Large femoral bone loss after hip revision using the uncemented proximally porous-coated Bi-Metric prosthesis

Figures & data

Figure 1. The proximally hydroxyapatite-coated Bi-Metric modular femoral stem. The prosthesis is tapered in 3 dimensions.

Table 1. Femoral bone defects at revision (22 hips)

Type	Gustilo and Pasternak	Endo-Klinik
I	6	1
II	16	17
III	0	4
IV	0	0

Figure 2. Radiographic findings in the different Gruen regions. Linear osteolysis at revision and remodeling after the rearthroplasty.

Table 2. Bone remodeling at follow-up (22 hips)

Stem stability parameters
Fixated stems	22
Subsidence (maximum 7 mm)	2
Change in varus-valgus alignment	0
Spot welds	12
Stress-shielding parameters
Calcar resorption	8
Calcar “round-off”	2
Distal cortical hypertrophy (1–4 mm)	6
Bone remodeling parameters
Osteolysis at revision	21
Regression of osteolysis	19
Newly formed osteolysis	1
Unspecific parameters
Pedestal formation	16
Reactive lines	7
Heterotopic ossification
grade 1	6
grade 2	2
grade 3	1
grade 4	0

Figure 3. Percentage side difference in BMD in different Gruen regions after the rearthroplasty. Median values (25–75 percentiles) are given. An asterisk indicates a difference between sides (p < 0.05).