title: Failure of PFNA: helical blade perforation and tip-apex distance.
authors.forename: Jia-Qian
authors.initials: JQ
authors.lastname: Zhou
authors.forename: Shi-Min
authors.initials: SM
authors.lastname: Chang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D005853:Geriatrics; D006620:Hip Fractures / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D058866:Osteoporotic Fractures / Q000000981:diagnostic imaging* / Q000601:surgery; D011475:Prosthesis Failure; D011859:Radiography; D020127:Recovery of Function