No medium-term advantage of electrochemical deposition of hydroxyapatite in cementless femoral stems

Figures & data

Figure 1. Consort flow chart.

Figure 2. The postoperative, 3-month and 5-year radiographs from the patient that was excluded from RSA analysis. The stem seems to be undersized in the postoperative image. There is macroscopic subsidence from postoperatively to 3 months, but no visible changes thereafter, consistent with the RSA data.

Figure 3. BMD difference from the postoperative scans up to 5 years in all Gruen zones for each group.

Figure 4. BMD difference from the postoperative scans in Gruen zone 1 and 7.

Table 1. Percentage BMD changes (g/cm²) from the postoperative scans in BM and HA Taperloc stems. The upper half shows the bone remodelling rates per month, and the lower shows the total 5-year reduction

Gruen zone	BMD changes – BM		BMD changes – HA
	Mean	95% CI	Mean	95% CI	p-value
	2- to 5-year monthly remodeling rate (%)
G1	-0.1	-0.30 to 0.01	-0.1	-0.30 to 0.01	1.0
G2	0.03	-0.07 to 0.13	0.1	0.00 to 0.25	0.3
G3	-0.01	-0.09 to 0.08	0.03	-0.08 to 0.13	0.6
G4	-0.01	-0.07 to 0.05	-0.1	-0.14 to 0.01	0.3
G5	-0.1	-0.19 to -0.01	-0.09	-0.20 to 0.03	0.9
G6	0.08	-0.01 to 0.16	0.05	-0.06 to 0.15	0.6
G7	-0.1	-0.19 to -0.04	0.01	-0.08 to 0.10	0.04
5-year total reduction (%)
G1	-25		-20		1.0
G2	-13		-11		0.7
G3	-11		-7		0.3
G4	-12		-11		0.3
G5	-15		-16		0.4
G6	-9		-13		0.8
G7	-34		-31		0.6

Figure 5. Y-translation. Individual curves for each stem in both groups.

Figure 6. Y-rotation. Individual curves for each stem in both groups.

Table 2. Monthly rates for y-translation (subsidence), y-rotation (retroversion) and z-rotation (coronal rotation) during the early (0–3 months) and late (2–5 years) migration period

	Monthly rates – BM (n = 29)		Monthly rates – HA (n = 20)
	Mean	95% CI	Mean	95% CI	p-value
	Subsidence (mm) ^a
Early	0.11	0.07 to 0.15	0.10	0.06 to 0.14	0.6
Late	0.002	-0.003 to 0.006	0.001	-0.004 to 0.006	0.4
Retroversion (°) ^b
Early	0.17	0.11 to 0.23	0.06	0.01 to 0.12	0.006
Late	0.004	-0.001 to 0.009	0.005	-0.004 to 0.013	0.3
Coronal rotation (°)
Early	-0.04	-0.06 to -0.01	-0.02	-0.05 to 0	0.5
Late	0	-0.003 to 0.003	0	-0.002 to 0.005	0.3

a Precision 0.11 mm

b Precision 0.66°