Risk Factors for Anterior Cortical Impingement of Short Cephalomedullary Nail in Chinese Elderly Patients with Intertrochanteric Fracture

Figures & data

Figure 1 Flowchart for inclusion and exclusion of patients.

Table 1 Baseline Characteristics among Patients with Impinged and Matched Group (Mean±SD)

Parameters	Impinged Groups (n=51)	Matched Groups (n=43)	P-value
Gender			0.041*
Male	10 (19.6%)	17 (39.5%)
Female	41 (80.4%)	26 (60.5%)
Age (years)	80.12±10.42	79.88±8.44	0.905
Male	80.18±9.61	78.70±6.83	0.646
Female	80.08±11.10	80.17±8.45	0.971
Suffered limb
Left	24 (47.1%)	21 (48.8%)	0.514
Right	27 (52.9%)	22 (51.2%)
Height (cm)	1.62±0.07	1.61±0.07	0.511
Male	1.68±0.05	1.71±0.05	0.207
Female	1.58±0.05	1.59±0.05	0.676
Weight (kg)	60.76±13.10	61.14±12.74	0.887
Male	63.15±9.56	66.50±9.71	0.395
Female	59.19±14.93	59.83±13.14	0.859
BMI (kg/m^2)	23.12±4.74	23.63±4.95	0.615
Male	22.40±3.38	22.77±2.94	0.772
Female	23.57±5.47	23.84±5.34	0.775

Note: *Statistical significance was considered when P<0.05.

Abbreviation: BMI, body mass index.

Table 2 Difference between Two Groups of Clinical and Radiographic Parameters (Mean±SD)

Parameters	Impinged Groups (n=51)	Matched Groups (n=43)	P-value
Percentage of nail length			0.001*
170	2 (3.8%)	12 (26.7%)
200	39 (73.6%)	30 (66.7%)
240	12 (22.6%)	3 (6.6%)
Entry point			0.386
Anterior	2 (3.9%)	3 (7.0%)
Middle	38 (74.5%)	35 (81.4%)
Posterior	11 (21.6%)	5 (11.6%)
ASA score			0.92
I	18 (35.3%)	14 (32.6%)
II	17 (33.3%)	13 (30.2%)
III	10 (19.6%)	11 (25.6%)
IV	6 (11.8%)	5 (11.6%)
Singh index			0.837
I	22 (43.1%)	23 (53.5%)
II	15 (29.4%)	10 (23.3%)
III	6 (11.8%)	3 (6.9%)
IV	6 (11.8%)	5 (11.6%)
V	2 (3.9%)	2 (4.7%)
Fracture classification			0.364
Type of A1	13 (25.5%)	14 (32.6%)
Type of A2	36 (70.6%)	25 (58.1%)
Type of A3	2 (3.9%)	4 (9.3%)
Reduction quality			0.799
Good	23 (45.1%)	20 (46.5%)
Acceptable	21 (41.2%)	19 (44.2%)
Poor	7 (13.7%)	4 (9.3%)
Implantation			0.216
PFNA	43 (84.3%)	36 (83.7%)
Intertan	2 (3.9%)	5 (11.6%)
TFNA	5 (9.8%)	2 (4.7%)
Gamma3	1 (2%)	0 (0%)
TAD (mm)	21.08±5.61	21.45±7.14	0.33
Length of stay (days)	11.17±15.59	8.79±3.02	0.781
Implantation failure	7 (13.7%)	1 (2.3%)	0.067

Note: *Statistical significance was considered when P<0.05.

Abbreviations: PFNA, proximal femoral nail antirotation; TFNA, trochanteric femoral nail antirotation; TAD, tip apex distance.

Table 3 Comparison between Clinical and Radiographic Parameters among the Impinged and Matched Group in Male Patients (Mean±SD)

Parameters	Impinged Groups (n=0)	Matched Groups (n=17)	P-value
Percentage of nail length			0.506
170	0	2 (11.8%)
200	9 (90%)	14 (82.3%)
240	1 (10%)	1 (5.9 %)
Entry point			0.704
Anterior	1 (10%)	3 (17.6%)
Middle	6 (60%)	11 (64.8%)
Posterior	3 (30%)	3 (17.6%)
ASA score			0.691
I	4 (40%)	6 (35.3%)
II	4 (40%)	5 (29.4%)
III	1 (10%)	5 (29.4%)
IV	1 (10%)	1 (5.9 %)
Singh index			0.391
I	5 (50%)	9 (52.9 %)
II	4 (40%)	3 (17.6%)
III	1 (10%)	2 (11.9%)
IV	0	3 (17.6%)
V	0	0
Fracture classification			0.31
Type of A1	3 (30%)	2 (11.8 %)
Type of A2	7 (70%)	13 (76.4%)
Type of A3	0	2 (11.8%)
Reduction quality			0.496
Good	3 (30%)	6 (35.3%)
Acceptable	4 (40%)	9 (52.9%)
Poor	3 (30%)	2 (11.8%)
Implantation			0.371
PFNA	10 (100 %)	14 (82.3%)
Intertan	0	2 (11.8%)
TFNA	0	1 (5.9 %)
Gamma3	0	0
TAD (mm)	25.25±6.78	23.66±8.08	0.607
Length of stay (days)	18.70±34.94	7.65±3.12	0.358
Implantation failure	2 (20%)	0	0.128

Abbreviations: PFNA, proximal femoral nail antirotation; TFNA, trochanteric femoral nail antirotation; TAD, tip apex distance.

Table 4 Comparison between Clinical and Radiographic Parameters among the Impinged and Matched Group in Female Patients (Mean±SD)

Parameters	Impinged Groups (n=41)	Matched Groups (n=26)	P-value
Percentage of nail length			0.002*
170	1 (2.4%)	8 (30.8%)
200	29 (70.8%)	16 (61.5%)
240	11 (26.8%)	2 (7.7%)
Entry point			0.285
Anterior	1 (2.4%)	0
Middle	32 (78.0%)	24 (92.3%)
Posterior	8 (19.5%)	2 (7.7%)
ASA score			0.979
I	14 (34.1%)	8 (30.8%)
II	13 (31.7%)	8 (30.8%)
III	9 (22%)	6 (23.0%)
IV	5 (12.2%)	4 (15.4%)
Singh index			0.623
I	17 (41.5%)	14 (53.8%)
II	11 (26.8%)	7 (27.0%)
III	5 (12.2%)	1 (3.8%)
IV	6 (14.6%)	2 (7.7%)
V	2 (4.9%)	2 (7.7%)
Fracture classification			0.13
Type of A1	10 (24.4%)	12 (46.2%)
Type of A2	29 (70.7%)	12 (46.2%)
Type of A3	2 (4.9%)	2 (7.6%)
Reduction quality			0.909
Good	20 (48.8%)	14 (53.8%)
Acceptable	17 (41.4%)	10 (38.5%)
Poor	4 (9.8%)	2 (7.7%)
Implantation			0.28
PFNA	33 (80.5%)	21 (80.8%)
Intertan	2 (4.9%)	4 (15.4%)
TFNA	5 (12.2%)	1 (3.8%)
Gamma3	1 (2.4%)	0
TAD (mm)	20.06±4.86	19.99±6.18	0.961
Length of stay (days)	9.32±3.42	9.54±2.76	0.782
Implantation failure	5 (12.2%)	1 (3.8%)	0.392

Note: *Statistical significance was considered when P<0.05.

Abbreviations: PFNA, proximal femoral nail antirotation; TFNA, trochanteric femoral nail antirotation; TAD, tip apex distance.

Figure 2 (A) Preoperative X-ray showing intertrochanteric fracture. (B) Postoperative X-ray showing poor reduction, the lateral position shows that the anterior cortex of the femur was obviously cortical encroachment. (C) One month later, the patient fell down resulting in fracture around the intramedullary nail of the femoral shaft.

Figure 3 (A) Preoperative X-ray showing intertrochanteric fracture. (B) Postoperative X-ray showing reduction was acceptable. The lateral position showed the anterior cortex of the femur was obviously cortical encroachment. (C) The cut out of lag screw was found at one year of postoperative follow-up.

Table 5 Risk Factors for Cortical Impingement by Logistic Regression

	Parameter	Odds Ratio	95% Confidence Interval	P-value
Total	Gender	2.662	1.010–7.018	0.0477
	Length of nail	1.047	1.016–1.079	0.0031
Female	Length of nail	1.051	1.015–1.089	0.0053