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What is Outpatient Unicondylar Knee Replacement?

A unicondylar knee replacement, also known as unicompartmental or partial knee replacement, is a procedure to replace a portion of the damaged knee joint with a prosthetic implant to relieve pain and improve function of the knee joint. Traditionally performed as an inpatient procedure, advances in technology have allowed this procedure to be performed in a minimally invasive manner on an outpatient basis allowing patients to go home the same day of the surgery

Knee Anatomy

The knee is made up of the femur (thighbone), the tibia (shinbone), and patella (kneecap). The lower end of the thighbone meets the upper end of the shinbone at the knee joint. A small bone called the patella (kneecap) rests on a groove on the front side of the femoral end. A bone of the lower leg (fibula) forms a joint with the shinbone. The bones are held together by protective tissues, ligaments, tendons, and muscles. Synovial fluid within the joint aids in smooth movement of the bones over one another. The meniscus, a soft crescent-shaped cartilage between the femur and tibia, serves as a cushion and helps absorb shock during motion.

When is Outpatient Unicondylar Knee Replacement Indicated?

The most common indications for outpatient unicondylar knee replacement not amenable to conservative treatment include:

  • Osteoarthritis of the knee joint
  • Skeletal dysplasias (a disorder that causes abnormal bone growth)
  • Avascular necrosis (death of bone in the knee joint due to issues with blood supply)
  • Rheumatoid arthritis
  • Knee deformity with loss of cartilage and pain
  • Injury or fracture of the knee
  • Gouty arthritis
  • Instability of the knee
  • Significant pain, swelling, and stiffness affecting mobility and quality of life

Diagnosis for Outpatient Unicondylar Knee Replacement

A detailed examination with an orthopedic surgeon will confirm whether or not you need an outpatient unicondylar knee replacement, including:

  • Review of medical history to assess general knee health, signs and symptoms, and previous injuries or surgeries
  • Physical examination to assess the range of motion, amount of swelling, disfigurement, and severity of pain
  • Imaging tests such as X-rays to determine the extent of deformity and damage and MRI scans for a detailed evaluation of soft tissues in your knee

What Happens during Outpatient Unicondylar Knee Replacement?

The operation is performed in an outpatient setting under anesthesia. After adequately sterilizing the surgical area, the surgeon makes a small cut to gain access to the affected knee compartment. The supporting structures of the knee are gently moved out of the way and the damaged cartilage and bone tissue from the surfaces of the femur and tibia are removed. Your surgeon prepares these surfaces appropriately to insert specifically sized prosthetic components to your joint. These components are then secured with the use of cement. All surrounding tissues and structures are restored to their normal anatomic position, and the cut is closed with sutures and sterile dressings.

Postoperative Care and Instructions

As it is an outpatient (same-day) surgery, you will be able to leave the hospital on the same day after your anesthesia wears off. Recovery depends on various factors but is generally quick. You will be given postoperative instructions on:

  • Use of assistive devices for walking, such as a cane
  • Limited weight-bearing activities
  • Surgical site care
  • Physical therapy and exercise regimen
  • Maintaining a healthy weight to minimize stress on the joint
  • Adherence to pain medications to keep you comfortable
  • Adherence to your follow-up appointments

What are the Advantages of Outpatient Unicondylar Knee Replacement?

The advantages of an outpatient unicondylar knee replacement procedure include:

  • Minimal surgical incision
  • Shorter recovery period
  • Shorter hospital stays with same day discharge
  • Reduced postoperative pain
  • Less blood loss during surgery
  • Less damage to surrounding tissues

What are the Risks and Complications Associated with Outpatient Unicondylar Knee Replacement?

Outpatient unicondylar knee replacement is relatively a safe procedure, but however, as with any procedure, it does carry some risks, including:

  • Blood clots
  • Infection
  • Bleeding
  • Injury to nerves and blood vessels
  • Leg length discrepancy
  • Fracture
  • Implant loosening
  • Excess bone and scar tissue formation around the artificial knee joint causing reduced mobility

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