How does knee replacement surgery work?
Knee replacement surgery is a procedure in which the damaged surfaces of the knee joint are removed and replaced with prosthetic components designed to restore alignment, stability, and smooth joint movement.
The knee joint is formed by the femur (thigh bone), tibia (shin bone), and patella (kneecap). When arthritis or joint damage causes deterioration of the cartilage surfaces, patients may experience pain, stiffness, deformity, and reduced mobility.
During surgery, the damaged cartilage and a small amount of underlying bone are carefully removed from the lower end of the femur and the upper end of the tibia. These surfaces are then replaced with specially designed metal components. A highly durable polyethylene (plastic) insert is positioned between the metal components to create a smooth bearing surface and facilitate movement.
In selected cases, the undersurface of the patella may also be resurfaced to improve joint mechanics and reduce anterior knee pain.
The prosthetic components are typically secured to the bone using specialised surgical cement, although cementless fixation may be considered in certain patients.
Surgical Planning and Joint Alignment
Successful knee replacement surgery relies on precise surgical planning, accurate implant positioning, and restoration of the knee's natural alignment and stability.
Before surgery, detailed radiographic assessment is performed to evaluate deformity, bone quality, joint wear patterns, and overall limb alignment. This information assists in selecting the appropriate implant design and surgical strategy.
During the procedure, careful attention is given to:
- Restoring mechanical alignment of the leg
- Achieving balanced soft tissues and ligaments
- Correcting deformities caused by arthritis
- Optimising knee stability throughout movement
- Ensuring accurate implant positioning
- Maximising implant longevity and function
Modern technologies, including robotic-assisted surgery where appropriate, may assist in improving the precision of implant placement and soft tissue balancing.
What types of implants are used?
Modern knee replacement implants are manufactured from highly durable materials designed to withstand the demands of daily activity.
Components commonly include:
- Cobalt-chrome or titanium femoral components
- Titanium or alloy tibial baseplates
- Highly cross-linked polyethylene inserts
- Optional patellar resurfacing components
The choice of implant is individualised and depends on factors such as patient anatomy, bone quality, activity level, and the severity of joint degeneration.
What should I know after knee surgery?
Following surgery, patients begin mobilisation under the supervision of a physiotherapist. Early movement is encouraged to restore joint function, improve strength, and reduce the risk of complications.
Most patients spend several days in hospital before being discharged once they can safely mobilise and manage daily activities.
Recovery continues over several weeks and months as swelling subsides, strength improves, and knee function progressively returns. Physiotherapy plays a crucial role in regaining range of motion, restoring mobility, and achieving the best possible long-term outcome.
Dr Naidu develops an individualised rehabilitation programme for each patient to support a safe recovery and return to normal activities.
