Continued stabilization of trabecular metal tibial monoblock total knee arthroplasty components at 5 years—measured with radiostereometric analysis

Figures & data

Table 1. Subject demographics and WOMAC scores. Only matched WOMAC data from earlier follow-ups are included. Values are mean (SD)

	Trabecular metal	Cemented	p-value
	(n = 27)	(n = 18)	(ANOVA)
Sex, M/F	10/17	8/10
Age	60 (8)	61 (9)	0.7
Body mass index	32 (5)	34 (5)	0.2
WOMAC preoperatively	51 (20)	44 (18)	0.2
WOMAC at 6 months	22 (23)	18 (20)	0.5
WOMAC at 12 months	15 (16)	14 (22)	0.9
WOMAC at 24 months	13 (16)	15 (14)	0.6
WOMAC at 60 months	18 (18)	19 (18)	0.8

Figure 1. Consolidated Standards of Reporting Trials (CONSORT) flow diagram.

Table 2. Summary of radiostereometric analysis (RSA) data by group and follow-up

	6-month follow-up		12-month follow-up		24-month follow-up		60-month follow-up		p-value^a
	TM	Cemented	TM	Cemented	TM	Cemented	TM	Cemented
	(n=30)	(n=24)	(n=29)	(n=23)	(n=28)	(n=21)	(n=27)	(n=18)
Mean maximum total point motion (range)	0.85 (0.07–3.11)	0.54 (0.12–1.99)	0.87 (0.12–3.25)	0.57 (0.16–1.87)	0.92 (0.06–3.40)	0.65 (0.18–2.12)	0.98 (0.16–3.11)	0.79 (0.06–2.16)	0.9
Lateral/medial translation (SD)	–0.02 (0.13)	0.01 (0.14)	–0.02(0.13)	–0.00(0.14)	–0.01 (0.14)	0.02 (0.16)	–0.02 (0.16)	0.01 (0.26)	0.7
Superior/inferior translation (SD)	–0.34 (0.31)	0.00 (0.08)	–0.34 (0.34)	–0.01 (0.11)	–0.35 (0.35)	–0.03 (0.10)	–0.38 (0.37)	–0.04 (0.11)	0.001
Anterior/posterior translation (SD)	0.02 (0.12)	0.02 (0.29)	0.03 (0.13)	0.06 (0.18)	0.02 (0.12)	0.09 (0.18)	0.01 (0.12)	0.08 (0.29)	0.3
Anterior/posterior tilt (SD)	–0.33 (0.73)	0.02 (0.43)	–0.40 (0.80)	–0.02 (0.30)	–0.39 (0.80)	–0.05 (0.40)	–0.45 (0.90)	–0.11 (0.26)	0.1
Internal/external rotation (SD)	0.19 (0.38)	–0.15 (0.47)	0.15 (0.39)	–0.14 (0.44)	0.19 (0.45)	–0.08 (0.60)	0.17 (0.45)	0.04 (0.82)	0.5
Varus/valgus tilt (SD)	–0.05(0.72)	0.07 (0.32)	–0.11 (0.73)	0.06 (0.32)	–0.10 (0.75)	0.06 (0.33)	–0.12 (0.73)	–0.02 (0.20)	0.6

^a5-year results only

Figure 2. Maximum total point motion (MTPM) (mean and standard deviation) according to the duration of follow-up in the trabecular metal and cemented groups. Lines joining data points do not indicate continuous measurement but are included to show the pattern of migration.

Figure 3. Individual maximum total point motion (MTPM) according to the duration of follow-up in the trabecular metal group (blue) and the cemented group (red). Lines joining data points do not indicate continuous measurement but are included to show the pattern of migration.