title: Does the study design really compare apples to apples?
authors.affiliation: UPMC Presbyterian-Shadyside Hospital.
authors.forename: Jacques E
authors.initials: JE
authors.lastname: Chelly
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D008297:Male; D009407:Nerve Block / Q000379:methods*; D010149:Postoperative Pain / Q000188:drug therapy*