Biomechanical Effects of Posterior Condylar Offset and Posterior Tibial Slope on Quadriceps Force and Joint Contact Forces in Posterior-Stabilized Total Knee Arthroplasty.

Kyoung-Tak Kang,Juhyun Son,Yong-Gon Koh,Oh-Ryong Kwon,Jun-Sang Lee,Sae Kwang Kwon

doi:10.1155/2017/4908639

Kyoung-Tak Kang, Juhyun Son + Show 4 more

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https://doi.org/10.1155/2017/4908639

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Abstract

This study aimed to determine the biomechanical effect of the posterior condylar offset (PCO) and posterior tibial slope (PTS) in posterior-stabilized (PS) fixed-bearing total knee arthroplasty (TKA). We developed ±1, ±2, and ±3 mm PCO models in the posterior direction and −3°, 0°, 3°, and 6° PTS models using a previously validated FE model. The influence of changes in the PCO and PTS on the biomechanical effects under deep-knee-bend loading was investigated. The contact stress on the PE insert increased by 14% and decreased by 7% on average as the PCO increased and decreased, respectively, compared to the neutral position. In addition, the contact stress on post in PE insert increased by 18% on average as PTS increased from −3° to 6°. However, the contact stress on the patellar button decreased by 11% on average as PTS increased from −3° to 6° in all different PCO cases. The quadriceps force decreased by 14% as PTS increased from −3° to 6° in all PCO models. The same trend was found in patellar tendon force. Changes in PCO had adverse biomechanical effects whereas PTS increase had positive biomechanical effects. However, excessive PTS should be avoided to prevent knee instability and subsequent failure.

Highlights

Total knee arthroplasty (TKA) is one of the most successful orthopedic surgical treatments for providing pain relief and improving knee function
The contact stress on the PE insert increased by 14% and decreased by 7% on average as the posterior condylar offset (PCO) increased by 3 mm and decreased by 3 mm, respectively, compared to the neutral position in all posterior tibial slope (PTS) cases
There was no difference in contact stress on the PE insert as PTS increased from the neutral PCO

Summary

Introduction

Total knee arthroplasty (TKA) is one of the most successful orthopedic surgical treatments for providing pain relief and improving knee function. It has reported survival rates exceeding 90% after 15 years [1, 2]. The fundamental goal of TKA is to reduce knee joint pain and maintain the range of motion (ROM) to facilitate the ability to perform daily activities [3]. With remarkable improvements in implant design and survival, most patients primarily consider objective functional outcomes such as knee kinematics to evaluate the success of TKA [4]. A recent study demonstrated that limited ROM is negatively correlated with patient satisfaction and functional ability after TKA [6]

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