Equivalent 2-year stabilization of uncemented tibial component migration despite higher early migration compared with cemented fixation: an RSA study on 360 total knee arthroplasties

Figures & data

Figure 2. 1-year MTPM migration by fixation (cemented, n = 222; uncemented, n = 138). Boxes enclose 25th–75th percentiles with internal horizontal line at the median, whiskers extend a further 1.5 times the inter-quartile range and points beyond this range are plotted individually.

Table 6. Subject demographics by fixation (cemented and uncemented) and by implant design

Implant	Fixation	Insert^a		n	Mean age (SD)	Mean BMI (SD)	% female
All implants				360	64 (7.8)	32 (6.1)	61
All cemented implants				222	64 (8.3)	33 (6.5)	68
Advance^b	MP, PS			59	64 (7.8)	32 (5.6)	69
NexGen^c	PS			30	66 (8.7)	32 (5.7)	60
Triathlon^d	PS, CR, CS			133	64 (8.4)	34 (6.9)	70
All uncemented implants				138	65 (7)	31 (5.2)	49
Advance Biofoam^b	porous coated, no screws	MP		22	69 (5.2)	30 (3.8)	55
Advance Biofoam^b	porous coated + screws	MP		20	69 (5.2)	31 (4.6)	35
TM Monoblock^c	trabecular metal	PS, CR		48	64 (7.7)	32 (5.4)	60
TM Modular^c	trabecular metal	PS		16	62 (8.7)	35 (4.8)	63
Triathlon PA-Coated^d	porous coated + periapatite	PS, CR, CS		32	65 (8.4)	29 (5.0)	31

a MP = medial pivot (posterior cruciate ligament resected), PS = posterior stabilized (posterior cruciate ligament resected),

CR = cruciate retaining, and CS = cruciate stabilized.

b Wright Medical Technology, Inc., Arlington, TN

c Zimmer, Warsaw, IN

d Stryker, Mahwah, NJ

Table 7. Tibial component 1-year MTPM migration and change in MTPM migration from 1 to 2 years by fixation and implant groups

Implant	n	1-year migration Mean (SD)	(MTPM, mm) Median (range)	Change in MTPM from Mean (SD)	1 to 2 years (mm) Median (range)
All cemented implants	222	0.41 (0.36)	0.31 (0.03–2.98)	0.06 (0.19)	0.04 (–0.38 to 1.76)
Advance	59	0.40 (0.24)	0.30 (0.16–1.13)	0.04 (0.14)	0.06 (–0.31 to 0.36)
NexGen	30	0.49 (0.34)	0.38 (0.14–1.66)	0.13 (0.38)	–0.01 (–0.16 to 1.76)
Triathlon	133	0.40 (0.41)	0.28 (0.03–2.98)	0.05 (0.14)	0.03 (–0.38 to 0.53)
All uncemented implants	138	0.98 (0.94)	0.63 (0.11–5.19)	0.07 (0.27)	0.04 (–0.76 to 1.30)
Biofoam	22	1.08 (1.05)	0.68 (0.18–4.09)	0.05 (0.32)	0.01 (–0.62 to 1.25)
Biofoam + screws	20	0.82 (0.75)	0.66 (0.29–3.80)	0.04 (0.31)	0.04 (–0.55 to 0.94)
TM Monoblock	48	0.89 (0.77)	0.55 (0.14–3.06)	0.05 (0.21)	0.04 (–0.76 to 0.78)
TM Modular	16	1.52 (1.24)	1.20 (0.31–5.19)	0.32 (0.35)	0.19 (–0.10 to 1.30)
Triathlon PA	32	0.85 (1.00)	0.50 (0.11–4.17)	–0.01 (0.19)	0.00 (–0.72 to 0.43)

Figure 3. 1-year MTPM migration for cemented and uncemented tibial components by implant design. Boxes enclose 25th–75th percentiles with internal horizontal line at the median, whiskers extend a further 1.5 times the inter-quartile range and points beyond this range are plotted individually.

Figure 4. Change in MTPM migration from 1 to 2 years by fixation (cemented, n = 222; uncemented, n = 138). Boxes enclose 25th–75th percentiles with internal horizontal line at the median, whiskers extend a further 1.5 times the inter-quartile range and points beyond this range are plotted individually.

Figure 5. Change in MTPM migration from 1 to 2 years for cemented and uncemented tibial components by implant design. Boxes enclose 25th–75th percentiles with internal horizontal line at the median, whiskers extend a further 1.5 times the inter-quartile range and points beyond this range are plotted individually.