Sunday, February 24, 2008

Otis Med: Shape Matching Custom Fit Total Knee Replacement

There is a movement under foot that runs counter current to the time tested principles used to position the implants in Total Knee Replacement. This principle is called Shape Matched Technology (this phrase is a trademark of Otis Med). It allows for what Otis Med terms a custom fit Total Knee Replacement.

Here is an excerpt from the Otis Med site (http://www.otismed.com) :

Shape-Match™ Technology

OtisKnee™ is based on OtisMed’s patent pending, proprietary Shape-Match™ technology. Using sophisticated 3-D software, the Shape-Match™ technique optimizes the size and placement of the Custom Fit Knee™ before surgery, based on the patient’s own normal (non-arthritic) knee anatomy. From this very precise 3-D image, custom cutting guides are created to assist the surgeon in making very accurate bone cuts that are specific to the individual patient. This allows for a “customized” implant fit and placement. Prior to the availability of Shape-Match™ technology, surgeons have relied on experience and intra-operative judgment to correctly size and place the implant in the patient. END of OTIS MED excerpt.


In essence Otis Med uses MRI images of the diseased arthritic knee. The proprietary software then calculates how much of the joint surface has been lost in the arthritic knee, calculates how much to "put back" to restore the knee to it's normal, naturally given position and then provides the surgeon with custom made tools to restore the knee "back to normal". A key principle in the Otis Med technique is to restore the axis of rotation to the knee, and this can only be done by identifying the normal axis of rotation on the reconstructed MRI scans. This information is then provided to the surgeon by fabricating custom cutting blocks that are used to re sect the bone when performing an OtisKnee. This can not be accomplished with traditional Total Knee Replacement in the same manner as OtisMed, even if the surgeon uses Surgical Computer Navigation. Otis Med technique can only be used with Stryker and Biomet implants (because of the shape specific to these two brands of implants).

The debate, which is just heating up and should be spirited, will compare the merits of the totally new concept of precisely how to position the knee implants using the Otis concept, to the traditional technique of making every replaced knee straight (mechanically aligned to match a straight line running from the hip to the center of the ankle) and balancing the knee ligaments by releasing contracted ligaments and tightening stretched knee ligaments.

As I begin to analyze this radically new way to position knee implants I must say I am somewhat intrigued by the OtisMed rhetoric. Their concept places critical importance on the balance and range of motion of the knee, with axial alignment secondary (almost an after thought). Traditional technique stresses axial alignment above all else, with balance by ligament release important as well. Traditional technique, which here to for has been the dogma for positioning implants, boasts long term results with 90 % success rates 10-20 years after implantation. There are only a few peer review published articles supporting the Otis Med concept.

As they say, the jury is still out on the Otis Med principle. As a surgeon living in an ever changing, high technology world I believe I owe it to my patients, myself and my profession to study the facts for and against the Otis Med technique. Ultimately I will make an informed decision based on the best information available as whether or not to incorporate this technique into my practice of Knee Surgery.

15 comments:

chad said...

I hope this gets responses by orthopedic surgeons. The philosophy of Otis Med has clinical support and is embraced by several surgeons around the country. Dr. Tarlow has done a great job elaborating on both the philosophy and science behind Otis Med. As this debate unfolds, it will be interesting to hear Dr. Tarlow's conclusions.

Anonymous said...

nice post...i just read the whole thing after talking with you on the phone...so, how will the jury decide? what metrics are you looking at to determine where your practice will ultimately go?
-branden

Anonymous said...

Having just visited the Phoenix and Sedona areas last month, and being 3 and 1/2 months post- bilateral total knee replacement, I felt I should comment.

RUN; do not walk, to training on the Custom Fit Total Knee Replacement technique. Your patients will love you for it!

I had my surgery at Bryn Mawr Hospital in Bryn Mawr, PA on a Monday, and was home on Saturday. I was walking with a cane only for 3 weeks; driving after 4 weeks, and I did 6 weeks of outpatient PT. All along the way, medical professionals and friends marveled at my progress.

After years of arthritic pain, I am giddy with excitement about being able to walk, do stairs, hike, and generally live my life again.

As I said, you owe it to your patients to offer a Custom Fit knee.

From a former Jazzercise instructor, age 50.

Anonymous said...

To Anonymous,

Your recovery is great but has nothing to do with the custom fit knee. My patients go home on the first day after surgery and use a cane for 2 weeks. And I do not use the custom fit technology. To most joint replacement surgeons, these numbers are not all that impressive, but more representative of a recent trend of rapid recovery

Eric said...

I'm scheduled for a right side replacement on Monday (4/7/08). I will have an OtisMed procedure and have no reservations about my decision. I'll be happy to keep you posted.

JDM said...

Dr. Tarlow,

Very interesting post. I just recently stumbled upon your blog, so let me begin by saying that I am very grateful to read the thoughts of a surgeon who clearly cares very much about providing the best, and sometimes newest treatments for his patients. I am currently an undergrad at the University of Southern California and I am very interested in pursuing a career in surgery, particularly orthopedics.

So as for your post, I have a few questions regarding knee replacement surgery. You mentioned in your post that in a traditional replacement, the knee is aligned with its axis perpendicular to a line running from hip to ankle. Is a normal knee not always aligned like this? As far as I understood, this is the driving concept behind the Otis Med system, but it seems to me that most knees ought to be pretty close to this ideal that is used in the traditional replacement. In other words, is “customization” really worth the two or three degrees that a patient’s knee may be off by? As you said, the majority of traditional knee replacements can be expected to last several decades.

Additionally, why is it that the Otis Med system looks at the degenerated knee and tries to reconstruct it to pick a replacement? Wouldn't it be easier to look at the healthy knee and assume symmetry? That way, no computer reconstruction would be necessary.

Forgive me if my comments seem uninformed or off-base. This is all very interesting to me, so I'm just trying to understand as much as I can.

Thanks,

JDM

BilateralJohn said...

Thank you for a clear description of the issues over the Otis Med debate. I await you conclusions.

But personally I couldn't wait for the years that it will take to vindicate this method and my surgeon was very positive about OtisMed methods. He says it is the biggest advance he has seen in the 18 years he has been doing tkr.

So far so good I am 61/2 weeks post bilateral tkr and have 132 and 137 flexion and 0 and -1 degrees extension. I work above my business and I climbed the 13 stairs at least 15 times today. Two days ago I got out of a restaurant chair without using my arms for help.

I am still a little stiff and my gait needs work but every day I show progress. I am happy my surgeon went with OtisMed's CFKR.

Barbara said...

Dr. Tarlow, It is about a year since your comments. Have you any further information to share at this time. I am scheduled to have the Otis knee put in on Aug. 28 and after reading different blogs I am very confused. thank you, Barbara

Stefan D. Tarlow MD said...

Barbara, Otis Med will work great for your knee. Go ahead as planned.
SDT

Anonymous said...

Barbara,

I would be interested to hear how it's going for you or anyone who has had a knee replacement with the Otis Med technique.

gflatt said...

DR. Tarlow
It only fair to tell the people that if they have had a osteotomy, the portion that is referenced does not take that into account. At least not for me. The 18th of Aug. I'm scheduled for yet another total knee replacement, that being followed by a revision to the initial. The revision, new center section, patella tagging in place, and ligament tweaking. May be I'm suffering from good technology in the wrong hands.
Bob

Mike said...

I had the Otis Med on both knees replacements in Oct 07. I knew by summer 08 that something was wrong. Both knees failed with one replaced Aug 09 and the second Jan 10. Can't say to much positive about the Otis method. I would advise one to strongly seek opinions from at lease two surgeons.

Annie in Ontario said...

Dr. Tarlow, It is about 3 years since your comments. Have you any further information to share at this time? My husband is at the point where he finally said "I have to get new knees" so we are anxious to be well informed. This method is new in Canada and I cannot find any stats that I can refer to. Any referrals would be most appreciated. -- thanks

Anonymous said...

There is NO published data on Otismed--peer reviewed--that would support the use of this unproven technique. The FDA had Otismed remove many claims from their website back in 2010. Ethically, patients should be advised that data should have AT LEAST 5 years at a minimum. Without that mininum time it is simply experimental. Top published clinical (surgeon/hospital) data at 15 years in most studies show a survival rate in excess of 95% plus. That is going to be very hard to surpass and today most patients are walking in a few weeks with or without this experimenting.
Are the patients and surgeons who received/used this technology from 2007-2010 aware that the product WAS NOT FDA APPROVED? There is a reason for that. Why were people using this product without FDA approval?
New is not always better as evidenced by the recent METAL HIP RECALLS. Surgeons were touting the benefits on that technology and look how many patients were injured. I call that irresponsible. This is currently being investigated.Are the major joint replacement centers in the USA usinbg this product--Mayo--Hosp. for Special Surgery- Jefferson MC etc. etc. etc.--why not? Are all of those top rated surgeons out of step? Probably not.

Anonymous said...

I had an Otis knee replacement put in about 2 years ago. I was told that it would be anatomically correct for me and I would have greater flexibility that a traditional knee. After surgery I was in extreme pain with swelling and was told that they had to do an unexpected additional adjustment called a "vernacular release", which was needed to help align the knee properly. I was in the hospital for 3 days and went to an overnight rehab. center for 3weeks and had therapy every day from morning to late afternoon. My therapists commented that my extreme pain was probably caused by the vernacular release. After 4 months of therapy, I only have a flexibility of 90 degrees, whch is barely functional. I am diappointed that I came out of this surgery with limited mobility. I am now in need of the other knee to be replaced, but I think I will go with the traditional knee and not the Otis knee.