what type of screws may be used + best natural bone graft substitutes

by Cheryl
(San Diego, Ca)

I had an acl reconstruction with calaxo screw and allograft approx. a year and a half ago. I had problems with the screw backing out and required an additional surgery. Additionally I had major systemic problems with use of polymer screw.

The doctors are now concerned about the enlarged bone tunnel as well as possibly my original graft may be at risk for failure.

I am facing an additional surgery, and am interested in different bone graft substitutes that are more natural in nature so as to hopefully prevent any additional systemic symptoms. Also, what are the screw options if in fact the acl needs to be reconstructed?

I appreciate your help!

Thank you,

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Jun 10, 2008
what type of allograft?
by: Bart - SII

I am not a surgeon, so my technical knowledge of screws and such is limited...however, here is what I do know...

Most interference screws are either bioabsorbable (some type of polymer) or they are metalic - usually titanium. It sounds like your original problem was that the screw did not set itself well, perhaps because it was a polymer. I would guess that a more sturdy screw would be used to allow a better "bite" and secure placement.

What type of graft did they use - patellar tendon, hamstring, etc?. A soft tissue graft like a hamstring tendon has more tendency to have problems not healing in well or migrating with the screws.

As far as bone grafting to help decrease the size of the tunnels - this type of graft is usually taken either from cadaver donors, or harvested from your own hip. Again, I am not well versed in this, but these are the two options I have seen in my patients.

All of your questions are probably best answered by your own surgeon, as they should be able to give you much more specific information regarding what they will be using, as well as all of the different options you can choose from.

I hope my little bit of knowledge helps - feel free to comment back with other questions.

Jun 12, 2008
Xenograft Screws
by: Anonymous

I can't speak specifically about your procedure but another option your doctor may have used is a xenograft screw. The screws are essentially a scaffold that allow your own bone to incorporate and the screw becomes a part of your body. An absorbable screw does just that, absorbs. For the xenograft screw, over time it will nearly impossible to tell it was even there.

By the way, xenograft is just like an allograft but instead of being human it's bovine (cow).

Hope that helps.

Jun 12, 2008
Appreciation of input!!!!
by: Anonymous

Thank you! This information is very helpful. (:

Jul 01, 2008
Calaxo recall
by: Just a thought

The Calaxo screw by Smith & Nephew has now been withdrawn from the market because of problems. I think the Bilok composite acl screw is performing well - being replaced by new bone as it slowly resorbes.
You should think about synthetic bone grafts to repair the bone tunnel.

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