EOS-Based Analysis of Lower Limb and Spinopelvic Parameters in Varus Knee Osteoarthritis: Implications for Total Knee Arthroplasty
摘要
To compare three-dimensional (3D) lower limb and spinopelvic alignment parameters between healthy Indian adults and patients with varus knee osteoarthritis (KOA) using EOS imaging, and to identify morphological factors with potential relevance for total knee arthroplasty (TKA) planning.
MethodsFifty patients with Grade 3–4 Kellgren and Lawrence (K–L) KOA (99 knees) and 25 age- and sex-matched healthy controls (50 knees) underwent weight-bearing EOS 2D/3D imaging. Geometric measurements included limb lengths, coronal alignment angles, femoral and tibial torsion, and spinopelvic parameters. Comparisons between groups and KOA grades were performed, and inter-observer reliability was assessed using the intraclass correlation coefficient (ICC).
ResultsKOA patients had shorter femoral length (38.95 vs. 40.0 cm, p = 0.015), greater varus deformity (hip–knee–ankle angle: 10.37° vs. 3.41°, p < 0.001), higher hip–knee–shaft angle (7.14° vs. 6.42°, p = 0.01), and increased tibial torsion (32.83° vs. 25.44°, p < 0.001) compared with controls. Pelvic incidence was significantly higher in KOA (57.17° vs. 49.64°, p = 0.013), while thoracic kyphosis was lower (29.97° vs. 36.3°, p = 0.011). Grade 4 KOA showed greater varus and tibial torsion than Grade 3. The difference in femoral torsion was not statistically significant. Measurement reproducibility was excellent (ICC = 0.83).
ConclusionEOS imaging reveals distinct morphological differences between healthy and arthritic knees in the Indian population, including increased tibial torsion, higher pelvic incidence, and reduced femoral length in KOA. In patients with marked tibial torsion or discordant coronal and rotational anatomy, surgeons may consider correlating multiple rotational landmarks and comprehensive preoperative imaging rather than relying on simplified coronal-plane assumptions alone; however, their direct influence on implant positioning and surgical execution requires further validation.
Level of EvidenceLevel III, comparative cross-sectional study.