The Logitech Performance MX Mouse is a premiere mouse from Logitech with darkfield tracking technology and a free-spinning scroll wheel. Released in 2009. Model number: 910-001105.
You might be able to snag one on eBay if you're lucky, but installing it may require soldering. You also might be able to send it to Logitech for repair (maybe), but if you think it would be too much effort, you should probably just buy a new one.