INTRODUCTION: Scaphoid fractures represent 5-10% of nonunion rate and the treatment options consist of an open reduction with correction of deformity, restoration of the scaphoid length with autologous wedge grafting and fixation. However, there is still no consensus in the literature on the best fixation method. Therefore, the purpose of the study is to compare plate fixation and screw fixation in treating scaphoid nonunion with humpback deformity and carpal instability. METHODS: Prospective, non-randomised study comparing the treatment of two groups of patients with scaphoid nonunion. A total of 19 patients were included in the study, the first ten patients were included in group 1 (plate fixation), subsequently nine patients were included in group 2 (screw fixation). The nonunion duration was longer than 6 months and patients did not present type III Scaphoid Nonunion Advanced Collapse (SNAC). Clinical evaluations included pain intensity, range of motion, grip strength, pinch test and functional scales Disabilities of the Arm, Shoulder and Hand (DASH) and Mayo Wrist Score. Radiographic evaluations consisted of radiographs of both wrists in AP, AP with ulnar deviation, lateral and oblique views. Patients further underwent a tomography of the affected wrist for bone deformity, carpal collapse and later consolidation evaluation. RESULTS: According to post-operative measurements, group 1 showed a significant improvement in the scapholunate angle (p = 0.011) and in the intrascaphoid angle (p = 0.002). Group 2 only showed an improvement in the scapholunate angle (p = 0.011). All patients in group 1 achieved consolidation in 8 weeks, while group 2 patients had a slower consolidation, with a mean of 14 weeks and standard deviation (SD) of 4.2, with statistical significance (p = 0.006). CONCLUSION: Our prospective study, despite the limitations, contributes to the literature for demonstrating a better fixation using plate, with a better correction of humpback deformity and Dorsal Intercalated Segment Instability (DISI) and a faster consolidation. LEVEL OF EVIDENCE: II, therapeutics studies; prospective comparative study.