title: [Functional results after surface replacement of the hip: comparison between dysplasia and idiopathic osteoarthritis].
abstract: OBJECTIVE
  To determine if there are differences in function after resurfacing arthroplasty of the hip in patients with primary osteoarthritis compared to patients with secondary osteoarthritis due to developmental dysplasia of the hip.
  
  
  METHODS
  In a controlled prospective study of Birmingham Hip Resurfacing (BHR) we included all patients with primary osteoarthritis (n = 54, average age 48.4 years) and osteoarthritis due to high grade dysplasia (Eftekhar B, n = 34, average age 55.8 years). Standardized clinical (Harris hip score) and radiographic examinations were performed 6 weeks, 3 months and 6 months and then every year after the operation.
  
  
  RESULTS
  All patients could be followed up to 1.5 years (1-4 years) after surgery. The average Harris hip score improved to 82-95 points in both groups 3 months postoperatively. Statistically significant differences could be found in the subscales "function" and "limp", where patients with dysplastic hips showed somewhat lower results after 6 (function) to 12 weeks (limp) postoperatively. This is probably attributable to extended non-weight-bearing after acetabular reconstruction in these cases, as the difference disappeared with full weight-bearing. Radiographically determined neck-shaft angles are slightly higher in dysplastic hips (142 degrees versus 135 degrees ), but we did not recognize any significant differences in implant positioning.
  
  
  CONCLUSIONS
  The short- to mid-term results showed no clinically relevant functional differences after surface replacement in patients with primary osteoarthritis of the hip and patients with secondary osteoarthritis due to higher grade dysplasia. Long-term observation is necessary, however, to determine if these positive functional results are reflected by appropriate radiographic survival.
authors.affiliation: Klinik für Orthopädie, Universitätsklinikum Carl Gustav Carus der TU Dresden, Dresden. Andre.Knecht@Mailbox.tu-dresden.de
authors.forename: A
authors.initials: A
authors.lastname: Knecht
authors.forename: W-C
authors.initials: WC
authors.lastname: Witzleb
authors.forename: T
authors.initials: T
authors.lastname: Beichler
authors.forename: K-P
authors.initials: KP
authors.lastname: Günther
mesh_terms: D000328:Adult; D005260:Female; D006618:Hip Dislocation, Congenital / Q000150:complications* / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000209:etiology* / Q000601:surgery*; D020127:Recovery of Function / Q000502:physiology*; D016896:Treatment Outcome