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Uni condylar Knee Replacement

Uni condylar Knee Replacement

Unicompartmental knee replacement is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant. It is also called a partial knee replacement. The knee can be divided into three compartments: patellofemoral, the compartment in front of the knee between the knee cap and thigh bone. The medial compartment, on the inside portion of the knee, and the lateral compartment which is the area on the outside portion of the knee joint.

Traditionally, total knee replacement was commonly indicated for severe osteoarthritis of the knee. In total knee replacement, all surfaces of the knee joint are removed and replaced with new artificial parts. Partial knee replacement is a surgical option if your arthritis is confined to a single compartment of your knee.

Disease Overview

Arthritis is inflammation and wear of a joint causing pain, swelling (inflammation), and stiffness.

Osteoarthritis is the most common form of knee arthritis in which the joint cartilage gradually wears away. It most often affects older people. In a normal joint, articular cartilage allows for smooth movement within the joint, whereas in an arthritic knee the cartilage itself becomes thinner or is completely absent. In addition, the bones become thicker around the edges of the joint and may form bony “spurs”. All of these factors can cause pain and restricted range of motion in the joint.

Causes

The exact cause is often unknown, however there are a number of factors that are commonly associated with the onset of arthritis and may include:

  • Injury or trauma to the joint
  • Fractures of the knee joint
  • Increased body weight
  • Repetitive overuse
  • Joint infection
  • Inflammation of the joint
  • Connective tissue disorders

Symptoms

Arthritis of the knees can cause knee pain, which usually increases after activities such as walking, stair climbing, or kneeling.

The joint may become stiff and swollen, limiting the range of motion. Knee deformities such as knock-knees and bow-legs may also occur.

Diagnosis

Your doctor will diagnose osteoarthritis based on your medical history, physical examination, and X-rays. A MRI may occasionally be needed to assist in the diagnosis.

X-rays typically show a narrowing of the joint space in the arthritic knee.

Surgical procedure

Your doctor may recommend surgery if non-surgical treatment options such as medications, injections, and physical therapy have failed to relieve symptoms.

During the surgery, a small incision is made over the knee to expose the knee joint. Your surgeon will remove any remaining meniscus. After shaping / trimming the shin bone (tibia) and the thigh bone (femur), the trial  implants are inserted. The knee is taken through a range of movement to ensure optimal positioning. The definitive implants are then inserted and fixed to the bones using bone cement. The plastic component is then placed into tibial implant. The knee capsule is repaired and the incision is closed.

Recent advances include robotic assistance in the planning and surgical technique. Further reading   Read More

Post-Operative Care

You may walk with the help of a walker or cane for the first 1-2 weeks after surgery. A physiotherapist will advise you on an exercise program to follow for 4 to 6 months to help maintain range of motion and restore your strength. You may perform exercises such as walking, swimming and biking but high impact activities such as jogging should be avoided.

Risks and Complications

Although uncommon, possible risks and complications associated with unicompartmental knee replacement include:

  • Knee stiffness
  • Infection
  • Blood clots (Deep vein thrombosis)
  • Nerve and blood vessel damage
  • Ligament injuries
  • Plastic liner wears 
  • Loosening of the implants

Advantages

The advantages of Unicompartmental Knee Replacement over Total Knee Replacement include:

  • Smaller incision
  • Less blood loss
  • Quick recovery
  • Less post-operative pain
  • Better overall range of motion
  • Feels more like a natural knee
  • AUSTRALIA ORTHOPAEDIC ASSOCIATION
  • AUSTRALIAN SOCIETY OF ORTHOPAEDIC SURGEONS
  • AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS
  • MONASH UNIVERSSITY
  • American Association of Hip and Knee Surgeons (AAHKS)