Hip replacement surgery can be a godsend for those who suffer from chronic, end-stage arthritis. Removal of arthritic joint surfaces and replacing them with artificial components can mean a significant improvement in quality of life. For all the benefits that hip replacement surgery offers, this procedure does not come without potential risks and complications.
Infection
One of the most devastating complications of any joint replacement surgery, let alone hip replacement, is infection. Infection can be a post-operative complication, but even more serious are late-onset infections---those that can occur months and even years after the initial replacement surgery.
Infections can be caused by several factors such as a weakened immune system, as seen in patients with diabetes and other auto-immune diseases. They can also be caused by a process known as seeding in which bacteria from other locations on or within the body are transported to the site of the hip replacement by the blood stream.
The microorganisms settle in the hip area where there is little defense because of the artificial components that lack blood supply. Critical antibiotics cannot adequately work because of the inability to reach the metallic and plastic components that can harbor the bacteria.
Prosthetic Loosening
According to the American Journal of Rheumatology, another complication of hip replacement is loosening of the components. Similar to infections, loosening can occur early after the surgery or months afterward. In cases where the components are cemented into place by special bone cement, loosening can occur in areas where the cement comes into contact with bone or with the surfaces of the components.
Prosthetic components that are not cemented into place as in the case of a press-fit---a type of surgery that stimulates bio in-growth, or the growth of a patient's own bone into the new components---can also loosen from insufficient attachment of the bone to the prosthetic components, or from improper sizing or insertion at the time of surgery.
Vastly improved surgical implantation techniques have reduce the incidence of loosening to approximately 3% at 11 years post replacement, versus over 1/3 of hips at 10 years out,
Component Breakage
In some cases, the use of space-age plastic spacers between two metallic components of the hip can result in breakage of that plastic over time. This can occur from a variety of factors, including too thin a spacer, impact from too vigorous activity or an injury such as a fall. In some rare instances, the stem of the component that is inserted into the femur, or thigh bone, can break from unusual or abnormal stress on the metal by factors including morbid obesity, high-impact activities and faulty manufacturing processes.
Blood Clots
One very important potential complication of hip replacement surgery is the formation of blood clots within the deep veins of the lower extremities. The American Association of Orthopaedic Surgeons has intimated that this is the most common complication of hip replacement surgery. The term commonly used for this condition is called deep vein thrombosis. These clots can be potentially dangerous in that, if they are of sufficient size, there is the risk that part or all of the clot can break away from its location and travel to the patient's heart and/or lungs. This causes a serious complication known as pulmonary embolism. Pulmonary embolus, or P.E., can, in rare cases, be fatal.
Peri-prosthetic Fracture
Peri-prosthetic fractures refer to injuries, namely broken bones, that occur around or very near the components of a hip replacement. The fracture occurs in such a manner as to involve the component, requiring surgical intervention to fix the problem. Fractures that involve the femoral, or thigh bone, component are the most common, while fractures in the pelvis which involve the acetabulum, or cup component, are rarer.
Peri-prosthetic fractures typically require some level of surgical fixation to stabilize the bone to allow for proper healing. If the injury is severe enough to dislodge, or otherwise alter the proper positioning of the component, that component may have to be removed and re-inserted, or be replaced with a component more suitable for this type of scenario.
