title: Locked tension band wiring using ring pins for patellar fractures: a method of minimising implant migration.
abstract: BACKGROUND
  A modified K-wire attached with ring (ring pin) was used to treat a displaced patellar fracture, and the ring pin was locked with tension band wiring. The purpose of this study was to evaluate the surgical outcome of this method with respect to its procedural safety.
  
  
  METHODS
  The authors retrospectively reviewed 36 patients treated for a displaced patellar fracture and assessed bone union, fixation failure, postoperative pain, range of motion, and incidence of hardware removal. Clinical outcome was evaluated using the Böstman scoring system. The mean follow-up period was 27 (range 13-47) months.
  
  
  RESULTS
  Bony union was achieved in all patients. No fixation failure and pin migration were detected. Hardware was removed in three cases (8.3 %). Reasons for removal were pain in one case and vague discomfort in two cases. The average Böstman scores at 12 months postoperatively were 29.6, with 34 (94.4 %) patients graded as excellent. The average active flexion of the knee joint was 130.4° (range 125°-150°), with an average flexion contracture of 3° (range 0°-10°).
  
  
  CONCLUSIONS
  This implant could facilitate satisfactory fixation, restore the integrity of the extensor mechanism, and reduce the possibility of implant migration and implant-related discomfort.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Min Bom
authors.initials: MB
authors.lastname: Kim
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Lee
authors.forename: Woo Cheol
authors.initials: WC
authors.lastname: Shin
authors.forename: Goo Hyun
authors.initials: GH
authors.lastname: Baek
mesh_terms: D000328:Adult; D000368:Aged; D001858:Bone Nails; D001864:Bone Wires; D020878:Device Removal; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000517:prevention & control*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000209:etiology; D010329:Patella / Q000293:injuries*; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D017211:Treatment Failure; D016896:Treatment Outcome