Objective To evaluate the effectiveness of medial buttress plate augmented hollow lag screws fixation in combination with sartorius pedicled iliac flap for the treatment of femoral neck fractures in young adults. MethodsThe clinical data of 11 young adult patients with femoral neck fractures between February 2013 and February 2019 were analyzed retrospectively. There were 7 males and 4 females with a mean age of 45 years (range, 32-58 years). Fractures were caused by falling from height in 6 cases, by traffic accident in 4 cases, and by sports injury in 1 case. There were 7 cases in the left hip and 4 cases in the right hip. The mean Pauwels angle was 64° (range, 55°-75°). All patients were treated by medial buttress plate augmented hollow lag screws fixation and sartorius pedicled iliac flap. The X-ray film of pelvis, lateral X-ray film of hip joint, CT scan and three-dimensional reconstruction of hip joint were taken after operation to assess fracture healing and position of the internal fixators. The postoperative hip function was evaluated according to the Harris score. Results All the incisions healed by first intention, and no complication such as incision infection and lateral femoral cutaneous nerve injury happened. Re-examination on the second day after operation showed that reduction and fixation of fractures was good. All patients were followed up 18-36 months (mean, 29 months). All fractures achieved bony union. The time of bony union was 16-23 weeks, with an average of 18.2 weeks. One patient (9.1%) got osteonecrosis of the femoral head (ONFH) at 30 months after operation. At last follow-up, Harris score was used to evaluate hip joint function, 9 cases were excellent, 1 case was good, 1 case was fair, and the excellent and good rate was 90.9%. Conclusion Medial buttress plate augmented hollow lag screws fixation in combination with sartorius pedicled iliac flap for the treatment of femoral neck fractures in young adults has the advantage of strong biomechanical stability and can effectively improve the blood supply of femoral head and neck, which subsequently reduce the incidence of ONFH. However, the surgical indication should be fully considered.