The Vascular Anatomy of the Capitate: New Discoveries Using Micro-Computed Tomography Imaging.
OBJECTIVE
To study the intraosseous 3-dimensional microvasculature of the capitate bone using a novel high-resolution micro-computed tomography (μCT) imaging technology, and to examine the blood supply as it relates to the most common fracture types.


METHODS
Ten cadaveric wrists were injected with a lead-based contrast agent. The capitates were harvested and imaged using a μCT scanner. The intraosseous vascularity was incorporated into a 3-dimensional image. We measured the vascular pattern as well as the vessels' cross-sectional area, number, and distribution. An average capitate fracture line was calculated using clinical data from 22 patients with capitate fractures. The fracture line was projected on the representative capitate to assess its relation with the nutrient vessels' entry points.


RESULTS
The capitate is a well-vascularized carpal supplied by dorsal and volar vascular systems that anastomose in 30% of cases. There was no predominance of one vascular system over the other. Most vessels enter the capitate at the distal half and supply the proximal pole in a retrograde fashion. In addition, most specimens (70%) also had at least one vessel entering the proximal pole through the volar capitate ligaments and supplying the proximal pole directly. The average fracture line had an oblique orientation, and 90% of the specimens had a blood vessel entering proximal to that line.


CONCLUSIONS
This μCT vascular study further verifies that the capitate receives most of its vasculature in a retrograde fashion, but the study also shows that most capitates have vessels supplying the proximal pole directly. These findings might explain why most capitate waist fractures do not progress to proximal pole avascular necrosis.


CONCLUSIONS
This study characterizes the microvasculature of the capitate and might shed light on processes involved in bone healing and the etiology of capitate avascular necrosis.
Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Orthopedic Division, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Assaf
A
Kadar
Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Department of Orthopedic Surgery, Assiut University Hospital, Assiut, Egypt.
Mohamed
M
Morsy
Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Department of Orthopedic Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, Catholic University of Korea, Uijeongbu, Republic of Korea.
Yoo-Joon
YJ
Sur
Division of Plastic Surgery, Mayo Clinic, Rochester, MN.
Alexis T
AT
Laungani
Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Department of Plastic Reconstructive and Aesthetic Surgery, Selcuk University, Konya, Turkey.
Osman
O
Akdag
Division of Plastic Surgery, Mayo Clinic, Rochester, MN. Electronic address: moran.steven@mayo.edu.
Steven L
SL
Moran
D002102:Cadaver; D051224:Capitate Bone / Q000098:blood supply* / Q000000981:diagnostic imaging*; D003287:Contrast Media; D006801:Humans; D021621:Imaging, Three-Dimensional; D008833:Microcirculation; D055114:X-Ray Microtomography
D003287:Contrast Media
Avascular necrosis; capitate; capitate fracture; vascular; μCT