Trabecular metal tibial knee component still stable at 10 years

Figures & data

Table 1. Flow chart of the patients

	Trabecular metal		NexGen cemented
	Patients	Knees	Patients	Knees
Initially operated	22	26	19	21
Women: men	11: 11		12: 7
Losses up to 2-year follow-up
No postop. RSA	1	1
Revision (infection)	1	1
Dementia			1	1
Available at 2 years	20	24	18	20
Losses between 2- and 5-year follow-up
Deceased	1	1
Moved abroad	1	1
Available at 5 years	18	22	18	20
Losses between 5- and 10-year follow-up
Too ill to attend	1	2
Refused to attend	1	1
Revision (instability)			1	2
Available at 10 years	16	19	17	18
Women: men	9: 7		10: 7

Figure 1. Maximum subsidence of the tibial component in the 2 groups with postoperative and 3-month examinations as reference. Mean with 95% CI (whiskers).

Figure 2. Maximum total point motion (MTPM) of the tibial component in the 2 groups, with postoperative and 3-month examinations as reference. Mean with 95% CI (whiskers).

Table 2. Migration at 10 years with postoperative examination as reference. In patients who were operated bilaterally, only the first-operated knee was included

	Trabecular metal				NexGen cemented
At 10 years	Median	IQR	Mean	95% CI	Median	IQR	Mean	95% CI
X-axis rotation [flexion-extension]^a	0.44	0.23–0.64	0.43	0.27–0.59	0.22	0.16–0.36	0.22	0.11–0.33
Y-axis rotation [internal-external]^a	0.48	0.32–0.79	0.45	0.22–0.68	0.18	0.16–0.36	0.17	0.09–0.25
Z-axis rotation [varus-valgus]^a	0.30	0.13–0.59	0.22	0.05–0.39	0.11	0.10–0.26	0.11	0.01–0.22
MTPM, mm	0.85	0.61–1.52	0.93	0.87–0.99	0.34	0.24–0.64	0.37	0.25–0.49
Maximum lift-off, mm	0.00	0.00–0.09	0.01	0.00–0.02	0.11	0.06–0.23	0.11	0.09–0.13
Maximum subsidence, mm	0.67	0.36–1.51	0.66	0.34–0.98	0.10	0.05–0.30	0.18	0.08–0.28

a degrees, absolute value.

IQR: interquartile range; 95% CI: 95% confidence interval for the mean. MTPM: maximum total point motion.

Table 4. Migration at 10 years with 3-month examination as reference. In patients who were operated bilaterally, only the first-operated knee was included

	Trabecular metal				NexGen cemented
At 10 years	Median	IQR	Mean	95% CI	Median	IQR	Mean	95% CI
X-axis rotation (flexion-extension)^a	0.22	0.02–0.37	0.15	0.02 to 0.28	0.11	0.05–0.38	0.12	0.04 to 0.20
Y-axis rotation (internal-external)^a	0.12	0.03–0.40	0.09	–0.02 to 0.20	0.16	0.10–0.40	0.17	0.09 to 0.25
Z-axis rotation (varus-valgus)^a	0.10	0.03–0.17	0.08	–0.01 to 0.17	0.14	0.06–0.23	0.11	0.04 to 0.18
MTPM, mm	0.39	0.22–0.62	0.37	0.23 to 0.51	0.39	0.20–0.58	0.34	0.22 to 0.46
Maximum lift-off, mm	0.10	0.02–0.20	0.06	–0.02 to 0.14	0.12	0.06–0.16	0.06	–0.02 to 0.14
Maximum subsidence, mm	0.21	0.15–0.32	0.19	0.12 to 0.26	0.07	0.05–0.21	0.15	0.06 to 0.24

a degrees, absolute value.

IQR: interquartile range; 95% CI: 95% confidence interval for the mean. MTPM: maximum total point motion.

Table 5. Median differences and 95% CI for migration at 10 years between trabecular metal (TM) and NexGen cemented (NG) tibial components with 3-month examination as reference. In patients who were operated bilaterally, only the first-operated knee was included

	NG − TM at 10 years
	Median difference	95% CI^a	p-value^b
X-axis rotation	−0.06	−0.24 to 0.06	0.6
Y-axis rotation	0.04	−0.15 to 0.16	0.5
Z-axis rotation	0.10	−0.08 to 0.10	0.3
MTPM	−0.55	−0.94 to −0.24	0.02
Maximum lift-off	0.00	−0.08 to 0.07	0.9
Maximum subsidence	−0.10	0.01 to 0.17	0.02

a 95% confidence interval for median difference.

b Mann-Whitney U-test.