Evaluation of Carpal Malalignment Before and After Interpositional Bone Grafting for Treating Scaphoid Nonunion

Background: Carpal malalignment following the treatment of scaphoid nonunion increases the risk of Dorsal Intercalated Segment Instability (DISI) and progressive radiocarpal arthrosis. Objectives: In this study, we aimed to investigate the outcome of interpositional bone grafting without preplanning to correct carpal malalignment in treating scaphoid nonunion. Methods: Patients and Methods: In a retrospective study, 96 patients who underwent surgery to treat scaphoid nonunion (interpositional bone grafting without correction of carpal malalignment) were included. Indices of carpal malalignment, including the lunocapitate and scapholunate angles, were assessed before and one year after the surgery. A lunocapitate angle of more than15° and a scapholunate angle of more than 60° were considered a sign of DISI. Results: The study population included 93 men (96.9%) and three women (3.1%) with a Mean±SD age of 26.1±3.1 years. The mean±SD time from fracture to nonunion surgery was 8.6±4.2 months. The Mean±SD lunocapitate angle was 15.2±13.1° before and 14.4±11° one year after the surgery (P=0.48). The Mean±SD scapholunate angle was 63.9±15.2° before and 64.5±14.6° after the surgery (P=0.69). DISI was present in 67 patients (69.8%) before and 66 (68.8%) after the surgery. This difference was not statistically significant, too (P=0.89). Conclusion: Correction of carpal malalignment should be preoperatively planned to treat scaphoid nonunion to reduce the risk of postoperative DISI and subsequent radiocarpal arthrosis.