Charles Karsner Mills' "patella-tractor".
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D004867:Equipment Design / Q000266:history; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D009462:Neurology / Q000266:history* / Q000295:instrumentation; D010329:Patella; D014143:Traction / Q000266:history* / Q000295:instrumentation