[A novel technique for a stable intramedullary fixation of static spacers in two-stage septic revision TKA with severe bone defects].

BACKGROUND

Articulating as well as static PMMA-spacers are routinely used in two-staged septic total knee arthroplasty (TKA) revision surgery. However, if bone defects are excessive and there is substantial instability, conventional spacers without additional stabilisation are inappropriate. Due to the increasing number of multiple revisions and larger bone defects, an absolutely stable spacer construct with appropriate fixation in the remaining bone is required.

METHODS

After TKA removal and debridement, AO external fixator steel rods were inserted "press-fit" into the femoral and tibial medullary canal in this technique. Both rods were sealed with bone cement (PMMA) and connected at the joint level in 5° of flexion by an AO external fixator "tube-to-tube" connector. Comparable to a conventional static spacer the joint space is filled with individual antibiotic loaded PMMA. The restoration of the leg axis as well as the distraction of the joint is crucial to preserve the joint space for the second stage TKA reimplantation. Postoperative mobilisation can be conducted under full weight-bearing conditions without external orthosis.

CONCLUSION

This technique allows a safe intramedullary fixation of a modified static spacer in septic TKA revision with large bone defects and substantial instability with avoidance of common spacer complications and excellent patient mobilisation.