Unicompartmental Knee Replacement

The knee can be divided into three compartments:

  • Patellofemoral Compartment
  • Medial Compartment
  • Lateral Compartment

Traditionally, total knee replacement was commonly indicated for severe osteoarthritis of the knee. In total knee replacement, all worn out or damaged surfaces of the knee joint are removed and replaced with new artificial parts.

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. Partial knee replacement is a surgical option if your arthritis is confined to a single compartment of your knee.

We have been doing this procedure since last 10 years. This requires a preoperative education program and intense postoperative pain management. The overall satisfaction rate with this procedure is approximately 90% and we expect the survivorship of the implant is approximately 20-25 years.

Unicompartmental knee replacement offers the patient with single compartment bone-on-bone knee arthritis the opportunity of improved quality of life with a fairly straightforward procedure. Often unicompartmental knee implants feel far more natural than total knee replacements because there is less disruption involved with the surgery and usually far greater range of motion and function. The operation should be performed early in the disease rather than late before other compartments of the knee are involved.


Arthritis is inflammation 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.


  • knee pain, which may increase after activities such as walking, stair climbing.
  • The joint may become stiff and swollen, limiting the range of motion.


We will diagnose osteoarthritis based on the medical history, physical examination, and X-rays.

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


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

During the surgery, a small incision is made over the knee to expose the knee joint. We will remove only the damaged part of the meniscus and place the implant into the bone by slightly shaping the shin bone and the thigh bone. The plastic component is placed into the new prepared area and is secured with bone cement. Now the damaged part of the femur or thigh bone is removed to accommodate the new metal component which is fixed in place using bone cement. Once the femoral and tibial components are fixed in proper place the knee is taken through a range of movements. The muscles and tendons are then repaired and the incision is closed.


  • Minimal disturbance to normal knee function
  • Less disruption to lifestyle
  • Less postoperative pain
  • Less bone removed
  • Less blood loss
  • Less risk of infection, bleeding and wound problems
  • Rapid return to normal knee function
  • Shorter hospital stay
  • Allows for future treatment options (TOTAL KNEE REPLACEMENT)
  • Smaller incision
  • Feels more like a natural knee


Patient stay at our hospital is around 1-2 days.

We allow immediate weight bearing on 2nd post op day and stair climbing before discharge.

Foot and ankle movement is encouraged immediately following surgery to also increase blood flow in your leg muscles to help prevent leg swelling and blood clots. Most patients begin exercising their knee the day after surgery. Our physiotherapists will teach you specific exercises to strengthen your leg and restore knee movement to allow walking and other normal daily activities soon after your surgery particularly concentrating on getting the knee fully straight and flat by quadriceps contraction. Bending is encouraged but not forced, and always comes once the swelling goes down. This may take 6 weeks or more.


  • For approximately 2 weeks after surgery, your activity level is usually limited, however you will be able to walk independently and use bathroom and kitchen facilities.
  • Within 6 weeks you will have resumed most of your normal activities. Squatting and kneeling come with time.
  • Complete surgical healing takes 6 to 8 weeks. During this time, some swelling and discomfort is normal and should be manageable with the prescribed medications.
  • After this time the knee tissues start to begin to soften and become more natural.
  • Some patients may require an injection of cortisone (after 12 weeks) to relieve tissue soreness due to surgery and readjustment of the knee.
  • Some patients may experience a small area of numbness on the lateral aspect (outside edge) of the incision. This may or may not resolve over time and can take 6 to 12 months.

Some physiotherapy exercises post surgery are like

Knee bending high sitting

Straight leg raise

Knee quadriceps extensor


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 out
  • Loosening of the implant
  • Bearing Dislocation


  • Many tablets can cause excessive bleeding at operation so it is essential to cease taking the medication well beforehand. However, if you are taking such medication for problems with your heart or blood vessels, please ensure you discuss this us.
  • Clopidogrel, Warfarin/Coumarin/Marevan cease 5 days pre-op.
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