title: Difference in Postoperative Periprosthetic Bone Mineral Density Changes Between 3 Major Designs of Uncemented Stems: A 3-Year Follow-Up Study.
abstract: Although few studies have examined the direct effect of stress shielding on clinical outcomes, periprosthetic bone loss due to stress shielding is still an issue of concern, especially when physicians perform uncemented total hip arthroplasty (THA) in younger patients. Differences in femoral stem design may affect the degree of postoperative stress shielding. Therefore, the characteristics of the behavior for stress shielding of each type of femoral stem should be determined. This study compares differences in bone mineral density (BMD) change in the femur after primary THA between 3 major types of uncemented stems.
  
  
  
  Among a total of 89 hips, 26 hips received THA with a fit-and-fill type stem (VerSys Fiber Metal MidCoat; Zimmer, Inc, Warsaw, IN), 32 hips received a tapered rectangular Zweymüller-type stem (SL-Plus; Smith & Nephew Inc, Memphis, TN), and 31 received a tapered wedge-type stem (Accolade TMZF; Stryker Orthopaedics, Mahwah, NJ). BMD measurements were performed with a HOLOGIC Discovery device (Hologic Inc, Waltham, MA).
  
  
  
  BMD in the medial-proximal femur was maintained for 3 years after THA in the group with the tapered wedge-type stem. BMD in the lateral-proximal femur was maintained for 3 years after THA in the group with the Zweymüller-type stem. There were no significant differences in the Harris Hip Score among the 3 stem groups preoperatively and 1, 2, and 3 years after surgery.
  
  
  
  There are clear differences in postoperative BMD loss of the proximal femur among these 3 commonly used uncemented stems.
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Inaba
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Oba
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ike
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Kubota
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University, Yokohama, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Saito
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D015519:Bone Density; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D009985:Orthopedics; D011184:Postoperative Period; D012189:Retrospective Studies
chemical_list: D008670:Metals
keywords: bone mineral density; stem design; stress shielding; total hip arthroplasty; uncemented arthroplasty