WPXI-TV reports the incident occurred around 2 a.m. Thursday in McKees Rocks. The truck driver heard the man yelling and called 911.
Officials say that while he was in the back of the truck the man realized his prosthetic lower leg was missing. He searched for it for about 30 minutes before police ordered him to stop.
The man didn't appear to be injured in the accident but was taken to a hospital to be evaluated. His name has not been released.
Authorities say they would continue searching for the missing prosthetic.
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