Trunnion Design for Long-Term Durability of Hip Joint Prosthesis

Description

The musculoskeletal system which comprises of different muscles, bones,

and ligaments give support, stability, shape, and movement to the human body.

The total number of bones in the skeletal system are 270 at birth and gradually

reduce in number to 206 at adulthood due to fusion of few bones. Hip joint is

amongst the largest of the weight-bearing joints after the knee and also one of the strongest joints.

Usually, the average male femur is about 480mm in length with a diameter

of 23.4mm. The hip joint is a classic example of a ball and socket joint

where the head of the femur articulates in the acetabulum of the pelvis. The head

of the femur and acetabulum are covered by a 63.5mm thick shiny white hyaline

which acts as a smooth cushion to the joint. This joint has synovial fluid

articulated in the mating surface which allows the joint to flex under different

pressures without causing wear and tear. The synovial fluid and the hyaline help

the bones move each other at different degrees of freedom without causing pain

to the human.

Usually, hip problems are associated with aged people due to worn-out hip

joints. However, hip joint disorders can be associated with any person

irrespective of age without proper care.

Hip replacement surgery is considered to be amongst the greatest

advances in health care of the twentieth century. In 1925 the first replacement

made out of glass was used for the surgery by an American surgeon Marius

Smith-Petersen. An American surgeon named Dr. Austin T. Moore at the

Columbia Hospital, South Carolina performed the first metallic hip replacement

surgery on September 28, 1940. Later, Sir John Charnley, who is considered

the father of modern total hip arthroplasty, modeled a low friction arthroplasty

in the early 1960s. This design was identical, in principle, to the

prosthesis used in the present day. It consisted of a stem and head of the femur

and an acetabular cup with a backing cup.