Abstract: A patient-adapted osteotomy template for precise resection of the femur in a total hip prosthesis operation with the use of a reamer comprises an upper abutment surface for abutment with the femur, a connecting surface fixed to the upper abutment surface and a guide surface, a guide slot provided in the connecting surface and an orientation indicator fixed to or provided in the osteotomy template. The guide surface and slot define the desired cutting plane and provide guidance of the resection instrument for the resection operation when the upper abutment surface is in abutment against the femur and when the osteotomy template is rotated about the drilling axis of the reamer so that the orientation indicator is in a specific position.