Some conditions that can cause hip pain after an artificial joint replacement are hip dislocation and heterotopic ossification. Blood clots, an infection of the joint or the surgical wound, a delay in healing or nerve injury can also cause pain, according to WebMD.
A blood clot can form in a vein in the leg and this is dangerous if it blocks the blood flow to the heart or if the clot moves to the lungs. Clots can cause pain and form more frequently in older people and those who are obese. Infection of the joint or the surgical wound is rare and is mainly caused by pre-existing diseases like chronic liver disease, rheumatoid arthritis and diabetes. Surgical wound infections are treated using antibiotics. An infection deep inside the joint can be very painful and may require additional surgery, states WebMD
Nerve injury after joint replacement takes place when the surgeon also corrects a joint deformity, in addition to replacing a part of it. Nerve injury makes it difficult to move the muscles around the joint. Another factor that may cause pain is delayed wound healing. Patients who are on corticosteroids or those who have impaired immunity due to diabetes or rheumatoid arthritis may experience delayed wound healing, notes WebMD.