As with all major surgeries, a hip replacement procedure is associated with several complications and risks, some of which may even be life threatening. The risk of complications is low, but some examples of potential problems include:
- Dislocation of the joint
- Loosening of the joint
- Wear and tear
- Joint stiffening
- Blood clot
Dislocation of the hip joint
The hip joint becomes displaced from its socket in around 3% of cases. After a hip replacement procedure, it can take up to twelve weeks for the soft tissues around the joint to heal after they have been cut during surgery. During this period, the joint is poorly supported and the femoral head can work its way free of the socket, leading to dislocation. The risk of hip dislocation is reduced when less tissue is cut, if cut tissue is repaired or if the femoral head prosthesis has a large diameter. When heads with a smaller diameter are used, lower dislocation rates are also seen with the anterior rather than posterior approach to surgery, but this has not yet been demonstrated for procedures that involve heads with a larger diameter. Patients can decrease their risk of dislocation by avoiding certain postures during the first several months following surgery. Alcohol use in the few months following surgery is associated with an increased risk of dislocation.
Loosening of the joint
This is the most common complication of hip replacement and occurs when the shaft of the prosthesis becomes loose in the socket of the thigh bone or the bone surrounding the implant starts to thin. This can lead to pain and a sensation that the joint is unstable. If the joint does loosen, it usually happens 15 to 20 years after the surgery took place, at which point a revision surgery may be required.
Wear and tear
Wear and tear of the artificial hip joint is another common complication of this procedure. Wearing of the prosthesis can cause the joint to become loose, requiring further surgery if the problem is severe. Metal-on-metal prostheses are thought to become subject to wear and tear sooner than expected and the annual checking of these implants is recommended.
The soft tissues that surround an implant can become stiff and lead to reduced mobility, although this does not usually cause pain. The problem can be prevented using radiotherpay or medication.
Sensitivity to the metal
Some people may be sensitive or allergic to the metal in the implants, causing local inflammation to develop or delayed healing, for example. The surgery may also fail altogether.
Some more rare but serious types of complications that may occur after a hip replacement procedure include:
The formation of blood clots
During the first few weeks after surgery, there is a small risk of thrombosis developing. The two main places a blood clot may form include the leg (deep vein thrombosis), or the lung, in which case, the clot is referred to as a pulmonary embolism. In cases where either is suspected, immediate medical attention should be sought. The risk of blood clot formation can be reduced by using anticoagulant therapies such as warfarin.
Hip replacements patients are at a small risk of bacterial infection occurring at the artificial hip joint. Patients should urgently seek medical attention if they develop symptoms such as fever, chills, persistent hip pain or inflammation/discharge at the surgery site.