Comparison of trabecular metal cups and titanium fiber-mesh cups in primary hip arthroplasty

Figures & data

Figure 1. Trilogy cup (left) and Monoblock cup (right).

Figure 2. Flow chart of patient recruitment and randomisation strategy.

Table 1. Double examination of 10 patients. The precision is presented as mean + 2.7 SD of the error from the double examinations (99% confidence limits for statistically significant migration/rotation)

	Cup migration
Migration
Medial-lateral (X)	0.11 mm
Proximal-distal (Y)	0.19 mm
Anterior-posterior (Z)	0.15 mm
Rotation
Transverse axis (X)	0.33°
Longitudinal axis (Y)	0.35°
Sagittal axis (Z)	0.45°

Table 2. Migration 2 years postoperatively. Values are mean with 95% confidence intervals

	Monoblock (n = 24)	Trilogy (n = 26)	p-value ^a
Translation, mm
Medial-lateral (x)	0.08 (−0.47 to 0.63)	0.13 (-0.24 to 0.51)	0.4
Proximal-distal (y)	0.08 (−0.22 to 0.38)	0.18 (-0.27 to 0.63)	0.2
Anterior-posterior (z)	0.06 (−0.20 to 0.32)	0.13 (-0.23 to 0.49)	0.3
Rotation, degrees
Transverse axis (x)	−0.01 (−0.11 to 0.12)	−0.60 (−0.72 to −0.48)	0.04
Longitudinal axis (y)	0.12 (−0.44 to 0.68)	0.44 (−0.92 to 1.8)	0.5
Sagittal axis (z)	−0.30 (−1.86 to 1.3)	−0.11 (−0.86 to 1.6)	0.4

^aANOVA.

Figure 3. Cup rotation.

Figure 4. Rotation along the x-axis of both cup types over time. Values are mean and SD.

Table 3. Change in BMD. Absolute values in g/cm² (95% confidence intervals)

	Region of interest (ROI)
Period (months)	1	2	3	4
Monoblock
0–12	–0.16 (–0.22 to –0.10)	–0.16 (–0.24 to –0.08)	–0.09 (–0.15 to –0.03)	–0.07 (–0.11 to –0.04)
12–24	–0.04 (–0.11 to 0.07)	–0.10 (–0.21 to 0.02)	0.00(–0.05 to 0.06)	0.00 (–0.03 to 0.03)
Total loss at 24 months	–0.19 (–0.23 to 0.04)	–0.26 (–0.37 to –0.15)	–0.09 (–0.13 to 0.05)	–0.08 (–0.12 to 0.04
Trilogy
0–12	–0.16 (–0.32 to 0.01)	–0.25 (–0.44 to –0.06)	–0.10 (–0.28 to 0.07)	–0.10 (–0.24 to 0.04)
12–24	–0.05 (–0.18 to 0.07)	–0.04 (–0.14 to 0.06)	–0.01 (–0.10 to 0.08)	–0.01 (–0.08 to 0.07)
Total loss at 24 months	–0.29 (–0.52 to –0.06)	–0.33 (–0.55 to –0.12)	–0.21 (–0.42 to 0.01)	–0.13 (–0.31 to 0.04)