material with his nail, concluded that the “poly” would be a similar
disappointment as Teflon, and told Craven he was wasting his time.
Undeterred, Craven kept the sample of the new polymer and planned on
analyzing it in a custom-made testing apparatus he had devised. The initial
results were astounding and incomparably better than Teflon had
performed on the same Wrightington machine. Charnley left the country
for a meeting in Copenhagen, and unknown to him, the machine churned
on, oscillating the stainless steel heads over the HMWP block.
No doubt Charnley had left for Copenhagen empty of optimism, not
even aware that HMWP was being tested in his lab. He had gained
notoriety for hip arthroplasty, but as the horror show unfolded before him,
Charnley had to wonder if he was a fool. When he returned from vacation,
he later recalled:
My office door opened to reveal Craven who asked me to
come down to the lab ... Down I went to see the HMWP. After
running day and night for three weeks, this new material,
which very few people even in engineering circles had heard
about at that time, had not worn as much as PTFE would have
worn in twenty-four hours under the same conditions.
There was no doubt about it: we were on.Charnley obtained more material from the German company,
Ruhrchemie (later purchased by Hoechst AG), and like his previous
experiment with Teflon, injected polyethylene into his thigh. After six
months, there was no nodule formation in his leg. He wrote a letter,
quickly published in the British journal Lancet on December 28, 1963, and
reported his worrisome reaction to Teflon and encouraging response to the
finely ground HMWP, partially motivated to warn surgeons about Teflon
because he had heard surgeons were contemplating using it in a
rudimentary knee replacement.
It only took a few months for Charnley to begin performing total hip
replacements with polyethylene cups, starting in November 1962. Many of
these early poly total hips were revision operations, taking out the failed
Teflon cups and cementing in the new poly cups. Initially, all the cups
were made by Charnley himself, and sterilized chemically by soaking