Given the task definition and input, reply with output. Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).

Abstract: Twenty patients were examined by standard radiography and roentgen stereophotogrammetric analysis (RSA) during a two-year period after total hip arthroplasty. Eleven of the acetabular components migrated cranially and three femoral components migrated distally. This migration was most rapid during the first four months after operation. Our findings support the possibility that mechanical loosening is initiated by thermal injury during polymerisation of the cement; the less frequent migration of the metallic femoral component compared with the polyethylene acetabular component may be because the metal acts as a heat sink. Standard radiographs were inadequate for assessment of early mechanical loosening, whereas RSA could reveal migration within four months of the arthroplasty.
Which is the apt title for the abstract? option1: Mechanical loosening of total hip prostheses. A radiographic and roentgen stereophotogrammetric study. option2: Infective endocarditis: a challenging disease.
Mechanical loosening of total hip prostheses. A radiographic and roentgen stereophotogrammetric study.