Purpose
Traumatic drill overshoot during dorsal fixation of coronal hamate and fifth metacarpal
base fractures risks iatrogenic ulnar nerve injury. This study describes the anatomic
relationships between exiting volar drill tips and ulnar nerve branches.
Methods
Dorsal drilling of hamate bones and fifth metacarpal bases was performed on cadavers.
Dorsal hamate bodies were subdivided into 4 quadrants: (1) distal-ulnar, (2) distal-radial,
(3) proximal-ulnar, and (4) proximal-radial. Screws measuring 5 mm more than the dorsal-to-volar
bone depths were placed in each quadrant to represent drill exit trajectories with
consistent overshoot. A single screw was similarly placed 5 mm distal to the midline
articular surface of the dorsal fifth metacarpal base. Distances between estimated
drill tips and ulnar nerve branches were measured.
Results
Ten cadaver hands were examined. The fifth metacarpal base screw tips directly abutted
the ulnar motor branch in 6 hands, and were within 1 mm in 4 hands (mean, 0.4 ± 0.5
mm). Distances from the tips to the ulnar motor and sensory branches were largest
in the distal-radial quadrant (11.8 ± 0.8 mm and 9.2 ± 1.9 mm, respectively) and smallest
in the proximal-ulnar quadrant (7.3 ± 1.5 mm and 4.3 ± 1.1 mm, respectively). Distances
to the ulnar motor and sensory branches were similar between the proximal-ulnar and
distal-ulnar quadrants, and between the proximal-radial and distal-radial quadrants.
Conclusions
Dorsal drilling of coronal hamate fractures appears to be safe, as volar drill tips
are well away from ulnar nerve motor and sensory branches. Distances to ulnar nerve
branches are largest, and theoretically safest, with dorsal drilling in the distal-radial
hamate. Dorsal drilling of fifth metacarpal base fractures appears to carry a high
risk for potential ulnar motor nerve injury.
Clinical relevance
These findings may help minimize potential risks for iatrogenic ulnar nerve injury
with dorsal drilling of hamate and fifth metacarpal base fractures.
Key words
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References
- Hook of hamate fractures in competitive baseball players.Hand (N Y). 2013; 8: 302-307
- Surgical excision of ununited hook of hamate fractures via the carpal tunnel approach.Injury. 2014; 45: 1554-1556
- Injury to the deep motor branch of the ulnar nerve during hook of hamate excision.Orthopedics. 2006; 29: 456-458
- Injury to the deep branch of the ulnar nerve in association with dislocated fractures of metacarpals II-IV.Scand J Plast Reconstr Surg Hand Surg. 2004; 38: 250-252
- Percutaneous pinning of fifth carpal-metacarpal fracture-dislocations: an alternative pin trajectory.Hand (N Y). 2008; 3: 251-256
- Hamate's coronal fracture: diagnostic and therapeutic approaches based on a long-term follow-up.GMS Interdiscip Plast Reconstr Surg DGPW. 2019; 8: Doc05
- Fracture of the body of hamate associated with a fracture of the base of fourth metacarpal: a case report and review of literature of the last 20 years.Int J Surg Case Rep. 2013; 4: 442-445
- Outcome following coronal fractures of the hamate.J Hand Surg Eur Vol. 2010; 35: 146-149
- Clinical classification and treatment strategy of hamate hook fracture.J Huazhong Univ Sci Technolog Med Sci. 2010; 30: 762-766
- Coronal fracture dislocation of the hamate and the base of the fourth metacarpal bone: a rare form of carpometacarpal injury.Handchir Mikrochir Plast Chir. 2011; 43: 140-146
- Classification and treatment of hamate fractures.Hand Surg. 2005; 10: 151-157
- Coronal fracture of the hamate body.Am J Orthop (Belle Mead NJ). 1997; 26: 568-571
- A case report of coronal fractures through the hamate, the capitate, and the trapezoid.Arch Orthop Trauma Surg. 2009; 129: 963-965
- Two-incision approach for the open reduction internal fixation of intra-articular hamate body fractures using a cannulated headless compression screw.Tech Hand Up Extrem Surg. 2020; 24: 187-193
- Functional outcome following headless compression screw fixation for hamate fractures.J Wrist Surg. 2020; 9: 164-169
Article info
Publication history
Published online: July 18, 2022
Accepted:
April 27,
2022
Received:
November 12,
2021
Publication stage
In Press Corrected ProofFootnotes
No benefits in any form have been received or will be received related directly or indirectly to the subject of this article.
Identification
Copyright
© 2022 by the American Society for Surgery of the Hand. All rights reserved.
