Today, I am going to discuss the Conformis iView. The Conformis iView is a unique plan that is customized for each patient’s surgery. And is provided to the surgeon at least two weeks before the procedure. The iView that I am currently looking at is of a right knee.
The first page of the iView shows us all of the necessary tibial images that we need to ensure a smooth procedure. The first sets of tibial images are going to show us the proper location of the tibial cutting jig.
While the surgeon is doing this procedure and placing the jig, he’s going to reference this image to ensure that the cutting jig is seated at the correct location. Once the correct location has been verified, the jig will be pinned into place and now the surgeon can make his proximal tibial resection.
The next image the surgeon will look at will show how much bone is going to be removed as a result of the cut through the T1 jig. Once the surgeon has finished this resection, he will take the cut bone to his back table and measure the cut thicknesses at various locations to make sure that it matches with the cut values that Conformis has provided. If it turns out that enough bone has not been removed, the surgeon can go back to his jig and continue to cut more bone until the proper amount of bone has been resected.
One specific cut value the surgeon will pay extra attention to is the LL cuts of the tibia. LL stands for lowest point lateral. If this cut value is greater than or equal to seven millimeters, the surgeon may decide to do a minus two cut, meaning they will take two millimeters less bone in order to preserve as much bone as possible and to help ensure that we use the thinnest polys possible at the end of the procedure, therefore creating the least amount of variance in the patient’s native joint line.
The next image is the location of the tibial tray. The tibial tray is the final implant that will stay inside the patient. The surgeon will use this image to ensure that the implant is placed at the proper location without any malrotation, also assuring maximum of the tibia with no overhang and no under coverage.
Since each tibia is customized for each patient, the fit of the implants on the bone should be precise. The final data provided on the tibial page of the iView will give us the thicknesses of the medial and lateral polys. The medial polys will always be 6.1 millimeters, 8.1 millimeters, 10.1 millimeters and 14.1 millimeters.
The lateral side of the poly will be the same as the medial side plus the patient’s distal femoral offset. This is different for every patient. And in this instance, the patient’s distal femoral offset is 0.5 millimeters. So in a 6.1 millimeter medial poly, the lateral side will be 6.6 millimeters. This offset allows us to achieve a neutral mechanical alignment, or in other words, allows us to give the patient back a straight knee.
The next page of the iView is going to show us all of the femoral images that are necessary in sharing a smooth procedure. The first image is going to show us the placements of the distal femoral cutting block. The surgeon will place the jig on the bone, and then will confirm with the image on the iView that the jig is seated in the right location.
The jig will reference as many osteophytes as possible to ensure that the location is proper. Once the correct location has been established, the jig will be pinned into place and then the surgeon can continue with his saw blade and make the distal femoral resection.
Once the bone has been cut, the resection can be taken to the back table and the surgeon can measure the cut bone and see if the thicknesses that have been cut matches the thicknesses that Conformis had recommended. If there is any variation, the surgeon can go back to this jig and continue to cut more bone until the proper amount of bone has been resected.
Next, the surgeon will look at the F4 jig, otherwise known as the 3-in-1 block. To ensure the proper placement of this jig, the surgeon will confirm that the medial of the jig matches the medial profile of the patient’s own. Once this location has been confirmed, the jig can be pinned into place and the surgeon can continue with his resections.
He will now cut the anterior portion of the femur, as well as the two posterior condyles. After the bone has been resected, the surgeon can take the resected bone to his back table and measure the thicknesses of the bone. If there is a mismatch between the amount of bone that has been resected and the amount of bone Conformis has recommended to be resected, the surgeon can go back to his jig and cut more bone until the proper amount has been removed.
The final set of images on the iView are going to show us how the final implants will look when it is placed on the patient’s bone. You will get an image of this from the front and the back with the knee straight and flexed at 90 degrees.
I am fellowship trained in joint replacement surgery, metabolic bone disorders, sports medicine and trauma. I specialize in total hip and knee replacements, and I have personally written most of the content on this page.
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