ABSTRACT
PURPOSE: A total of 27 carpal bone cysts were analyzed for their sites, relations of other wrist soft tissue ganglions and their results of treatment were evaluated. METHODS: Twenty-seven carpal bone cysts in 20 patients (bilateral 5, multiple 2) from February 2002 to June 2013 were evaluated. Mean follow-up period was 16.6 months. We investigated etiological classification, the site of carpal bone cyst, and their relationship with soft tissue ganglion in same wrist. Pain, range of motion, radiographic changes, and their satisfaction after treatment were assessed postoperatively. RESULTS: The carpal bone cysts occurred mainly at the radial wrist axial ray on the lunate (12 cases), scaphoid (6 cases), and triquetrum (5 cases), trapezium (2 cases), and capitate (2 cases). Based on the magnetic resonance imaging (MRI) findings in 25 cases, we classified carpal bone cysts into 4 distinct types; type I with purely intraosseous lesion (16 cases), type II with bone cyst associated cortical perforations (6 cases), type III with coexisting soft tissue ganglion communicating with intra-osseous lesion (2 cases), and type IV with coexisting soft tissue ganglion non-communicating intraosseous lesions (1 case). CONCLUSION: The carpal bone cysts can be classified by MRI into 4 distinct types. The purely intraosseous type is most common, suggesting the intrinsic cause in the development of carpal bone cyst.