yarmouth orthapaedic surgeon

Uni-Compartment Knee Replacement (UKR)

The knee is made up of 3 compartments: medial (inner knee), lateral (outer knee) and patello-femoral (under the kneecap).

Uni-compartment knee replacement (UKR) (also known as partial knee or half-knee replacement) is designed for younger, active patients with isolated arthritis affecting the medial or lateral compartments of the knee.

The main advantages of a partial over a total knee replacement are:

  1. The new knee will feel more “normal” due to the ACL being preserved
  2. the incision is smaller (10cm along inner side of knee cap)                                                                                                   
  3. the length of stay is shorter
  4. you will be able to resume sporting and daily activities sooner (ie quicker recovery)


  • 1. Localised pain of the affected compartment (usually medial).
  • 2. Decreased walking distance
  • 3. Increasing difficulty with daily activities e.g. running, climbing stairs
  • 4. Night pain.
  • 5. Increasing bowing of the leg


  • X-rays of the knee (standing frontal, lateral and skyline views)
  • MRI
  • Occasionally arthroscopy (to see if you are suitable for UKR)

As you can see, the cartilage in the medial compartment (inner knee) is completely worn out with bone touching bone

Photograph of a uni-compartment knee replacement    


Post operative x-rays

The usual hospital stay is 1 – 2 nights and you should be able to return to normal activities at 3 – 6 months.