Abstract: Objective To compare the short-term effects of hollow screw internal fixation and medial support plate-assisted hollow screw internal fixation via DAA approach on vertically unstable femoral neck fractures in young and middle-aged adults. Methods From April 2016 to February 2018, 23 young and middle-aged patients with unstable femoral neck fractures were randomly divided into two groups at admission： hollow screw internal fixation group （group A, 13 cases） and DAA approach medial support plate-assisted hollow screw internal fixation group （group B, 10 cases）. The intraoperative bleeding volume, operation time, intraoperative fluoroscopy times, postoperative wound infection, necrosis of femoral head, and nonunion of fracture, as well as Harris score and VAS pain score before and 6 months after operation were compared between the two groups. Results The group A showed less intraoperative bleeding volume, shorter operation time, and fewer fluoroscopy times than the group B did [（73.85±12.10） mL vs. （150.50±19.07） mL, （53.85±10.24） min vs. （86.00±12.65） min, （1.85±0.69） vs. （4.50±1.08）] （P<0.05）. The group A also showed a lower Harris score and a lower VAS pain score than the group B 6 months after operation （P<0.05）. Conclusion The internal fixation assisted by medial support plate via DAA approach for vertically unstable femoral neck fractures in young and middle-aged patients can achieve stable fixation and good recovery of hip function.

Key words: Femoral neck fractures, Hollow nail, Medial support plate, Young and middle-aged adults