Successful tibial component placement during total knee arthroplasty (TKA) entails accurate rotational alignment, minimal overhang, and good bone coverage, each of which can be facilitated with a tibial component that matches the resected tibial surface. Previous studies investigated bony coverage of multiple tibial component families on digitized resections. However, these studies were based on manual placement of the component that may lead to variability in overhang and rotational alignment. An automated simulation that follows a consistent algorithm for tibial component placement is desirable in order to facilitate direct comparison between tibia component designs. A simulation has been developed and applied to quantify tibial coverage in multiple ethnicities, including Japanese, Indian, and Caucasian. Here, this approach is taken to evaluate tibial coverage of five contemporary tibial designs in Chinese subjects. Digital models of 100 healthy Chinese tibiae (50 male, 50 female; age 68 ± 3 years; stature 1.65 ± 0.10 m) were virtually resected at 5° posterior slope referencing the anterior border of the proximal tibia, 0° varus/valgus rotation referencing the tibial mechanical axis, and 8 mm off the unaffected plateau (reflecting a 10 mm surgical cut, assuming a cartilage thickness of 2 mm). Neutral internal/external (I/E) alignment axis was derived from the medial third of the tubercle and the PCL attachment site. Five commercial tibial designs (Design A, Deluxe™, Montagne, Beijing, China; Designs B-E contemporary market-established symmetric designs from four US manufacturers) were virtually placed on the resected tibiae following an automated algorithm, which maximizes component size while ensuring proper rotational alignment (within 5° I/E) and minimizing overhang (<1 mm in zones 1–4, Fig 1). Tibial coverage (posterior notch excluded, zone 5 in Fig 1) and distance from the component to the exterior cortex of the tibia in four clinically relevant anatomical zones (anterior medial, anterior lateral, posterior medial, and posterior lateral, zones 1–4, Fig 1) were calculated. Statistical significance was defined at p < 0.05.INTRODUCTION:
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