persona design flaw

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Anonymous

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the femorals grow from the lugs posteriorly, yet uses posterior referencing instruments. Is this why at the back of the technique it goes on about 'tight in flexion' , 'air cut anteriorly'
Why do you think the NexGen had in between sizes for tightness in flexion. The same reason... the femorals grow posteriorly. Big problem for a surgeon.
Yet Zimmer 'spins' this by saying they have solutions for tightness in flexion...what ?
They had a chance with Persona to have the femoral grow anteriorly and missed.
Personalized knee ? Really? the 2 mm increments will not make up for the surgeon frustration.
 



The posterior/anterior reference sizers have nothing to do with the eventual femoral trial and the resultant lugs drilled, they only dictate the fixed reference point for the femoral finishing blocks to follow.

Try again.
 



Anonymous said:
the femorals grow from the lugs posteriorly, yet uses posterior referencing instruments. Is this why at the back of the technique it goes on about 'tight in flexion' , 'air cut anteriorly'
Why do you think the NexGen had in between sizes for tightness in flexion. The same reason... the femorals grow posteriorly. Big problem for a surgeon.
Yet Zimmer 'spins' this by saying they have solutions for tightness in flexion...what ?
They had a chance with Persona to have the femoral grow anteriorly and missed.
Personalized knee ? Really? the 2 mm increments will not make up for the surgeon frustration.
Click to expand...

I first thought that you were a competitive rep that was losing business to the Personna. Then after reading your totally inane post again, I realized that you were a rookie with no business. Take it from the old Zimmer pro….the NexGen is still the best knee on the market after 20 years. It is still the gold standard…I will agree that the Personna still has the jury out on it. That is why my surgeons implant the NexGen every day…best registry results of any knee implant in the world.
 



Anonymous said:
the femorals grow from the lugs posteriorly, yet uses posterior referencing instruments. Is this why at the back of the technique it goes on about 'tight in flexion' , 'air cut anteriorly'
Why do you think the NexGen had in between sizes for tightness in flexion. The same reason... the femorals grow posteriorly. Big problem for a surgeon.
Yet Zimmer 'spins' this by saying they have solutions for tightness in flexion...what ?
They had a chance with Persona to have the femoral grow anteriorly and missed.
Personalized knee ? Really? the 2 mm increments will not make up for the surgeon frustration.
Click to expand...

Actually, Zimmer old pro I have had a couple of surgeons mention this issue to me. And he is correct about the half sizes. I worked for Zimmer and the -2 femoral was there to address flexion issues.
 






Anonymous said:
the femorals grow from the lugs posteriorly, yet uses posterior referencing instruments. Is this why at the back of the technique it goes on about 'tight in flexion' , 'air cut anteriorly'
Why do you think the NexGen had in between sizes for tightness in flexion. The same reason... the femorals grow posteriorly. Big problem for a surgeon.
Yet Zimmer 'spins' this by saying they have solutions for tightness in flexion...what ?
They had a chance with Persona to have the femoral grow anteriorly and missed.
Personalized knee ? Really? the 2 mm increments will not make up for the surgeon frustration.
Click to expand...

Zimmer M/G , NexGen and Persona femorals are all based on anterior referencing instruments, because the femorals grow posteriorly. The poster is correct. If you use PRI for NexGen you will see the problems. Persona has the same.
Have a look at the back pages of the Persona technique to see all the excuses for 'tight in flexion', 'air ball cut' cut. The femurs growing posteriorly from the posts is a design flaw.
 









PRI instrumentation, regardless of knee implant, can cause issues with the flexion-extension gap balancing. As a rep, you must know, if the balancing is tight in flexion, the surgeon just needs to take slightly more off the proximal tibia. That's why surgeons check Flexion-Extension gaps!!
 



Anonymous said:
PRI instrumentation, regardless of knee implant, can cause issues with the flexion-extension gap balancing. As a rep, you must know, if the balancing is tight in flexion, the surgeon just needs to take slightly more off the proximal tibia. That's why surgeons check Flexion-Extension gaps!!
Click to expand...

Taking more off the proximal tibia effects both flexion and extension. If a knee is tight in flexion, you should increase the posterior slope of the tibial resection. If the tibia is already cut in 3-7ish degrees, you should consider downsizing the femur with an anterior referencing block to further resect the posterior and posterior chamfer cuts. Please don't tell a surgeon to cut more tibia and expect the only change to be in flexion.
 



Correct, but with 1mm incrementally sized surfaces, they are able to cut more proximal tibia to open up flexion gap, while keeping the extension gap close. Every other system offers 2mm increments, creating a more difficult time balancing. Taking 2mm of proximal tibia, and only increasing poly thickness by 1mm would allow the knee to be better balanced than having a knee system with 2mm increments on the poly.
 






Anonymous said:
Downsizing could cause you to notch the anterior cortex, resulting in a distal femoral peri prosthetic fracture.
Click to expand...

Not if you use anterior referencing 4 in 1 blocks like I stated. In referencing the anterior cortex, you are resecting posteriorly. You should also know that several other systems offer 1mm polys (Vanguard, Attune) Vanguard has had it for years, it wasn't advertised to keep inventory down. Mechanically, an additional 1mm off the tibia is still not going to cure a flexion/extension mismatch.
 



Anonymous said:
PRI instrumentation, regardless of knee implant, can cause issues with the flexion-extension gap balancing. As a rep, you must know, if the balancing is tight in flexion, the surgeon just needs to take slightly more off the proximal tibia. That's why surgeons check Flexion-Extension gaps!!
Click to expand...

Please tell me you do not mention to take more proximal tibia. That is more for when the joint is tight in both flexion and extension. Hm...

As for Persona, it is a good knee system. Like all systems, there are some kinks to work out, but only time will tell if is as good as NexGen.
 



Anonymous said:
Please tell me you do not mention to take more proximal tibia. That is more for when the joint is tight in both flexion and extension. Hm...

As for Persona, it is a good knee system. Like all systems, there are some kinks to work out, but only time will tell if is as good as NexGen.
Click to expand...

the history of zimmer reps is that they do not know surgery. you guys have always depended on instruments and don't get problems in surgery such flexion contracture, lose in flexion, patella problems, whatever
It shows by some of the comments in this message trail
good luck trying to get your surgeon out of problems with Persona
 



agreed

I don't think anyone at Zimmer understands posterior referencing or much else about knee surgery.

Just keep telling everyone that Nexgen has the best Registry results. Have any of you read the Australian Registry?
 



Some of the comments about gap balancing on here are scary. I wish there were more reps like you in my area. They should teach you how to trouble shoot gap balancing in sales school.
 



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