Ghana's fullback Baba Rahman has undergone a successful knee surgery in Germany after his recent injury that ruled him out of the rest of the current Africa Cup of Nations. Rahman, currently on loan at Schalke from Chelsea, was replaced in the Black Stars' 1-0 win over Uganda in last week's Group D opener after picking up a knee injury. Medical scans revealed that the 22-year-old player tore the anterior cruciate ligament in his left knee. "The left-back underwent the surgery under the supervision of one of the world's leading specialists in knee operations Prof. Dr. Bonisch," Ghanasoccernet revealed on Tuesday. The player is now facing a long spell on the sidelines according to the Ghanaian website. Ghana, who secured their place in the last eight with a narrow 1-0 victory over Mali on Saturday, will face Egypt in the last round on Wednesday. Egypt is second in the group with four points from two games, two behind leaders Ghana. Ghana are bidding to win their first Nations Cup title in 39-years. (For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports)