Objective To investigate the methods and effects in repairing fracture of the fifth metatarsal base bone with Acutrak headless compression screws.Methods From May 2006 to October 2012,75 patients with fracture of the fifth metatarsal base bone were reduced and fixed using Acutrak headless compression screws.There were 38 males and 37 females with a mean age of 36 years (range,21-65 years).Injury arose from fall from height (35 cases),road traffic accidents (23 cases),and fall of heavy objects (17 cases).Fracture of the left foot occurred in 29 cases and the right foot in 46 cases.Results were evaluated using American Orthopedic Foot and Ankle Society (AOFAS) ankle and midfoot score.Results Seventy-two patients were followed up for mean 15 months (range,13 months5 years).Operative incision obtained primary healing without any complications.Mean AOFAS ankle and midfoot score increased to (93.0 ± 6.5) points (range,79-100 points) at postoperative 1 year,compared with the preoperative (28.0 ± 3.9) points (range,0-42 points) (t =7.650,P ＜ 0.05).Muscle force and valgus or abduction of mid-forefoot of the affected and unaffected sides demonstrated no significant difference after operation.Conclusion Acutrak headless compression screw system shows advantages of rigid fixation,few complications,and early healing in treatment of the fifth metatarsal base fracture.

Aim: To evaluate the reliability and effectiveness of Latin Square experimental design through biomechanical contract study. Methods: The Latin Square design were compared with others according to a concrete biomechanics experiment. Result: Because of the reasonable experiment design, three models would be needed. But in other designs, twelve models would must be needed. experiment saved the large quantity specimen and guaranteed the stability of term experiment. Conclusion: In experiment of spinal column biomechanics, the Latin Square design is a good choice.