Ultrasonographic Classification of Scapholunate Interosseous Ligament Injury Associated With Distal Radius Fracture.

PURPOSE: Although scapholunate interosseous ligament (SLIL) injury is often associated with distal radius fracture, it is frequently missed in x-rays. The purpose of this study was to develop a diagnostic classification based on ultrasonography for SLIL injury and evaluate its diagnostic accuracy.

METHODS

Patients who required surgery for distal radius fracture were included in this study. Ultrasonography and arthroscopy were performed in all patients. The original ultrasonography-based classification of the dorsal part of SLIL was developed as follows: for type A, the SLIL surface was outlined clearly as a continuous flat line; for type B, the SLIL surface was outlined clearly as a continuous bulged line; and for type C, the SLIL surface was not continuous, smooth, or outlined clearly. Arthroscopy was performed at the time of osteosynthesis. We classified its findings according to the arthroscopic classification system of Geissler et al and evaluated interobserver and intraobserver reliabilities for our classification on ultrasonography. We also studied the relationship between the ultrasonographic and arthroscopic classifications.

RESULTS

In total, 40 patients were included in this study. Weighted κ values for interobserver and intraobserver reliabilities for our ultrasonographic classification were 0.83 (95% confidence interval, 0.70-0.96) and 0.88 (95% confidence interval, 0.77-0.99), respectively. There were 17 patients with type A, 14 with type B, and 9 with type C on ultrasonography. Ultrasonography had a sensitivity of 64% and specificity of 93% for the assumption that type C on ultrasonography corresponded to Geissler grades 3 and 4 on arthroscopy. No patient with type A on ultrasonography was classified as Geissler grades 3 and 4 on arthroscopy.

CONCLUSIONS

We concluded that ultrasonography has a high specificity but low sensitivity for the diagnosis of SLIL injury.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic Ⅱ.