The hip is one of the largest weight-bearing joints in the body. When it's working properly, it lets you walk, sit, bend, and turn without pain. Unlike the shoulder, the hip sacrifices degree of movement for additional stability. To keep it moving smoothly, a complex network of bones, cartilage, muscles, ligaments, and tendons must all work in harmony.
The hip is a ball-and-socket joint where the head of the femur articulates with the cuplike acetabulum of the pelvic bone. The acetabulum fits tightly around the head of the femur. The ball is normally held in the socket by very powerful ligaments that form a complete sleeve around the joint (the joint capsule). The capsule has a delicate lining (the synovium).
The head of the femur is covered with a layer of smooth cartilage which is a fairly soft, white substance. The socket is also lined with cartilage. This cartilage cushions the joint, and allows the bones to move on each other with very little friction. An x-ray of the hip joint usually shows a "space" between the ball and the socket because the cartilage does not show up on x-rays. In the normal hip this "joint space" is approximately 1/4 inch wide and fairly even in outline.
Knee Replacement Surgery also known Total Knee Arthroplasty is a cure of painful knees, knee arthritis and other knee related issues. Knee Replacement is a surgical procedure during inwhich the bones of the knee are resurfaced with metal and plastic implants.
The weight passing through the knee should be well distributed for which the bones of the knee are well aligned. The need for knee replacement surgery in most cases is knee osteoarthritis or degenerative joint disease. With age the cartilage surface at the end of the bones is worn away which inflames the knees and affects the normal functioning of the knee. The injured cartilage, sore tissues and exposed bone causes pain. Swelling of the knee, knee pain, bow-legged deformities, loss of motion are some of the symptoms of serious arthritis of the knee joint.
A total shoulder arthroplasty, or joint replacement, is sometimes performed to repair a fracture of the proximal (or upper third of the) humerus, the large bone of the upper arm. 'One of the problems with the proximal, or ball, part of the shoulder joint,' says Dr. Garg, 'is that its blood supply can be somewhat precarious, and if there's been a fracture with numerous fragments, some of those fragments don't have a good supply and may not heal, or the bone actually may die there.' More often, a shoulder arthroplasty is done because of arthritic change. Someone may have completely worn out the articular cartilage in their shoulder joint, either as a result of osteoarthritis - in which case it's usually someone in their 60s or 70s -