Anatomical differences between the resected tibial surface and tibial component in normal Chinese

Abstract

Objective To obtain the linear parameters of proximal tibia in normal Chinese,and study the anatomical differences between the resected tibial surfaces and tibial baseplates of total knee prostheses.Methods A total of 82 normal Chinese / 135 knees (include 85 male and 50 female knees) was included,with an average age of 47.2 (range,19-82) years.All of the volunteers were scanned by Spiral CT,and the original CT images were stored in the work station (Adw 4.3).Then 3-D models of Chinese normal knees were reconstructed and two parameters were measured through volume reconstruction software,including mediolateral (ML) width and anterioposterior (AP) length.A coordinate system was formed with the mediolateral width as the X-axis and anterioposterior length as the Y-axis.A circle,5 mm in diameter,was used as the maximum coverage criterion.Three contemporary products (A,B,C) were used to analyze the data.From the results,we calculated the coverage percentage of the patients.Results The average ML width and AP length of the proximal tibia section were 78.03±2.92 mm and 50.62±2.46 mm in male,and 69.85±2.70 mm and 46.14±2.61 mm in female,respectively.The average ratio of AP length and ML width (RAP/ML) was 0.649 ±0.032 in male and 0.661± 0.031 in female,respectively.AP length and ML width showed statistical significance between different genders.The RAP/ML was larger in female,and the difference was statistically significant.The average coverage rate of prosthesis A,B and C was 42.55％,44.61％ and 27.41％,respectively.There was no statistically significant difference between prosthesis A and B.However,all of them showed statistical significance with prosthesis C.Conclusion The geometry and anatomy of proximal tibia in Chinese showed significant differences with that in Western.Those characteristic differences should be considered when we use the tibial plateau prosthesis designed by the Westerners. Key words: Tibia; Imaging, three-dimensional; Arthroplasty, replacement, knee