Image‐based design and 3D‐metal printing of a rat hip implant for use in a clinically representative model of joint replacement

The aim of this study was to obtain micro‐computed tomography derived measurements of the rat proximal femur, to create parameterized rat hip implants that could be surgically installed in a clinically representative small animal model of joint replacement. The proximal femoral anatomy of N = 25 rats (male, Sprague‐Dawley, 390‐605 g) was quantified. Key measurements were used to parameterize computer‐aided design models of monoblock rat femoral implants. Linear regression analysis was used to determine if rat hip dimensions could be predicted from animal weight. A correlation analysis was used to determine how implants could be scaled to create a range of sizes. Additive manufacturing (3D printing) was used to create implants in medical‐grade metal alloys. Linear regressions comparing rat weight to femoral head diameter and neck‐head axis length revealed a significant nonzero slope (P