title: Constraint choice in revision knee arthroplasty: study protocol of a randomised controlled trial assessing the effect of level of constraint on postoperative outcome.
abstract: The proper management of total knee arthroplasty (TKA) in patients with severe deformities regarding the preferable prosthetic design and the required amount of constraint is a controversial subject. In the absence of any high-level clinical evidence, we designed a randomised clinical trial to investigate if rotating hinged (RTH) and constrained condylar knee (CCK) designs yield similar outcomes.
  
  
  
  This study is a multicentre, randomised clinical trial including two groups of 85 patients. Patients will be randomised to a CCK knee design group or an RTH knee design group. Patients will be followed for 2 years. The study will be designed as an equivalence trial. The primary study outcome will be the postoperative functional outcome as measured by the self-administered Knee Injury and Osteoarthritis Outcome Score. Secondary outcomes will be postoperative joint awareness during various activities of daily living as measured by the Forgotten Joint Score-12, the Knee Society Score, along with the incidence and location of radiolucent lines using the Knee Society TKA radiographic evaluation system.
  
  
  
  This study is approved by the ethics committee of the Landesärztekammer Brandenburg ((S 10(a)/2013) from 27.08.2013, amended on 25.04.2016) and will be conducted according to the principles of the World Medical Association Declaration of Helsinki and the ISO14155:2011.
  
  
  
  DRKS00010539.
authors.affiliation: Krankenhaus Märkisch Oderland GmbH BT Wriezen, Klinik für Orthopädie, Sportmedizin und Rehabilitation, Wriezen, Germany.|Lehrkrankenhaus der Medizinischen Hochschule Brandenburg (MHB) Theodor Fontane, Neuruppin, Germany.
authors.forename: Hagen
authors.initials: H
authors.lastname: Hommel
authors.affiliation: Krankenhaus Märkisch Oderland GmbH BT Wriezen, Klinik für Orthopädie, Sportmedizin und Rehabilitation, Wriezen, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Wilke
authors.affiliation: Krankenhaus Märkisch Oderland GmbH BT Wriezen, Klinik für Orthopädie, Sportmedizin und Rehabilitation, Wriezen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kunze
authors.affiliation: Krankenhaus Märkisch Oderland GmbH BT Wriezen, Klinik für Orthopädie, Sportmedizin und Rehabilitation, Wriezen, Germany.
authors.forename: Peggy
authors.initials: P
authors.lastname: Hommel
authors.affiliation: AMR Advanced Medical Research GmbH, Männedorf, Switzerland.
authors.forename: Peter
authors.identifier: 0000-0002-3549-398X
authors.initials: P
authors.lastname: Fennema
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation / Q000706:statistics & numerical data*; D016896:Treatment Outcome
keywords: Osteoarthritis, knee; arthroplasty, knee replacement; clinical equivalency; trials, randomized clinical