As recipients of DePuy metal-on-metal hips continue to experience premature implant failure, metallosis, and other side effects, the medical device maker... read more
Defective Hip Implant Designs
Artificial hip implants are all designed in basically the same way. They are made to reproduce the body's natural hip joint, consisting of the:
- Acetabulum –a cup-shaped indentation in the pelvis. It holds the femoral head.
- Femoral head – a ball-shaped bone that is at the top of the femur, or thigh bone.
The artificial acetabulum replaces the person's own acetabulum. It is cup-shaped and may be made of metal, polyethylene plastic or ceramic. The artificial femoral head is a rounded piece of metal, plastic, or ceramic and is attached to the person's femur by an artificial stem that fits into the thigh bone where it is secured. A neck may connect the femoral head to the artificial stem
Hip implants are made with three different types of materials:
Problems with Prosthetic Implants
One of the biggest concerns when fitting a person with an artificial hip is the longevity of the implant. For various reasons the implant can come loose and must be replaced. Other problems occur when friction between the femoral head and acetabulum causes implant failure or causes pieces of debris to be shed from the artificial substance.
This debris can inflame tissue surrounding the implant, including causing infection and loss of tissue. It can cause the bone into which the implant is seated to be destroyed and can also spread throughout the body via the blood stream and lodge in various tissues or organs.
In the case of the DePuy metal-on-metal implant, cobalt chromium ions have been detected in various organs throughout the body. Cysts also have developed as a result of the debris. Not enough time has passed to determine if these ions, which continue to collect, are harmful in the long term. About one-third of the approximately 250,000 hip implants performed each year in the U.S. have been the metal-on-metal design.
Because of the growing problems of metal-on-metal implants, surgeons around the country are using less of this type of device. Revision surgery, or another surgery to correct problems with the initial implant, has been performed because of the debris problem more than two dozen times at institutions like the Mayo Clinic and Rush University Medical Center.
Ceramic implants, where both the lining of the acetabular cup and the femoral head are made of ceramic, are becoming more popular. They reportedly last longer than the metal-on-metal implants and shed much less debris. One problem with these implants is that they have gone through what has been called catastrophic failure and the implant breaks.
For more information about a possible legal case, contact our defective hip attorneys today.