In a normal hip joint, the top of the upper leg bone (femoral head) fits into the hip socket of the pelvis, known as the acetabulum. Hip replacement surgery involves replacing the stem (long part of the bone) and head of the femur and the acetabular "cup" with prosthetic components. First used in the 1960s, the procedure has shown great success over the decades, with 95 to 97 percent of operations considered successful after 15 to 20 years.
Artificial femoral head components are generally made of cobalt chrome, which is resistant to degeneration. Femoral stems are made of titanium or cobalt chrome. Polyethylene (a form of plastic) is the standard material for acetabular cups. Depending on patient bone strength, the pieces are either held in place by cement or by "ingrowth" technology, in which the bone grows between small beads or mesh on the surface of the prosthetic components.
Hip replacement surgery is done through an incision about 6 to 12 cm (2 to 5 inches) in length, which is later closed with sutures or staples. The operation takes between 60 and 90 minutes. Physical therapy, the key to successful joint replacement, begins in the hospital the day after surgery. For more information about surgery and recovery, please visit the Patient Care Process page.
Most patients find that hip replacements provide immediate pain relief. Patients with cemented hip replacements can put pressure on the leg right away, while those with ingrowth replacements need to allow about 6 weeks for the bone to grow in and be more protected.
Hip replacements make it possible for patients to engage without pain in light activities, such as walking, doubles tennis and golf. However, more strenuous athletic pursuits - such as basketball, jogging, downhill skiing and other activities that put intense pressure on the hip -- should be avoided. These activities can loosen the replacement joint, making it more likely that patients will later require a revision joint replacement. Patients should also avoid crossing their legs or lifting the leg with the prosthetic joint above a 90 degree angle in relation to the body. In rare cases, these movements can dislocate the replacement joint.
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