title: Complications of medial unicompartmental knee arthroplasty.
abstract: BACKGROUND
  We report intra- and postoperative complications of unicompartmental knee arthroplasty (UKA).
  
  
  METHODS
  This study was conducted on 246 cases of UKA which were performed for degenerative osteoarthritis confined to the medial compartment, from May 2002 to May 2010, for which follow-up periods longer than one year were available. Complications were divided into intra- and postoperative complications. Pre- and postoperative clinical scores, the range of motion, and radiologic findings were analyzed.
  
  
  RESULTS
  Complications developed in a total of 24 cases (9.8%, 24/246). Among them, 6 cases had intraoperative complications while 18 had postoperative complications. Among the 6 intraoperative complications, one fracture of the medial tibial condyle, two fractures of the intercondylar eminence, one rupture of the medial collateral ligament, one widening of the peg hole leading to femoral component malposition and late failure, and one total knee arthroplasty (TKA) conversion of a large bony defect of tibial avascular necrosis were observed. Among the 18 postoperative complications, four cases of aseptic loosening of the femoral component, one soft tissue impingement due to malalignment, nine cases of polyethylene bearing dislocation, one case of suprapatellar bursitis, one periprosthetic fracture, one TKA conversion due to medial component overhanging, and one TKA conversion due to pain of unexplained cause were observed.
  
  
  CONCLUSIONS
  The mid-term clinical outcomes of UKA were excellent in our study. However, the incidence of complications was very high (9.8%). To prevent intra- and postoperative complications, proper selection of the patients and accurate surgical techniques are required.
authors.affiliation: Department of Orthopedic Surgery, Daejeon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Daejeon, Korea.
authors.forename: Jong Hun
authors.initials: JH
authors.lastname: Ji
authors.affiliation: Department of Orthopedic Surgery, Daejeon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Daejeon, Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Sun General Hospital, Daejeon, Korea.
authors.forename: In Soo
authors.initials: IS
authors.lastname: Song
authors.affiliation: Department of Orthopedic Surgery, Daejeon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Daejeon, Korea.
authors.forename: Hanvit
authors.initials: H
authors.lastname: Kang
authors.affiliation: Department of Orthopedic Surgery, Daejeon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Daejeon, Korea.
authors.forename: Ji Yoon
authors.initials: JY
authors.lastname: Ha
authors.affiliation: Department of Orthopedic Surgery, Daejeon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Daejeon, Korea.
authors.forename: Jae Jung
authors.initials: JJ
authors.lastname: Jeong
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D011183:Postoperative Complications; D011859:Radiography; D012189:Retrospective Studies
keywords: Intraoperative complications; Postoperative complications; Unicompartmental knee arthroplasty