Journal Article

PSI kinematic versus non-PSI mechanical alignment in total knee arthroplasty: a prospective, randomized study

Budde, Stefan, Windhagen, Henning, Ettinger, Max, Bauer, Kamil, Calliess, Tilman, Stukenborg-Colsman, Christina

2017

Overview

Purpose Kinematic alignment in TKA is supposed to restore function by aligning the components to the premorbid flexion–extension axis instead of altering the joint line and natural kinematic axes of the knee. The purpose of this study was to compare mechanically aligned TKA to kinematic alignment. Methods In this study, 200 patients underwent TKA and were randomly assigned to 2 groups: 100 TKAs were performed using kinematic alignment with custom-made cutting guides in order to complete cruciate-retaining TKA; the other 100 patients underwent TKA that was manually performed using mechanical alignment. The WOMAC and combined Knee Society Score (KSS), as well as radiological alignment, were determined as outcome parameters at the 12-month endpoint. Results WOMAC and KSS significantly improved in both groups. There was a significant difference in both scores between groups in favour of kinematic alignment. Although the kinematic alignment group demonstrated significantly better overall results, more outliers with poor outcomes were also seen in this group. A correlation between post-operative alignment deviation from the initial plan and poor outcomes was also noted. The most important finding of this study is that applying kinematic alignment in TKA achieves comparable results to mechanical alignment in TKA. This study also shows that restoring the premorbid flexion–extension axis of the knee joint leads to better overall functional results. Conclusion Kinematic alignment is a favourable technique for TKA. Clinical relevance The kinematic alignment idea might be a considerable alternative to mechanical alignment in the future. Level of evidence II.

• Publisher: Springer Berlin Heidelberg,John Wiley & Sons, Inc
• Subject: Aged / Alignment / Arthroplasty (knee) / Arthroplasty, Replacement, Knee - methods / Biomechanical Phenomena / Biomedical materials / Cutting parameters / Female / Humans / Joint surgery / Kinematics / Knee / Knee Joint - diagnostic imaging / Knee Joint - physiology / Knee Joint - surgery / Male / Medicine / Medicine & Public Health / Orthopedics / Osteoarthritis, Knee - diagnostic imaging / Osteoarthritis, Knee - physiopathology / Osteoarthritis, Knee - surgery / Patients / Prospective Studies / Radiography / Recovery of function / Surgical implants