Vet Comp Orthop Traumatol 2014; 27(02): 102-106 DOI: 10.3415/VCOT-13-08-0105
Original Research
Schattauer GmbH
The microvasculature in the equine distal phalanx: Implications for fracture healing
S. M. Schade
1
Michigan State University, College of Veterinary Medicine, Laboratory for Comparative Orthopaedic Research, East Lansing, Michigan, United States
,
S. P. Arnoczky
1
Michigan State University, College of Veterinary Medicine, Laboratory for Comparative Orthopaedic Research, East Lansing, Michigan, United States
,
R. M. Bowker
1
Michigan State University, College of Veterinary Medicine, Laboratory for Comparative Orthopaedic Research, East Lansing, Michigan, United States
› Author AffiliationsThe authors thank Drs. John A. Stick and Frank Nickels for their assistance in this study. Funding was provided by The Laboratory for Comparative Orthopaedic Research and the Wade O. Brinker Endowment, College of Veterinary Medicine, Michigan State University; and the American Quarter Horse Association and the United States Equestrian Federation.
To describe the intra-osseous microvasculature of the distal phalanx of the equine forelimb with regard to its potential clinical relevance.
Methods
Eleven clinically normal equine forelimbs were used from six adult horses (range: 4 to 18 years old) euthanatized for reasons unrelated to lameness. In each limb the median artery was catheterized at the level of the carpus and India ink was injected under constant manual pressure. The limbs were frozen and 5 mm thick sections of the foot were cut in the sagittal, coronal, or transverse planes on a band saw. The sections were fixed in 10% formalin and cleared using a modified Spalteholz technique. Once cleared, the sections were photographed and the microvascular anatomy identified.
Results
The vascular injections revealed a rich intra-osseous microvascular supply of the distal phalanx originating from the medial and lateral palmar digital arteries. In addition, numerous smaller vessels from the terminal arch, formed by anastomosis of the medial and lateral palmar digital arteries, could be seen branching into the distal aspects of the distal phalanx. This distal portion of the distal phalanx appeared more densely vascularized than the proximal part in all specimens examined.
Clinical significance
The increased vascularity demonstrated in the distal portion of the distal phalanx appears to correlate with improved fracture healing reported in this area. This may also explain why healing fractures which involve both the distal and proximal portions of the distal phalanx have been described as progressing from distal-to-proximal.
3
Rijkenhuizen AB,
de Graaf K,
Hak A.
et al. Management and outcome of fractures of the distal phalanx: a retrospective study of 285 horses with a long term outcome in 223 cases. Vet J 2012; 192: 176-182.
4
Honnas CM,
O’Brien TR,
Linford RL.
Distal phalanx fractures in horses: a survey of 274 horses with radiographic assessment of healing in 36 horses. Vet Radiol 1988; 29: 98-107.
6
Kaneps AJ,
Turner TA.
Diseases of the Foot. In:
Hinchcliff KW,
Kaneps AJ,
Geor RJ.
editors. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. New York: Saunders; 2004. pg. 2004-260.
7
Honnas CM,
O’Brien TR,
Linford RL.
Solar margin fractures of the equine distal phalanx. Proceedings of the 33rd Annual Convention of the American Association of Equine Practitioners. 1987. November 29-December 2 New Orleans, Louisiana, USA: pg. 399-410.
9
Collins JN,
Galuppo LD,
Thomas HL.
et al. Use of computed tomography angiography to evaluate the vascular anatomy of the distal portion of the forelimb of horses. Am J Vet Res 2004; 65: 1409-1420.
14
Rhinelander FW,
Wilson JW.
Blood supply to developing, mature, and healing bone. In:
Sumner-Smith G..
editor. Bone in Clinical Orthopaedics: A study in comparative osteology. Toronto: W.B. Saunders; 1982. pg. 1982-81.
15
Von Horst C,
Henry RW.
User-oriented plastination. Proceedings of American Association of Veterinary Anatomists Meeting. 2011 August 6-8 Ithaca, NY, USA: pg. 8.
16
Dugat D,
Rochat M,
Ritchey J.
et al. Quantitative analysis of the intramedullary arterial blood supply of the feline tibia. Vet Comp Orthop Traumatol 2011; 24: 313-319.
17
Franch J,
Garcia F,
Dela Fuente J.
et al. Microangiographic pattern of bone healing in canine tibial osteotomies treated with type II external fixators. Vet Comp Orthop Traumatol 1998; 11: 118-124.
19
Trumble TN,
Arnoczky SP,
Stick JA.
et al. Clinical relevance of the microvasculature of the equine proximal sesamoid bone. Am J Vet Res 1995; 56: 720-724.
22
Smith JW,
Arnoczky SP,
Hersh A.
The intraosseous blood supply of the fifth metatarsal: implications for proximal fracture healing. Foot Ankle 1992; 13: 143-152.
23
O’Sullivan CB,
Dart AJ,
Malikides N.
et al. Nonsurgical management of type II fractures of the distal phalanx in 48 Standardbred horses. Aust Vet J 1999; 77: 501-503.
25
Prosby RD,
Ramsey MW,
Behnke BJ.
et al. Aging reduces skeletal blood flow, endothelium-dependent vasodilation, and NO bioavailability in rats. J Bone Miner Res 2007; 22: 1280-1288.
27
Bloomfield S,
Hogan HA,
Delp MD.
Decreases in bone blood flow and bone material properties in aging Fischer-344 rats. Clin Orthop 2002; 396: 248-257.
30
Roche B,
Vanden-Bossche A,
Normand M.
et al. Validated laser Doppler protocol for measurement of mouse bone perfusion - response to age or ovariectomy with genetic background. Bone 2013; 55: 418-426.
32
Dejardin LM,
Arnoczky SP,
Cloud GL.
Determination of strain patterns in the normal equine hoof using photoelasticity: an in vitro study. Equine Vet J 1999; 31: 232-237.
