ABSTRACT
Objective To investigate a special optimization technique for computer aided measure, and provide anatomical basis for screw internal fixation in the cavitas glenoidalis through the coracoid process of scapula. Methods Thirty accurate scapula models were reconstructed from CT data sets. First, special optimization objective function was designed for single screw internal fixation configuration, and the optimal placement of screw was found automatically under constraints. Then, the placements of double screws internal fixation configuration were searched taking advantage of principal component analysis. Finally, statistical measure data were provided according to new anatomical reference landmarks for clinical use. Results For single screw internal fixation configuration, the distance from the optimal screw entry point P to the acromion process point X was (39.15±2.28) mm, to the coracoid process point Y was (28.66±2.68) mm, to the angulus superior point Z was (61.13±6.57) mm;The angle was (81.27±7.15)° between PX and PY, and (133.27±6.84)° between PX and PZ. The mean inclination of the lag screw was (104.08±4.41)° for the angle with line PX, (101.29±3.51)° with line PY, and (76.23±5.03)° with line PZ. For double screws configuration, the distance from the original single screw entry point P to the screw entry point E was (5.12±1.37)mm,to the screw entry point F was (3.88±0.94)mm. The angle between the long axis of coracoid process and line EF was (27.41±3.51)°. Conclusion The automatic optimization technique for computer aided measure is very efficient and has many advantages over the conventional manual dissection methods, and is convenient to design new anatomical reference landmark system for clinical use.