Home » Services » Hip & Knee Replacements » Knee Replacement » Robotic Unicompartmental knee replacement

Robotic Unicompartmental knee replacement

Unicompartmental knee resurfacing is a surgical procedure which involves replacement of only the diseased surface of the joint instead of the entire joint. The knee can be divided into three compartments: patellofemoral, the compartment in the front of the knee between the knee cap and thigh bone, medial compartment, on the inside portion of the knee, and lateral compartment which is the area on the outside portion of the knee joint. Your doctor may recommend unicompartmental knee resurfacing if your arthritis is limited to only the medial or lateral compartments of the knee.

Mr Clark has commenced performing unicompartmental knee replacement (UKR) with Robotic assistance. SJOG Subiaco have purchased the Stryker Mako Robotic Surgical System. This system utilises pre-operative CT scans. During the operation the surgeon collects information about the soft tissue balance of the knee. This information is combined with the CT scan and allows the surgeon to perform a virtual operation on the computer. Once the optimum position has been ascertained for the femoral (thigh bone) component and the tibial (leg bone) component, the robotic arm is then utilised to mill the bone ends and allow exact placement of the implants. This technology has been utilised in the United States since 2006. It was introduced into Australia by Mr Clark (together with Mr Dermot Collopy) in April 2015. The indications for partial knee replacement are not changed by the use of the robot. Accuracy of implantation has been shown to be improved. Currently all robotic cases in Australia are closely followed up to determine if this technology will decrease the previously high revision rates seen in unicompartmental knee replacement.

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. In a normal joint, articular cartilage allows for smooth movement within the joint, where as in arthritic knee the cartilage itself becomes thinner or completely absent. When arthritis affects the knee joint, it commonly occurs in two compartments, usually the medial and patellofemoral compartment. Unicompartmental osteoarthritis is a loss of the articular cartilage in only one compartment, either the medial or lateral compartments. The medial compartment is more commonly affected than the lateral compartment.

The exact cause is unknown, however there are a number of factors that are commonly associated with the onset of arthritis and may include:

  • Injury or trauma to the joint
  • Fractures at the knee joint
  • Increased body weight
  • Repetitive overuse
  • Joint infection
  • Inflammation of the joint
  • Connective tissue disorders


Unicompartmental osteoarthritis of the knees can cause knee pain and limited range of motion usually localized to the outer and inner aspect of the knee. The joint may become stiff, swollen, and a sensation of knee giving out. If the pain is severe you may have difficulty in performing normal activities.


Your doctor 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.

Surgical procedure

Your doctor may recommend surgery if non surgical treatment options such as activity modification, weight reduction, pain medications, injections, orthotic devices and physical therapy have failed to relieve the symptoms. Unicompartmental knee resurfacing procedure can be performed with a surgical robot. The Mako robot is designed to assist the surgeon with pre-surgical planning and provides optimal positioning of the implants. This procedure can substantially reduce or eliminate your arthritis pain. This surgery preserves the knee parts not damaged by arthritis as well as stabilise anterior and posterior ligaments, ACL and PCL. This surgery is useful for young and more active patients as the implant placed more closely mimics actual knee mechanics than does a total knee surgery. Another advantage of this surgery is that it will not change the ability of the patient to finally move to a total knee replacement in the future unless it is required.

The surgery is performed under sterile conditions in the operating room under spinal or general anaesthesia. A small incision is made over the inside area of the knee to expose the medial compartment of the knee joint. Your surgeon will use to surgical robotic arm to remove the damaged cartilage from the medial compartment of your knee. The new artificial component is placed into the new prepared area and is secured with bone cement. Once the new components are fixed in proper place the knee is taken through a range of movements. The muscles are then repaired and the incision is closed.

Postoperative care

Following the surgery, you will be taken to the recovery room to be monitored. Your doctor may also recommend pain medications to relieve pain. To help reduce the swelling elevate the leg and apply ice packs on the knee. You will be instructed about the activities to be avoided and exercises to be performed for faster recovery. A rehabilitation program may be advised for a speedy recovery.

Risks and complications

Possible risks and complications associated with patellofemoral knee replacement include:

  • Infection
  • Blood clots(Deep vein thrombosis)
  • Nerve and blood vessel damage
  • Ligament injuries
  • Arthrofibrosis(thick fibrous material around the joint)
  • Wear
  • Dislocation
  • Fractures or breaks
  • aaos
  • AOS
  • RACS
  • SJOG
  • Robotic Arm Assisted TKA
  • Robotic Arm Assisted THA
  • Robotic Arm Assisted PKA