Comparison of articulating and static spacers regarding infection with resistant organisms in total knee arthroplasty

Figures & data

Figure 1. Flow diagram of enrollment.

Table 1. Demographic data

	Articulating spacer	Static spacer
	(n = 23)	(n = 22)
Age (years)	71 (65–78)	72 (67–80)
Sex (female / male)	13 / 10	10 / 12
Infected TKA	19	18
Infected revised TKA	4	4
After debridement	13	9
Medical co-morbidities	9	11
Diabetes mellitus	6	7
PAOD	1	1
End-stage renal disease	2	1
Rheumatoid arthritis	1	2
Others	1 breast cancer	1 liver cirrhosis, Child A
Bacteriology
MRSA	19	20
MRCNS	4	2
Intravenous antibiotics (weeks)	3.4 (2.5–4.5)	3.1 (2.5–4.5)
Oral antibiotics (weeks)	8.3 (4–11)	8.1 (4–10)
Spacer stage (months)	3.4 (2.5–5)	3.1 (2–4)
Re-implantation	22	21
Surgical approach
Medial parapatellar	22	14
Quadriceps snip	0	6
V-Y plasty	0	1
Mean follow-up (months)	41 (24–61)	40 (24–59)

PAOD: peripheral arterial occlusion disease;

MRSA: methicillin-resistant Staphylococcus aureus;

MRCNS: methicillin-resistant coagulase-negative staphylococci.

Figure 2. Spacers cast with PDMS molds provide a smooth interface. Care should be taken to balance the gap tension and restore the proper joint line when implanting articulating spacers.

Table 2. Clinical results

	Articulating spacer	Static spacer
	(n = 23)	(n = 22)
Re-infection rate	1/22	2/21
Success rate	21/23	19/22
ROM at spacer stage (°)	84 (50–105)	0
Post-revision ROM (°)	113 (95–125)	85 (70–100) ^b
Post-revision HSS score	90 (86–94)	82 (81–88) ^b
Patella baja
Preoperative (%)	0	0
Mean ISR ^a	0.98	0.95
Postoperative (%)	0	33 ^b
Mean ISR ^a	0.93	0.81 ^b
Satisfaction rate	21/23	7/22 ^b

^a Insall-Salvati ratio.

^b p < 0.05