Wednesday, March 27, 2013

Hip revision surgery

From Smith and Nephew's site (a manufacturer of hips)
 
If your orthopaedic surgeon has determined you need revision hip surgery, it is most likely because your hip has unrelieved pain and X-rays show damage has occurred to the hip replacement, causing its failure. The purpose of this procedure is to remove your failed implants, and replace them with new ones, which will help make your hip strong, stable and flexible again.
Over 30,000 revision hip replacement surgeries are performed in the United States every year, and new advanced technologies have made this a safe and effective way to restore the function of your joint.


 
ComponentfailureWhile your hip implant may shift slightly after surgery, thus leading to unbalanced weight distribution and premature implant failure, the most common reason for hip implant failure is the wearing down of the plastic insert in the hip socket.

In the years following your first hip replacement surgery, the metal portion of your implant slowly wears down this plastic portion. In fact, your regular daily activities may produce as many as 2 million cycles per year on these parts.

Depending on the amount of wear to this plastic piece, your surgeon may be able to replace only the plastic piece alone. In other cases, though, you may have worn through it and damaged the metal components as well. In this case the entire implant will be replaced.

Osteolysis
The wearing down of the plastic component has an unfortunate side effect. The tiny plastic particles that wear off are attacked by your body’s immune system, and this immune response also attacks the healthy bone around your implant. This leads to a condition called osteolysis, in which the bone in the area around the joint implant softens as it is absorbed by the body, thus making your implant unstable and in need of revision. Your orthopaedist usually will be able to detect osteolysis on your standard X-rays.


Dislocation
Some patients do experience dislocation of the implant after surgery. In approximately half of these cases, your physician may be able to put your hip implant back in place without surgery. However, if your surgeon determines the implant was damaged, certain components of the ball-and-socket joint may need to be replaced in a revision procedure.

Fracture
If the bone next to your primary implant is fractured in an accident, revision surgery may be required in order to provide a safe, stable joint. In this case, the original implant may need to be removed, the fracture addressed and a revision joint implanted.

Infection
In a low percentage of cases, your hip may become infected after surgery. Although it may be successfully treated with antibiotics, there are severe cases where a follow-up revision surgery may be required. In this surgery, the primary implants will be removed, and temporary, antibiotic-laced “spacers” are implanted. These spacers allow for joint function and are intended to give your body time to heal before the new revision prostheses are surgically implanted. Most likely, you will be put on a six-week course of antibiotics in order to eliminate the infection. At a follow-up evaluation, your surgeon will determine if your body is ready for the revision procedure.

TheImplant
Some questions you are probably thinking about are: what kind of implant device you will be receiving, what is it made of, and why is your surgeon using a particular kind of device? If you haven’t discussed this with your surgeon, you should, because not all revision hip implant devices are made of the same material.

Due to significant advancements in technology, there is a new material for revision hip implant devices called OXINIUM Oxidized Zirconium that is a superior metal for use in hip implants. This is due to its hardness, smoothness and resistance to scratching and abrasion. It also exhibits superior performance characteristics over the alternative material options of cobalt chrome and ceramic. Ask your orthopaedic surgeon about OXINIUM and if it is the right implant option for you.

The revision hip implant is comprised of four parts that work together to restore the original function of your ball-and-socket joint.

  • A metal hip stem that is inserted into the top of your thighbone
  • A metal cup which holds the cup liner
  • A cup liner which holds the femoral head
  • The femoral head or ball which is attached to the top of the hip stem and is inserted into the liner to form the ball-and-socket joint

Hip implants are not one-size-fits-all, therefore your surgeon will choose the right hip implant for your body. Your surgeon will determine which of the four component’s design options will work best together to restore your accurate leg length, while minimizing the risks of post-operative dislocation and premature implant wear.

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