title: The influence of surgical factors on dislocation of the meniscal bearing after Oxford medial unicompartmental knee replacement: a case-control study.
abstract: The aim of this study was to evaluate the risk factors for dislocation of the bearing after a mobile-bearing Oxford medial unicompartmental knee replacement (UKR) and to test the hypothesis that surgical factors, as measured from post-operative radiographs, are associated with its dislocation From a total of 480 UKRs performed between 2001 and 2012, in 391 patients with a mean age of 66.5 years (45 to 82) (316 female, 75 male), we identified 17 UKRs where bearing dislocation occurred. The post-operative radiological measurements of the 17 UKRs and 51 matched controls were analysed using conditional logistic regression analysis. The post-operative radiological measurements included post-operative change in limb alignment, the position of the femoral and tibial components, the resection depth of the proximal tibia, and the femoral component-posterior condyle classification. We concluded that a post-operative decrease in the posterior tibial slope relative to the pre-operative value was the only significant determinant of dislocation of the bearing after medial Oxford UKR (odds ratio 1.881; 95% confidence interval 1.272 to 2.779). A post-operative posterior tibial slope < 8.45° and a difference between the pre-operative and post-operative posterior tibial slope of > 2.19° may increase the risk of dislocation.
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 80, Guro-Dong, Guro-Gu, Seoul, 152-703, South Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 516, Gojan 1-Dong, Danwon-Gu, Ansan, 425-707, South Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Bae
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 516, Gojan 1-Dong, Danwon-Gu, Ansan, 425-707, South Korea.
authors.forename: J G
authors.initials: JG
authors.lastname: Kim
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 80, Guro-Dong, Guro-Gu, Seoul, 152-703, South Korea.
authors.forename: K M
authors.initials: KM
authors.lastname: Jang
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 80, Guro-Dong, Guro-Gu, Seoul, 152-703, South Korea.
authors.forename: W Y
authors.initials: WY
authors.lastname: Shon
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 516, Gojan 1-Dong, Danwon-Gu, Ansan, 425-707, South Korea.
authors.forename: K W
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Korea University College of Medicine, Department of Orthopaedic Surgery, 80, Guro-Dong, Guro-Gu, Seoul, 152-703, South Korea.
authors.forename: H C
authors.initials: HC
authors.lastname: Lim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012307:Risk Factors
keywords: Bearing dislocation; Risk factor; Unicompartmental knee arthroplasty