Constraint choice in revision knee arthroplasty: study protocol of a randomised controlled trial assessing the effect of level of constraint on postoperative outcome

BMJ Open. 2017 Mar 27;7(3):e012964. doi: 10.1136/bmjopen-2016-012964.


Introduction: 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.

Methods and analysis: 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.

Ethics and dissemination: 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.

Trial registration number: DRKS00010539.

Keywords: Osteoarthritis, knee; arthroplasty, knee replacement; clinical equivalency; trials, randomized clinical.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Activities of Daily Living
  • Aged
  • Arthroplasty, Replacement, Knee* / adverse effects
  • Arthroplasty, Replacement, Knee* / instrumentation
  • Arthroplasty, Replacement, Knee* / methods
  • Female
  • Follow-Up Studies
  • Germany / epidemiology
  • Humans
  • Incidence
  • Joint Instability / diagnostic imaging
  • Joint Instability / physiopathology
  • Joint Instability / surgery*
  • Knee Joint / diagnostic imaging
  • Knee Joint / physiopathology
  • Knee Joint / surgery*
  • Knee Prosthesis
  • Male
  • Osteoarthritis, Knee / diagnostic imaging
  • Osteoarthritis, Knee / physiopathology
  • Osteoarthritis, Knee / surgery*
  • Postoperative Complications / diagnostic imaging
  • Postoperative Complications / physiopathology
  • Postoperative Complications / surgery*
  • Postoperative Period
  • Prosthesis Failure
  • Radiography*
  • Range of Motion, Articular
  • Reoperation / statistics & numerical data*
  • Treatment Outcome

Associated data

  • DRKS/DRKS00010539