the joints of the afflicted were still wrecked. As Themistocles Gluck
painfully learned in 1890, replacing an actively infected joint was no
solution at all. But now, Charnley could consider surgically confronting
diseased joints, TB or not, with the inclination that one of mankind’s great
burdens, arthritis, could be relieved, even cured.
While still working in Manchester (he still worked there part-time until
1958), Mr. Charnley evaluated a patient who had undergone a partial hip
replacement with a Judet acrylic prosthesis (a clear plastic ball taking the
place of the arthritic femoral head). The patient informed the sagacious
surgeon that his replaced hip squeaked when he leaned forward. So severe
was the screech that his wife could not tolerate his company. Instead of
merely discounting the story (or even being amused by it), Charnley began
to turn over in his mind why the noise was occurring. He observed that the
sound rarely happened when the femoral head had been replaced following
a femur fracture, where the cartilage from the hip socket was still intact
(and ostensibly, still providing a slippery articulating surface), but these
types of sounds only happened in arthritis cases where the hip socket had
only roughened bone on both sides of the hip joint, squeaking when the
replaced plastic ball interfaced with the arthritic hip socket. Importantly,
instead of primarily focusing on implants and gadgets, Charnley turned
his scrutiny toward the organic, considering the biomechanics (“the
mechanical laws relating to the movement or structure of living
organisms,” according to the Oxford English Dictionary) of the vital and
diseased tissues he was pondering. His mentor, Sir Harry Platt, described
Charnley as a surgeon-biologist, rather than a surgeon-engineer. To
generate a solution for hip arthritis, he would first need to understand the
function of healthy articular cartilage. This would become the pattern for
every implant ever invented: comprehending function before proposing a
cure. It now seems laughable that Gluck was implanting ivory implants in
1890, before antibiotics, sterilization, modern biomechanics, and the
presence of metal alloys and polymers.
The Industrial Revolution brought machines and engines, with their
crankshafts, pistons, gears, and axles—all of which required lubrication.
Engine grease and distillated viscous fluids, newly discovered from the
nascent petroleum industry, were used to lubricate the metal interfacing
machine parts. If man is a machine, it was a reasonable conclusion that our
parts had similar biomechanical relationships. Reasonable, but wrong.
marcin
(Marcin)
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