What Does Hip Replacement Surgery Involve?
The hip joint is located where the upper end of the femur, or thigh bone, meets the pelvis, or hip bone. A ball at the end of the femur, called the femoral head, fits in a socket (the acetabulum) in the pelvis to allow a wide range of motion.
During a traditional hip replacement, which lasts from 1 to 2 hours, the surgeon makes a 6- to 8-inch incision over the side of the hip through the muscles and removes the diseased bone tissue and cartilage from the hip joint, while leaving the healthy parts of the joint intact. Then the surgeon replaces the head of the femur and acetabulum with new, artificial parts. The new hip is made of materials that allow a natural gliding motion of the joint.
In recent years, some surgeons have begun performing what is called a minimally invasive, or mini-incision, hip replacement, which requires smaller incisions and a shorter recovery time than traditional hip replacement. Candidates for this type of surgery are usually age 50 or younger, of normal weight based on body mass index, and healthier than candidates for traditional surgery. Joint resurfacing is also being used.
Regardless of whether you have traditional or minimally invasive surgery, the parts used to replace the joint are the same and come in two general varieties: cemented and uncemented.
Cemented parts are fastened to existing, healthy bone with a special glue or cement. Hip replacement using these parts is referred to as a "cemented" procedure. Uncemented parts rely on a process called biologic fixation, which holds them in place. This means that the parts are made with a porous surface that allows your own bone to grow into the pores and hold the new parts in place. Sometimes a doctor will use a cemented femur part and uncemented acetabular part. This combination is referred to as a hybrid replacement.
Is a Cemented or Uncemented Prosthesis Better?
The answer to this question is different for different people. Because each person's condition is unique, the doctor and you must weigh the advantages and disadvantages.
Cemented replacements are more frequently used for older, less active people and people with weak bones, such as those who have osteoporosis, while uncemented replacements are more frequently used for younger, more active people.
Studies show that cemented and uncemented prostheses have comparable rates of success. Studies also indicate that if you need an additional hip replacement, or revision, the rates of success for cemented and uncemented prostheses are comparable. However, more long-term data are available in the United States for hip replacements with cemented prostheses, because doctors have been using them here since the late 1960s, whereas uncemented prostheses were not introduced until the late 1970s.
The primary disadvantage of an uncemented prosthesis is the extended recovery period. Because it takes a long time for the natural bone to grow and attach to the prosthesis, a person with uncemented replacements must limit activities for up to 3 months to protect the hip joint. Also, it is more common for someone with an uncemented prosthesis to experience thigh pain in the months following the surgery, while the bone is growing into the prosthesis.
What Can Be Expected Immediately After Surgery?
Your elderly parent will be allowed only limited movement immediately after hip replacement surgery. When your mom or dad is in bed, pillows or a special device are usually used to brace the hip in the correct position. Your aging parent may receive fluids through an intravenous tube to replace fluids lost during surgery. There also may be a tube located near the incision to drain fluid, and a type of tube called a catheter may be used to drain urine until you are able to use the bathroom. The doctor will prescribe medicine for pain or discomfort.
On the day after surgery or sometimes on the day of surgery, therapists will teach your elder exercises to improve recovery. A respiratory therapist may ask your parent to breathe deeply, cough, or blow into a simple device that measures lung capacity. These exercises reduce the collection of fluid in the lungs after surgery.
As early as 1 to 2 days after surgery, your parent may be able to sit on the edge of the bed, stand, and even walk with assistance.
While you are still in the hospital, a physical therapist may teach exercises such as contracting and relaxing certain muscles, which can strengthen the hip. Because the new, artificial hip has a more limited range of movement than a natural, healthy hip, the physical therapist also will teach you the proper techniques for simple activities of daily living, such as bending and sitting, to prevent injury to your elderly parent's new hip.