We report a case of humeral lengthening in an adolescent, 6.5 years after interscapulothoracic resection for an osteosarcoma of the scapula. The lengthening external fixator was augmented by ipsilateral rib fixation in order to prevent cephalad migration of the proximal fragment. At a 3-year follow-up, the patient was satisfied, with an improved cosmesis and function of his limb.