title: Medial Protrusio Technique in Cementless Total Hip Arthroplasty for Developmental Dysplasia of the Hip: A Prospective 6- to 9-Year Follow-Up of 43 Consecutive Patients.
abstract: The medial protrusio technique may be used during total hip arthroplasty (THA) on patients with developmental dysplasia. However, studies have yet to determine whether a cementless cup can be sufficiently stable to withstand loading forces. This study aimed to assess the clinical and radiographic outcomes of this technique. Furthermore, we sought to determine the relationship between the rate of medial protrusion and the incidence of cup loosening.
  
  
  
  Thirty-nine patients (43 hips) underwent cementless THA between April 2006 and March 2009 by using the medial protrusio technique. These patients participated in a 6- to 9-year follow-up. Their clinical and radiographic data were gathered prospectively.
  
  
  
  The average Harris Hip Score improved from 43.1 ± 15.4 points preoperatively to 91.9 ± 12.8 points at the final follow-up (P < .001). The mean height of hip center and the distance of hip center medialization were 2.4 ± 0.6 and 2.5 ± 0.9 cm, respectively. The rate of medial protrusion and the rate of cup coverage were 42.1 ± 12.4% and 96.8 ± 5.1%, respectively. The rate of medial protrusion ranged from 18.3% to 58.3% in 38 hips (group A) and from 61.3% to 68.9% in 5 hips (group B). None of the cups in group A loosened or failed, 2 failures occurred in group B (0% vs 40.0%; P = .011).
  
  
  
  Developmental dysplasia was treated through THA using the medial protrusio technique, which easily achieves a sufficient superolateral host bony coverage of the cup and promotes socket reconstruction at the true acetabulum. The rate of medial protrusion of <60% may be necessary to obtain excellent clinical and radiographic midterm results.
authors.affiliation: Department of Orthopedic Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu, P.R. China.
authors.forename: Guo-Chun
authors.initials: GC
authors.lastname: Zha
authors.affiliation: Orthopaedic Department, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, P.R. China.
authors.forename: Jun-Ying
authors.initials: JY
authors.lastname: Sun
authors.affiliation: Department of Orthopedic Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu, P.R. China.
authors.forename: Kai-Jin
authors.initials: KJ
authors.lastname: Guo
authors.affiliation: Department of Orthopedic Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu, P.R. China.
authors.forename: Feng-Chao
authors.initials: FC
authors.lastname: Zhao
authors.affiliation: Department of Orthopedic Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Pang
authors.affiliation: Department of Orthopedic Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zheng
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006615:Hip / Q000601:surgery; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D016896:Treatment Outcome; D055815:Young Adult
keywords: acetabular dysplasia; cementless; insufficient acetabulum; medial protrusio technique; total hip arthroplasty