Prevalence of Os Styloideum in National Hockey League Players

Abstract

Background: Os styloideum describes an accessory carpal ossicle between the trapezoid, the capitate, and the second and third metacarpals. Injuries to this tissue have been described as part of the carpal boss syndrome. While the etiology of os styloideum remains uncertain, it may represent a physiologic response to altered loading forces in the wrist, similar to the development of cam-type deformity in the hips of ice hockey players or the Bennett lesion in the shoulders of baseball pitchers.

Hypothesis: Professional hockey players will have a higher prevalence of os styloideum compared with the general population.

Study design: Case series.

Level of evidence: Level 4.

Methods: A retrospective review of 16 professional hockey players from 4 different National Hockey League (NHL) teams who underwent unilateral imaging of the wrist was performed. Seventeen wrists were reviewed for the presence of os styloideum.

Results: Thirteen of 16 players (81%) had an os styloideum, representing an increased prevalence compared with the general population. Previous clinical and cadaveric studies estimated a general prevalence of up to 19% ( P < 0.001). For the 10 players who had their leading wrist scanned, 9 had an os styloideum (90%). Ten of 11 (91%) players demonstrated a bone marrow edema pattern within the metacarpal and the os styloideum on magnetic resonance imaging. There was no significant association between the presence of an os styloideum and the player's position, leading wrist, or years in the league.

Conclusion: There appears to be an increased prevalence of os styloideum among NHL players, and team physicians should consider this finding while formulating a differential diagnosis for dorsal wrist pain.

Clinical relevance: This study identified NHL players as having an increased prevalence of os styloideum compared with the general population. By doing so, these findings represent an opportunity to enhance our understanding of the etiology, clinical significance, and treatment of os styloideum.

Keywords: MRI; hand; ice hockey; os styloideum; sports medicine; wrist.

Figure 1.

(a) Sagittal and (b) axial proton-density magnetic resonance images of the wrist in 24-year-old National Hockey League player demonstrating an os styloideum (arrow) at the base of the long finger metacarpal. The dashed arrow in Figure 1a demonstrates the fibrous union with the base of the second metacarpal. The player presented for a triangular fibrocartilage injury and was asymptomatic. C, capitate; L, lunate; MC, metacarpal.

Figure 2.

(a) Sagittal and (b) coronal magnetic resonance images of the wrist demonstrating a carpal boss (arrows) with medullary continuity with the base of the second metacarpal in a 40-year-old man who was asymptomatic with regard to his os styloideum. (c) Sagittal reformatted computed tomography image of the wrist demonstrates the appearance of a large carpal boss with osseous remodeling. MC, metacarpal.

Figure 3.

(a) Coronal inversion-recovery magnetic resonance image (MRI) of the left hand in a 22-year-old National Hockey League player demonstrating bone marrow edema pattern (arrow) within the long finger metacarpal bone after getting hit with the puck. (b) Sagittal proton-density MRI demonstrates a large os styloideum (arrow) with a ganglion cyst (dashed arrow), which represents an incidental finding in this case. C, capitate; MC, metacarpal.

Figure 4.

(a) Coronal proton-density magnetic resonance image (MRI) demonstrating an os styloideum (arrow) at the base of the long finger metacarpal in a 26-year-old National Hockey League center with dorsal wrist pain referable to the area. (b) Coronal inversion recovery MRI demonstrates a bone marrow edema pattern (arrow) on both sides of the articulation. MC, metacarpal.

Figure 5.

(a) Posteroanterior radiograph of the wrist in a 24-year-old National Hockey League player with a prior triangular fibrocartilage complex injury and repair at follow-up. Os styloideum is not typically seen in this view and is not appreciated here. (b) Lateral radiograph demonstrates a large os styloideum (arrow).

Figure 6.

(a) Axial and (b) sagittal reformatted computed tomography images demonstrating a small os styloideum (arrow) in a 25-year-old National Hockey League player who underwent evaluation for a scaphoid fracture.