Complex sentence: However, his prolific career was often hampered by injuries and medical conditions: in 2002, Zickler had surgery to remove a tumor from his right shin bone which caused him to miss out on participation in the 2002 FIFA World Cup.
Split into simpler sentences: However, his prolific career was often hampered by injuries and medical conditions. In 2002 Zickler had surgery to remove a tumor from his right shin bone which caused him to miss out on participation in the 2002 FIFA World Cup.