What Is MAKOplasty?

Photo © MAKO Surgical Corp.

In order to talk about MAKOplasty we first have to talk about unicompartmental knee arthroplasty (UKA or ‘uni’ for short).  On initial inspection  that may be an intimidating medical term, it simply means single-compartment knee replacement (or knee re-shaping if you want to be technical). The knee has three compartments: medial (inside of knee), patellofemoral (between knee cap and femur), and lateral (outside section of knee joint).


The most common form of osteoarthritis is a tri-compartmental arthritis that affects all 3 compartments of the knee. Therefore, it makes sense that the traditional knee replacement is a tri-compartmental arthroplasty that replaces all 3 compartments of the knee. A small subgroup of people with osteoarthritis of the knee have uni-compartmental OA. This type of arthritis affects on one of the 3 compartments. A UKA has been designed to address unicompartmental OA. UKAs are traditionally designed for isolated arthritis of the medial compartment of the knee, however, newer designs have become available that are specific to lateral knee OA.

While isolated medial-sided knee OA is the traditional indication for UKA, this may not be the best option for all patients with this condition. Whether a UKA is a viable option also depends on a person’s weight, functional status, age, and the presence of any alignment abnormality of the knee (if the person is bowlegged or knock-kneed).

 So with all these limitations why get a UKA versus a traditional total knee arthroplasty? The answer to that questions is complicated and multifaceted. For the perfect patient, the UKA feels more natural, as one study found that asked patients that had a UKA done on one side and a total knee on the other found.

Now that we have the basics of what a ‘uni’ is covered, the discussion can shift to MAKOplasty. A MAKOplasty is simply a ‘uni’ that is put in using computer navigation and a specialized robotic arm. The combination of computer navigation, and the robotic arm, make it easier for the surgeon to put in the components in proper mechanical alignment. Robotics and computer navigation are an easy sell to consumers, and this has made MAKOplasty an increasingly popular option.

While studies have shown that computer navigation in joint replacement surgery does lead to more consistent mechanical alignment, to date there are no studies that show improved clinical outcomes with the use of this technology. The use of computer navigation requires drilling of additional pins into the femur and tibia. Some surgeons argue that this creates the potential for creating an accidental fracture in those bones. Another important point is that surgeons that are experienced with UKAs are able to put in well-aligned prostheses without the added cost and time required to use a MAKOplasty.

A strong argument can be made is that the use of computer navigation will help those surgeons that are less experienced. This will eliminate the ‘outliers’, meaning the small number of ‘unis’ that those surgeons put in that may result in poor alignment; computer navigation will make sure that all the installed ‘unis’ fall into a consistent range.

So if you are a patient with isolated, end-stage, osteoarthritis of the medial compartment of the knee, does it make sense to get a MAKOplasty? Hard to say, that requires a long conversation with your surgeon. And the best route may be to pick a surgeon that you trust, and let him pick the tool that is most appropriate for you and he feels most comfortable with.  At the end of the day, the tool that your surgeon feels most comfortable with and has the most experience with is the one that is most likely to lead to the best outcome. The best takeaway is to do our best to not fall prey to effective marketing: robots are great, but may not make the best surgeons.


MAKOplasty Partial Knee Resurfacing. Patient Education.

MAKOplasty Partial Knee Resurfacing. Q & A.

JAAOS: http://www.jaaos.org/content/16/1/9.abstract


Edited by Vadim Goz, M.D.

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