Patellar chondral defect returns after DeNovo graft - TTT?

[stephlouise]

Looking for some input:

In November 2015, I had a DeNovo implant surgery to repair a Grade 4 defect in my patella. After a very long recovery, I was back to full activity (cycling, walking, hiking, etc.) approximately Spring 2018. For the past 2.5 years, I have been able to mostly ignore my knee and considered the DeNovo surgery a complete success.

Fast forward to this winter ... after a few traumas to the knee that I considered minor (lateral impact by my two large dogs at high speed being the most recent in Dec. 2020, no pain at the time, didn't fall), I began feeling the sharp pain again behind my kneecap. Then my knee began to give out at random times. Then I felt the catching and locking of my femur when I bent my knee which is very painful. The pain and frequency of giving out/catching is increasing and an MRI of my knee shows that the patellar defect is back. Whether the DeNovo implant was dislodged or just worn down again is unknown.

My surgeon is hesitant to consider another graft. At the time of DeNovo surgery he had suggested we also do TTT and I refused (due to cost, invasiveness, fear...), and he has raised it again as a proposed path forward.

My questions: are there any options available to me for a patellar defect after a DeNovo implant has failed? Is it reasonable to try another implant, be it cadaver, autologous, or otherwise? And should I do the TTT surgery now, even without a new graft/implant, or is it too late if I'm already back to a bone on bone defect?

Bonus: are insurance companies any more likely now to pay for the graft/implant surgeries than they were 5 years ago? I paid out of pocket for my 2015 surgery and am still paying it off... 


Thanks in advance for any feedback or input.

[Brandon123]

Hi there,

I'm not sure about success rates of new implants after failed (if it is failed) DeNovo. However, I do know that success rates for any implants are much lower in the patella than anywhere else in the knee. So it's a tricky problem. Many OS insist on TTT as well to unload the area of the patella where they put the graft, in order to protect it better. But TTT seems to be no fun at all, I agree.

In sum, I think you must discuss this with one or several additional patellofemoral experts who do these kinds of grafts, and see what they say. Maybe they agree with your surgeon. Or they have ideas about other types of implants that might work. Either way, depending on the location of your patella defect, TTT will probably be recommended (especially if you're relatively young). 

[willrunagain]

HI Steph - From my research, it seems that MACI is one of the few cartilage repair procedures in the US that insurance companies are (mostly) covering.  My surgeon said he is getting insurance companies to cover in over 85% of his cases.  I had cartiform back in 2015 and it seems I got that procedure in at just the right time because it is no longer covered by any insurance carrier from what I have seen. 

Unfortunately, I had a new onset of pain back in November and just had a knee scope two weeks ago. The findings were both bad news and good news.  I somehow got a new small cartilage defect on my medial femoral condyle (2cm^2).  The good news is my patella cartiform graft was still in place.  My ortho said it was a little softer than normal cartilage when probed, but was still well attached to the underlying bone.  My surgeon took a biopsy for a potential future maci procedure. 

Like you, I am going through all of my options.  MACI likely is the best option right now for patella defects.  There have been some recent studies showing that when combined with an osteotomy (if necessary) are showing good/excellent results in over 80% of patients.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358829/
https://pubmed.ncbi.nlm.nih.gov/28910133/

 

[Brandon123]

There have been some recent studies showing that when combined with an osteotomy (if necessary) are showing good/excellent results in over 80% of patients.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5358829/
https://pubmed.ncbi.nlm.nih.gov/28910133/

Thanks for sharing these, interesting studies!

[stephlouise]

@Brandon123: thank you! If nothing else, you’ve confirmed what I’ve uncovered through discussions with my OS, and my own research. I’m seriously regretting forgoing the TTT back when the DeNovo graft was done. Live and learn, I guess.

@willrunagain: these are great studies, thank you so much. I’ll be discussing with my OS when I go back in a couple weeks to schedule surgery. Back in 2015, my OS successfully harvested cells for MACI, but insurance wouldn’t cover it. So it’s an exciting prospect to think they may now.  Went with DeNovo because it cost about 1/3 of the MACI procedure, out of pocket.
Congrats on your successful patellar graft! (Though I’m sorry to hear of the defect on the condyle. At least those *should* be easier to treat/more successful.) Did you undergo a tibial osteotomy at the same as your cartiform graft?

I wonder how long the cells are retained for MACI, and if they would still be around  Thank you for the input. I’ve resigned myself to needing another major knee surgery after the initial shock of it all. Now I just need to make the right decision so I can get back to life post-op without undue delay and complication.

[willrunagain]

I did not have a TTO or any type of osteotomy with my patellar cartiform graft.  Back before I had the cartiform surgery, I specifically asked my OS if I would need it and he said no.  My OS was Dr. Jack Farr and he is one of the top patellofemoral experts in the country, so I trusted his judgment.  Although TTO's are common with patella defects, mine was the result of trauma and not wear from malalignment, so any TTO would've just messed up my normal alignment rather than correct it.  My left knee has never had a single issue and it has the exact same alignment as my right knee, so this made sense to me.

To answer your second question, MACI biopsies can be held for up to 5 years.