Scaphoid nonunion with DISI deformity treated in a two-stage operation with the Ilizarov mini fixator: A case report

Scaphoid nonunion causes humpback deformity and dorsal intercalated segment instability (DISI) deformity due to dorsal rotation of the proximal scaphoid fragment. In the treatment of scaphoid nonunion, it is important to not only achieve bone union, but also to improve DISI deformity and carpal bone alignment in order to attenuate pain, increase the range of motion, and prevent the development of osteoarthritis. We encountered a case of DISI deformity caused by the long-term neglect of scaphoid nonunion that was treated in a two-stage operation with the Ilizarov mini fixator. A 28-year-old male had been injured during a soccer game 10 years ago. Although he had wrist pain, he did not visit a hospital. This led to chronic scaphoid nonunion with DISI deformity. Since 10 years had passed from the initial injury, DISI deformity was considered to be difficult to correct using a single stage procedure. Therefore, a two-stage operation was performed. The Ilizarov mini fixator was used to gradually correct DISI deformity in the first stage, and screw fixation with bone grafting was performed in the second stage. Difficulties are associated with achieving good clinical results in cases of long-term scaphoid nonunion. In cases of DISI deformity, it is important to correct the alignment of lunate dorsiflexion and the distal carpal row as well as achieve bone union. Although the Ilizarov external fixator has been used for scaphoid nonunion, it has not yet been applied to scaphoid nonunion with DISI deformity. The Ilizarov mini fixator may be useful to correct long-term deformities, and good results were obtained in the present case. It represents an option for the treatment of scaphoid nonunion with DISI deformity.