Low bone mineral density is not related to failure in femoral neck fracture patients treated with internal fixation

Figures & data

Figure 1. Flow chart of patient enrollment. DXA: Dual-energy X-ray absorptiometry; BMD: bone mineral density; HA: hemiarthroplasty; DHS: dynamic hip screw.

Table 1. Key patient demographics for 140 patients

	No failure	Failure	Total
Patients	70	70	140
Age (IQR)	82 (73–86)	79 (70–84)	80 (70–85)
Sex M / F	21 / 49	14 / 56	35 /105
Undisplaced fracture	32	10	42
Displaced fracture	38	60	98
Total hip T-score > –2.5	45	46	91
Total hip T-score ≤ –2.5	25	24	49

Figure 2. Assessment of implant positioning. A. Anterior-posterior view. B. Axial view.

Figure 3. A. Modified Garden’s alignment index, anterior-posterior angle through capital trabeculae and medial femoral cortex. B. Modified Garden’s alignment index, axial angulation of the femoral head center and midline of the femoral neck.

Figure 4. Kaplan-Meier hip survival according to fracture displacement and total hip BMD.

Table 2. Results from the extended stratified Cox regression^a

	Hazard ratio	95% CI	p-value
Low total hip BMD	0.8	0.5–1.5	0.5
Implant positioning	66	4–1,240	0.005
Quality of reduction	0.8	0.4–1.5	0.4
Sex	1.5	0.8–2.9	0.2
Age	1.6	0.8–3.3	0.2
Alcohol	1.6	0.6–4.3	0.4
Walking disability	1.0	0.6–1.8	0.9

^a n = 115 due to lack of one or more covariates.

Table 3. Results from a subgroup-based Cox regression analysis of the undisplaced fractures ^a

	Hazard ratio	95% CI	p-value
Low total hip BMD	6	0.5–74	0.1
Implant positioning	22	2–292	0.02
Sex	6	0.3–112	0.2
Age	0.3	0.1–2.4	0.3
Alcohol	0.5	0.1–3.8	0.5
Walking disability	0.1	0.1–1.0	0.05

^a n = 37 due to lack of one or more covariates.