Prosthetic Joint Infection Score- Medical Algorithm

Zimmerli developed a score for evaluating a patient for a prosthetic joint infection. The author is from University Hospitals Basel.

Parameters:

(1) pain

(2) fever

(3) wound redness

(4) wound warmth

(5) wound sinus tract

(6) wound induraiton

(7) radiology score

(8) C-reactive protein (CRP)

Parameter	Finding	Points
pain	none	0
	slight, occasional	1
	severe requiring pain medication, pain limits mobility	2
	major with severe limits on mobility	3
fever	< 37°C	0
	37 to 37.9°C	1
	38 to 38.5°C	2
	>= 38.6 °C	3
wound redness	absent	0
	present	1
wound warmth	same as adjacent skin	0
	detectable difference	1
	significant difference (>= 1°C)	2
wound sinus tract	absent	0
	present	3
wound induration	none	0
	< 2 square cm	1
	>= 2 square cm	2
radiology score	no signs of infection	0
	periprosthetic demineralization OR loosening at the bone cement interface OR lucent zone at bone-cement interface OR implant wandering	1
	pathologic dislocation or slipping of the prosthesis	2
CRP	< 5 mg/L	0
	5 to 10 mg/L	1
	11 to 20 mg/L	2
	21 to 50 mg/L	3
	> 50 mg/L	4

where:

• 2 square cm indicates a diameter of 1.6 cm or 0.62 inches.

total score =

= SUM(points for all 8 parameters)

Interpretation:

• minimum score: 0

• maximum score: 20

• A stable score <= 5 indicates normal healing and no infection if there has been followup for >= 2 years.

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Prosthetic Joint Infection Score of Zimmerli