Authors: Sandro Giannini Matteo Romagnoli John J O’Connor Francesco Malerba Alberto Leardini
Publish Date: 2010/06/18
Volume: 468, Issue: 10, Pages: 2746-2753
Abstract
A threepart ankle replacement was developed to achieve compatibility with the natural ligaments by allowing fibers on the medial and lateral sides to remain isometric during passive motion Unlike all current prostheses the new design uses nonanatomically shaped components on the tibia and talus and a fully conforming interposed meniscal bearingWe reviewed 51 patients in whom 51 prostheses were implanted in a sevencenter trial from July 2003 to July 2006 The mean age of the patients at surgery was 615 years range 351–825 years We used the AOFAS score to assess clinical outcome We used lateral radiographs to assess function The minimum followup was 24 months mean 30 months range 24–48 monthsThe mean preoperative AOFAS score of 385 increased to 769 791 764 and 790 at 12 24 36 and 48 months respectively We observed a correlation between meniscal bearing movement on the tibial component mean 34 mm range 2–12 mm and range of flexion at the replaced ankle mean 274º range 16º–53º We revised one arthroplasty in the second postoperative year for lateral impingement providing a 3year cumulative survival rate of 97 and performed one other secondary operation for hindfoot painEach clinician in the list of authors certifies that his or her institution approved the human protocol for this investigation that all investigations were conducted in conformity with ethical principles of research and that informed consent for participation in the study was obtainedThe design and development work were performed at Istituto Ortopedico Rizzoli Bologna Italy at Oxford Orthopaedic Engineering Centre Oxford UK and Finsbury Orthopaedic Ltd Leatherhead UK The surgery and clinical examinations took place at Bologna and at the six other hospitals listed in the Acknowledgments Data analysis was performed at BolognaWe acknowledge the contribution of clinical data from Livio Nogarin Mantova Bruno Magnan Verona Leo Massari Ferrara Marco Guelfi Novara and Antonio Volpe Abano Terme We are grateful to Adler Ortho srl Bologna Italy for support in arranging communication and data collection among the centers and to Mike Tuke and Rob Wozencroft for cooperation in the development of components and instruments We also acknowledge the statistical analysis performed by Barbara Bordini of the IOR and the advice of Dr John Bithell of St Peter’s College Oxford
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