Former Czech international Patrik Berger has retired from football. Berger's club Sparta Prague said Wednesday the 36-year-old midfielder has decided to retire because of a long term knee injury. Sparta coach Jozef Chovanec said "we thank Patrik for what he did for Sparta and the entire Czech football." Berger was a key member of the Czech team that was runner-up at the 1996 European…