Functional alignment (FA) in total knee arthroplasty (TKA) aims to achieve balanced gaps by adjusting implant positioning while minimizing changes to constitutional joint line obliquity (JLO). Although FA uses kinematic alignment (KA) as a starting point, the final implant positions can vary significantly between these two approaches. This study used the Coronal Plane Alignment of the Knee (CPAK) classification to compare differences between KA and final FA positions. A retrospective analysis compared pre-resection and post-implantation alignments in 2,116 robotic-assisted FA TKAs. The lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were measured to determine the arithmetic hip-knee-ankle angle (aHKA = MPTA – LDFA), JLO (JLO = MPTA + LDFA), and CPAK type. The primary outcome was the proportion of knees that varied ≤ 2° for aHKA and ≤ 3° for JLO from their KA to FA positions, and direction and magnitude of those changes per CPAK phenotype. Secondary outcomes included proportion of knees that maintained their CPAK phenotype, and differences between sexes.Aims
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Valgus subsidence of uncemented tibial components following medial unicompartmental knee arthroplasty (UKA) poses a challenge in the early postoperative phase, necessitating a comprehensive understanding of its prevalence, risk factors, and impact on patient outcomes. This prospective multicentre study analyzed 97 knees from 90 patients undergoing UKA across four participating hospitals. A standardized surgical technique was employed uniformly by all participating surgeons. Postoperative evaluations were conducted preoperatively, and one day, four weeks, three months, and one year postoperative, encompassing weightbearing radiographs, bone mineral density assessments, and clinical outcome reports using the Forgotten Joint Score and Oxford Knee Score. Statistical analyses, including non-parametric correlation analysis using the Kendall correlation coefficient and Mann-Whitney U test, were performed to explore associations between subsidence and various patient-related or radiological parameters.Aims
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