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Native coronal patellar tracking demonstrates three distinct patterns associated with coronal alignment in
Takaaki Hiranaka1, Andrew Mao Li2, Chris Hewison3
1Sydney Orthopaedic Research Institute, Sydney, Australia; Department of Sports Medicine, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
Objectives:
This study aimed to objectively identify and describe intraoperative patellar tracking patterns in osteoarthritic knees and examine their relationship with coronal alignment according to the coronal plane alignment of the knee (CPAK) classification.
Methods:
A retrospective analysis was performed on 252 knees that underwent robotic-assisted primary total knee arthroplasty (TKA). Intraoperative patellar tracking was assessed prior to any bone cuts. Patellar tracking was recorded using a previously described technique with the CORI robotic system. Preoperative full-length standing radiographs were used to assess coronal alignment parameters. Knees were classified according to the CPAK classification. Associations between patellar tracking patterns and radiographic parameters were analyzed.
Results:
The mean age of the cohort was 71.4 ± 7.1 years. Preimplantation patellar tracking was classified into three patterns: central tracking in 58% (n = 147), lateral tracking in 35% (n = 89), and medial tracking in 6% (n = 16). A statistically significant association was observed between coronal alignment category (varus, neutral, or valgus) and coronal patellar tracking pattern (p = 0.006). Central tracking was more frequently observed in varus knees, whereas lateral tracking showed a relative predominance in neutral-to-valgus alignment. Consistently, lateral patellar tracking was associated with more valgus limb alignment.
Conclusion:
Three distinct native coronal patellar tracking patterns were identified using robotic intraoperative assessment prior to implantation. Patellar tracking patterns were associated with coronal limb alignment, with lateral tracking relatively more frequent in neutral-to-valgus knees. The clinical significance of these passive intraoperative tracking patterns requires further investigation.
Level Of Evidence:
Level III, Retrospective Comparative Cohort Study.