title: Valgus subsidence of the tibial component in cementless Oxford unicompartmental knee replacement.
abstract: The cementless Oxford unicompartmental knee replacement has been demonstrated to have superior fixation on radiographs and a similar early complication rate compared with the cemented version. However, a small number of cases have come to our attention where, after an apparently successful procedure, the tibial component subsides into a valgus position with an increased posterior slope, before becoming well-fixed. We present the clinical and radiological findings of these six patients and describe their natural history and the likely causes. Two underwent revision in the early post-operative period, and in four the implant stabilised and became well-fixed radiologically with a good functional outcome. This situation appears to be avoidable by minor modifications to the operative technique, and it appears that it can be treated conservatively in most patients.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Windmill Road, OX3 7LD, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Liddle
authors.forename: H G
authors.initials: HG
authors.lastname: Pandit
authors.forename: C
authors.initials: C
authors.lastname: Jenkins
authors.forename: P
authors.initials: P
authors.lastname: Lobenhoffer
authors.forename: W F M
authors.initials: WF
authors.lastname: Jackson
authors.forename: C A F
authors.initials: CA
authors.lastname: Dodd
authors.forename: D W
authors.initials: DW
authors.lastname: Murray
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000601:surgery*; D011474:Prosthesis Design; D011859:Radiography; D012086:Reoperation; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D017211:Treatment Failure; D016896:Treatment Outcome
keywords: Arthroplasty; Cementless fixation; Hydroxyapatite; Loosening; Revision; Unicompartmental knee replacement