Os subepicondylare mediale ossicle as a cause for cubital tunnel syndrome: A case report

Figure 1 Plain radiograph of the left elbow. A and B: Anteroposterior and lateral view. The orange arrow indicates an accessory bone located beneath the medial epicondyle, featuring a distinctive, well-defined oval ossicle with smooth margins.

Figure 2 Computed tomography and magnetic resonance imaging. A: Computed tomography scan (sagittal view) of the left elbow joint (orange arrow = ossicle, blue arrow = medial humeral epicondyle, yellow arrow = ulna); B: Magnetic resonance imaging of the left elbow joint. The orange arrow indicates the small corticated ossicle separated from the medial epicondyle with a thin, low-intense signal cleft. It lies within or adjacent to the ulnar collateral ligament; the fibers remain continuous. The fragment demonstrates marrow signal identical to native bone with thickened ulnar nerve (T1 hyperintense, T2 intermediate), suggestive of synchondrosis (accessory ossicle).

Figure 3 Intraoperative images. A: An ossicle was identified (orange arrow) and carefully excised through the Taylor and Scham approach to relieve compression on the ulnar nerve; B: The yellow arrow indicates the ulnar nerve, retracted and freed from the accessory ossicle.

Figure 4 Histopathological examination of the excised specimen. Histopathological examination showing mature bony trabeculae with interspersed marrow fat (H&E stain; 10 × and 40 × magnification).

Figure 5 At 1-year follow-up, the hand grip strength had returned to near-normal levels with complete restoration of the range of movements with no radiological recurrence.