F Zambianchi1, V Digennaro, A Giorgini, G Grandi, F Fiacchi, R Mugnai, F Catani. 1. Department of Orthopaedic Surgery, Azienda Ospedaliero-Universitaria Policlinico di Modena, University of Modena and Reggio-Emilia, Via del Pozzo 71, 41124, Modena, Italy, francesco.zambianchi@gmail.com.
Abstract
PURPOSE: Concerns exist regarding prosthetic positioning and post-operative limb alignment in unicompartmental knee arthroplasty (UKA). In this study, we hypothesized deviations of the post-op anatomical femoro-tibial angle (aFTA) and the tibial component alignment to be factors influencing UKA survivorship. Moreover, by a comparison between all-poly and metal back UKAs, we hypothesized that prosthetic design plays a role in implant survivorship. METHODS: One hundred ninety-five medial UKAs were performed on 176 patients by two experienced surgeons and one low-UKA user. One hundred and forty-seven UKAs were included in the study: 72 all-poly and 75 metal back. Measurements were performed on radiographs: mechanical femoro-tibial angle, Cartier angle, aFTA and tibial posterior slope (PS) on pre-op radiographs; femoral and tibial component varus/valgus, aFTA and tibial component PS on post-op radiographs. RESULTS: At an average follow-up of 61 months (min. 30, max. 107), 147 UKAs were evaluated: The reported survivorship rate was 93.1 %. Eleven implants underwent revision: ten all-poly and one metal back. No differences were reported between the two groups in the radiographic measurements. Significant radiographic differences were reported between revised and not revised UKAs: Revised UKAs were associated with overcorrection of the pre-op Cartier angle and under correction of pre-op aFTA. Most of revised UKAs were performed by the low-volume UKA surgeon. CONCLUSIONS: Surgeon's experience is essential to achieve good results in UKA: Preserving the tibial epiphyseal axis and avoiding excessive or insufficient corrections of the pre-operative limb alignment are predictor of successful replacement, while prosthetic designs, models and fixation geometry do not affect UKA outcome. LEVEL OF EVIDENCE: IV.
PURPOSE: Concerns exist regarding prosthetic positioning and post-operative limb alignment in unicompartmental knee arthroplasty (UKA). In this study, we hypothesized deviations of the post-op anatomical femoro-tibial angle (aFTA) and the tibial component alignment to be factors influencing UKA survivorship. Moreover, by a comparison between all-poly and metal back UKAs, we hypothesized that prosthetic design plays a role in implant survivorship. METHODS: One hundred ninety-five medial UKAs were performed on 176 patients by two experienced surgeons and one low-UKA user. One hundred and forty-seven UKAs were included in the study: 72 all-poly and 75 metal back. Measurements were performed on radiographs: mechanical femoro-tibial angle, Cartier angle, aFTA and tibial posterior slope (PS) on pre-op radiographs; femoral and tibial component varus/valgus, aFTA and tibial component PS on post-op radiographs. RESULTS: At an average follow-up of 61 months (min. 30, max. 107), 147 UKAs were evaluated: The reported survivorship rate was 93.1 %. Eleven implants underwent revision: ten all-poly and one metal back. No differences were reported between the two groups in the radiographic measurements. Significant radiographic differences were reported between revised and not revised UKAs: Revised UKAs were associated with overcorrection of the pre-op Cartier angle and under correction of pre-op aFTA. Most of revised UKAs were performed by the low-volume UKA surgeon. CONCLUSIONS: Surgeon's experience is essential to achieve good results in UKA: Preserving the tibial epiphyseal axis and avoiding excessive or insufficient corrections of the pre-operative limb alignment are predictor of successful replacement, while prosthetic designs, models and fixation geometry do not affect UKA outcome. LEVEL OF EVIDENCE: IV.
Authors: Scott R Small; Michael E Berend; Merrill A Ritter; Christine A Buckley; Renee D Rogge Journal: J Arthroplasty Date: 2010-09-25 Impact factor: 4.757
Authors: Leena Sharma; Jing Song; Dorothy Dunlop; David Felson; Cora E Lewis; Neil Segal; James Torner; T Derek V Cooke; Jean Hietpas; John Lynch; Michael Nevitt Journal: Ann Rheum Dis Date: 2010-05-28 Impact factor: 19.103
Authors: Johannes F Plate; Marco A Augart; Thorsten M Seyler; Daniel N Bracey; Aneitra Hoggard; Michael Akbar; Riyaz H Jinnah; Gary G Poehling Journal: Knee Surg Sports Traumatol Arthrosc Date: 2015-04-12 Impact factor: 4.342