Mismatch of anatomically pre-shaped locking plate on asian femurs could lead to malalignment in the minimally invasive plating of distal femoral fractures: a cadaveric study

Abstract

Background LCP-DF (locking compression plate-distal femur) has been introduced as an anatomically pre-shaped plate that does not require further contouring. However, the LCP-DF was developed based on skeletal measurements in Caucasians. It is unknown whether the LCP-DF fits Asians. Objective The purpose of this study was to assess the conformity of the LCP-DF in Asian adult femurs and also to determine the matching pattern of this anatomically pre-shaped LCP-DF in normal Asian adult femurs and the clinical implications of the matching pattern. Methods Sixty adult cadaver femurs were obtained from 41 male and 19 female cadavers with an average age of 63 years (31-95). An 11-hole LCP-DF was applied to the lateral surface of the distal femur according to the contour. Any mismatches between the bone and the plate were recorded. Then the distance from the inner surface of the plate to the cortex was measured at the sites of mismatch. C-arm AP image of the distal femur was taken and the angle between the distal most locking screw and the joint line was measured, and it was named as joint screw angle (JSA). Results Mismatch was found at the level of proximal 4-5 holes of the plate with an average distance of 11.36 mm (range 0-32 mm) at the tip of the plate. Otherwise, the overall conformity of the LCP-DF was good. The average JSA was 2.15 +/- A 1.78A degrees (ranged from 0A degrees to 5A degrees). Conclusion A rather consistent pattern of mismatch was found at the proximal part of the 11-hole LCP-DF. An attempt to fit the plate to the bone at this level may cause valgus malalignment at the fracture site.