083, 42.991)	0.439
Myocardial infarction	75.858	0.033	(−58.472, 210.188)	0.268
Heart failure	−9.902	−0.005	(−137.800, 117.995)	0.879
Valvular heart disease	102.928	0.034	(−68.813, 274.669)	0.240
Lung disease	−7.148	−0.007	(−70.802, 56.506)	0.826
Respiratory failure	−54.919	−0.019	(−240.032, 130.194)	0.561
Hepatobiliary disease	31.705	0.012	(−116.029, 179.439)	0.674
Digestive system disease	47.396	0.018	(−105.221, 200.012)	0.542
Renal dysfunction	−11.257	−0.006	(−125.816, 103.301)	0.847
Tumor	−26.176	−0.009	(−193.585, 141.233)	0.759
Hypoproteinemia	45.051	0.046	(−18.025, 108.127)	0.161
DVT
Intermuscular vein thrombosis	25.355	0.030	(−24.721, 75.430)	0.321
Posterior tibial vein thrombosis	112.614	0.070	(19.240, 205.987)	0.018*
Popliteal vein thrombosis	−38.236	−0.015	(−183.269, 106.796)	0.605
Superficial femoral vein thrombosis	−18.188	−0.006	(−193.940, 157.564)	0.839
Common femoral vein thrombosis	0.758	0.000	(−139.202, 140.718)	0.992

Notes: *p<0.05, statistical significance. ^aIn the multi-category variables, ASA-grade I, normal BMI, no DVT, and patients in conservative treatment group (group A) were chosen as standard, others were converted into dummy variables.

Abbreviations: ASA, American Society of Anesthesiologists; BMI, body mass index; DVT, deep venous thrombosis.

Figure 2 Kaplan–Meier survival curves for elderly patients with intertrochanteric fractures. The Kaplan–Meier survival curve of patients without surgery was significantly lower than that of surgical patients (p<0.001, log-rank). Within 1 year after injury, patients treated nonoperatively had a risk of death at 1 month that was 3.2-times as high, a risk of death at 3 months that was 6.6-times as high, a risk of death at 6 months that was 8.2-times as high, a risk of death at 9 months that was 5.3-times as high, and a risk of death at 12 months that was 4.2-times as high as the risk compared with the patients who received operations. Higher mortality was also obtained in patients with surgical delay than acute surgery patients (p=0.001, log-rank).