Hip Replacement

Zimmer Fitmore Prosthesis, ML taper stems, Kinectv modular stems, trabecular metal technology.

South Valley Orthopedics & Sports Medicine strives to improve patient quality of life by using minimally invasive solutions and procedures with leading-edge advancement in surgery.

There are many ways to treat the pain caused by arthritis. One way is total hip replacement surgery. The decision to have total hip replacement surgery should be made very carefully after consulting your doctor and learning as much as you can about the hip joint, arthritis, and the surgery.

In total hip replacement surgery, the ball and socket that have been damaged by arthritis are removed and replaced with artificial parts made of metal and a durable plastic material. We call these artificial parts "implants," or "prostheses."

Signs you are Ready for Hip Arthroplasty

Total hip arthroplasty is a significnt surgery, and therefore deciding to have the surgery done is a serious decision. Here are some signs to help you decide if the time is right for hip replacement surgery.

• you have hip/groin pain that keeps you awake, or awakens
  
• you have hip pain that limits activities necessary to go about your daily activities
  
• you have hip pain that limits activities that give you pleasure
  
• you have tried other treatments for a reasonable period of time, and still have persistent hip pain

Alternatives to Hip Replacement

Not having surgery is always an option. Patients who have severe arthritis of the hip, but function adequately, can choose to live with their condition. There are effective treatments for hip arthritis that may help patients avoid the need for a surgical answer.

Conservative Treatment

• Physical therapy , walking aids, antiinflamatorty meds, cortisone injections may at times help.

Hip Resurfacing

• This is an alternative surgical procedures for certain patients. This procedure allows for the preservation of more native bone through the use of a smaller implant. A metal cap is placed on the femoral side, while a normal acetabulum is used on the pelvic side. The inclusion criteria is very stringent.

Resection Arthroplasty

• A resection arthroplasty is a procedure whereby the upper end of the femur is removed and the joint space is allowed to fill with scar tissue. The main indication for this type of procedure is an uncontrollded infection, or patients that have little chance of normal walking secondary to normal walking.

Hip Osteotomy

• This is a procedure that is done to realign the bones of the hip joint. The bone that is cut and realigned can be the femur, the pelvis or both. Osteotomies are usually performed on patients with bony malalignment issues that have led to early arthritis. Examples include hip dysplasia, and coxa vara.

Hip Fusion (Arthrodesis)

• Hip fusion is a very rarely performed now. The fusion eliminate all motion at the hip joint by healing the bones of the femur and pelvis. Typically they are held in this position by a large metal plate and screws. They are usually performed in young patients who are heavy laborers. The hip fusion will not wear out in these patients whereas a replacement might. The hip fusion allows the patient to perform physically demanding tasks that could lead to early wear on a total hip replacement. The problem with a fusion is that patients will walk with a limp, and eventually may need a surgery to convert the fusion to a total hip.

Two Types of Hip Fixation

There are two main types of fixation philosophies-cemented and porous. Both can be effective in the replacement of hip joints. The physician (and the patient) will choose the best solution that is specific to the patient's needs.

Cemented Hip Implants

The cemented hip implant is designed to be implanted using bone cement (a grout that helps position the implant within the bone). Bone cement is injected into the prepared femoral canal. The surgeon then positions the implant within the canal and the grout helps to hold it in the desired position.

Porous Hip Implants

The porous hip implant is designed to be inserted into he prepared femoral canal without the use of bone cement. Initially, the femoral canal is prepared so that the implant fits tightly within it. The porous surfaces on the hip implant are designed to engage the bone within the canal and permit bone to grow into the porous surface. Eventually, this bone ingrowth can provide additional fixation to hold the implant in the desired position.

During Surgery

The patient is first taken into the operating room and given anesthesia. After the anesthesia has taken effect, the skin around the upper thigh is thoroughly scrubbed with an antiseptic liquid. An incision of appropriate size is then made over the hip joint.

One type of implant that replaces the socket consists of a metal shell that is lined with a strong plastic liner.

Removing the Surface of the Socket

The leg is maneuvered until the femoral head is dislocated from the socket.

A special reamer is then used to remove the damaged cartilage and bone surface from the acetabulum, and to shape the socket so it will match the shape of the implant that will be inserted.

Inserting the Implant

The shell portion of the socket implant may be attached either by using a special kind of epoxy cement for bones, or by pressing the implant into the socket so that it fits very tightly and is held in place by friction. Some implants may have special surfaces with pores that allow bone to grow into them to help hold the implant in place. Depending on the condition of the patient's bone, the surgeon may also decide to use screws to help hold the implant in place.

When the shell portion of the socket implant is in place, the plastic liner is locked into place inside the shell.

Replacing the Ball Portion of the Joint

The implant that replaces the ball consists of a long metal stem that fits down into the femur. The metal ball is mounted on top of this stem.

Removing the Ball

A special power saw is used to remove the damaged femoral head.

Clearing and Shaping the Canal

The upper leg bone has relatively soft, porous bone tissue around the center. This part of the bone is called cancellous bone. It surrounds the canal, which mainly contains blood vessels and fatty tissue.

Special instruments are used to clear some of the cancellous bone from the canal, and then to mold the inside walls of the canal to fit the shape of the implant stem.

Inserting the Implant

The stem implant may be held in place by either using the special cement for bones, or by making it fit very tightly in the canal. If cement is used, it is injected into the canal first, and then the implant is inserted into the canal. If cement is not used, the implant is simply inserted into the canal. Like the socket implant, the stem implant may have a special surface with pores that allow bone to grow into them.

On some implants, the stem and ball are one piece. On others, they may be two separate pieces. If the ball is a separate piece, it is usually secured to the top of the stem after the stem has been inserted.

Closing the Wound

When all the implants are in place, the surgeon places the new ball that is now part of the upper leg bone into the new socket that is secure within the pelvic bone. If necessary, the surgeon may adjust the ligaments that surround the hip to achieve the best possible hip function.

When the ligaments are properly adjusted, the surgeon sews the layers of tissue back into their proper position. A plastic tube may be inserted into the wound to allow liquids to drain from the site during the first few hours after surgery. After the tube is inserted, the edges of the skin are sewn together, and a sterile bandage is applied to the hip. Finally, the patient is taken to the recovery room.

Information provided by Zimmer Orthopedics