Effect of the axial alignment of prosthesis in total knee arthroplasty: Correlated patient satisfaction and clinical observations

Esmailiejah, Ali Akbar; Mavaeian, Ali; Kazemi, Seyyed Morteza; Safdari, Farshad; Shekarchi, Babak

doi:10.22034/ijos.2025.469699.1092

Effect of the axial alignment of prosthesis in total knee arthroplasty: Correlated patient satisfaction and clinical observations

Document Type : Original Article

Authors

Ali Akbar Esmailiejah ¹

Ali Mavaeian ²

seyyed Morteza Kazemi ²

Farshad Safdari ³

Babak Shekarchi ⁴

¹ Bone, Joint and related tissues research center, Akhtar hospital, Shahid Beheshti University of medical sciences

² Bone, Joint and related tissues research center, Akhtar hospital, Shahid Beheshti University of medical sciences, Tehran, Iran

³ a) Bone, Joint and related tissues research center, Akhtar hospital, Shahid Beheshti University of medical sciences, Tehran, Iran; b) department of orthotics and prosthetics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran

⁴ AJA University of medical sciences, Tehran, Iran

https://doi.org/10.22034/ijos.2025.469699.1092

Abstract

Purpose: Correct axial positioning of the prosthetic knee components remains challenging. In the current study, the effects of the axial alignment of the components on patient satisfaction and functional outcomes after total knee arthroplasty (TKA) were investigated. It was investigated whether parallel axial axes of the components can affect the outcomes.
Methods: There were 89 TKA patients with correct coronal alignment investigated at least 1 year after the operation. Using CT scanning, the axial alignment of the components and prosthetic joint were evaluated. To measure the mismatch angle between two axes, the related CT images were superimposed. The criteria for the correct axial alignment of the prosthetic joint included: 1) correct axial alignment of the femoral component; 2) correct axial alignment of the tibial component; and 3) parallel rotational axes of the components. Patient satisfaction was measured using the visual analogue scale (VAS). Further, the Knee injury and Osteoarthritis Outcome Score (KOOS) was completed.
Results: The correct axial alignment of the femoral and tibial components was found in 80.9% and 67.4% of the patients, respectively. The correct axial alignment of the prosthetic joint was found in 35 patients (39.3%) and was not related to better KOOS and VAS scores. However, a mismatch >10° significantly decreased the KOOS and patient satisfaction (p<0.05).
Conclusions: The current study showed that a rotational mismatch > 10° between the axial axes of the prosthetic knee components is associated with poor functional outcomes and decreased satisfaction.

Keywords

osteoarthritis

total knee replacement

patient satisfaction

alignment

Subjects