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Impaction Bone Grafting (IBG)This is a technique to restore bone stock lost when aseptic loosening has eaten bone away. It was originally popularised by Dr Tom Slooff and colleagues at Nijmegen in the Netherlands and further perfected by Mr Graham Ghie working with Professor Robin Ling in Exeter, UK. The basic idea is to take allograft bone harvested from human donors and grind this into a form suitable for packing into the cavities created by aseptic loosening. Special tools and techniques are used to achieve a tightly packed bed of bone onto which new components are cemented in place. It sounds simple enough but requires experience! The (dead) allograft bone is gradually replaced by your own living bone in a process known as creeping substitution. One could therefore think of allograft as a sort of compost helping the body to repair itself and lay down bone to replace what was lost. The allograft bone is obtained from human donors whose femoral heads would otherwise be thrown away at the time of primary Total Hip Relacement (THR). These donors are tested for transmissable diseases eg HIV, hepatitis and their bone is not used until a second set of blood tests 6 months later remains negative. In this respect, the precautions are even more stringent than those surrounding blood transfusion. To learn more click on this link http://www.blooddonor.org.uk/pages/tissserv.html IBG is particularly indicated for younger patients who are still active and have had a THR which has failed. Older patients may be more suitably managed by simply using longer stems or larger socket components. To use longer components in younger patients creates the situation where if this device also loosens, even less bone is available should the revision fail again. Revision hip surgery is unsurprisingly just as controversial as primary THR and each case needs to be assessed on merit. The stakes are high because revision surgery carries a significantly increased risk of complications. The results are often less gratifying to the patient than the original THR.
Diagrams above show the use of bone graft to build up the proximal femur in a sequential fashion. A new stem and cup can then be placed as shown below.
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