Publication: Postural coronal alignment shift after total knee arthroplasty diminishes with age and becomes negligible in elderly patients
0
0
Issued Date
2025-01-01
Resource Type
ISSN
09422056
eISSN
14337347
Scopus ID
2-s2.0-105018634327
Journal Title
Knee Surgery Sports Traumatology Arthroscopy
Rights Holder(s)
SCOPUS
Bibliographic Citation
Knee Surgery Sports Traumatology Arthroscopy (2025)
Suggested Citation
Plangsiri K., Chotiwatanadilok B., Chaiyakit P., Kongmalai P. Postural coronal alignment shift after total knee arthroplasty diminishes with age and becomes negligible in elderly patients. Knee Surgery Sports Traumatology Arthroscopy (2025). doi:10.1002/ksa.70085 Retrieved from: https://hdl.handle.net/20.500.14740/50622
Author's Affiliation
Corresponding Author(s)
Other Contributor(s)
Abstract
Purpose: To investigate whether patient age moderates the change in coronal hip–knee–ankle (HKA) alignment between supine and standing positions following total knee arthroplasty (TKA). Methods: In this cross-sectional study, 113 consecutive patients after primary TKA for osteoarthritis underwent standardized full-length radiographs in both supine and standing positions. The postural shift (ΔHKA) was defined as standing minus supine alignment. Associations between age and ΔHKA were examined using a linear mixed-effects model with restricted cubic splines, adjusting for body mass index (BMI), sex, preoperative alignment and time since surgery. Equivalence testing (±1° margin) was performed in patients aged ≥60 years. Results: Younger patients demonstrated a standing varus drift of approximately 2–3°, whereas the effect progressively diminished with advancing age. The age–position interaction was significant (p = 0.011), while BMI, sex, preoperative alignment and time since surgery were not. In patients ≥60 years, the mean ΔHKA was −0.01° (90% confidence interval = −0.55° to +0.53°), meeting statistical equivalence to 0 (p = 0.008). Collateral ligament laxity on stress radiography showed no association with ΔHKA. Conclusion: Postural coronal alignment change after TKA is strongly age dependent. Younger patients show a measurable varus drift, whereas older patients demonstrate negligible change within radiographic error. Age should be considered when tailoring intraoperative alignment strategies to ensure durable functional outcomes. Level of Evidence: Level III.