Purpose of the study Intramedullar nailing is now widely used for fractures of the tibia. Extension of nailing indications to proximal, distal, and comminuted fractures has led to a significant rate of complications. The purpose of this study was to analyze decortication and medial plating for the treatment of tibial nonunion after intramedullary nailing. Material and methods Eighteen cases of aseptic tibial nonunion after nailing for fracture were treated in three women and fifteen men, mean age 39 years (19-57). The initial classification was open (n = 8), segmental (n = 3), single-focus (n = 15). The fracture site was inferior (n = 6), middle (n = 7), and superior (n = 2). Primary nailing used reaming in 15 cases (83%), unreamed in 3 (17%) static in 13 and dynamic in 5. Four plaster cabts were also applied. Complications were: infection (n = 1), compartmental syndrome (n = 2), tibial nerve palsy (n = 1), dysesthesia (n = 2), and protrusion of the nail into the knee (n = 1). Dynamization was performed in 11 patients, one with additional bone graft and fibulectomy. Repeated reamed nailing was performed in one patient. Seven nonunions were atrophic and 11 were hypertrophic. There were 13 malpositionings associated with the nonunion. Treatment of the nonunion was performed 300 days on average (90-900) after nailing: cancellous bone graft was associated with decortication in four cases because of bone loss (n = 3) or atrophic nonunion (n = 1). Results Union rate was 94%. Mean time for union was 108 days (80-180) with no significant difference (Student t-test) between atrophic (119 days) and hypertrophic (103 days) nonunion. Correction of the malposition was incomplete in seven patients, with angular malunion of less than 6° in five patients and greater than 10° in two. One late infection occurred and finally healed after external fixation and antibiotic therapy. No skin necrosis occurred. Five patients had pain on the hardware. Removal was performed in one time and pain resolved. Improvement of knee and ankle stiffness was achieved in all patients. Discussion This technique has been used in our department since 1967. Different studies have found a union rate ranging from 94% to 100% with this procedure. Intramedullary nailing, sometimes associated with bone graft or decortication, is also used for tibial nonunion with a good rate of union. The main problem of intramedulary nailing for nonunion, as for fracture, is the difficulty in avoiding malunion. Plating a nonunion, as a fracture, enables better reduction. Skin problems can occur with the medial plate if the soft tissues are damaged. This situation is very uncommon in secondary surgery. Conclusion Decortication and medial plating was a safe and efficient treatment for tibia nonunion after failure of intramedullary nailing and allows better reduction and repeated nailing.