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Types of Hip Implants and Types of Hip Replacement Procedures

January 9th, 2013

Total hip replacements are performed to treat a variety of conditions affecting the hip joint, including degenerative joint disease, arthritis, congenital hip dysplasia, and physical trauma. Hip ailments are more common in elderly people, but younger people can suffer from these conditions as well. Besides various diseases of the joints, physical trauma usually occurs due to falls, auto accidents, or other acute injuries.

The hip is a ball and socket joint. The hip bone itself has a rounded gap, or socket, which the rounded ball of the femur, or thigh bone, fits into. This type of joint has a lot of flexibility as the joint can swivel in any direction. This is why hips can bend in more directions than knees or elbows, for example. It also makes broken hips particularly difficult to heal, which is why surgical intervention is sometimes necessary to promote mobility.

Types of Hip Implants

  • Metal on polyethylene implants. This is the most common type of implant. In this method, both the ball and socket portions of the joint are removed and replaced with a metal prosthesis. A polyethylene spacer is then placed between them. The metal used is usually titanium-aluminum, stainless steel or cobalt-chrome. These implants do wear down over time, so subsequent replacements may be necessary in patients who live a long time post-surgery. A relatively new type of polyethylene is quite popular now due to its strength and durability. These new implants rely on a wear-resistant type of plastic that is manufactured to be stronger than regular polyethylene. Because these implants are new, long-term studies have not been completed to determine whether they will truly wear down more slowly than other types of implants
  • Metal on metal implants. These work similarly to the above type, but there is no plastic spacer between the metal elements. This reduces the amount of wear that the artificial hip takes, but it does pose a potential risk to patients due to the release of metal ions into the patient’s bloodstream.
  • Ceramic on ceramic implants. These implants use ceramic pieces for the ball and socket portions of the joint. Ceramic is much less prone to wear than metal or plastic, but it can be brittle and prone to breaking.

Regardless of the materials used, the implant will generally be held in place with a special type of medical cement. It may also be wedged into place without cement so that the bone can heal over the implant and hold it in place.

Types of Hip Replacement Procedures

Surgeons utilize a variety of surgical options to address pain experienced by patients suffering from diseases of the hip joints. These options include total hip replacements where an artificial ball, socket, and stem is implanted into the joint to replace the existing diseased or damaged bone. Surgeons may also perform a total hip resurfacing where an artificial ball and socket is implanted, but the stem is very short in length and does not penetrate deep into the femoral bone. A resurfacing procedure is generally less invasive than a total hip replacement. Surgeons may also perform a partial hip replacement, also known as a hemi-arthroplasty, in which only the ball is replaced with an artificial implant. For physical trauma, depending on the extent of an injury, a broken hip can sometimes be healed naturally by limiting a patient’s movement. More serious injuries may require surgical intervention.

A traditional hip replacement surgery requires an incision through either upper thigh or buttocks of the patient. Less-invasive techniques use smaller incisions and specialized instruments to complete the procedure.  Regardless of the procedure completed or the materials used, a hip replacement surgery takes time and therapy to recover from. Some complications can arise if the new hip does not form a strong attachment to the existing bone. The patient may also continue to experience pain in the joint long after recovery is over. Fortunately, as technology improves, hip replacement surgeries become more effective.

Information on the recall of Stryker hip implants

Seeger Weiss LLP

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