Partial Knee Replacement

Partial 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 Unicompartmental knee replacement.

Knee Anatomy

The knee is divided into three compartments:

• Medial: Inner part of the knee 
• Lateral: Outer part of the knee 
• Patellofemoral: Front portion of the knee, between the kneecap (patella) and thighbone (femur)

The Oxford Partial Knee

The Oxford Partial Knee consists of two components – the tibial and femoral implants, which are supported by a mobile bearing. The tibial and femoral components are made up of biocompatible metal whilst the bearing is made up of plastic. The Oxford Knee implants are available in different sizes to provide an optimal fit for unique anatomies of individual patients.

Advantages of Partial Knee Replacement

The advantages of a Partial Knee Replacement over total knee replacement include:

• Smaller incision, less damage to soft tissue and bone.
• Less blood loss
• Quick recovery
• Less postoperative pain 
• Better overall range of motion
• Feels more like a natural knee (improved kinematics)

Indications and Contraindications for Partial Knee Replacement

Partial Knee Replacement surgery is an excellent alternative to the total knee replacement procedure for patients with osteoarthritis or osteonecrosis in one compartment (area) of the knee. Usually 1 out of 3 patients with knee osteoarthritis are eligible for a partial knee replacement.

However, the plan may change during the operation and a Total Knee Replacement may be performed instead if there are findings of significant wear and tear in other areas of the knee or damage to the ligaments.

Partial Knee Replacement surgery is contraindicated for rheumatoid arthritis, for arthritis involving more than one compartments, or when the ligaments of the knee are not functionally intact.

Pre-surgical Preparation for Partial Knee Replacement

You will be required to undergo a medical check-up to assess your overall health and a physical examination to determine the location and intensity of your knee pain. X-rays will be performed to determine the extent of the damage, which will help determine if you are suitable for a partial knee replacement. Magnetic resonance imaging (MRI) scanning may also be ordered for better assessment of the knee and cartilage.

Partial Knee Replacement Procedure

The Partial Knee Replacement is performed under regional (spinal) or general anaesthesia using a tailored RAPID RECOVERY PROTOCOLS to ensure you are comfortable and pain-free during the procedure.

You will be placed in a supine position - face-up - with one leg bent at about 90 degrees and the other leg extended on the operation bed. 

The Oxford Partial Knee Replacement is a minimally invasive surgery performed using the following steps:

• Incision: The area to be operated on is marked and a cut is made in the specific section of the knee to access the damaged joint. At this stage Mr Sakis Pollalis will inspect all areas of the knee and confirm that you are suitable for a partial knee replacement.
• Preparing the bone: The damaged cartilage on the tibia and femur are removed with the use of accurate instrumentation.
• Soft tissue balancing: Using trial implants Mr Pollalis will assess the tension of the soft tissues with you knee in flexion and extension to ensure good balancing.
• Insertion of the implant: The Oxford Partial Knee Implants are introduced on the tibia and the femur without the use of cement. After a final trial the appropriate size mobile-bearing implant is inserted.
• Closing the incision: The incision is closed with sutures. An X-Ray will be performed before you go to recovery to confirm the success of your knee surgery.

The entire surgery usually takes less than 1 hour.

Care and Recovery after a Partial Knee Replacement

Post-surgery, you will be monitored in recovery and in the ward. Most patients can be discharged on the day of surgery or the next day.

• You will be prescribed pain medications to keep you comfortable. 
• You will be encouraged to walk immediately after surgery. Crutches, a walker, or a cane will be needed for weight-bearing in the first few weeks. 
• You will be asked to commence mild exercises as per your physiotherapist’s recommendations to remain active. Depending on the pace of your recovery, you should gradually increase the intensity of your regular activities.
• Your complete recovery may take up to 6 weeks although most patients are able to return comfortably to full activities sooner.
• Mr Sakis Pollalis will review you regularly whilst in hospital and after your discharge to make sure you are progressing well.

Risk and Complications of Partial Knee Replacement

As with most surgical procedures, Oxford Partial Knee Replacement may be associated with the following complications:

• Conversion to Total Knee Replacement
• Infection
• Blood clots in the leg or lung

• Knee pain, stiffness, or limited mobility

• Bone fracture

• Nerve or Blood Vessel Injury

• Bleeding and Hematoma

• Dislocation of the mobile bearing
• Progression of osteoarthritis to other compartments

• Prosthesis Failure or Loosening

• Requirement of additional surgery

• Cardiovascular risks, also leading to life-threatening complications
• Allergic reaction
• Anaesthetic risks

If you would like to have additional information on the treatment of various knee conditions or would like to learn more about unicompartmental/partial knee replacement, please contact Mr Sakis Pollalis, serving the communities of Buckinghamshire and Berkshire.