title: De-escalation exchange of loosened locked revision stems to a primary stem design: complications, stem fixation and bone reconstruction in 15 cases.
abstract: BACKGROUND
  Femoral stem revision with a locked stem after total hip arthroplasties treats severe bone defects by favoring spontaneous bone reconstruction. Initially, once reconstruction was obtained, the temporary implant was to be replaced by a standard primary component. The use of locked stems has increased, but repeat revision with a short stem which is also called "de-escalation" has not been extensively studied.
  
  
  OBJECTIVE
  Repeat revision of a locked stem with a short stem is not associated with any specific morbidity and does not affect the quality of reconstruction obtained, or fixation of the subsequent standard length primary design stem.
  
  
  METHODS
  Fifteen patients whose locked femoral stem was exchanged due to thigh pain and/or radiographic images showing failed osteointegration were analyzed. These 15 patients were all followed-up and evaluated by the Postel Merle d'Aubigné score. Progression of bone defects was evaluated using the Hofmann cortical index.
  
  
  RESULTS
  There were no difficulties extracting the locked stem and a standard length primary stem was inserted with no associated procedures or bone complications in any of the cases. At a mean follow-up of 55 months (36-84months), thigh pain had disappeared and the Postel Merle d'Aubigné score had increased from 12.6±2.9 (7-16) to 16.5±0.9 (15-18) (P=0.0001). The use of a locked femoral stem resulted in bone reconstruction in all cases, the Hofmann index increased from 30.5%±17.9% (12-71%) before insertion of the locked stem to 43.6%±25.6% (19-90%) at exchange (P<0.05). Bone reconstruction was durable after the exchange with a stable Hofmann index 43.7%±26.2% (17-92%) at the final follow-up (P=0.9). No recurrent loosening occurred.
  
  
  CONCLUSIONS
  Revision of a loosened locked femoral stem with a standard design primary stem does not result in any specific increased morbidity, or modify bone reconstruction obtained with the locked stem and results in stable fixation of a new standard length stem.
  
  
  METHODS
  IV: retrospective or historical series.
authors.affiliation: Lille North of France University, 59000 Lille, France. br.miletic@gmail.com
authors.forename: B
authors.initials: B
authors.lastname: Miletic
authors.forename: O
authors.initials: O
authors.lastname: May
authors.forename: N
authors.initials: N
authors.lastname: Krantz
authors.forename: J
authors.initials: J
authors.lastname: Girard
authors.forename: G
authors.initials: G
authors.lastname: Pasquier
authors.forename: H
authors.initials: H
authors.lastname: Migaud
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D001862:Bone Resorption / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*; D020878:Device Removal / Q000379:methods*; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D019651:Plastic Surgery Procedures / Q000379:methods*; D012086:Reoperation / Q000379:methods*; D012189:Retrospective Studies