What Is Dislocation of a Prosthetic Hip?

Prosthetic hips are designed to mimic the function of a normal hips and provide near-normal ranges of hip motion. However, prosthetic hip joints have certain disadvantages, including increased hip dislocation risk. Hip dislocation is a risk factor inherent to prosthetic hip implants.

Function

• Dislocation of a prosthetic hip occurs when the femoral head, or hip bone, slips out of the hip socket, or acetabulum. This generally occurs as the result of a fall or injury that twists the hip in an abnormal and excessive manner.

Significance

• When a prosthetic hip dislocates, the hip joint becomes very unstable and painful. Walking is generally not possible without the use of a crutch. Immediate medical attention is required to put the dislocated femoral head back into the hip socket. This is normally done under anesthesia by an orthopedic surgeon.

Considerations

• A prosthetic hip joint is less stable than a normal hip joint and, as a result, is more prone to dislocation. This is due primarily to the fact that prosthetic hip implants use femoral heads that are smaller in size than normal femoral heads and, as a result, are easier to dislocate.

Prevention/Solution

• Prosthetic hip recipients are advised to exercise caution and restraint when performing physical activities and/or hip motions that require deep bending or twisting. These movements place significant stress on a prosthetic hip and increase the risk of dislocation.

Potential

• Many hip replacement surgeries are being performed with the use of large diameter femoral heads, which are purported to offer increased hip joint stability and decreased chance of hip dislocation. These large diameter femoral heads are generally made of cobalt chrome.