CT-Free Robotic Assisted Partial Knee Replacement Surgery
Partial knee replacement with the NAVIO Surgical System
For people suffering from knee pain caused by osteoarthritis, whose damage is limited to a single compartment or area of the knee, partial knee replacement may be an option because it preserves healthy bone and ligaments while replacing the damaged area.1, 2 The NAVIO Surgical System uses robotics-assisted technology to help tailor partial knee replacement procedures to the unique shape and motion of each patient’s knee anatomy.
Robotics-assisted Planning for Better Surgical Outcome
While it may seem counterintuitive, replacing only part of a knee joint can be more challenging than replacing the entire joint. This is because partial knee replacement must achieve an exact balance between the new implant – made of metal and plastic components – and the remaining portions of your natural anatomy made of bone and cartilage. As a result, one of the primary challenges of all partial knee replacements is precisely positioning the implant for each unique patient. Even minor changes in an implant’s size or placement can cause the knee to function poorly or result in early failure of the implant and the need for future surgery. The NAVIO Surgical System addresses the challenge of partial knee replacement by using both computer and robotic assistance to accurately map the surface of your knee, align your implant to your anatomy, and physically remove the bone necessary to place your new implant.3 This added level of assistance is important because implant alignment is a crucial factor in determining how long the implant will last. 5, 6
Robotic Knee Surgery without Radiation
Other robotic knee replacement systems use computerized tomography, or CT, scans to help a surgeon visualize a patient’s knee anatomy. While CT scans are effective at showing the layers of knee anatomy, they can expose the patient to potentially harmful radiation. In fact, a single CT scan is equivalent to the radiation exposure received in 48 chest X-rays.4 The NAVIO system eliminates the need for CT scans by using an advanced computer program (similar to GPS navigation on your phone) to collect anatomic and alignment information about your knee. Once captured, this information is used to build a precise, computer-rendered 3D model of your knee that your surgeon will use to plan your surgery.
NAVIO Robotics-assisted Partial Knee Replacement Surgery
After all of the information about your knee is gathered and your surgical plan is created, your surgeon will use a robotics-assisted surgical tool (the NAVIO handpiece) to physically remove the damaged surface of your bone so that your new implant fits properly. Using the same 3D model of your knee, the handpiece is able to differentiate between the damaged areas that need to be removed, and the healthy areas that will remain. The NAVIO handpiece uses a burr that removes damaged bone for your implant. The NAVIO system doesn’t replace your surgeon. Rather, it assists your surgeon by adding an extra layer of planning to the procedure.
Partial Knee Replacement with Traditional Techniques
By comparison, traditional surgical methods for partial knee replacement use a combination of long, metal IM (Intra-medullary) rods that are drilled into the central bone canal to determine anatomic alignment and mechanical cutting guides that help guide a saw blade as it removes the bone necessary to place the implant. The NAVIO Surgical System helps tailor your partial knee replacement procedure to your unique knee anatomy without the need for intramedullary rods or cutting guides.
Individual results may vary. There are risks associated with any surgical procedure including NAVIO-enabled Knee Replacement. NAVIO is not for everyone. Children, pregnant women, patients who have mental or neuromuscular disorders that do not allow control of the knee joint, morbidly obese patients, or any other patients contraindicated for UKR, PFA, or TKA should not undergo a NAVIO procedure. Consult your physician for details to determine if NAVIO is right for you.
- Willis-Owen, Charles, et al, Unicondylar knee arthroplasty in the UK National Health Service: An analysis of candidacy, outcome and cost efficacy, The Knee 16, 473-478, http://www.academia.edu/22765713, January 3, 2009
- Liddle, A.D., Pandit, H., Et al, Optimal Usage of Unicompartmental Knee Arthroplasty, The Bone & Joint Journal, http://www.bjj.boneandjoint.org.uk/content/97-B/11/1506, November 3, 2015
- Lonner, Jess, Moretti, Vince, “The Evolution of Image-Free Robotic Assistance in Unicompartmental Knee Arthroplasty.” The American Journal of Orthopedics, May/June 2016, 249-254. Accessed June 7, 2016
- Ponzio DY, Lonner JH, Preoperative Mapping in Unicompartmental Knee Arthroplasty Using Computed Tomography Scans Is Associated with Radiation Exposure a…, J Arthroplasty (2014)
- Collier, Matthew, et al., “Patient, Implant, and Alignment Factors Associated With Revision of Medial Compartment Unicondylar Arthroplasty.”, Jour of Arthro, Vol 21 No 6, Suppl. 2, 2006
- Hernigou, Ph, Deschamps, G., “Alignment Influences Wear in the Knee after Medial Unicompartmental Arthroplasty.”, Clin Orthop Relat Res., Volume 423, June 2004, pp 161-165
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Navio Surgery – Frequently Asked Questions
Q: What is partial knee replacement/resurfacing?
Partial Knee Replacement, or Partial Knee Resurfacing, or Partial Knee Arthroplasty represents a surgical procedure which replaces diseased (OA) bone with artificial surfaces. The surgical procedure occurs through a smaller or minimally invasive incision, and can treat either the medial, the lateral (inside or outside) compartment of the knee. Additionally, the patellofemoral joint (PFJ) (beneath the patella/knee cap) can be singularly resurfaced if damaged or more commonly in conjunction with the medial compartment. A PFJ and medial PKR combination surgery is referred to as bi-compartmental (two compartments of the knee) knee replacement. During PKR, the surgeon not only replaces the damaged joint, but re-balances the knee’s alignment. If a patient is several degrees out of neutral mechanical leg alignment, the PKR procedure can correct to near neutral – fixing bow-legged or knock-kneed deformities.
Q: Why would I choose partial knee replacement over total knee replacement?
Partial Knee Replacement has certain potential benefits over a Total Knee Replacement procedure for those patients who are properly indicated for PKR1. Whereas TKR completely reconstructs the knee and often sacrifices both the ACL and PCL, a partial knee procedure preserves any functioning and healthy ligaments and only replaces the compartment(s) of the knee that have osteoarthritic damage. This means that the patient may recover quicker from PKR surgery than TKR because of the smaller incisions and limited disruption to the soft-tissue capsular structure2.
Q: What are the results of partial knee replacement?
A well-done partial knee replacement in an appropriately selected patient can have the survival rate that is comparable to that achieved with a total knee replacement in the first decade following surgery. The literature suggests that after the second decade, the revision rate may be somewhat higher for partial knee surgery than for total knee surgery. There may be an advantage to prolonging function and reducing pain in the patient’s joint prior to a total knee replacement, which is an end-of-the-line option2.
Q: Why does the Navio system work well for PKR?
The Navio system works well for PKR because it allows the surgeon to utilize advanced robotic-assisted technology for accurate bone cutting in a platform that does not require a pre-operative CT scan. The robotic-controlled handpiece puts the power of a robotic-arm into the surgeon’s hands for them to engage fully with the operational technique.
Brown, NM, et al., “Total Knee Arthroplasty has Higher Postoperative Morbidity than Unicompartmental Knee Arthroplasty: A Multicenter Analysis,” The Journal of Arthroplasty, 2012.
Borus T, Thornhill T. Unicompartmental knee arthroplasty. J Am Acad Orthop Surg. 2008;16(1):9-18.
OrthoNeuro Physicians that Perform this Procedure: