Posterior Radioscaphoid Angle as a Predictor of Wrist Degenerative Joint Disease in Patients With Scapholunate Ligament Tears.

OBJECTIVE: The purpose of this study is to determine whether the posterior radioscaphoid angle, a marker of posterior displacement of the scaphoid, is associated with degenerative joint disease in patients with scapholunate ligament tears. MATERIALS AND METHODS: Images from 150 patients with wrist pain who underwent CT arthrography and radiography were retrospectively evaluated. Patients with and without scapholunate ligament ruptures were divided into two groups according to CT arthrography findings. The presence of degenerative changes (scapholunate advanced collapse [SLAC] wrist) was evaluated and graded on conventional radiographs. Images were evaluated by two readers independently, and an adjudicator analyzed the discordant cases. Posterior radioscaphoid angle values were correlated with CT arthrography and radiographic findings. The association between posterior radioscaphoid angle and degenerative joint disease was evaluated. Scapholunate and radiolunate angles were considered in the analysis. RESULTS: The posterior radioscaphoid angle was measurable in all patients, with substantial interobserver agreement (intraclass correlation coefficient, 0.75). The posterior radioscaphoid angle performed better than did the scapholunate and radiolunate angles in the differentiation of patients with and without SLAC wrist (p < 0.02). Posterior radioscaphoid angles greater than 114° presented an 80.0% sensitivity and 89.7% specificity for the detection of SLAC wrist. CONCLUSION: Posterior radioscaphoid angles were strongly associated with degenerative wrist disease, with potential prognostic implications in patients with wrist trauma and scapholunate ligament ruptures.