Jean Louis Prudhon1, Jacques H Caton2, Thierry Aslanian3, Régis Verdier4. 1. Clinique des Cèdres, 21 rue Albert Londres, 38432, Echirolles, France. 2. Clinique Emilie de Vialar, 116 rue Antoine Charial, 69003, Lyon, France. 3. Groupe lépine, Genay, 175 rue Jacquard, CS 50307-69727, Genay Cedex, France. 4. Groupe lépine, Genay, 175 rue Jacquard, CS 50307-69727, Genay Cedex, France. r.verdier@groupe-lepine.com.
Abstract
INTRODUCTION: Since the first measurement method of patella height in 1929 (Janssen), more than 16 methods have been described. Most of these measures are not suitable to measure patella height after total knee arthroplasty (TKA). One of us (JC) modified the original Caton Deschamps (oCD), index with a new relative index called modified Caton Deschamps (mCD) index, by using new landmarks. The purpose of this study was to determine how patella height is modified after TKA. MATERIAL AND METHOD: Sixty primary TKAs were consecutively prospectively enrolled. One type of implant was used (cementless postero-stabilized TKA, rotating plateau, cemented patella resurfacing). Patient's characteristics, functional and radiological outcomes were recorded pre-operatively and at one year follow-up. Pre-operative and post-operative outcomes were compared by paired t-test. Post-operative outcomes were compared between groups by one-way analysis of variance. RESULTS: Average difference between pre and post-operative mCD was 0.19 in this series. In 81.7% of cases, patella was lowered. Patients were classified in three groups according to patella height lowering. Between these three groups, no significant statistical differences (IKS score knee and function, range of motion) could be identified. DISCUSSION: In TKA, patella assessment in sagittal plane is as important as frontal or horizontal planes. True patella infera (TPI) is mostly due to patella tendon shortening measured by oCD. Pseudo patella infera (PPI) measured by mCD is mostly due to joint line elevation (over femoral cut with an over thickness of the tibial component). In this study a moderate patella lowering (minor than 15%) does not have a significant impact on the functional results (IKS, ROM) nevertheless in 80% patella is lowered. The next step will be to analyze precisely what factors are influencing this lowering and what prevention could be suggested in primary and revision TKA.
INTRODUCTION: Since the first measurement method of patella height in 1929 (Janssen), more than 16 methods have been described. Most of these measures are not suitable to measure patella height after total knee arthroplasty (TKA). One of us (JC) modified the original Caton Deschamps (oCD), index with a new relative index called modified Caton Deschamps (mCD) index, by using new landmarks. The purpose of this study was to determine how patella height is modified after TKA. MATERIAL AND METHOD: Sixty primary TKAs were consecutively prospectively enrolled. One type of implant was used (cementless postero-stabilized TKA, rotating plateau, cemented patella resurfacing). Patient's characteristics, functional and radiological outcomes were recorded pre-operatively and at one year follow-up. Pre-operative and post-operative outcomes were compared by paired t-test. Post-operative outcomes were compared between groups by one-way analysis of variance. RESULTS: Average difference between pre and post-operative mCD was 0.19 in this series. In 81.7% of cases, patella was lowered. Patients were classified in three groups according to patella height lowering. Between these three groups, no significant statistical differences (IKS score knee and function, range of motion) could be identified. DISCUSSION: In TKA, patella assessment in sagittal plane is as important as frontal or horizontal planes. True patella infera (TPI) is mostly due to patella tendon shortening measured by oCD. Pseudo patella infera (PPI) measured by mCD is mostly due to joint line elevation (over femoral cut with an over thickness of the tibial component). In this study a moderate patella lowering (minor than 15%) does not have a significant impact on the functional results (IKS, ROM) nevertheless in 80% patella is lowered. The next step will be to analyze precisely what factors are influencing this lowering and what prevention could be suggested in primary and revision TKA.
Entities:
Keywords:
Patella alta; Patella height; Patella infera; Total knee arthroplasty
Authors: Philip P Roessler; Randa Moussa; Cornelius Jacobs; Karl F Schüttler; Thomas Stein; Frank A Schildberg; Dieter C Wirtz Journal: Int Orthop Date: 2018-08-01 Impact factor: 3.075
Authors: Ludo A H van Engen; Ellie B M Landman; Ydo V Kleinlugtenbelt; Hans-Peter W van Jonbergen Journal: Int Orthop Date: 2018-10-12 Impact factor: 3.075
Authors: Philip P Roessler; Matthias D Wimmer; Cornelius Jacobs; Rahel Bornemann; Thomas Stein; Matthias Lahner Journal: Int Orthop Date: 2018-09-17 Impact factor: 3.075
Authors: Femke F Schröder; Corine E Post; Sjoerd M van Raak; Frank F J Simonis; Frank-Christiaan B M Wagenaar; Rianne M H A Huis In't Veld; Nico Verdonschot Journal: J Exp Orthop Date: 2020-07-31