Update 12/12/07: I added pictures from the casting for my second prosthetic to illustrate the original text.
Two weeks ago I got a cast made for my first prosthetic leg. Last week I tried on the leg and walked (albeit assisted by crutches) for the first time in a month and a half. Since then, I have been proudly showing off my new foot.
To make the hard shell of the prosthetic into which the stump of my leg fits, it was necessary to make a cast of my leg starting from just above the knee. Making the cast was a multi-step and multi-layer process. First, my prosthetist wrapped the stump of my leg in a transparent silicone sleeve similar to the compression sleeve I had been wearing since the second appointment. Then, he left the room and returned with a four foot long, one foot wide latex balloon.
He pressed the top of the balloon against the end of my leg, and in one quick motion, opened the other end of the balloon and inverted the latex around the silicone wrapping as the air rushed out.
He smoothed out a few wrinkles, then outlined the knee joint, kneecap, tibia, and other important points with a blue marker. These were points where the technician would have to create bumps or dips in the hard shell of the prosthetic. The prosthetist noted that I appear to be slightly bowlegged, which was news to me. I suspect it is because I favored my left leg for so long.
I asked if he planned to stretch the latex over the final casting. That seemed strange, since he couldn't know that the markings were in the right places. No, he replied, the markings would transfer to the inside of the next layer, a fiberglass cast just like one gets to protect a broken bone.
He pulled over a tub of bright pink grease, a bucket of water, a thick rubber sleeve with a flexible tube sticking out of the bottom, and a mean-looking vacuum pump with valves and pipes sticking out of its gray surface.
He coated my leg with a thin layer of the grease to help it slip out of the hard casting once it set. Then, he dipped a roll of fiberglass casting material in the bucket of water and wrapped my leg from the top down.
The rubber sleeve went over that, with the tube running to the intake of the vacuum pump. He turned on the vacuum, which tightened the sleeve and casting material around my leg.
It did not take long for the casting material to set. The rubber sleeve came off as soon as he turned off the vacuum. Then came the cast. Inside I could see the mirror image of the blue markings he had made.
The latex sleeve rolled off like a surgical glove. As it snapped off the end of my leg, a plume of powder flew all over the prosthetist.
Last week I got the prosthetic.
My leg fit snugly in the plastic shell, but the prosthetist had to make a few adjustments to make it as supporting and comfortable as possible. He marked a few tight spots with the same blue marker as in the previous visit. He expanded the tight spots by heating the plastic in a back room.
To figure out the correct height, the prosthetist had me stand on foot-shaped sheets of varying thickness. I would stand on one then another while—just like an eye doctor—he asked, "Which is better... this one? ...or this one?"
When I decided on a height that felt comfortable, he removed the foot assembly with a metric hex wrench and cut the corresponding thickness off of the top of the pipe that forms the ankle using a C-shaped pipe cutter like any plumber would use. He noted my interest in the tools he was using and warned me not to try to disassemble the prosthetic myself. Darn!
With all the adjustments complete, I finally got a chance to walk! First, in the examination room using two parallel bars for support, then in the hallway using my crutches.
Dad and Sue came with me to the prosthetist's, and they were both beaming when they saw me stand on two feet again. It felt great to get some of the weight off of my hands when crutching. The prosthetic also helps my balance, and it looks completely normal when covered by my pants.
My prosthetist wants me to stay on crutches for at least another week to allow my leg to acclimate to the prosthetic. At that point, I will probably switch to using one crutch or a cane. Not long after that I can start walking normally. I can't wait!