Aim: The current study was undertaken to evaluate the clinical efficacy of end-threaded intramedullary pinning for management of various long bone fractures in canines.

Materials and Methods: This study was conducted in two phases, managing 25 client-owned dogs presented with different fractures. The technique of application of end-threaded intramedullary pinning in long bone fractures was initially standardized in 6 clinical patients presented with long bone fractures. In this phase, end-threaded pins of different profiles, i.e., positive and negative, were used as the internal fixation technique. On the basis of results obtained from standardization phase, 19 client-owned dogs clinically presented with different fractures were implanted with end-threaded intramedullary positive profile screw ended self-tapping pin in the clinical application phase.

Results: The patients, allocated randomly in two groups, when evaluated postoperatively revealed slight pin migration in Group-I (negative profile), which resulted in disruption of callus site causing delayed union in one case and large callus formation in other two cases whereas no pin migration was observed in Group-II (positive profile). Other observations in Group-I was reduced muscle girth and delayed healing time as compared to Group-II. In clinical application, phase 21st and 42nd day post-operative radiographic follow-up revealed no pin migration in any of the cases, and there was no bone shortening or fragment collapse in end-threaded intramedullary positive profile screw ended self-tapping pin.

Conclusion: The end-threaded intramedullary positive profile screw ended self-tapping pin used for fixation of long bone fractures in canines can resist pin migration, pin breakage, and all loads acting on the bone, i.e., compression, tension, bending, rotation, and shearing to an extent with no post-operative complications.

Keywords: Admit pin, canine, end-threaded, fracture, intramedullary, orthopedics, pinning, positive profile.

1. Kumar, P. and Gahlot, T.K. (2013) Clinical evaluation of intramedullary pinning and interlocking nailing technique for stabilization of femoral fractures in dogs. J. Anim. Sci. Adv., 3(6): 310-313. [Crossref]

2. Lidbetter, A.D. and Glyde, M.R. (2000) Supracondylar femoral fractures in adult animals. Compend. Contin. Educ. Practising. Vet., 22: 1041-1054.

3. Hulse, D., Ferry, K., Fawcet, A., Gentry, D., Hyman, W., Geller, S. and Slater, M. (2000) Effect of intramedullary pin size on reducing bone plate strain. Vet. Comp. Orthop. Traumatol., 13: 185-190.

4. Kapler, M. (2015) A practitioner's guide to fracture management Part 3: Selection of internal fixation Technique. Tod.Vet.Pract., 5: 6.

5. Karen, M. T. and Spencer, A. J. (2012) Veterinary Surgery: Small Animal. Saunders Elsevier, St. Louis.

6. Coetzee, G.L. (2002) Basic Principles for the Application of Bone Plates and Screws in Small Animal Patients. CPD Course for Veterinary Surgeons, Pretoria, September 7, 2002. Roth Medical Components (Pty) Ltd, Pinelands, South Africa. p1-23.

7. Lanz, O.I., Lewis, D.D. and Newell, S.M. (1999) Stabilisation of a physical fracture using an ortho fix partially threaded Kirschner wire. Vet. Comp. Orthop. Traumatol., 12: 88-91.

8. Denny, H.R. and Butterworth, S.J. (2000) Fracture management. In: A Guide to Canine and Feline Orthopaedic Surgery. 4th ed. Blackwell Science, Oxford, London. p87-152. [Crossref]

9. Piermattei, D.L., Flo, G.L. and DeCamp, C.E. (2006) Brinker, Piermattei and Flo's Handbook of Small Animal Orthopaedics and Fracture Repair. 4th ed. WB Saunders Company, Phlapdeiphia. p512, 633-660.

10. Kaur, J. (2017) Evaluation of Interlocking Nailing Technique for Fixation of Long Bone Fractures in Small Animals. M.V.Sc Thesis, Department of Veterinary Surgery and Radiology, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, India.

11. Kumar, H. (2016) Comparative Evaluation of Different Techniques for Fixation of Femoral Fractures in Dogs. M.V.Sc Thesis, Department of Veterinary Surgery and Radiology, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, India.

12. Nunamaker, D.M. (1985) Methods of internal fixation. In: Newton, C.D., Nunamaker, D.M., editors. Textbook of Small Animal Orthopaedics. JB Lippincott Company, Philadelphia. p261-286.

13. Einhorn, T.A. (1998) The cell and molecular biology of fracture healing. Clin. Orthop. Relat. R., 355 Suppl: S7-21. [Crossref]

14. Ozsoy, S. (2004) Fixation of femur, humerus and tibia in cats using intramedullary threaded Steinmann pins. Vet. Rec., 155: 152-153. [Crossref] [PubMed]

15. Gilley, R. and Gold, R. (2006) Instrumentation: Orthopaedic pinning and wiring. University of Pennsylvania School of Veterinary Medicine. Available from: http://www.cal.vet.upenn.edu/projects/orthopod /csfr/terms/pinning and wiring.htm. Last accessed on 16-04-2017.

16. Claes, L., Heitemeyer, U., Krischak, G., Brau, H. and Heirholzer, G. (1999) Fixation technique influences osteogenesis of comminuted fractures. Clin. Orthop. Relat. R., 365: 221-229. [Crossref]

17. Johnson, A.L., Houlston, J.F. and Vannini, R. (2005) AO Principles of Fracture Management in Dog and Cat. AO Publishing, Thieme Publishers Series, Switzerland.

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