Signature Custom Designed Knee

	Signature custom cutting guide applied to the diseased knee.

Up until know, a small but significant percentage of total knee replacement patients have been unhappy with their surgery because the new knee “hurts”, is “too tight”, is ”too  loose”, or just “doesn’t feel right”.  Signature technology is now being shown to improve on this situation and provide a better chance for a given patient to have a perfect result.  But, what is a “perfect result”?  To me it is a knee that works great and feels great. This means that the knee obtains a full range of motion (bends and straightens all the way) and feels great with no pain or instability.  In short, a perfect result feels like a natural, normal knee.

Patients call and email all the time about which brand of implant I use or which is the best implant for them.  In my opinion this is due to the direct advertising of knee implants to the public by the various manufacturers.  In the United States there are five major companies that compete and several smaller ones. The major five companies are Biomet, Depuy, Smith and Nephew, Stryker, and Zimmer in alphabetical order.  The truth is all of the top of the line implants of these companies are about the same. The differences between the design and materials used in these competitor's implants is minimal.  The truth is that what makes the difference in how well a total knee replacement surgery turns out, is how well it is placed into the knee, not which brand of implant is used.  The patient should be shopping for the best surgical implantation, and not try to pick a brand of implant for his or her case.  The patient  needs to understand that the motion of the knee is very complex. As the knee bends, the lower leg rotates internally. The knee is not a simple hinge joint.  Signature technology is aimed at implanting the new knee into the correct position so that the complex motion of the human knee is retained. This is why a Signature knee can feel like a normal knee!  The technique of implantation (How good is the surgeon and what technique of implantation does he or she use?),  and the position of the knee in the patient is what counts, NOT which brand of knee is used. 

Up until Signature and Otis technology, the surgeon used standard external knee guides (click here to see them). With a standard knee replacement, the surgeon designs the implantation at surgery as he is going a long during the procedure.  Many surgeons always cut the posterior cruciate ligament and then perform soft tissue balancing once the implant is cemented in the knee.  Soft tissue balancing requires cutting or lengthening the collateral ligaments on the side of the knee.  These additional procedures can cause more post -operative swelling and pain, and a longer recovery.  In Signature surgery the posterior cruciate ligament is never cut.  Soft tissue balancing is not necessary because the implantation is designed to be balanced from the very beginning.  

The breakthrough of Signature technology is that a computer plans the procedure so that the implant size and placement is custom designed to the patient's bones and soft tissues. Ligament releases (or cuts) are rarely, if ever, required, and the knee will obtain a more natural range of motion, both bending and straightening, automatically, as a result of the knee replacement being specifically designed for the patient's own knee anatomy. This is accomplished by obtaining an MRI of the knee four weeks before surgery to obtain precise digital data as to the exact size dimensions of the patient's arthritic knee. The data is then sent to Biomet corporation and a virtual digital model of the diseased knee is made by computer. Special computer software then restores the bone shape and the alignment of the knee to what it was before any disease occurred, correcting either the bow leg or knock knee deformity that usually occurs with advanced arthritis. Next, the correct size of knee implant is selected and designed into the proper position in the knee. Single use custom made cutting guides are then made in Belgium (click here to see them).  When the new knee is put in, the Signature knee feels like the knee felt before the arthritis occurred because the knee is now back in its natural pre-disease alignment. This is what makes this breakthrough in surgery amazing. (see illustration below)

MRI derived model of diseased knee bones with arthritis. Signature software is shown as well.

This patient-specific Signature knee replacement design technology procedure is now a technical advance beyond "Gender Specific" implant design, which only offers smaller and more tapered sizes of "off the shelf" implants, or "Computer Navigation" which only helps align the knee but does not size and place the implant to the bones or balance the soft tissues in order to return the knee to its natural state. Computer navigation has now been shown to not improve the implantation or final result.

Signature knee Replacement technology shortens the operating time, which reduces the chance of infection and other systemic complications. The patient's recovery to normal function is enhanced because soft tissue releases (or cutting of the ligaments) are not required, and it is not a struggle for the patient to recover a more full range of motion of the knee because range of motion recovery has been designed into the implantation itself. Instead of taking three to four months to recover from a total replacement, it now appears possible for some patients to return to normal daily activity in as little as six weeks with much greater satisfaction about the surgery.

Dr. Likover has performed over 500 MRI computer designed knee replacement procedures either with Otis knee or Signature technology.  You should take advantage of his vast experience.

In summary, Signature and Otis knee patients have reported: 

• Greater range of motion, immediately after surgery and throughout recovery
• Better flexion to allow for more natural kneeling
• Quicker return to every day activity (driving, shopping, golfing)
• Shorter operative time, which reduces time under anesthesia
• Less post-operative pain

For further information go to www.biomet.com/patients/signature.cfm

Case Study 1		Case Study 2
This is a photograph of a gentleman with severe bowleg due to advanced osteoarthritis of the knee.   This is the correction obtained with a CustomFit  knee. This man has a perfect result and is super happy		The worst pair of bowlegs I have ever seen, the left was especially bad.
These are this man's xrays with severe arthritis causing a bowed leg.   The arthritis involves two compartments, the medial  compartment (inside) and the patellofemoral joint (kneecap joint). In this case a CustomFit total replacement, not an Oxford is required.		Pre-op xrays with severe bow. There is bone on bone on the inside of the knee, and screw in place from previous surgery.
Custom Fit Total Knee Replacement in place, with complete correction of the bow leg and with resurfacing of the kneecap joint.		Both knees are now replaced.  The left is 9 weeks and the right is three weeks after surgery. The patient is now very happy with full motion of both knees and he is actually slightly taller!
This is the computer-generated image of the patient's knee bones for this case, with the disease taken out, the deformity corrected, and the implant positioned for an ideal result. The patient-specific cutting guides are then made from this design.		Post-op xrays with bio-ingrowth tibial component (screws not cement initially holding it in place) and complete correction of the deformity

Click here to see actual surgical photographs of what arthritis looks like and what an installed total knee looks like. DON’T  CLICK IF YOU DON’T WANT TO SEE INSIDE THE HUMAN BODY. 

People ask me all the time what are the restrictions after a Signature knee.  The answer is that it is made for everything but running every day, basketball and volleyball. You can play tennis, golf, fish, hunt, exercise in the gym on any machine, lift weights, hike, ski, bowl and dance.  If you have any further questions, please email me on the “Send a message to Dr. Likover” form on right of this page.

Please read the testimonials about the CustomFit - Click Here

Custom Fit Knee™ Replacement and Shape-Match™ are registered trademarks of OtisMed Corporation.