Hemiarthroplasty

A hemiarthorplasty as its name suggests is only a hemi/half replacement of the hip joint where in the ball is replaced while the socket which is the acetabulum remains intact.

Indication

Neck femur fractures
Unstable inter trochanter is fractures

The ceramic or metal ball is attached to a metal stem. This is called a hip implant. The stem is set down into the core of the thighbone (femur). It is firmly fixed in the femur in one of two ways:

Cemented
Cemented to the bone.

Uncemented
This kind of stem has a porous coating that the bone grows into.

As described earlier, the hemiarthroplasty prosthesis replaces the femoral head. The prosthesis is composed of a metal stem that fits into the hollow marrow space of the thighbone (the femur). It also has a metal ball that fits into the socket of the hip joint (the acetabulum).

The femoral head that attaches to the stem may be a separate part. Two types are commonly used by surgeons. Some surgeons prefer a solid metal ball to replace the femoral head. This type of prosthesis is called a unipolar type. Other surgeons prefer to use a bipolar type of prosthesis. The bipolar type has a femoral head that swivels where it attaches to the stem. The bipolar prosthesis was designed to try to reduce the wear and tear on the articular cartilage inside the acetabulum. It is unclear whether the swivel offers any significant advantages. Both types seem to work well.