Knee Replacement Surgery
Knee Replacement Surgery
Knee replacement, also called knee arthroplasty or total knee replacement, is a surgical procedure to replace a knee damaged by arthritis. Metal and plastic components are commonly used to cap the ends of the femoral and tibial bones that form the knee joint, along with the kneecap, called the patella. This surgery should only be considered for individuals with severe arthritis or a significant knee injury who are good surgical candidates with low risk.
Many types of arthritis can affect the knee joint. Osteoarthritis is a degenerative joint disease that affects most middle-aged and older adults, causing the breakdown of joint cartilage and the surrounding bones of the knee joint. Rheumatoid arthritis causes inflammation of the synovial membrane (the fluid lining of the joint), resulting in excessive synovial fluid, which leads to inflammation, pain, and stiffness. Arthritis secondary to trauma, on the other hand, is due to an injury that damages the cartilage of the knee joint.
Anatomy of the knee
Joints are the areas in the body where two or more bones meet. Most joints are mobile, allowing the bones to move. The knee consists of two long leg bones held together by muscles, ligaments, and tendons. Each bone end is covered with a layer of cartilage that absorbs shock and protects the knee.
There are two main groups of muscles involved in knee movement: the quadriceps muscles (located at the front of the thighs), which straighten the leg, and the hamstring muscles (located at the back of the thighs), which bend the leg at the knee joint.
Tendons are strong cords of connective tissue that connect muscles to bones. Ligaments are elastic, band-like tissues that connect bone to bone. Some ligaments in the knee provide stability and protect the joint, while others help limit the forward and backward movement of the tibia (shin bone).
Components of the knee include:
- Tibia: This is the shin bone is the largest bone of the lower leg.
- Femur: This is the big thighbone or upper leg bone.
- Patella: This is the kneecap.
- Cartilage: A type of soft tissue tissue that covers the surface of a bone at a joint. It helps reduce the friction of movement within a joint.
- Synovial membrane: A mucus-like tissue that lines the joint and seals it into a joint capsule. The synovial membrane secretes synovial fluid (which is a clear, sticky fluid) around the joint to lubricate it.
- Ligament: Is a tough, elastic connective tissue that surrounds the joint giving it support and limiting the joint’s movement.
- Tendon: Is a type of tough connective tissue that connects muscles to bones and which helps to control movement of the joint.
- Meniscus: Is a soft curved part of cartilage in the knees and other joints that acts as a shock absorber, and which increases the contact area, and deepens the knee joint.