Lunate Bone Morphology and Wrist Arthrosis: a Radiographic Study of the Type 2 Lunate

It is well known that there are two lunate types. The type II variation of the lunate is of clinical importance since significant cartilage erosion at the proximal pole of the hamate bone is evident in more than half of the type II lunates, but is not seen in the type I lunates. The aim of this study is to determine the incidence of lunate types, using posteroanterior hand X-rays and to establish a connection with radiocarpal, midcarpal, or thumb carpometacarpal joint osteoarthritis. We retrospectively analyzed 1000 X-rays of subjects who were admitted to the Clinical Centre of Vojvodina complaining for trauma of the hand. In each of the analyzed X-ray, the lunate was classified as type I or type II according to the method of Viegas et al. and analyzed for degenerative changes on 9 different locations. The study group consisted of 753 subjects with type I lunate and 247 subjects with type II lunate. Osteoarthritis was found on 305 wrist X-rays. There was no statistically significant difference between wrist osteoarthritis and lunate type. The present study revealed a 24.7% incidence of type II lunate, which is lower than reported in previous literature. Furthermore, there was no correlation between lunate type and radiocarpal, midcarpal, or thumb carpometacarpal joint osteoarthritis.