title: The Synergy cementless femoral stem in primary total hip arthroplasty at a minimum follow-up of 15 years.
abstract: We report on the outcome of the Synergy cementless femoral stem with a minimum follow-up of 15 years (15 to 17).
  
  
  
  A retrospective review was undertaken of a consecutive series of 112 routine primary cementless total hip arthroplasties (THAs) in 102 patients (112 hips). There were 60 female and 42 male patients with a mean age of 61 years (18 to 82) at the time of surgery. A total of 78 hips in the 69 patients remain in situ; nine hips in eight patients died before 15 years, and 16 hips in 16 patients were revised. Clinical outcome scores and radiographs were available for 94 hips in 85 patients.
  
  
  
  In all, four stems were revised. One stem was revised for aseptic loosening; two stems because of deep infection; and one because of periprosthetic femoral fracture. There was a significant improvement in all components of the Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up (total: p < 0.001, pain: p < 0.001, stiffness: p < 0.001, function: p < 0.001). The mean Harris Hip Scores improved from 47 points (27 to 59) pre-operatively to 89 points (65 to 100) at the latest follow-up (p < 0.001). Kaplan-Meier survivorship, with stem revision for aseptic loosening as the endpoint, was 98.9% at 15 years (95% confidence interval (CI) 96.9 to 100, number at risk at 15 years: 90) and with stem revision for any reason was 95.7% (95% CI 91.7 to 99.8, number at risk at 15 years: 90).
  
  
  
  The Synergy cementless femoral stem demonstrates excellent survivorship and functional outcomes at 15 years. Cite this article: Bone Joint J 2017;99-B:29-36.
authors.affiliation: Hospital for Special Surgery, Complex Joint Reconstruction Center, Department of Orthopaedic Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: I
authors.initials: I
authors.lastname: De Martino
authors.affiliation: Catholic University of the Sacred Heart, Agostino Gemelli University Hospital, Orthopaedic Surgery Division, Department of Geriatrics, Neurosciences and Orthopaedics, Largo Agostino Gemelli 8, Rome, 00168, Italy.
authors.forename: V
authors.initials: V
authors.lastname: De Santis
authors.affiliation: Catholic University of the Sacred Heart, Agostino Gemelli University Hospital, Orthopaedic Surgery Division, Department of Geriatrics, Neurosciences and Orthopaedics, Largo Agostino Gemelli 8, Rome, 00168, Italy.
authors.forename: R
authors.initials: R
authors.lastname: D'Apolito
authors.affiliation: Hospital for Special Surgery, Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: P K
authors.initials: PK
authors.lastname: Sculco
authors.affiliation: Hospital for Special Surgery, Adult Reconstruction and Joint Replacement Division, Department of Orthopaedic Surgery, 535 East 70th Street, New York, NY, 10021, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Cross
authors.affiliation: University of Catanzaro Magna Græcia, Orthopaedic Surgery Division, Department of Medical and Surgical Sciences, Viale Europa, Localitá Germaneto, Catanzaro, 88100, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Gasparini
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods; D001843:Bone Cements / Q000627:therapeutic use*; D002484:Cementation / Q000379:methods; D017886:Durapatite / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D057068:Periprosthetic Fractures / Q000209:etiology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology / Q000601:surgery; D012086:Reoperation; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D001843:Bone Cements; D017886:Durapatite
keywords: Cementless; Proximally-coated; Tapered stem; Total hip arthroplasty