title: Cement removal and bone bed preparation of the femoral medullary canal assisted by flexible endoscope in total hip revision arthroplasty.
abstract: OBJECTIVE
  The flexible endoscope was applied to cemented femoral medullary canal to obtain better visual field and assist surgical procedures in total hip revision arthroplasty.
  
  
  METHODS
  Fifteen cases of failed cemented total hip joints were analyzed. Efficacy of cement removal was assessed, combined with degree of implant loosening and bone defect, postoperative radiographic findings, and perioperative status of the patients and complications. Status of the bone bed between bone and cement and that of bone grafting were also evaluated.
  
  
  RESULTS
  The cement mantle was efficiently extractable in all cases under good exposure and with maintenance of efficient working space. Endoscopic time for cement removal was dependent on the status of the cement-bone interface and bone defect. Rigid and less loosened interfaces, as well as cases of minimal bone defect, required a longer time. However, it was effective to confirm the status of the bone bed during the procedure. Occult foreign-body reaction was detectable in three cases of unloosened interface under endoscopic inspection. Impaction bone grafting was performed in eight cases. The scope was also helpful to confirm the status of a grafted bone bed. Three fractures occurred, of which two cases revealed minor cement leakage and one required additional osteosynthesis with extensive approach. JOA Hip Score was improved, and the implants were stable at latest follow-up. Dislocation was found in two cases. Neither thromboembolic events nor infection was found.
  
  
  CONCLUSIONS
  Cement removal in the femoral medullar canal was effectively performed not only in the cases of loose interface but also those of rigid and less-loosened interface under flexible endoscopic inspection. The scope could support cement removal in femoral revisions under good exposure and maintenance of working space, as well as confirmation of bone bed state. Although one case required an additional approach, application of the flexible endoscope has potential merit to contribute to less invasive total hip revision arthroplasty, possibly combined with other refined devices of cement extraction.
authors.affiliation: Department of Orthopaedic Surgery, Yamagata University School of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Takagi
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Tamaki
authors.forename: Shinji
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Kan
authors.initials: K
authors.lastname: Sasaki
authors.forename: Yuya
authors.initials: Y
authors.lastname: Takakubo
authors.forename: Masaji
authors.initials: M
authors.lastname: Ishii
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D002484:Cementation / Q000379:methods; D004724:Endoscopy / Q000379:methods*; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D012086:Reoperation / Q000295:instrumentation / Q000379:methods