Hip Hemiarthroplasty (Unipolar)

Hip Hemiarthroplasty (Unipolar)

When a person is in need of a hip replacement, there are several options for surgical procedures. One of these is hip hemiarthroplasty, which is not a total hip replacement. This type of surgery only replaces the “ball” part of the ball-and-socket hip joint, whereas total hip replacement replaces both parts. This type of surgery is considered invasive and does take time to heal. Every patient should be educated before their surgery and understand the risks and benefits of the procedure from their doctor. 

Common Causes of Hip Replacement

Most patients who need a hip hemiarthroplasty are experiencing extreme wear and tear on their hip joint. Some patients do have serious injuries that cause the head of the femur to break off, which is called a femoral neck fracture. This usually occurs as a result of a serious accident. if a patient is elderly, a fall or other trauma can cause this if there is underlying weakness in the joint. Some people have bone diseases like osteoarthritis or osteoporosis which can make the femur weaker. Any way that this occurs, hip disease or damage is very painful, and one of the goals of hip hemiarthroplasty is to relieve that pain and wear on the hip joint. 

The Hip Hemiarthroplasty Procedure 

When the patient is ready for the surgery, they are put under anesthesia and the area is prepped. The surgeon then makes an incision to expose the head of the femur. The head of the femur is then manipulated out of the socket. This is done as carefully as possible so as to not damage the surrounding tissues. Then, the head of the femur is completely removed. The top of the femur is also hollowed out down into the shaft of the bone. A piece of the implant called the stem is inserted into the shaft of the bone and hammered into place. The stem is very strong and keeps the main implant from shifting too much, and it strengthens the femur to be able to hold up the heavy metal of the implant. Then, the “ball” portion of the implant is placed on the stem. This is able to swivel and move around on the end of the stem, giving mobility to the patient. Then, the ball portion is inserted into the socket of the hip joint. The joint is moved to test the pieces together. Then, the incision is closed. 

Unipolar Hemiarthroplasty 

The difference between unipolar and bipolar hemiarthroplasty is in the type of “ball” implant used. For a unipolar replacement, the implant is a large metal ball. This is simple and functional. A bipolar hemiarthroplasty uses a bipolar replacement head, which is a metal ball with a cover on it made of polyethylene. This is meant to help prevent wear on the acetabulum portion of the pelvis, but there have been studies that show that there is no measurable difference between the two implants. 

Hemiarthroplasty Recovery

Once the surgery is complete, the patient can return home within a few days. There are some complications that can occur, including infections, blood clots, loosening of the implant, or even dislocation. If the patient follows the instructions of the surgeon, these complications are much less likely to occur. The patient should also begin physical therapy shortly after the surgery to help regain movement. Some people take longer than others to heal. Many people can function with mild activity after about 4-6 weeks, with full recovery after about 6 months. Most patients do experience a full and healthy life after the recovery period is over, especially if they take care of their body as best they can.