Treatment of patients with posttraumatic infected nonunions or highly contaminated open fractures with segmental bone loss of the long bones of the upper extremity is demanding. The use of a 2-stage reconstruction technique, being the first stage characterized by thorough debridement, copious lavage, soft tissue coverage, and placement of a cement spacer with antibiotics at the infected site, and the second stage by cement spacer removal, internal fixation, and placement of bone graft with local antibiotics, is presented. We carried out this technique in 20 cases, in 12 cases the cement was molded to fit the defect and placed as a solid interposition mass, in 3 cases it was placed lateral to the affected bone, and in the remaining 5 cases a Rush nail covered with a cement mantle was used. Follow-up averaged 18 months. All nonunions and fractures healed after an average of 5 months. Disabilities of the arm, shoulder, and hand (DASH) score at last follow-up in nonunions averaged 14 points and 21 points in bone losses. Although generally 2 surgical procedures are needed, 1 to cure or prevent infection and another to achieve bony union, this approach for complex open fractures with segmental bone loss and for infected nonunions of the long bones of the upper extremity represents a valid treatment alternative.