Total Hip Revision Arthroplasty Techniques - Techniques To Restore Bone Stock

Impaction grafting

This is used in order to create a femoral bone bed which will support a cemented long stem.

Technique:

  • Fully expose the femur.
  • Any segmental defects must be converted to contained defects – mesh or strut grafts with circlage fixation.
  • Prophylactically circlage wire the femur.  It must be able to withstand the significant hoop stresses which need to be generated for this technique to work successfully.
  • Insert a thick intramedullary plug at least 2m pass the most distal lytic defect – hold it there by interference fit, and by passing a K-wire transversely beneath it.
  • Pass an IM guide-wire down and into the centre of the plug – confirm its central location.
  • Use a cannulated system to systematically impact morsellised bone graft chips into the femur, creating a solid endosteal canal.
  • Chips should be 3-5mm in size – too small will allow poor fixation.
  • Pack the bone in a distal to proximal fashion.
  • Final tamp will be 1-2 sizes larger than the stem to be used.
  • Remove the IM guide wire.
  • Broach in normal fashion.
  • Cement the stem in routine fashion – insert cement slightly more liquid than normal.
  • Insert a highly polished, collarless, double-tapered stem (Exeter).
  • Protected weight bear for 3 months and results are encouraging.
  • Main problem is with excessive subsidence.

APC (allograft prosthesis composites) and strut grafts

Indications:

  • Calcar defect > 5cm – if it is < 5cm use a calcar replacing prosthesis.
  • Large intra-medullary defect with a thin cortical shell.
  • This generally involves applying strut grafts using circlage wires.
  • How much load these grafts can then support is controversial; some advocate loading them to encourage their incorporation. Others bypass them (distally fit stems) suggesting that you can’t expect them be true structural supports – most apply this approach.
  • Create a step cut at site of junction with the native diaphysis.

Osseointegration Group of AustraliaNorwest Advanced OrthopaedicsThe Sports & Arthritis Clinic NorwestNorwest Advanced Specialty Services