Computer-Assisted Surgery (CAS) with Minimally-Invasive Surgery (MIS) Total Knee Replacement

Knee Information

Computer-Assisted Surgery (CAS) with Minimally-Invasive Surgery (MIS) Total Knee Replacement using VectorVision® knee TKR Navigation

Dr Haber is one of the first in the Illawarra to use a computer-aided imaging system during total knee replacement surgery. This very new technique is referred to as computer-assisted surgery (CAS).

CAS assists the surgeon align the knee components precisely in the bone.

This will increase the long term survival of knee replacement by sharing the wear evenly across the joint replacement.

VectorVision® knee TKR Navigation Enables Knee Replacement Surgery with Greater Precision and Control

3D Bone Morphing provides 3D anatomical information

Navigation of Bone Resections enables precise position and alignment of the planned bone cuts.

VectorVision software provides the actual anatomy of the patient without the need of diagnostic imaging. The model is easily created based on acquired anatomical information like axes, landmarks ( and important bone surface areas with a wireless pointer).

The system digitizes these landmarks and morphs this information onto an in the software stored 3D model. The model provides comprehensive 3D information to allow best orientation during the surgery.

The system automatically creates a treatment plan intra-operatively.

During computer-assisted surgery, a model of the knee is created using information obtained from a special instrument that outlines the contour of the knee.

The wireless pointer communicates with a computer. The computer then develops a model of the knee. This image is projected onto a monitor and helps guide the surgeon's attachment of the components to the bone. Precise alignment of the knee can be achieved using this system.

To insert the knee as perfectly as possible the computer need to know some bony landmarks. Small spheres are attached to the bone which the computer can sense. By simply moving the leg around in all directions the computer can calculate the centre of the hip joint.

A probe is placed on the inside and outside of the ankle and the inside, outside and centre of the knee. The computer then calculates the alignment of the leg.

The probe is then placed on parts of the tibia and femur. The computer indicates which parts of the bones to place the probe. It then creates a computer image of the knee joint.

Once it has this information it can dictate the direction the bony cuts should be made to fit the components in as close to perfect position as possible.

Above the hand held probe with the three dots attached is used to identify for the computer some boney landmarks.

Above the knee is in flexion as the computer identifies position of the knee.

Below are further examples of images seen on the computer during surgery.

The surgeon has also the option to make individual modifications of the treatment plan, including the size, position, and orientation of the implant. Surgical instruments are continuously tracked by the navigation system to judge the precise position and alignment of the planned bone cuts

This provides the surgeon with comprehensive real-time information, which allows him to make confident decisions for greater control over the surgical outcomes.

For further information on the system used by Dr Haber please visit by clicking on the Brainlab site on VectorVision® knee TKR Navigation

A summary of orthopaedic articles on CAS TKR's can be view by clicking on CAS in knee replacements- the literature

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