We wanted to study the risk of systemic toxic effect of gentamycin/vancomycin loaded spacers, and to investigate whether there is any difference in the elution of gentamycin and vancomycin to the joint fluid between theatre- made and in factory ready-made spacers

The study consists of 28 patients.

In group one, 14 patients were given a in factory ready-made spacer containing gentamycin 1,1g – 3,2g and vancomycin 1,1g – 3,2g depending of the size of the spacer.

In group two, 14 patients were given spacers made in the operating theatre. from PMMA containing 0,5 g gentamycin in each 40 g batch. 4 g vancomycin were added to each batch of 40 g PMMA.

The concentration of gentamycin and vancomycin was measured from drainfluid and in serum day 1 and 2 after the operation

Group one Group two Significance

Vancomycin drain day 1 10,3 (2,0–23.3) 88,5 (11,7–242,9) p<0,001

Vancomycin drain day 2 6,3 (2,0–17,5) 55,2 (7,5–161,0) p<0,001

Vancomycin serum day 1 2,0 (2,0–2,0) 1,8 (0,7–2.0) ns

Vancomycin serum day 2 2,0 (1,6–2,2) 1,9 (1,0–2,0) ns

Gentamycin drain day 1 23,4 (0,5–68,0) 44,3 (11,0–117,5) p=0,05

Gentamycin drain day 2 8,7 (0,8–16,1) 18,0 (6,8–45,3) p<0,005

Gentamycin serum day 1 0,2 (0,2–0,2) 0,3 (0,2–1,3) ns

Gentamycin serum day 2 0,2 (0,0–0,2) 0,3 (0,2–1,1) ns

In theatre-made spacers had a significant higher concentration of both gentamycin and vancomycin in the joint fluid. Even with very high consentrations of gentamycin and vancomycin in the joint fluid the concentrations in serum were far below the toxic limit and no toxic reactions were observed

Gentamycin and vancomycin added to the hip spacers only to a very small degree passes to the circulation system.

In theatre-made spacers have a significantly higher elution of gentamycin and vancomycin than in factory ready-made spacers. If a high initial concentration of gentamycin and vancomycin in joint fluid is desired. in theatre-made spacers should be considered.