Scientists Create Artificial Bones From Wood 138
steve_thatguy writes "According to Discovery News, Italian scientists have made artificial bone from wood. Created by blasting wood blocks with heat until they are nearly pure carbon then coating them with calcium, the scientists say the material allows bones to heal faster and more securely. Unlike titanium, the wood-based artificial bones flex slightly much like real bone, and the porous nature of the wood allows for better bio-activity with surrounding tissue. Though human testing is still likely years away, the material is currently being used successfully in sheep and may have other industrial applications."
Re:those poor chickens with boneless breasts (Score:5, Informative)
Re:those poor chickens with boneless breasts (Score:2, Informative)
The wet wood chips are there for flavor, not for fire.
Re:Safer than Titaniam (Score:4, Informative)
Right. All levity aside, this could be a revolutionary medical step. Artificial bone is one of the most challenging materials science problems going, and has been for decades.
When an artificial hip, or other load-bearing bone implant, has a higher modulus than bone (and they invariably do), they cause the load to be transmitted unevenly to the bone. The artificial hip is on a pin that goes down into the marrow on the top of the femur. In natural loading, each segment of bone (taken from top to bottom) is loaded equally in compression. With an artificial hip implanted, some of the force is transmitted directly to a deeper part of the femur. The top of the bone is loaded less heavily than it would have been under natural circumstances?
Who cares? Your bones do. They're dynamic. When they're unloaded, they break down. So now, by unloading the top of the femur, you've given your body permission to dissolve it. Now your hip implant is bare, and only being held by its tip--fractures are the final result. This is why a hip replacement has a "lifespan" of only a few years--young people who have hips replaced have to go get new ones at some point, and have to lose a chunk of femur each time.
Things have probably improved since I was an engineering undergrad discussing these problems (~8 yrs ago), but those are the big issues. I'm going to be really curious to read more about this.
Re:Safer than Titaniam (Score:3, Informative)
I'm not sure if this is what GPs source was saying, but I would think the real problem with the extra-strong wall is the same with the extra-strong bones (if there is a problem with the former at all): it doesn't flex, so if its attached firmly to another weaker section, and that weaker section is subject to a load which causes the weaker section to deform, instead of the stronger section deforming elastically and removing the strain on the connection with the weaker section, the stronger section stays firm and the connection fails.
I think they mean charcoal. (Score:4, Informative)
When you take wood and heat it in such a way that almost only pure carbon is left, it's called charcoal. I bet they avoided that little term because it doesn't sound nearly as cool (or strong) as wood.
Re:Safer than Titaniam (Score:5, Informative)
My BS is Bioengineering (Materials), but I've been a physics teacher since I graduated, so I'm a little rusty. Take this with the requisite grain of salt =)
You're right, if you could just replace the whole femur, you'd eliminate the loading biocompatibility problems. The problem is that the femur as-a-whole is part of a complex and interconnected system, and would be many orders of magnitude more difficult to replace than the head alone. That tendons-and-cartilage problem is much, much harder than it sounds.
For starters, the top of the femur isn't connected to any muscles or ligaments, so we don't have to worry about reattaching them. Once the head of the femur is dislocated from the hip socket, the socket is replaced by a bioengineered version, and the top of the femur is cut off and replaced. The new ball/socket joint is reconnected, and the muscles naturally fold back around it.
Sounds simple, but this by itself is one of the most traumatic "routine" operations in the book. It's a massive, multi-hour undertaking, and requires a lot of blood and a lot of elbow grease. Removing the entire femur, while preserving all of the soft tissue around it, would be unimaginably difficult by comparison.
To replace the whole femur, all of the tendons and ligaments attached to the lower femur would have to be removed. Attaching them to a bioengineered substrate may be difficult or impossible. These aren't trivial connections, either. They're attached to the strongest muscles on your body, so they are subject to the most extreme forces in the body--hundreds if not thousands of PSI during heavy exertion (running, jumping, etc).
Titanium, in particular, would be a great candidate for a whole-bone replacement, if all it had to do was be a "mechanical" member. But getting the body to integrate with titanium--which you'd need, to keep those ligaments attached--is insidiously hard. One of the reasons why this new material is exciting is because the body integrates it much differently, by using it as a frame for normal growth (filling in the holes in the artificial bone with natural bone). Titanium is treated differently--the body effectively walls it off with a special type of soft tissue. It's "biocompatible" only in the sense that it doesn't provoke any kind of dangerous immune response; it is not a good substrate for normal tissue growth. Very, very few materials are, and most of them are highly engineered plastics with special protein coatings.
You also can't easily engineer a "half" replacement for the knee--knee replacements replace both sides of the joint. So, now you're chopping up the top of the tibia to provide a mate for your artificial femur. Which leads you right back to the same kind of problem.
Hip replacements used to be much worse than they are now; the mechanics have improved by leaps and bounds. They've gotten to the point where most people who need one (elderly, >60 yrs) will ONLY need one during their lives; it's younger athletes (Bo Jackson) and rheumatoid arthritis sufferers who have the bulk of their life ahead of them who are in danger of needing multiple rounds of replacement.
Re:Safer than Titaniam (Score:3, Informative)
Hips have made excellent progress, with newer (metal on metal) and (ceramic on ceramic), or ceramic on metal, the wear rate is minimal, and many are thought to last a persons lifetime, if they avoid stressful things like running/jumping. So patients in their 30's are getting them now.
Knees - not so good - still about 12-15 years
Total femur replacements usually take about 4 hours, but a routine hip can be done in 90 minutes.
Re:Surgeons profits vs implant company (Score:3, Informative)
Just to play devils advocate, there was a situation only a few years ago where a hip manufacturer failed to re-validate its manufacturing process after an equipment change. They ended up shipping contaminated hips (thin veneer of lubricant from the machine), an entire batch of which all failed catastrophically.
I'm a fan of tort reform too, and I agree that (many but not all) of these prices are somewhat artificially inflated, but all of that exhaustive testing needs to happen. Unfortunately, in our system, the medical companies also play the Fight Club Insurance Adjuster game, instead of "doing the right thing" the first time, and a crippling lawsuit is just about the only thing on the other side of the scales.