title: [The role of large femoral head components in revision of total hip arthroplasty].
abstract: OBJECTIVE
  To study the efficiency of decreasing instability of large femoral head components in revision total hip arthroplasty (THA).
  
  
  METHODS
  From August 2005 to December 2010, 107 patients (112 hips) with 28 mm femoral head components (28 mm group) and 46 patients (46 hips) with 36 mm femoral head components (36 mm group) in revision THA were analyzed retrospectively in order to find if the dislocation rate and Harris hip score were different between the two groups at the time of last follow-up. All the operations were performed by the first author. There were 81 male patients (85 hips) and 26 female patients (27 hips) in 28 mm group with mean age of (62±17) years (26-79 years) and 33 male patients (33 hips) and 13 female patients (13 hips) in 36 mm group with mean age of (60±16) years (31-77 years).
  
  
  RESULTS
  The mean follow-up period was 43.3 months (33-71 months) for 28 mm group and 26.7 months (12-37 months) for 36 mm group. There were 7 patients dislocated after revision in 28 mm group, including 2 revised with reinforcement rings (with dislocation rate 9.5%), 3 revised with impaction bone grafting technique (with dislocation rate 8.3%) and 2 revised with cementless cups (with a dislocation rate 3.6%). The dislocation rate of this group was 6.2%. While the dislocation rate of 36 mm group was 2.2%, the only dislocated patient was because of loss of gluteus medius muscle function in the index operation. If this case was excluded, the dislocation rate of 36 mm group would be 0. There was significant difference between the two groups (χ2=103.0095, P<0.01). The Harris hip score was 88±11 for 28 mm group and 89±9 for 36 mm group, there was no significant difference between the two groups (P>0.05).
  
  
  CONCLUSIONS
  The large femoral head components can significantly decrease the instability after revision THA, which should be used in revision THA.
authors.affiliation: Department of Orthopaedic Surgery, General Hospital of Chinese People's Liberation Army, Beijing 100853, China.
authors.forename: Yong-gang
authors.initials: YG
authors.lastname: Zhou
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ji-ying
authors.initials: JY
authors.lastname: Chen
authors.forename: Guo-qiang
authors.initials: GQ
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Chai
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D012189:Retrospective Studies