title: Is reverse hybrid hip replacement the solution?
abstract: OBJECTIVE
  Reverse hybrid hip replacement uses a cemented all-polyethylene cup and an uncemented stem. Despite increasing use of this method in Scandinavia, there has been very little documentation of results. We have therefore analyzed the results from the Norwegian Arthroplasty Register (NAR), with up to 10 years of follow-up.
  
  
  METHODS
  The NAR has been collecting data on total hip replacement (THR) since 1987. Reverse hybrid hip replacements were used mainly from 2000. We extracted data on reverse hybrid THR from this year onward until December 31, 2009, and compared the results with those from cemented implants over the same period. Specific cup/stem combinations involving 100 cases or more were selected. In addition, only combinations that were taken into use in 2005 or earlier were included. 3,963 operations in 3,630 patients were included. We used the Kaplan-Meier method and Cox regression analysis for estimation of prosthesis survival and relative risk of revision. The main endpoint was revision for any cause, but we also performed specific analyses on different reasons for revision.
  
  
  RESULTS
  We found equal survival to that from cemented THR at 5 years (cemented: 97.0% (95% CI: 96.8-97.2); reverse hybrid: 96.7% (96.0-97.4)) and at 7 years (cemented: 96.0% (95.7-96.2); reverse hybrid: 95.6% (94.4-96.7)). Adjusted relative risk of revision of the reverse hybrids was 1.1 (0.9-1.4). In patients under 60 years of age, we found similar survival of the 2 groups at 5 and 7 years, with an adjusted relative risk of revision of reverse hybrids of 0.9 (0.6-1.3) compared to cemented implants.
  
  
  CONCLUSIONS
  With a follow-up of up to 10 years, reverse hybrid THRs performed well, and similarly to all-cemented THRs from the same time period. The reverse hybrid method might therefore be an alternative to all-cemented THR. Longer follow-up time is needed to evaluate whether reverse hybrid hip replacement has any advantages over all-cemented THR.
authors: Department of Orthopaedic Surgery, Lovisenberg Deaconal Hospital, Oslo, Norway. eli@lds.no
authors: Einar
authors: E
authors: Lindalen
authors: Leif I
authors: LI
authors: Havelin
authors: Lars
authors: L
authors: Nordsletten
authors: Eva
authors: E
authors: Dybvik
authors: Anne M
authors: AM
authors: Fenstad
authors: Geir
authors: G
authors: Hallan
authors: Ove
authors: O
authors: Furnes
authors: Oystein
authors: O
authors: Høvik
authors: Stephan M
authors: SM
authors: Röhrl
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D002484:Cementation; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway; D017063:Outcome Assessment, Health Care; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012042:Registries; D012086:Reoperation; D012307:Risk Factors; D055815:Young Adult