1) Anesthesia and incision
The first step in surgical preparation is anesthesia and the covering of the knee area. Once you are under anesthesia, an incision is made over the front of your knee to expose the knee joint, so your surgeon has free access to the diseased or damaged bones.
During the next step, reference markers small reflective spheres that function as landmarks for the infrared camera of the navigation system are attached to the thighbone and the lower leg.
These markers are attached with temporary pins that are inserted into the bone or the incision. These pins are removed at the end of the procedure.
2) Anatomy correlation
The next step is a registration process. Your surgeon uses a small instrument that has the same type of reference markers attached to it. This tool is used to detect various points on your bones and communicate these anatomical landmarks to the software. With this information, the navigation software can calculate correct values for the alignment and positioning of the artificial knee implant.
In other words, the navigation system sees the markers on you, registers them with the software and then virtually re-creates your anatomy on the computer screen.
Software-guided knee surgery is performed without any additional images. This means that, except for diagnosis and planning, surgeons do not use further X-Rays, MRI or CT images during knee navigation. This is why registering the anatomy with the landmarks during the procedure is essential.
3) Pre-surgical simulation
Before surgery proceeds, your surgeon uses the software guidance system to perform stability tests on your knee. This gives valuable information, which the surgeon takes into account to create a stable knee with the artificial components.
After a check of the initial leg situation in flexion and extension, the navigation software provides important information for the successive surgical steps before any bone cuts are made.
In a later step, with the trial implants inserted, the final leg alignment is stored and analyzed, and then factors like implants and ligament position can be adjusted accordingly.