Alignment options for total knee arthroplasty: A systematic review

Abstract

In spite of improvements in implant designs and surgical precision, functional outcomes of mechanically aligned total knee arthroplasty (MA TKA) have plateaued. This suggests probable technical intrinsic limitations that few alternate more anatomical recently promoted surgical techniques are trying to solve. This review aims at (1) classifying the different options to frontally align TKA implants, (2) at comparing their safety and efficacy with the one from MA TKAs, therefore answering the following questions: does alternative techniques to position TKA improve functional outcomes of TKA (question 1)? Is there any pathoanatomy not suitable for kinematic implantation of a TKA (question 2)? A systematic review of the existing literature utilizing PubMed and Google Scholar search engines was performed in February 2017. Only studies published in peer-reviewed journals over the last ten years in either English or French were reviewed. We identified 569 reports, of which 13 met our eligibility criteria. Four alternative techniques to position a TKA are challenging the traditional MA technique: anatomic (AA), adjusted mechanical (aMA), kinematic (KA), and restricted kinematic (rKA) alignment techniques. Regarding osteoarthritic patients with slight to mid constitutional knee frontal deformity, the KA technique enables a faster recovery and generally generates higher functional TKA outcomes than the MA technique. Kinematic alignment for TKA is a new attractive technique for TKA at early to mid-term, but need longer follow-up in order to assess its true value. It is probable that some forms of pathoanatomy might affect longer-term clinical outcomes of KA TKA and make the rKA technique or additional surgical corrections (realignment osteotomy, retinacular ligament reconstruction etc.) relevant for this sub-group of patients. Longer follow-up is needed to define the best indication of each alternative surgical technique for TKA. Level I for question 1 (systematic review of Level I studies), level 4 for question 2.

Analysis of differences in laxities and neutral positions from native after kinematically aligned TKA using cruciate retaining implants

“…One outcome goal of kinematically aligned total knee arthroplasty (KA TKA) is to restore objective metrics of biomechanical function such that they are not different from those of the native (i.e., pre‐arthritic) knee . To achieve this outcome goal, the surgical goal of KA TKA is to align the femoral and tibial components to restore the native joint lines (i.e., lines tangent to the distal femoral condyles and the tibial plateau in the coronal plane, to the posterior femoral condyles in the axial plane, and to the medial tibial plateau in the sagittal plane), which in turn should restore the native alignments of the limb and knee without soft tissue release . By doing so, KA TKA might limit differences in biomechanical function from native .…”

Personalised medicine in knee arthroplasty: we need more science!

“…In the last years, the dogma that all knees should have a neutral hip-knee-ankle angle (HKA) after TKA has been questioned for native varus knees [11]. In addition, there is an ongoing discussion about the optimal alignment in TKA [3,5,[8][9][10]. In fact, it appears that there is not only the mechanical alignment that matters, but there are more alignment options to be considered such as anatomic, kinematic and adjusted alignment [3,5,[8][9][10].…”

Tibial subchondral trabecular bone micromechanical and microarchitectural properties are affected by alignment and osteoarthritis stage

“…Knee osteoarthritis (OA) is a multi-factorial disease that affects all the joint tissues and leads to significant functional disabilities. Lower limb malalignment predicts OA progression [1][2][3][4] and is associated with load distribution within the knee joint 5 : the lateral compartment is overloaded in patients with a valgus deformity, and the medial compartment in patients with a varus deformity 6 .…”