Hip Replacement Implants Can Loosen

Osteolysis Viewed as #1 Cause of Hip Replacement Implant Failures / Revisions

Hip implant
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Hip Replacement Surgery

For people suffering with intense pain and limited mobility from hip arthritis, hip replacement surgery can seem like a miracle. Although it is miraculous, hip replacement is not always a permanent solution.

People who have their first hip replacement when they are in their sixties or older are likely to live the rest of their lives without needing revision of their hip replacement.

However, younger patients are more likely to need revision surgery at some point. Wear of the materials and loosening of the implant are the most common reasons for needing revision surgery.

Hip Implants

Hip implants are designed to replicate the ball and socket structure of the normal hip in human anatomy. The hip implant consists of a component which fits into the pelvic socket or acetabulum, commonly a metal cup with a plastic polyethylene lining, and a metal ball on a long stem which fits into the thigh bone or femur.

As normal wear occurs, the friction caused by the metal ball rubbing against the polyethylene plastic lining can result in the degradation of the polyethylene and the flaking off of the small polyethylene particles. The body's immune system reacts to the particles as foreign matter and attacks it. Since the particles typically settle near the implant, the immune system also attacks surrounding bone, a process known as osteolysis.

As bone loss occurs, the hip implant can loosen, become painful, and begin to function improperly. Osteolysis is regarded by many orthopedic surgeons as the number one cause of hip implant failure. Other causes include incomplete fixation and infection.

Revision Hip Replacement Surgery

When implant failure occurs patients must have another surgery to replace the failed implant, known as revision hip replacement surgery.

Since valuable bone can be lost when an implant fails, revision surgery is more complicated than the primary or original hip replacement.

Though the procedure for revision hip replacement is similar to primary joint replacement, there are some differences:

  • Revision surgery takes longer than the primary surgery because it is more complicated.
  • Joint aspiration may be necessary to ensure no infection.
  • Revision surgery requires more blood than the primary surgery.
  • Since revision patients are typically older, a more extensive pre-op examination may be needed.
  • The risk of complication and recovery period are greater for revision surgery.
  • Revision surgery often necessitates the replacement of lost bone either by bone grafting or the use of special implants.
  • Revision implants may be cemented or uncemented but the design of the implant may differ from the original implant.

Since revision surgery is regarded as more difficult, it is imperative to have an experienced surgeon and seasoned surgical team. A properly equipped hospital ready for any situation is a consideration as well.

Today's implants, such as metal-on-metal and ceramic-on-ceramic, are being used with the hope that they are more durable. The prostheses are made with stronger metals. 

It's also important for the patient to follow their surgeon's advice about which activities are allowed following hip replacement surgery. Abuse of the implant could contribute to its failure. Appropriate exercise is good, so that the muscles and other supporting structures around the implant remain healthy. Discuss with your surgeon or physical therapist which activities and exercises you should be doing.


Arthritis of the Hip & Knee, Ronald J. Allen, Victoria Anne Brander, M.D., S. David Stulberg, M.D.

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