**1. Introduction**

Hip arthroplasty is a surgical procedure where the entire or part of the hip joint is replaced with a prosthetic implant. Hip arthroplasty comes in a wide range of variations. There are two types of procedures involving femoral head replacement: total hip arthroplasty and hemiarthroplasty. The femoral head is replaced with a prosthesis while the native acetabulum and acetabular cartilage are kept in hemiarthroplasty. The acetabulum, as well as the femoral head, are both replaced during total hip replacement.

A hip or proximal femoral fracture in an elderly patient is the most common reason for hemiarthroplasty. The displaced intracapsular fracture is the most common type of hip fracture treated with arthroplasty. The majority of extracapsular fractures are treated with fracture internal fixation. There is still debate about the best treatment for displaced intracapsular fractures in the elderly. Internal fixation reduces

operative trauma, but complications such as fracture displacement, nonunion, and avascular necrosis may necessitate revision. Although internal fixation is still preferred in some countries, most surgeons now treat this fracture with arthroplasty.

The Moore prosthesis (1952) and the FR Thompson Hip Prosthesis (1954) are the most well-known early hemiarthroplasty designs (1954). Both of these implants are monoblocks that were designed prior to the development of poly (methyl methacrylate) bone cement, so they were initially inserted as a "press fit." The Moore prosthesis has a fenestrated femoral stem as well as a square stem with a shoulder to allow for stability within the femur and to resist rotation within the femoral canal. It is commonly used without cement, and bone in-growth into the fenestrations can occur over time. Thompson prostheses have a smaller stem with no fenestrations and are frequently used in conjunction with cement. There are numerous other designs of unipolar hemiarthroplasties that are based on stems used for total hip replacements [1].

In bipolar prostheses, there is an articulation in the femoral head component itself. In this type of prosthesis, there is a spherical inner metal head with a size of between 22 and 36 millimeters in diameter. This fits into a polyethylene shell, which in turn is enclosed by a metal cap. The objective of these condjoints is to reduce acetabular wear by promoting movement at the interprosthetic articulation rather than with the native acetabulum. There are a number of different types of prostheses with different stem designs. Examples of bipolar prostheses are the Charnley-Hastings, Bateman, Giliberty, and Monk prostheses, but many other types with different stem designs exist [1].

The femoral stem can be fixed during hip arthroplasty using cement or by bone growth into a porous-coated implant, depending on the surgeon's inclination. In elective total hip arthroplasty for osteoarthritis, some orthopedic surgeons now use uncemented femoral components, whereas some prefer cemented stems [2].

Hemiarthroplasty requires different considerations than complete hip arthroplasty. In the latter, clear exposure of both the femur and the acetabulum is essential, necessitating a very long exposure. Because patients are often older and more sensitive to anesthetics and surgical procedures, hemiarthroplasty requires a quick yet successful surgery with the least amount of stress and physiological disruption. There have been several surgical methods for the hip documented [3].
