August 17, 2015 Fred Hernandez

Centri – Torsion Adapter

2015-08-07 15.03.01On Friday August 7th I drove down from Vegas to meet with my prosthetist Mark Schall over at Quality Care Prosthetics. We had been looking for a torsion device to use with the Kinterra by Freedom Innovations and Mark had ordered a Torsion Adapter from Centri for me to try. Fillauer distributes the device and it is the only one we found short enough to fit between my VGK and the Kinterra since the foot lacks any height adjustment. The adapter offers three stiffness options and is rated up to 275lbs. It has a build height of 2.28 inches with a maintenance free titanium core that offers 45 degrees of rotation in either direction. It comes in three colors that correlate to the level of stiffness one desires. Given my weight, Mark ordered the black one which offers the greatest stiffness level. Although I find the rotation force to be a bit light.

The initial impression was good. I regained the rotation in the ankle that I like, as it took pressure off the implant giving me more of a natural gait movement. You may recall during my last visit to Marks office we had tried another rotator but it was too tall. I met Adam O from Game Changer that day and I ended up leaving on the Game Changer foot to trial. Even though the Game Changer is a really nice foot that has great movement, it is missing the ankle rotation I enjoy walking with (Although Adam does have plans to add a built in torsion adapter in the future). One thing I noticed when going off the Reflex Rotate by Ossur, was that as I rolled over the new foot on slippery surfaces (like tile); the foot would rotate inward in a kind of sliding motion. The lack of rotation transfers torque directly to the bottom of my foot instead. One thing to remember is the fact that I no longer have a socket and thus rotational forces are no longer transferred to the interface between the socket and the soft tissue of my stump. I have to rely on the small amount of movement within my hip, unless I use a torsion device. A normal leg gives one movement in the hip, knee and ankle as one walks; yet in comparison the use of prosthetic components typically don’t accommodate this type of natural movement. Imagine walking with your good leg as simply a hinged knee and ankle with no rotational movement. It feels like I am walking with a stiff gait when coupled with the implant. By using a torsion adapter my gait to feels more freeing and natural.

I put the new Centri torsion adapter through my normal real world drunk test that first night by hitting a number of bars in the Newport Beach area with my brother in law. We had a bit of a boy’s night out and had a great time drinking, smoking cigars and socializing with friends. The device worked well and I walked fairly well for just having switching to a different foot and by adding the torsion device only hours before. I had been exclusively walking on the Game Changer prior to this, which has a very different affect on my gait and is an extremely smooth and fully patient adjustable foot.

The next morning I noticed a small amount of movement in my safety adapter while walking around the hotel room and immediately thought of a Phoenix Osseo patient who has been complaining about similar issues. I tend to break components pretty regularly and thought “what luck” but I normally travel with the proper tools to make repairs. So I proceeded to take the device apart to see what the issue could be but ultimately found nothing wrong with it. The safety pin wasn’t broken and everything was torqued down and in place. The movement was accompanied by the sound of metal grinding at times and squeaking at other times. A bit strange, as it never happened before and it would come and go. Since everything checked out, I continued on my way for the day and figured I would address it properly once I returned home but would keep an eye on it.

Later that night I had plans to attend the annual Rocky Patel Cigar Cruise in Marina del Rey. My buddy Lou met me at the hotel and we drove to the pre party being held at the Hyatt. Here was an opportunity to put the device through round two. Lou is a bilateral Ak / Bk amputee who wears traditional socket technology on top of Ossur components. We did a fair amount of walking and standing in differing environments; from ramps, to stairs, inside and outside and through crowds etc. I was still getting the grinding feeling at times but nothing failed.

The next morning my daughter and I went to a late breakfast and ultimately ended up at my sister’s place in Newport Beach. As we had plans to attend the Dirty Heads concert at the Orange County Fair that night. I really put the torsion adapter through the ringer and did a lot of walking and drinking alike that evening. The extra pressure and movement I put on devices while intoxicated can’t be compared in some gait lab under controlled circumstances. This is real world testing and a wooden ramp or stairs in an office doesn’t provide a realistic scenario like my kind of testing does. If a device is going to fail, this is where it is going to happen in my world.

That night I had a great deal of grinding and clunking movement but luckily no failures. One thing I did take notice of was with the Kinterra though. As I stood in the limited space between the rows of seats as the band played; I found it extremely difficult to keep myself steady. It was pretty difficult to keep from leaning forward in such a tight space and it put a lot of stress on my good leg. At one point I had to sit down from the pain I was experiencing in my ankle. It reminded me of the time I trialed the Echelon VT where I experienced the same issue; only in normal every day situations. Admittedly I was pretty intoxicated, although normally I can lean into my prosthetics in those situations and stay steady by relying on the components. The Kinterra has an articulating ankle and it a really nice feature normally but in this environment it became an issue for me. The Relfex Rotate would have been a much better choice for me that night.

I have continued to experience the grinding, clunking movement and squeeking sounds since getting home but wasn’t able to identify the issue until recently. It was 110 here in Vegas the other day, so my daughter and I went to the strip to enjoy the air-conditioned casinos, restaurants and even took in a movie. It was here that I was finally able to narrow the issue down to a specific component. It turns out the new torsion adapter is the problem. Due to the direct interface I have with the implant and bone, the movement feels like it is coming from my quick release safety adapter that attaches the two. The torque adapter feels and sounds like it is just going to come apart but it doesn’t have any movement when I take it off.

Another Osseo patient I know from the Phoenix area uses the same Centri torsion adapter and has been complaining lately about how she has been experiencing movement in the quick release safety adapter we use with the implant. We have been going back and forth trying to figure out what the issue is without any luck and now we know why.

Mark is going to order me a replacement torsion adapter to see if it is simply a defective unit. You might recall from some of my earlier blogs over the Relflex Rotate, I had experienced failures in a half a dozen units before Ossur figured out the issue. Hopefully I don’t have to go through an equal amount of units this time around but I will let everyone know what my findings are in the event you are considering this device for yourself.

Regarding the Kinterra. I noticed something over the weekend that is worth mentioning. I did a good deal of walking in crowds while on the strip. So a lot of abrupt stopping in order to avoid running into people. Due to the injuries with my “good leg” I find it difficult to simply come to an immediate stop. It puts a good deal of pressure on my leg and I have a difficult time keeping my balance when this happens. I find it  much easier to dart in and out of such situations than try to stop most times. Although the Kinterra allowed me to come to an abrupt stop without stressing my other leg or losing balance. It happened enough times that I took notice and was quite pleased with the how the foot performed in that environment.


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