Marvel Fanboy

Higher, further, faster. 

Okay I wrote an entire essay on this and decided no one was going to be interested because it was so technical so I spent hours rewriting it but it turned out to be an essay anyway….

I hope this is helpful for anyone writing fics about Bucky’s time in Hydra cos you really don’t need to think up new torture methods when you consider the medical procedures he had to go through…

The TL;DR version: Bucky's implant doesn't obey the laws of biophysics but neither does Steve's shield; all that matters is they both look cool.

As you can see from this picture, compared to what I referred to in the amputation meta, the amputation level has moved from forearm (transhumeral) to above shoulder (probably forequarter) level.

How was Bucky's arm implanted?

The thing about Bucky's prosthesis and the way it's implanted is we don't have anything close to it in the real world, and there are some practical issues with it.

I dislike anatomy too but we gotta see it to understand, so bear with me.

What's important about this picture? Look at the ball and socket joint. The glenoid cavity i.e. "the socket" is basically a tea plate to the golf “ball” of the humerus - you rock it hard enough and the ball will fall out (e.g. shoulder dislocations). It's held in place by tendons and muscles that are built for mobility rather than durability, which is why rotator cuff tears are so common (and annoyingly debilitating when they do happen). To add to that mobility, the socket is formed by the shoulder blade/scapula, which itself is just a dinner plate sliding across the back of the rib cage, held in place only by a few flaps of muscles. Now look at that flimsy clavicle, then at that tiny point of contact between the clavicle and the sternum - that is the only attachment the shoulder has with the main (axial) skeleton.

What I'm getting at is that the entire human shoulder stays in place by the sheer miracle of opposing tendons and muscles and ligaments. This means at Bucky's level of amputation, all the things that hold the arm onto the body are gone, and just fusing metal components onto what remains is not going to cut it.

But he's still got his pecs, you say. Maybe he's still got his scapula, which means he'll also have his rotator cuffs. Yes, that brings me to the other unrealistic issue about his implant. In real life, we simply don't have the technology to do this - the components we have bond to bone but do not bond to soft tissue, i.e. muscles, fat and skin. Even if you have muscles left you can't attach them in a way that holds the joint on.

Directly attaching metal next to skin, as it appears for Bucky, has its own problems. One of the newest techniques these days is interosseus implants (Source), which inserts a metal shaft into a long bone and attaches the prosthesis at the end. A major drawback is fluid leak and infection because the soft tissue simply does not bond to the metal and form a good seal over/around it, so you essentially have a chronic open wound going all the way through to bone.

In Bucky's case, he doesn't even have any long bones left to even consider this technique. Where are you going to attach an entire arm? The clavicle? The ribs? The flappy scapula? Have you seen how easily these bones snap like legit grannies just have to trip over and they'll crack 8 ribs on the way down.

Of all the ways Bucky was attacked and injured in CACW, this is the one scene that makes me wince every time. That’s what, a 10 meter drop? I know what you’re thinking Bucky - it's gonna look impressive in front of Steve. Well, GOOD F**KING JOB BUCK YOU'VE JUST RIPPED YOUR IMPLANT OUT OF YOUR BONES. On a scale of "freezing yourself in cryo" to "breaking Zemo out of jail" can you STOP being such a self-destructive drama queen for FIVE minutes and—

Okay, but Bucky's arm is canon. Can it theoretically work if we take into account futuristic technology and super soldier serum?

So let's talk about what it needs to achieve: - Very strong attachment to axial skeleton WITHOUT use of muscles/tendons - Full range of motion as a normal human arm - Ability to connect to neural supply (won't go into detail in this post)

Let's pretend the metal-skin interface won't be a major issue because of better skin healing/better materials.

Even with the serum's healing/durability, the implant still needs a stronger attachment than a single clavicle. One (imaginary) possibility is having most of his left ribs and clavicle filled by (not replaced by) implants with attachment sites, to which the metal arm actually attaches. This distributes the loading forces more evenly throughout his thorax. Remember though the weak point is always at connection points, and at high enough impacts something will give, and if it's not his bones it'll be the metal work, and that will still hurt.

That leaves the issue of scapular movements. I just want you to take a moment to appreciate the many directions this bone flap spins in. It’s vital in positioning the shoulder relative to the rib cage, and it’s every anatomy student’s nightmare (or dream, I guess, depending on which end of the spectrum you fall).

Two (imaginary) possibilities: this is built into the prosthesis - ie the scapula is removed and jointed components pull the shoulder across the rib cage - this method means more bone/muscle have to be removed. The second is if they develop technology to attach muscle to metal implant, and I almost don’t want to think about that possibility because the amount of experimentation that would take, the amount of muscle tears and tendon rupture and repeat surgical procedures and pain is just horrific to consider.

CBB reading all that, can you just tell me what it practically means for Bucky?

He would have to: - Undergo multiple revisions to reach his current level of amputation: this could be from unsalvageable implant failures or injuries forcing them to go up higher (amputate more) for attachment points. - Undergo multiple rounds of experimental implant techniques: failures in those early decades are common due to the materials used and the immature techniques. Metal shattering within bone or snapping outside of bone can happen especially at the huge forces he puts the arm through. For perspective, people are advised against running after a hip replacement because that counts as "high impact" ARE YOU LISTENING TO THIS BUCKY. - Complications? Pain, infection (painful), bleeding (painful), nerve damage (painful), fractures (painful), implants breaking (painful), rejection of implant material (painful), reaction to sediments produced by crappy implant material (painful). I don't know if you see a common theme or... - After each surgery there will be a necessary healing time (even for a super soldier) where he will be vulnerable while the bone heals.

All of this suggests - and not to minimise what Isaiah was able to do single-handedly - that the early Winter Soldier was not the sleek machine that Steve fought, and was likely far more prone to injury and damage.

And finally, as a heartfelt thank you for getting this far, someone pointed out that Bucky cradles his metal hand for comfort. That itself suggests that despite the amount of pain that he inevitably endured to get a functioning prosthesis - his life was infinitely worse without it.

3/3

pt 2