Arthroplasty, or hip replacement surgery is used to replace damaged, dislocated or deformed hips. Hip joint damage can be caused by trauma or by osteoarthritis, rheumatoid arthritis, avascular necrosis or bone tumours. These conditions cause the bone to wear down or become weakened by bone loss and are the main causes that lead to the need for hip replacement surgery.
Hemiarthroplasty is a partial hip replacement, where only one joint (usually the femoral head) is replace with a prosthesis or implant, whilst the socket section or acetabulum, is left intact. Hemiarthroplasty or partial hip replacement is normally recommended if the femur becomes fractured just below the femoral head. The femoral head is replaced with an implant or prosthesis which is held in place by a type of cement or by being snugly fitted into a pre-prepared cavity. In the latter case, the implant is made from a porous surface and is slightly bigger than the cavity allowing for a tight fit. The pores in the implant encourage the bone to receive the implant by growing into it creating a more secure bonding of the implant to the bone.
Just following partial hip replacement surgery, the patient will be seen by a physiotherapist who will advise the patient on the exercises needed to encourage healing. Respiratory exercises may be necessary to reduce the amount of liquid that the lungs can retain after surgery. The physical exercises are aimed at strengthening the joints and muscle to support normal activity. The patient will be advised on how to properly sit and posture themselves in order to avoid the dislocation or damage of the implant. Patients are generally not kept hospitalized for more than two weeks and many patients can sit on the edge of a bed, stand and even walk with aid within 2 days.
Hip replacement surgery is reported to have a success rate of over 90% but complications can still occur. The most common complication of a hip replacement is the loosening of microscopic particles on the implant that is absorbed by the local tissue and cause inflammation. The inflammation can in turn cause a reaction by local cells. These cells react by eating away at bone tissue which loosens the implant. Anti inflammatory medications are sometimes used to treat this complication or revision surgery (repeat surgery) may be required.