The Volar Distal Radioulnar Portal in Wrist Arthroscopy: An Anatomical Study.

 Advances in wrist arthroscopy and the emergence of novel surgical techniques have created a need for new portals to the wrist. The aim of this study was to define and verify the safety of the volar distal radioulnar (VDRU) portal.  The VDRU portal is located ∼5 to 10 mm proximal to the proximal wrist crease, just on the ulnar edge of flexor carpi ulnaris tendon and radial to the dorsal cutaneous branch of the ulnar nerve. The ulnar styloid marks the distal point of the portal.  An anatomical study was performed on 12 upper extremity specimens of 6 human cadavers. Iatrogenic injuries of neurovascular structures potentially at risk were assessed, and the distance from the portal to these structures was measured.  No iatrogenic injuries of the structures at risk occurred. Mean distances from the VDRU portal to the ulnar neurovascular bundle, the radial branch of the dorsal sensory branches of the ulnar nerve (DSBUN), and the ulnar branch of the DSBUN were 9.29 ± 0.26 mm, 8.08 ± 0.25 mm, and 10.58 ± 0.23 mm, respectively. There were no differences between left and right wrists. The distances from the VDRU portal to the ulnar neurovascular bundle and the ulnar branch of the DSBUN were significantly shorter in women; this distance was not less than 7 mm in any case.  The VDRU portal is safe, reproducible, and facilitates the implementation of various techniques related to triangular fibrocartilage complex pathology.