Hemiarthroplastik

Hemiarthroplastik, or hemiarthroplasty, is a partial joint replacement in which only one side of a ball-and-socket joint is replaced with a prosthesis. It is commonly applied to the hip or the shoulder. The aim is to relieve pain and restore function while preserving the remaining socket or glenoid. In hip applications, implants may be unipolar or bipolar.

In a hip hemiarthroplasty, the femoral head and neck are replaced with a prosthetic component while the acetabulum is left intact. A unipolar prosthesis presents a single articulating head against the native socket, whereas a bipolar design has an additional articulating interface within the implant, potentially reducing wear on the acetabulum.

Indications include displaced intracapsular femoral neck fractures in older patients where rapid recovery is prioritized and total hip arthroplasty is deemed less suitable due to medical comorbidity. It is also used for certain conditions such as avascular necrosis or specific tumors. Shoulder hemiarthroplasty is performed for complex proximal humerus fractures or severe shoulder arthropathy when the glenoid is not involved.

The procedure is performed under regional or general anesthesia. The prosthetic stem may be fixed with bone cement or implanted press-fit, depending on bone quality and surgeon preference. Choice of unipolar versus bipolar designs and cemented versus cementless stems influences stability and wear patterns.

Outcomes typically include rapid pain relief and early mobilization. Long-term issues may include acetabular wear with unipolar implants, dislocation, infection, prosthetic loosening, and periprosthetic fracture. Rehabilitation focuses on early safe weight-bearing and joint protection to reduce complications.

Historically, hemiarthroplasty emerged in the mid-20th century, with bipolar designs developed to lessen acetabular wear and improve function.