Painful os styloideum: bone scintigraphy in carpe bossu disease

Current Concepts of the Carpal Boss: Pathophysiology, Symptoms, Clinical or Imaging Diagnosis, and Management

“…In an early description of the disorder, Apple et al reserved the term carpal boss for the presence of a post-traumatic osseous protuberance connected to the capitate, third metacarpal, or both, while the os styloideum alternatively represented an embryologic variant without a discrete osseous connection to the adjacent bones [12]. Not all descriptions thereafter stress this distinction in nomenclature.…”

“…Not all descriptions thereafter stress this distinction in nomenclature. The os styloideum has been described as an anatomical variant accessory ossicle, dubbed the "ninth carpal bone", and occurs at the dorsal quadrangular trapezoid-capitate-metacarpal joint [9,12,13]. This accessory bone is thought to arise from an embryologic variant resulting from non-fusion of primordial cartilaginous units [12,13].…”

“…The presence of a carpal boss may result in altered biomechanics of the surrounding joints [9]. Additionally, symptoms may be the result of extensor tendon irritation (extensor carpi radialis longus and brevis) (Figure 2), irritation following trauma or repetitive use, or secondary arthritis [1,6,7,9,12,13] (Figure 3). The formation of a ganglion or inflamed bursa has also been described [1,6] (Figure 3).…”

“…The diagnosis is made based on the presence of an abnormal ossicle along the dorsal base of the second or third metacarpal [8,12,13] (Figure 1). The bony protuberance can have a fragmented appearance if not in continuity with an adjacent carpal or metacarpal bone.…”

Achados de imagem por tomografia computadorizada e ressonância magnética do os styloideum em atleta sintomático

“…However, pathological conditions associated with this accessory ossicle cannot be appropriately assessed with this imaging method. Bone scintigraphy has also been utilized, demonstrating an increase in radiotracer uptake ( 99m Tc MDP) at the ossicle site (1,8) . Multiplanar CT with three-dimensional reconstruction is useful in the evaluation of the relationship between the os styloideum and adjacent bones (8) .…”