S05.KL3 TWO-STAGE REVISION WITH PREFORMED SPACERS. PART 2 – KNEE

Abstract

Two-stage revision is the most widely accepted and performed intervention for chronically infected joint prosthesis. The choice of this option relies on the following considerations:

1. higher antibiotic concentrations may be used in the spacers, compared to the cement used for prosthetic fixation in a single-stage procedure, since high dose antibiotic-loaded cement may be too fragile for long term prosthesis fixation (Bucholz, 1986);

2. the frequent occurrence of bone loss and the smooth cortical bone surface, encountered at revision may prevent effective cementing;

3. two-stage revision allows the use of uncemented modular stems, useful for intra-operatively balancing legs’ length, offset and muscular tension;

4. distal fixation allows to overcome proximal frequent bone loss;

5. bone grafts, eventually plus growth factors, may be safely added;

6. a second debridment may enhance the possibility of eradicating the infection;

7. there is a large and growing international literature evidence in support to this option.

Two-stage reimplantation using an articulated interval spacer of antibiotic-impregnated bone-cement has been previously investigated and proved as an effective Method:

1. to adequately fill the void created by the implant removal,

2. to prevent limb shortening and soft-tissue contracture,

3. to allow a better function,

4. to provide local antibiotic therapy,

5. to eradicate infection,

6. to facilitate reimplantation.

However a considerable variation in the form and function of interval spacers exists. A spacer may in fact be commercially made, or it may be custom-made in the operating room. It may be made entirely of polymethylmethacrylate cement, or it may be a cement-coated metal composite. Favorable results have been reported with each of these types of spacers.

Preformed antibiotic-loaded spacers (InterSpace® Hip and InterSpace® Knee, Tecres SpA, Verona, Italy – Hexactech Inc. Gainesville, Florida) offer:

1. known mechanical resistance;

2. predictable antibiotic release;

3. reduced surgical time;

4. joint function preservation and partial weight bearing;

5. standardized technique. In particular, as to concern the hip, their most peculiar feature is their availability in short and long stem shapes, that allows to overcome frequent proximal femoral bone defects

6. Acceptable costs (< 5% of the total costs for a two-stage procedure).