Medial tibial defects in varus knee osteoarthritis (KOA) challenge alignment and tibial support in primary total knee arthroplasty (TKA). A stem-free metaphyseal screw-cement strategy supported by computed tomography (CT)-based three-dimensional (3D) planning, with artificial intelligence (AI)-assisted segmentation used for model generation in the planning software, may be a bone-preserving alternative to conventional two-dimensional (2D) radiograph planning with short tibial stems. This study compared early tibial alignment and clinical outcomes between two reconstructive pathways in Anderson Orthopaedic Research Institute (AORI) type I–II medial tibial defects. In this single-centre retrospective cohort, 97 patients with varus KOA and AORI type I–II medial tibial defects undergoing TKA were managed using either a CT-based 3D planning-supported stem-free screw-cement pathway (n = 38) or a 2D radiograph-planned short-stem pathway (n = 59). Given non-randomised pathway allocation, analyses assessed associations. The primary outcome was the absolute deviation of the mechanical medial proximal tibial angle (mMPTA) from 90° at 4–8 weeks. Secondary outcomes included achievement of mMPTA within 90° ± 3°, intraoperative visible blood loss, pain and function measured by the visual analogue scale (VAS), Knee Society Score (KSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at 3 and 24 months, and complications. Between-pathway comparisons used standard univariable tests, findings were interpreted as associative given non-randomised allocation. Baseline characteristics were comparable between pathways (all P > 0.05). Postoperative tibial alignment did not differ, with comparable absolute deviation of mMPTA from 90° and similar rates within 90° ± 3°. Operative time was similar, but visible blood loss was lower in the CT-3D screw-cement pathway than in the 2D short-stem pathway (262.7 ± 75.3 vs 381.9 ± 71.3 mL, P < 0.001). At 3 months, the CT-3D screw-cement pathway showed lower VAS and better KSS/WOMAC, whereas outcomes were comparable at 24 months. No deep infection, radiographic loosening, periprosthetic fracture, or revision was observed within 24 months. The CT-3D screw-cement pathway was associated with tibial alignment and 24-month function comparable to the 2D short-stem pathway, with lower blood loss and better early recovery. Fixation-related inferences are limited to early radiographic stability.
Lu et al. (Mon,) studied this question.