Humeral Shaft Non-union in a Patient with Osteogenesis Imperfecta Treated with Mandible Locking Plate Fixation: A Case Report

INTRODUCTION: Osteogenesis imperfecta (OI) is a heritable disorder of connective tissue. Due to poor bone quality, patients with OI develop bone fracture and subsequent non-union at high rates. We report the rare case of humeral shaft non-union successfully treated by a locking plate used formandibular bone in a patient with OI. CASE REPORT: A 26-year-old man with Type III OI and a history of corrective osteotomy with Kirschner wire fixation of his right humerus at the age of 8 years developed gradually increasing pain in his humerus. He sustained humeral shaft non-union due to a broken Kirschner wire used in the previous operation and was referred to our hospital. He underwent internal fixation using an elastic nail with an iliac bone graft. However, 2 years after the operation, bony union was not achieved due to elastic nail breakage, and he complained of pain and activity limitation. He underwent re-operation for the humeral non-union using a locking plate to achieve rigid fixation. Because his humeral shaft was extremely narrow with severe deformity, we used a locking plate for the mandibular bone, which was contoured to fit the medial side of the humeral shaft. Bony union was achieved, the pain was relieved, and the patient returned to his pre-injury activity with no symptoms.4years after the operation, a new fracture line was found in radiographs of the distal part of the non-union. Bony union was achieved by conservative treatment. At present, the function has recovered. CONCLUSION: Humeral non-union in this patient with OI was successfully treated by a mandible locking plate. Although the optimal fixation device for fractures or non-unions in patients with OI has not yet been established, this plate could be a good treatment option for narrow and severely deformed bone.