Biology Today — January 2018

Total Knee Replacement Surgery

K

nee replacement is a surgical procedure wherein the diseased knee joint is replaced with artificial material. It is

also called arthroplasty or resurfacing as only the surface of bones are replaced. The knee replacement surgery is

considered only for those patients whose knee joints have been damaged by either progressive arthritis or other rare

destructive diseases of the joint. There are different types of knee replacement surgery-total knee replacement, partial

knee replacement, kneecap replacement, revision knee replacement, etc. Out of these, the most common form is total

knee replacement surgery in which the surfaces of thigh bone and shin bone that connect the knee are replaced. Patella

may or may not be resurfaced depending upon the requirement.

Knee is the largest joint (hinge

joint) in the body and is required

to perform most of the day to day

activities. It is formed from lower

end of thigh bone (femur), the

upper end of shin bone (tibia) and

kneecap (patella).

Normally, all the components of

knee work in harmony but a disease

such as osteoarthritis can disrupt

it, resulting in chronic knee pain

and disability. The progressively

increasing pain and stiffness lead

to total knee replacement.

BIO-GRAM

Normal Knee vs Diseased Knee Due to Osteoarthritis

Process of Total Knee Replacement Surgery

An incision is made in the right

knee exposing the joint.

The arthritic surface of the tibia

is removed with a bone saw.

The arthritic surfaces of the femur are

removed with a bone saw.

Bone saw

Femoral

cut guide

Patella

Removed

surface

Completed

tibal cut

Completed

femoral cut

The femoral and tibial prostheses

are put into place.

Femoral prosthesis

allows kneecap to move

up and down smoothly

against bone.

Tibial prosthesis

a flat metal platform

with a cushion of

strong, durable

plastic.

Patellar prosthesis is a dome

shaped piece of polyethylene that

duplicates the shape of patella.

A button is placed over the back of

the patella and the wound is closed.

Replaced knee

Plastic spacer

(provide smooth

gliding surface)

Fibula

Tibia

Tibial

component

of prosthesis

Femoral
component
of prosthesis

Femur

Normal knee Diseased knee

Patella

(Kneecap)

Femur

(Thigh Bone)

Tibia

(Shinbone)

Lateral

collateral

ligament

(LCL)

Meniscus located

between femur and

tibia is a C-shaped

cartilage that

acts as a shock

absorber, increase

contact area and

deepens the knee

joint.

Posterior cruciate

ligament (PCL)

Anterior cruciate

ligament (ACL

Medial collateral

ligament (MCL)

Articular cartilage lines the

ends of three bones, i.e.,

femur, tibia and patella. It

is a smooth substance that

protects the bones and

helps to reduce the friction

of movement within a joint. Articular

cartilage

loss

Joint space

narrowing

Bone spurs