Table 1 Summary of two-stage studies

Fehring 2000

55 (30 articulating/25 static) all with antibiotics

4 (7%)

98 in static spacers 105 in articulating spacers

Static spacers 36 months (range, 24–72 months). Articulating spacers was 27 months (range, 24–36 months)

Static spacer- 83 points (HSS) Articulating spacer 84 points (HSS)

Not reported

Not reported

Ferrari 2011

50

4 patients 8%

Not reported

Followed up for a minimum of 24 months maximum 126

Mean IKSS clinical was 35.38 (clinical) & 37.96 (function) on presentation; it improved to a mean of 75.38 (clinical) & 80.58 (function) at the final review. Mean WOMAC (function and pain scores) was respectively 17.38 and 60.67 on presentation, it improved to a mean of 8.67 and 31.04 at final review

Not reported

Not reported

Freeman 2007

76 procedures in 74 patients, Static spacers were used in 28 procedures, and articulating spacers were used in 48 procedures

Articulating group was 5.3% (4 of 76 knees) compared to 7.9% (3 of 38 knees) in the static group.

Not reported

71.2 months (range, 24–196 months)

No significant difference between articulating and static spacers in KSS pain and functional scores, although the functional scores were higher in articulating group.

67 (range, 41-87 years)

38 were men and 36 were women

Goldman 1996

64

6 patients (9%)

Average 94 (30–120)

Average 7.5 years (2–17 years)

Mean HSS score 78 points

Average 67 (37–89)

21 males 39 females

Gooding 2011

110 patients 115 knees

14 knees (13%)

Postoperative knee flexion of 93.2 (range, 30 –140) and preoperative knee flexion of 86.2 (range, 15 –140)

Minimum 5 years

We observed an improvement in the mean postoperative WOMAC function, WOMAC pain, and WOMAC global scores. An improvement was also noted in the Oxford and the SF-12 (mental) scores and the satisfaction scores were recorded at last follow-up. The mean postoperative UCLA score at final follow-up was 4.1. WOMAC function (p = 0.001), WOMAC pain (p = 0.02), and WOMAC global (p = 0.002) scores as well as the Oxford (p = 0.0003) and the SF-12 (mental) (p = 0.008) scores all improved at last follow-up

68 years (range, 35–86 years)

(60 male and 50 female)

Haddad 2000

45

4 failures (9%)

Mean flexion at final follow-up 94.5 (20–135)

Mean follow-up 48 months (20–112)

Mean HSS score 71.4

69 years (26–83)

26 women 19 men

Haleem 2004

94 patients and 96 knees

9 knees (9%)

ROM at last follow-up had a median of 90° (range 30°–120°).

Median follow-up was 7.2 years (range, 2.5–13.2 years)

Preoperative KSS pain scores improved (p 0.001) from a median of 49 points (range, 4–85 points) to a median of 89 points (range, 35–97 points) postoperatively Preoperative functional scores improved (p 0.001) from a median of 5 points (range, 0–80 points) to a median of 50 points (range, 0–100 points) postoperatively.

69 years (range, 37–89 years)

50 men and 44 women

Hart 2006

48

6 patients (12%)

Mean fixed-flexion deformity of 1° (0° to 15°). Five patients had a fixed-flexion deformity of more than 10°. The mean maximum flexion was 92° (30° to 120°)

Average 48.5 months (26–85)

Not reported

Mean age 68.2 (37.2-81.3)

28 men 20 women

Hirakawa 1998

55 knees 54 patients

14 knees developed recurrent deep infection at an average of 50.8 weeks (range, 12–144)

Average knee flexion was 92° (range, 72°- 128°) before infection and 83° (range, 54°-130°) after reimplantation

61.9 months (range, 28–146 months).

Average HSS knee score was 85.3 points (range, 69–100) before infection and 78.6 points (range, 52–98) after reimplantation. NB In successful only

67 years (range, 41-83 years)

29 women and 25 men

Johnson 2012

111 patients 115 knees (Dynamic 34 Static 81)

Six patients in the dynamic spacer cohort (17%; 95% CI, 8%–34%) and 14 patients in the static spacer cohort (17%; 95% CI, 10%–27%)

Postoperative Knee Society objective scores and ROMs improved to 83 points (range, 48–99 points; 95% CI, 79–87 points) and 99″ (range, 60″–120‵; 95% CI, 92‶–104‶), respectively, for the dynamic spacer group and 84 points (range, 48–100 points; 95% CI, 81–87 points) and 95′ (range, 30″–130‶; 95% CI, 90″–101‶),

(Dynamic spacer group: mean, 27 months; range, 12–72 months; static spacer group: mean, 66 months; range, 12–121 months)

See rom box

Dynamic 62 (59–65) Static 61 (58–64)

Not Reported

Kalore 2012

53

15/53(28%) overall- (5/15 AOC; 2/16 NFC; 8/22 SMC)

95.7, 98.3, and 93.8 for SMC, NFC, and AOC spacers, respectively

Mean 39 months (12–105)

Not reported

Mean 64

38 men 15 women

Kurd 2010

96

26 patients (27%) (14 reinfected with same micro-organism)

Na

(Mean, 35 months; range, 24–90 months

Not reported

67 years (range, 17–88 years)

46 women and 56 men (6 subsequently lost to f/u)

Lonner 2001

53

9 (17%)

Not reported

56 months (24–144)

Not reported

Not reported

not reported

Mahmud 2012

253 knees

16 failures (7%)

Not reported

Median 48/12 (12–276)

The preoperative WOMAC score, and The Knee Society Clinical Rating scores were 48 (± 21) and 64 (± 31), respectively. The postoperative WOMAC and The Knee Society Clinical Rating scores were 60 (± 21) and 129 (± 41), respectively. The difference between the pre- and postoperative WOMAC and The Knee Society Clinical Rating scores were 12 and 65, respectively.

Mean age of 70 ± 10 years

104 were men and 135 women

Meek 2004

54 (47)

2 (4%)

N = 47 RoM preop 78.2 (SD 29.4); RoM postop 87.1 (14.7)

Average follow up 41 months

SF12 Mental 53.7 (11.9); SF12 Physical 41.2 (13.4); Oxford 67.3 (24.3); WOMAC-function 68.9 (21.9)-pain 77.1 (25.2)-stiffness 70.2 (24.2)

Not reported

27 females and 20 males

Mont 2000

69 two stage (group I-35, group II-34)

Group I-5/35 (14%; Group II 1/34 (3%). Total reinfection rate 6/69 (8.7%)

Group I 68 months (36–114); group II 58 months (36–91)

KSS (infection free knee only) 86 (80–95) in group I; 88 (64–98) in group II

Group I 64 (46–80); Group II 69 (56–82)

M:F group I 17:18 group II 16:18

Mortazavi 2011

117

33 failures (28%)

Not reported

Mean followup was 3.8 years (range, 2–9.4 years)

No functional outcomes reported

67.5 years (range, 37–88 years)

55 (47%) were female

Van Thiel 2011

58

7 failures (12%)

The mean extension before placement of the spacer was 3.2 (range, 0 –30) and a mean of 2.0 at final followup (range, 0 –10); the mean pretreatment flexion of 90.6 (range, 10 –125) improved to a mean of 101.3 (range, 0 –130) at final followup

(mean, 35 months; range, 24–51 months)

Mean pretreatment Knee Society score of 53 (range, 10–100) improved to a mean of 79 (range, 37–100) at most recent followup

66 years (range, 42–91 years).

29 women and 31 men

Westrich 2010

72 patients (75 knees)

7 knees (9.3%)

Not reported

52.4 months (range, 24–108 months)

Mean Knee Society knee score improved from 65.1 preoperatively to 90.1 at last follow-up, and the mean Knee Society functional score improved from 29.4 preoperatively to 90 at last follow-up.

65.5 (range, 39–86)

37 men (51.4%) and 35 women (48.6%)

Hofman 2005

50

6 patients (12%)

Pre reimplantation 6–91; Post implantation 4-104

73 months (24–150)

Average modified HSS after revision 89pts(70–100)

67 yrs (38–92)

25 men 25 women