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Low-Dose Gentamicin-Loaded Spacers are Effective for Two-Stage Revision

Authors: Romano Cl, Drago L, Logoluso N. IstitutoOrtopedicoIrccsGaleazzi , Milan, Italy

Title: Low-Dose Gentamicin-Loaded Spacers are Effective for Two-Stage Revision

Background: Peri-prosthetic infection is among the most common reason for revision in the USA and in Europe. Two-stage revision with antibiotic-loaded spacers is the golden standard option with an eradication rate >90%. High antibiotic concentration (>2%) and the association of more than one antibiotic in the spacer are proposed by different authors in limited series of patients.

Hypothesis/Purpose: Are high antibiotic concentrations and antibiotic associations necessary for interim spacers in routine two-stage revision surgery?

Methods: A systematic review of published papers on two-stage revision of infected total hip and knee arthroplasty, treated with the routine use of an industrial low-dose (1.9%) gentamicin-loaded preformed spacer has been performed. Inclusion criteria were: papers published in peer-reviewed journal from year 1995 to present, reporting the infection eradication rate of two-stage hip or knee joint prosthesis with the use of an industrial preformed low-dose gentamicin spacer (Spacer G or Spacer K, Tecres SpA, Italy). Exclusion criteria were: case reports, clinical series with <10 patients, duplicate studies, mean follow-up < 24 months.

Results: 24 papers were retrieved, 10 of which met the inclusion criteria (Table 1), for a total of 491 spacers implanted in 10 centers (7 Europe, 2 North America, 1 Oceania). 19 patients (3.9%) had an infection recurrence /persistence that required spacer exchange or a resection arthroplasty. Of the 480 patients that underwent the second stage procedure, 25 (5.2%) had an infection recurrence/persistence at an average follow-up of 46 months.

White blood cell count was elevated in 36% of patients, erythrocyte sedimentation rate (ESR) in 94%, and C-reactive protein (CRP) in 90% of patients. Elevated ESR or CRP was present in all patients.

Candida albicans was the most common fungus isolated (36%, 13/35). Mycobacterium tuberculosis was the most common mycobacterium (77%, 10/13). A co-existing bacterial pathogen was isolated in 77% (37/48) of cases. Mycobacterial infections had a significantly higher rate of hematogenous spread (92% vs. 23%, p<0.001), involvement of joints (100% vs. 44%, p<0.001), and delayed diagnosis (214 vs. 35 days, p<0.001)

Discussion: The relatively heterogeneous material available notwithstanding, this systematic review provides evidence in favor of the routine use of an industrially preformed spacer, loaded with a standardized relatively low-concentration of gentamicin only, that in different centers showed an average infection eradication rate of 96.1% at spacer removal and of 94.8% at the latest follow-up after reimplantation.

Conclusion: This systematic review does not support the hypothesis that antibiotic associations or antibiotic concentrations higher that 1.9% are routinely needed for spacers used in two-stage revision surgery.

Musculoskeletal Infecton Society
Musculoskeletal Infecton Society