TITLE:
Coronal Alignment of Three Different Types of Implants in Kinematically Aligned Total Knee Arthroplasty: A Comparative Study
AUTHORS:
Yoshinori Soda, Mitsuhiro Nakamura, Nobuo Adachi
KEYWORDS:
Total Knee Arthroplasty, Kinematic Alignment, Mechanical Alignment, Calipered Technique
JOURNAL NAME:
Open Journal of Orthopedics,
Vol.11 No.6,
June
28,
2021
ABSTRACT: Background: The number of total knee arthroplasty (TKA) surgeries performed each year
is increasing worldwide and mechanical alignment (MA) is currently seen as the
gold standard procedure. However, taking neutral alignment as the universal
goal may be mistaken. In our hospital, we currently conduct kinematically aligned
TKA (KA-TKA). Three different types of implants are used: the cruciate-retaining (CR)
type, cruciate-sacrificing (CS) type, or bi-cruciate-retained (BCR) type. We
aimed to compare the coronal alignment observed following KA-TKA and MA-TKA and
in normal knees, as well as that achieved with different types of implants. Methods: The study comprised 206 knees of Japanese patients who underwent KA-TKA using
varying implants in our Hospital between May 2019 and April 2020. Measurements
of pre- and postoperative coronal alignment were determined from weight-bearing
full-leg standing radiographs. The postoperative results were compared to measurements taken from patients who
underwent MA-TKA (N = 96) and normal knees (N = 60). Results: No
significant differences between the KA-TKA group and normal knees were found
for the medial proximal tibial angle (MPTA) (–4.2°± 2.6° vs –3.8° ± 2.5°) or
joint line orientation angle (JLOA) (0.2° ± 1.9° vs 0.3° ± 1.4°).
However, when MA-TKA was compared to KA-TKA and normal knees, there were
significant differences in both the MPTA and JLOA (p Conclusions: Here, we demonstrated that following KA-TKA, the articular surface of the tibia
exhibited a similar varus alignment as that of normal knees, meaning that the
technique reproduces the native knee. Furthermore, KA is patient-specific, and
does not have the same failures as MA-TKA. Therefore, we anticipate a paradigm
shift from mechanical to kinematic alignment, which may help reduce the
dissatisfaction rate of TKA patients.