Preparation of the femoral bone cavity in cementless stems: broaching versus compaction

Figures & data

Table 1. Descriptive data regarding arthroplasty components

	Broaching	Compaction
Variable	(n = 20)	(n = 20)
Size of femoral stem^b	12 (11–14)	12 (10–14)
Size of acetabular cup^b	60 (54–68)	60 (54–68)
Implant side, right/left	9/11	11/9

a Mean (range)

Figure 1. The 2 different instrument configurations used in this study: smooth tamp used for the compaction technique (left) and sharped rasp used for the broaching technique (right).

Table 2. Measurement of error for the RSA double-examination stereo radiographs (n = 14), for translations and rotations

	Translation, mm				Rotation, degrees
Axis	x	y	z	TT^a	x	y	z	TR^b
Mean diff.^c	−0.06	−0.24	0.16	0.11	−0.09	0.32	−0.12	−0.16
SDdiff. ^d	0.47	0.71	0.59	0.83	0.51	1.26	0.39	0.84
CR^e	0.92	1.39	1.16	1.63	0.99	2.47	0.76	1.65

a The total translation was calculated using the 3-D Pythagorean theorem (TT = √(x² + y² + z²)).

b The total rotation was calculated using the 3-D Pythagorean theorem (TR = √(x² + y² + z²)).

c Mean difference represents the systematic error of the system.

d SD_diff. is the random variation in the method comparing the double examinations.

e Coefficient of repeatability (1.96 × SD_diff.) reflects the precision of the system on the individual basis.

Table 3. Signed migrations of the Bi-metric femoral stem as mean (95% CI) along and about the 3 orthogonal axes, measured with RSA at 6 weeks, 12 weeks, 1 year, 2 years, and 5 years after surgery

	Rotations, degrees			Rotations, degrees
	Broaching	Compaction		Broaching	Compaction
Medial-lateral (x-axis)			Anterior/posterior tilt (x-axis)
6 weeks	0.07 (0.006 to 0.13)	0.19 (0.08 to 0.30)	6 weeks	−0.09 (−0.45 to 0.28)	0.01 (−0.20 to 0.23)
12 weeks	0.06 (−0.07 to 0.20)	0.17 (0.03 to 0.30)	12 weeks	−0.04 (−0.31 to 0.22)	0.08 (−1.70 to 0.03)
1 year	0.07 (−0.05 to 0.18)	0.19 (0.05 to 0.33)	1 year	−0.13 (−0.49 to 0.23)	−0.01 (−0.35 to 0.33)
2 years	−0.02 (−0.20 to 0.15)	0.07 (−0.22 to 0.35)	2 years	−0.13 (−0.63 to 0.36)	0.01 (−0.49 to 0.53)
5 years	−0.01 (−0.15 to 0.13)	0.16 (−0.003 to 0.32)	5 years	−0.40 (−0.82 to −0.05)	−0.21 (−0.62 to 0.26)
Proximal-distal (y-axis)			Anteversion/retroversion (y-axis)
6 weeks	−1.06 (−1.85 to −0.27)	−0.90 (−1.62 to −0.16)	6 weeks	1.99 (0.53 to 3.47)	1.89 (0.69 to 3.10)
12 weeks	−1.05 (−1.91 to −0.19)	−0.96 (−1.72 to −0.19)	12 weeks	1.71 (0.24 to 3.18)	1.78 (0.50 to 3.08)
1 year	−0.99 (−1.81 to −0.18)	−0.82 (−1.61 to −0.04)	1 year	1.99 (0.44 to 3.56)	1.93 (0.71 to 3.15)
2 years	−0.54 (−1.10 to 0.20)	−0.32 (−0.67 to 0.03)	2 years	0.91 (0.28 to 1.54)	1.08 (0.18 to 2.09)
5 years	−0.88 (−1.77 to 0.003)	−0.67 (−1.45 to 0.12)	5 years	1.67 (0.13 to 3.50)	1.61 (0.37 to 2.86)
Anterior-posterior (z-axis)			Valgus/varus tilt (z-axis)
6 weeks	−0.46 (−0.74 to −0.17)	−0.37 (−0.66 to 0.07)	6 weeks	−0.18 (−0.29 to −0.06)	−0.24 (−0.36 to −0.13)
12 weeks	−0.32 (−0.65 to 0.007)	−0.41 (−0.60 to −0.21)	12 weeks	−0.16 (−0.27 to −0.04)	−0.24 (−0.40 to −0.09)
1 year	−0.41 (−0.78 to −0.03)	−0.37 (−0.61 to −0.14)	1 year	−0.24 (−0.45 to −0.04)	−0.25 (−0.43 to −0.05)
2 years	−0.11 (−0.14 to −0.02)	−0.20 (−0.53 to −0.12)	2 years	−0.15 (−0.32 to −0.02)	−0.04 (−0.32 to 0.25)
5 years	−0.18 (−0.61 to −0.03)	−0.11 (−0.37 to −0.14)	5 years	−0.39 (−0.68 to −0.11)	−0.30 (−0.51 to −0.09)

Table 4. Bone mineral density in the femoral Gruen zones, as mean (95% CI) percentage of baseline values at 1, 2, and 5 years

Femoral zone	Broaching	Compaction
Gruen 1
1 year	103 (94–113)	93 (86–99)
2 years	102 (94–110)	93 (86–100)
5 years	100 (91–109)	93 (84–101)
Gruen 2
1 year	95 (86–105)	94 (86–101)
2 years	92 (87–98)	91 (85–98)
5 years	93 (84–102)	95 (87–102)
Gruen 3
1 year	103 (96–110)	95 (99–101)
2 years	101 (94–108)	93 (88–97)
5 years	103 (94–112)	98 (93–104)
Gruen 4
1 year	101 (98–106)	97 (93–101)
2 years	102 (96–107)	97 (94–101)
5 years	102 (95–109)	100 (95–105)
Gruen 5
1 year	108 (95–111)	102 (94–111)
2 years	102 (96–109)	102 (96–107)
5 years	103 (96–110)	104 (97–113)
Gruen 6
1 year	92 (83–102)	93 (87–99)
2 years	90 (81–99)	92 (85–98)
5 years	87 (76–97)	92 (83–101)
Gruen 7
1 year	76 (66–86)	72 (66–77)
2 years	71 (63–78)	69 (63–75)
5 years	67 (59–76)	68 (60–76)
Mean for all zones
1 year	96 (90–103)	92 (88–97)
2 years	94 (90–98)	91 (87–95)
5 years	93 (88–99)	93 (87–98)

Figure 2. CONSORT flow diagram showing the inclusion/exclusion process and follow-up until 5 years.

Figure 3. Medio-lateral migration (in mm) illustrated as a pairwise comparison of broaching and compaction at 6 weeks, 12 weeks, 1 year, 2 years, and 5 years after surgery.

Figure 4. Total rotations and total translations measured at 6 weeks, 12 weeks, 1 year, 2 years, and 5 years.