Quadrilateral plate (QLP) is a relatively thin bony structure located below the pelvic brim proximal to the hip joint, so management of its fractures is challenging. Evaluation of the functional and radiological outcomes of internal fixation of quadrilateral plate acetabular fractures; comparison of two methods of fracture fixation. A prospective multicentric study including 30 patients who underwent open reduction and internal fixation of QLP fractures through modified Stoppa approach. Patients were divided into two groups according to the method of fixation (anatomical QLP plate vs suprapectineal and infrapectineal plates). Post-operative quality of reduction was evaluated using Matta score. Radiographical assessment according Matta's grading criteria and clinical outcome assessment using the Harris Hip Score (HHS) were repeated at follow-up and at one year to assess displacement. Mean age of patients was 34.9 ± 12.1years. After one year follow-up, clinically mean HHS was 88. ± 5.74. Radiologically post-operative reduction quality was anatomical in 21 (70%) patients, satisfactory in eight (26.7%) patients and unsatisfactory in one (3.3%) patient. Matta's grading at the last follow-up was excellent in 21 (70%) patients, good in six (20%), fair in two (6.7%) patients and poor in one (3.3%) patient. No significant difference was recorded between the two groups in terms of radiographical and clinical results and rate of complications. Accurate reduction of quadrilateral plate fracture with secure fixation through modified Stoppa approach provides good and reproducible outcomes with few complications regardless the type of the implant.