Overview of Operative principles in orthopaedics

Uses of Bone Grafts

  • To fill cavities e.g. Cysts
  • To bridge joints - arthrodesis
  • To bridge major defects and restore continuity of a long bone
  • To provide a bone block and limit joint motion (arthrodesis)
  • To promote union in a pseudoarthrosis (nonunion)
  • To promote union in delayed union , non union or fresh fractures or osteotomies.

 Functions of Bone Grafts

  1.  Mechanical Strength - to immobilise a bone cortical graft e.g. an intact fibula can be used.
  2. Ostogenesis- marrow bone such as bone removed from the pelvis. e.g. delayed union of a tibial fracture. This is laid about he fracture gap.
  3. Replacement - loss of a section of long bone may be bridged by bone graft. .If the gap is significant a vascurarised graft is indicated.

Terminology

  • Autografts Transposition of bone tissue from one site to an other in the same individual
  • Allograft  Use of grafts between different individuals of the same species. Use is made of a bone bank that stores the bone harvested from cadavers or femoral heads from hip replacements. The bone is preserved by freeze drying or  irradiation. This bone has poorer osteogenic potential than allografts.
  • Xenograft Transplantation from an individual of one species to another of a different species.

Harvesting bone graft from anterior pelvis

Harvest from the anterior Crista Iliaca

Donor Site Complications - Pelvis

  • Fracture e.g. Sartorius fractures off SIAS
  • Hernia - through pelvic defect
  • Nerve damage e.g. lat. cutaneous of thigh
  • Pain

Harvesting bone from the posterior pelvis for grafting

Posterior pelvic bone graft.
Useful in spinal surgery. More bone can be obtained than anteriorly