Anatomic cadaveric study of the extensile extensor digitorum communis splitting approach for exposing the ulnar coronoid process

Background:The extensile extensor digitorum communis (EDC) splitting approach can access the ulnar coronoid process (UCP), which can be used to treat terrible triad injuries. The present study anatomically examined the extensile EDC splitting approach for exposing the UCP.Methods:Twenty fresh frozen cadaveric upper limbs were dissected. The splitting length of the EDC and detachment length of the extensor carpi radialis brevis (ECRB)–extensor carpi radialis longus (ECRL)–brachioradialis (BR) origin were measured to expose the UCP. The distance between the most distal site of the EDC splitting and the point at which the posterior interosseous nerve (PIN) crosses the anterior aspect of the radial shaft, and the distance between the most proximal site of the ECRB-ECRL-BR origin detachment and the point at which the radial nerve crosses the anterior aspect of the humeral shaft were measured.Results:The splitting length of the EDC was 45.4 ± 4.8 mm, the detachment length of the ECRB-ECRL-BR origin was 30.2 ± 4.7 mm, the distance between the distal site of the EDC splitting and PIN was 10.6 ± 6.1 mm (minimum distance, 1.1 mm), and the distance between the proximal site of the ECRB-ECRL-BR origin detachment and the radial nerve was 49.5 ± 9.7 mm (minimum distance, 31.7 mm).Conclusions:The extensile EDC splitting approach can sufficiently expose the UCP. However, splitting must be performed carefully because the most distal site of the EDC splitting is close to the point at which the PIN crosses the anterior aspect of the radial shaft (average distance, 10 mm; minimum distance, 1 mm).