A new measurement for posterior tilt predicts reoperation in undisplaced femoral neck fractures

Figures & data

Figure 1. Preoperative anterior-posterior and lateral radiographs of a 60-year-old male patient who sustained a Garden I–II femoral neck fracture. The posterior tilt is measured as the angle (α) between the mid-collum line (MCL) and the radius collum line (RCL), which is drawn from the center (c) of the caput circle to the crossing of the caput circle and the mid-collum line.

Figure 2. Distribution of posterior tilt and rates of reoperation in the 113 patients who were operated on with internal fixation for a Garden I–II femoral neck fracture. Numbers in parenthesis are (reoperated patients / patients) in the relevant group.

Table 1. Data for the 113 patients operated on with internal fixation for a Garden I–II femoral neck fracture

	Posterior tilt < 20 °	Posterior tilt ≥ 20 °	p-value
Number of patients ^a	88 (100)	25 (100)
Female sex ^a	66 (75)	16 (64)	0.3
Age (years) ^b	80 (75–86)	74 (66–87)	0.09
Prefracture NMS ^c 0–5 ^a	40 (46)	10 (40)	0.6
ASA ^d score III–IV ^a	37 (42)	10 (40)	0.9
Low cognitive function ^a	27 (31)	4 (16)	0.1
> 1 day from admission to operation ^a	8 (9)	1 (4)	0.4
Senior surgeon procedure ^a	70 (80)	20 (80)	1
Postoperative posterior tilt (degrees) ^b	6 (0–10)	7 (2–14)	0.2
Implant distance to calcar (mm) ^b	6 (4–8)	6 (5–8)	0.3
Implant distance to posterior cortex (mm) ^b	5 (3–7)	4 (2–6)	0.4
Reoperation within 1 year ^a	12 (14)	14 (56)	< 0.001

^a Number of patients (percentage) and p-values determined with the chi-square test.

^b Median (interquartile range) and p-values derived with the Mann-Whitney test.

^cNMS: new mobility score.

^d ASA: American Society of Anesthesiologists.

Table 2. Relationship between reoperation within 1 year postoperatively and patient characteristics for the 113 patients operated on with internal fixation for a Garden I–II femoral neck fracture

		Reoperation within 1 year postoperatively
		Univariate analysis		Multivariate analysis
		Odds ratio (95% CI)	p-value	Odds ratio (95% CI)	p-value
Female sex ^a	82 (73)	3.6 (1–13)	0.04	3.0 (0.7–13)	0.1
Age (years) ^b	79 (72–86)		0.9	1.0 (1.0–1.0)	0.4
Prefracture NMS ^c 0–5 ^a	50 (44)	0.5 (0.2–1.2)	0.1	0.5 (0.2–1.9)	0.3
ASA ^d score III–IV ^a	47 (42)	0.7 (0.3–1.7)	0.4	0.8 (0.3–2.5)	0.7
Low cognitive function ^a	31 (27)	0.4 (0.1–1.3)	0.1	0.9 (0.2–3.6)	0.8
> 1 day from admission to operation ^a	9 (8)	1.0 (0.2–4.9)	1	1.3 (0.2–8.7)	0.8
Senior surgeon procedure ^a	90 (80)	0.8 (0.3–2.3)	0.7	0.8 (0.2–2.7)	0.7
Postoperative posterior tilt (degrees) ^b	6 (0–11)		0.7	1.0 (0.9–1.1)	0.4
Implant distance to calcar (mm) ^b	6 (4–8)		0.2	0.9 (0.7–1.1)	0.2
Implant distance to posterior cortex (mm) ^b	5 (3–7)		0.3	1.0 (0.8–1.1)	0.6
Posterior tilt ≥ 20° ^a	25 (22)	8.0 (3–22)	< 0.001	13 (4–46)	< 0.001

^a–dSee Table 1