In spite of the generally good results after total hip replacement, it is still necessary to revise the hip implants due to various reasons. This fortunately, happens much less frequently now than was the case when hip replacements were first invented. In general, the common causes for a hip revision are due the effects of ‘wear’ of the implants or to infection.
Even though pre-operative planning is important with any joint replacement surgery, for a revision hip surgery, it is essential that a thorough planning is done to have different options available during surgery.
BLOOD LOSSAs revision hip surgery requires a larger surgical approach and complex bone reconstruction, the blood loss during surgery is usually more that a standard primary total hip replacement. To minimise the requirement for blood transfusion, a Cell Saver is used during surgery. The cell-saver machines make it possible to collect, clean and save the blood lost during and after surgery, thus minimising the need for blood transfusions.
The most common cause of failure nowadays is loosening of the one (commonly the socket component) or both components.Infected hip replacement that usually requires either one-stage or two-stage revision.Sometimes it is necessary to revise the hip because it is unstable and dislocates or slips out of the joint frequently.Relatively rarely, surgery may be required because of bone loss caused by particles generated from wearing down of the replacement. This condition is called osteolysis.Fracture around the implants, particularly on the femoral side usually requires revision of the implant.The implants used for the revision operation are broadly similar to the ones used for primary procedure. In many instances however, the implants required for revision surgery are more complicated and have to be selected for each individual patient depending upon the prevailing clinical situation. The socket component The socket components used in revision surgery tends to be the one that does not require cement for fixation. The fixation of these sockets is usually enhanced with screws that are used to fix the cup to the pelvis. On occasions, the bone loss around the failed old socket is so severe that a normal socket may not fit well due to large defects in the bone. These can be filled with either Bone Grafts or some specialised components that have "add ons" to allow better filling of these defects. Rarely, it may be necessary to use some special cages and plates to provide scaffolding and additional fixation around severe defects.
With regards to the femoral components, it is important to retrieve the old failed component carefully without further bone loss. This sometimes may mean that the top end of the femur may need to be split open in a planner manner to retrieve the old implant. The new implant is usually fixed using uncemented technique. This uncemented implant usually comes with different ‘add-on’ options so that the implant can be "fabricated" in the operation theatre taking into account the best fit and suitability for the patient. Often the surgeon will have a wide choice of components to put together in each section of the implant for maximum flexibility. Sometimes, it may be necessary to use a ‘strut bone graft’ to provide additional stability and promote new bone formation around defects.
The outcome of a revision hip surgery depends on various factors including the cause for the revision procedure. Mr Kavarthapu will provide you with specific information on the expectation following your revision hip replacement procedure.
