Piriformis syndrome is a rare neuromuscular condition that happens when the piriformis muscle in the butt presses on the sciatic nerve, according to the Genetic and Rare Diseases Information Center (GARD).

Andie MacDowell opened up about her piriformis syndrome diagnosis during an appearance on 'The Drew Barrymore Show,' admitting she thought she might 'have to have hip replacement.'

"I thought I was gonna have to have a hip replacement." Andie MacDowell has been diagnosed with piriformis syndrome, a painful muscle condition that compresses the sciatic nerve. As she explained during an appearance on The Drew Barrymore Show,