title: Medium-term outcome of total hip replacement for dysplastic hips in Singapore.
abstract: OBJECTIVE
  To review medium-term outcomes of 46 patients who underwent total hip replacement (THR) for osteoarthritis secondary to dysplastic hips.
  
  
  METHODS
  Records of 58 hips in 6 men and 40 women aged 32 to 76 (mean, 62) years who underwent THR for osteoarthritis secondary to dysplastic hips and had been followed up for a mean of 4 (range, 2-8) years were retrospectively reviewed. The hips were classified according to the Crowe's grading, Sharp's acetabular angle, and centre-edge angle. The radiological uncoverage of acetabular cup (RUAC) index was calculated. The outcomes of THR were evaluated in terms of cup inclination, RUAC index, cup migration, lysis or loosening (radiolucency), heterotopic ossification, component incorporation and positioning, thigh pain, and subsidence.
  
  
  RESULTS
  51 of the hips were Crowe's type I, 6 were type II, and one was type IV. The mean acetabular angle was 46.3 degrees and the mean centre-edge angle was 15.4 degrees. The mean cup, head, and stem sizes were 50.4 mm, 28.7 mm, and 10.9 mm, respectively. The mean RUAC index was 16.9% and the mean cup inclination was 40.7 degrees. Radiolucency of 1 mm in the acetabular zone I was observed in 16 cases, but only one failed. For cemented and uncemented stems, the most common positioning was neutral and valgus, respectively. Five patients had complications of greater trochanter fracture, aseptic loosening, split calcar, stem loosening, and/or heterotopic ossification.
  
  
  CONCLUSIONS
  Conventional THR can achieve good medium-term results in low-grade dysplastic hips.
authors.affiliation: Division of Adult Reconstruction, National University Hospital, Singapore.
authors.forename: Jajodia Nirmal
authors.initials: JN
authors.lastname: Kumar
authors.forename: Jain Sumit
authors.initials: JS
authors.lastname: Kumar
authors.forename: Victor T J
authors.initials: VT
authors.lastname: Wang
authors.forename: Shamal
authors.initials: S
authors.lastname: Das De
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D044466:Asian People; D015331:Cohort Studies; D005260:Female; D006618:Hip Dislocation, Congenital / Q000150:complications / Q000208:ethnology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000208:ethnology* / Q000209:etiology / Q000601:surgery*; D012189:Retrospective Studies; D012846:Singapore; D013997:Time Factors; D016896:Treatment Outcome