Anthropometric measurements of knee joints in Thai population: correlation to the sizing of current knee prostheses

Abstract

Anthropometric data on distal femoral condyle , proximal tibiae and patellar of 200 knees in 200 Thai subjects were measured using magnetic resonance imaging (MRI). The mean resected femoral anterior-posterior (AP) length and femoral medial-lateral (ML) width of all subjects were 45.43 mm and 64.06 mm, respectively. The mean resected femoral AP length and femoral ML width of males were 48.53 mm and 70.15 mm respectively. The mean resected femoral AP length and femoral ML width of females were 43.32 mm and 59.91 mm respectively. The mean tibial AP length and tibial ML width of all subjects were 46.04 mm and 68.7 mm respectively. The mean tibial AP length and tibial ML width of males were 49.49 mm and 73.6 mm respectively. The mean tibial AP length and tibial ML width of females were 43.23 mm and 64.95 mm respectively. The mean patellar thickness, SI length and ML width of all subjects were 18.95 mm, 35 mm and 40.63 mm respectively. The mean patellar thickness, SI length and ML width of males were 20.42 mm, 36.43 mm and 43.02 mm respectively. The mean patellar thickness, SI length and ML width of females were 17.7 mm, 32.97 mm and 38.64 mm respectively. The differences in the knee joint structure between males and females were significant (p<0.0001). All parameters of the distal femoral condyle, the proximal tibia and the patellar were compared to the size of the total knee prosthesis (femoral component, tibial component and patellar component) with 4 prosthetic systems which currently used in Thailand; NexGen (Zimmer, Warsaw, Indiana), P.F.C. Sigma (Depuy-Johnson and Johnson, Warsaw, Indiana), Genesis II (Smith&nephew), Scorpio tm (Stryker). For the distal femoral condyle, the Scorpio tm systems were suitable for Thai male population. The NexGen and Sigma systems were suitable for Thai female population. For the proximal tibia, the Sigma and the Scorpio tm systems were suitable for Thai male and female population. This finding shows that an implant component suitable for using in Western population may not be suitable for Thai population. The results of the project could provide fundamental data for the design of knee prostheses suitable for the Thai population.