Substitution of the posterior cruciate ligament in total knee arthroplasty: Advantages and pitfalls

Abstract

The substitution of Posterior Cruciate Ligament (PCL) was introduced during the mid seventies by Insall with the IB II Postero-Stabilized (PS) which demonstrated an improvement in kinematics and function by comparing with the Total Condylar PCL sacrificing (37). Thereafter, during the eighties, the preservation of PCL was promoted, in theory to improve knee kinematics (range of flexion in stairs, quadriceps efficiency) and subsequently the knee function (2). In spite of excellent results usually reported with PS prostheses (37, 64), the popularity of PCL sparing designs increased until the late eighties when some adverse effects were highlighted: instability (21), wear (9, 78), and patello-femoral disorders (8). The number of reports advocating PCL substitution increased after 1990 and the popularity of PCL sparing designs decreased in parallel, particularly when in vivo kinematics of TKA retaining the PCL was identified as abnormal by comparing with older PS designs (19, 75, 77, 82). However, some questions remain concerning PCL sacrifice or substitution: Are theoretical advantages of PCL retaining effective? Which adverse effects should we be aware of with PCL retaining? Which are the advantages of PCL substitution (postero-stabilised or deep-dished)? The aim of the present paper is to investigate these topics in order to give consistent arguments to support the PCL substitution. We will focus on five headings which had been considered in the past as major arguments to preserve the PCL: 1 Proprioception in TKA; 2 Ligament balance, tibial slope and joint line height; 3 TKA kinematics; 4 TKA and wear; 5 Function with PCL sparing and PS designs in TKA.