Subscribe to RSS
Bony Anatomy around the Watershed Line of the Distal RadiusFunding None.
Background An important surgical landmark in the distal radius is the watershed line. The watershed line is a landmark for the positioning of volar locking plates (VLP) in the distal radius. Inconsistencies remain in the literature as to the presence and dimensions of landmarks in this compact area. We studied the detailed anatomy and dimensions of the distal radius with reference to bony anatomy around the watershed line, with special attention to the area between the pronator quadratus (PQ) and radial styloid.
Materials and Methods The distal radius regions of 31 cadavers (23 right sided and 8 left sided) were dissected and studied. The heights at the junction of the scaphoid and lunate fossa, at the radial styloid, at the midpoint in between, and the widths of the PQ line, scaphoid, and lunate fossa were measured. The angle subtended by the pronator fossa and the radial styloid was also recorded.
Results The mean heights at the junction of the scaphoid and lunate fossa, radial styloid, and midpoint in between were 5.1, 15.7, and 8.2 mm, respectively. The widths of the PQ line, scaphoid, and lunate fossa were 27, 19.4, and 10.6 mm, respectively. The mean angulation between the pronator fossa and the radial styloid was 128.9 degrees.
Conclusion The area between the PQ and watershed line comprises a narrow area of bone which tapers to a point at its medial extent largely below the lunate fossa, thus it can hardly contain any implant proximal to the lunate fossa. The anterior orientation of this area and the concave anatomy of the articular surface mean careful screw direction is imperative to avoid inadvertent joint penetration. An angulation exists between the pronator fossa and the radial styloid, below the scaphoid fossa.
This is to state that no clinical patients or patient identifiable data were utilized in this study, hence no ethical committee was required at our institution.
Received: 29 April 2020
Accepted: 01 September 2020
Article published online:
04 November 2020
© 2020. Thieme. All rights reserved.
Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA
- 1 Nelson DL. Anatomy notes and their clinical significance for the volar approach. Available at: http://www.davidlnelson.md/articles/Radius_Anatomy_Annotated.htm. Accessed September 14, 2020
- 2 Imatani J, Akita K, Yamaguchi K, Shimizu H, Kondou H, Ozaki T. An anatomical study of the watershed line on the volar, distal aspect of the radius: implications for plate placement and avoidance of tendon ruptures. J Hand Surg Am 2012; 37 (08) 1550-1554
- 3 Obert L, Loisel F, Gasse N, Lepage D. Distal radius anatomy applied to the treatment of wrist fractures by plate: a review of recent literature. SICOT J 2015; 1: 14
- 4 Matityahu AM, Lapalme SN, Seth A, Marmor MT, Buckley JM, Lattanza LL. How placement affects force and contact pressure between a volar plate of the distal radius and the flexor pollicus longus tendon: a biomechanical investigation. J Hand Surg Eur Vol 2013; 38 (02) 144-150
- 5 Tanaka Y, Aoki M, Izumi T, Fujimiya M, Yamashita T, Imai T. Effect of distal radius volar plate position on contact pressure between the flexor pollicis longus tendon and the distal plate edge. J Hand Surg Am 2011; 36 (11) 1790-1797
- 6 Rikli DA, Regazzoni P. Fractures of the distal end of the radius treated by internal fixation and early function. A preliminary report of 20 cases. J Bone Joint Surg Br 1996; 78 (04) 588-592
- 7 Orbay JL, Touhami A. Current concepts in volar fixed-angle fixation of unstable distal radius fractures. Clin Orthop Relat Res 2006; 445 (445) 58-67
- 8 Gasse N, Lepage D, Pem R. et al. Anatomical and radiological study applied to distal radius surgery. Surg Radiol Anat 2011; 33 (06) 485-490
- 9 Kwon BC, Lee JK, Lee SY, Hwang JY, Seo JH. Morphometric variations in the volar aspect of the distal radius. Clin Orthop Surg 2018; 10 (04) 462-467
- 10 Daniele L, McLean A, Cocks N, Kalamaras M, Bindra R, Tan SLE. Anatomic variation in volar tilt of the scaphoid and lunate facet of the distal radius. J Hand Surg Am 2016; 41 (11) e399-e404
- 11 Imatani J, Akita K. Volar distal radius anatomy applied to the treatment of distal radius fracture. J Wrist Surg 2017; 6 (03) 174-177