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Partial Lateral Knee Replacement

What is Partial Lateral Knee Replacement?

Partial lateral knee replacement is a surgery to replace only the lateral part of your damaged knee. It is also called unicompartmental knee replacement.

The knee is one of the largest and complex joints in your body. The joint is connected to your thigh bones and bones of the lower leg by various ligaments. The knee joint is made of three compartments. The lateral, the medial and the patellofemoral compartment. The outside part of the knee is the lateral compartment. It consists of a Lateral Collateral Ligament (LCL).

Indications for Partial Lateral Knee Replacement

Lateral knee replacement is less common when compared to a medial and total knee replacement. Aging and joint conditions such as osteoarthritis cause breakdown of the cartilage leading to pain and inflammation which may not respond to pain medicine or non-surgical treatment and may require surgery. Lateral knee replacement is necessary when your knee bends outwards.


Your doctor physically examines your knee by performing specific movements to assess the problem. The exact location and severity of the pain are essential to identify the type and extent of the damage. Your doctor will also take your medical history and may order an X-ray or CT-scan or MRI to confirm the diagnosis.

Preparation for Surgery

Talk to your doctor about the medicines you are taking and those you should stop taking prior to the procedure. Inform your doctor if you are allergic to any medicines or anesthesia.

Partial Lateral Knee Replacement Procedure

  • Surgery is performed under general anesthesia or spinal anesthesia. The surgical procedure involves the following steps:
  • You are positioned to lie on your back (supine position).
  • The surgery is usually performed by arthroscopy. An arthroscope is a narrow tube with a tiny video camera on one end. The structures inside the knee are visible to your surgeon on a monitor in the operating room.
  • A few small incisions are made at the lateral side of the knee and an arthroscope is inserted to view the surgical area.
  • The damaged cartilage at the lateral portion of your knee is debrided. Some amount of bone may also be removed.
  • Debridement of some part of the distal femoral portion may be involved.
  • Metal components with a spacer in between are replaced at the lateral side of your knee to allow smooth gliding.
  • The incisions are closed and covered with a bandage.

After the Surgery

You may have to stay at the hospital for about 3 days. Your doctor prescribes pain medications to keep you comfortable.

Post-Surgery Rehabilitation

Your physiotherapist teaches you how to use your walker or crutches and may begin with light weight-bearing exercises. Specific physical exercises will be given to help you recover fast. You should regularly follow-up with your surgeon. You may return to sports after a few months with your surgeon’s approval.

Complications of the Surgery

Complications are rare. Some of the possible complications may include:

  • Formation of blood clots
  • Surgical site infection
  • Wear and tear of the implant
  • Injuries to ligaments or nerves
  • Dislocation of the implant
  • Patella problems

Advantages of the Surgery

The advantages of partial medial knee replacement surgery include:

  • Smaller incision
  • Minimum bone removal
  • Shorter hospital stay
  • Shorter recovery period
  • Blood transfusion rarely required
  • Better movement in the knee
  • Less need for physiotherapy
  • Able to be more active than after a total knee replacement
  • American Academy of Orthopedic Surgeons
  • American Medical Association
  • State Orthopedic Society UTAH
  • Medical College of Wisconsin