Abstract: 18 surgeries were realized in dogs with diaphyseal fractures of long bones, using for their heal the orthopedic staple with clamps in six dogs with simple fractures and not too much weight, as an auxiliary implant for the Steinmann pin. Other six dogs were treated with the antirotational plate and intramedullary pin with orifice, each implant is cross with two screws that joins the plate, the bone and the intramedullary pin, this system is recommended for dogs of medium size and a single fracture line. The last six dogs were of large size with complex comminuted fractures with absence of bone were treated with the double internal skeletal fixation, this system consists in a plate join to the bone and intramedullary pin by screws in the proximal and distal fragments, achieving extreme stability and resistance at the disruptive forces that acts in the fracture.

INTRODUCTION

The orthopedic staple with clamps is a versatile, efficient auxiliary implant used for fracture healing, in which we use a Steinmann intramedullary pin. This device fit together to the bone by the introduction of his acute extremes and in straight angle at his axial axis, by two orifices previously drilling over the osseous cortex, one in the proximal fragment and the other in the distal fragment, of the fracture bone and mediating the use of clamps that adjust at the circumference of the bone achieve to counteract the rotation forces that acts over the fracture line.

The antirotational plate is a stronger version of the orthopedic staple with clamps, in this case the fracture is reduced by using an intramedullary pin which is drilled all along each 10mm, therefore is place the antirotational plate over the osseous cortex having the plate clamps just like the orthopedic staple, but it doesn't have the acute and double dealing extremes, the plate is also drilled in his axial axis each 10mm this permits to put in, two screws that cross the plate, the bone and the intramedullary pin achieving a great stability of the fracture line.

The double internal skeletal fixation consists in a intramedullary pin with the same drillings for the pin used in the antirotational plate, but in this case we used a straight plate with circle orifices all along and each 10mm so it's a combination of implants well known: a bone plate and a intramedullary pin, they are directly connected by the screws they also fix at the bone on both cortex, achieving a great resistance and stability in the fracture lines.

The hypothesis for each one of these methods of healing is that they achieve the adequate quantity in form, size mass, weight of the implants and for their original form of collocation and subjection of the fracture extremes we obtain an adequate reduction and stability of the focus of fracture which fall in a best osseous reparation

OBJECTIVE

The principal objective is in an efficient manner neutralize the compression, rotation, tension and traction, forces that acts in a fracture, to obtain a great osseous reparation by using the intramedullary pin and the orthopedic staple with clamps for dogs with not too much weight; the antirotational plate for dogs of medium size, and the double internal skeletal fixation for dogs of large and extra large size with comminuted fracture or absence of bone.

MATERIAL AND METHODS

 18 dogs: 6 of small size, 6 of medium size and 6 of large size, each one with diaphyseal fractures of long bones.

 6 Steinmann pins with thickness of 3/32 inches.

 12 pins for intramedullary use with drillings each 10mm for screws 2.7 and 3.5.

 6 orthopedic staple with clamps.

 6 antirotational plates.

 6 straight plates with drillings each 10mm, for screws 2.7 and 3.5.

 46 orthopedic screws of 2.7 and 3.5.

 1 general soft tissue surgical instrumental.

 1 general orthopedic instrumental.

 1 special orthopedic instrumental for placement plates.

 Routine material for 18 surgeries: anesthesia, surgical equipment, sutures, etc.

For each fracture healing the routine methodology that we use was:

1.  General physical exam and record.

2.  Laboratory test: pre surgical profiles.

3.  Radiographic exam of the fracture bone.

4.  Fulfillment of the inclusion criterion to operate the dogs.

5.  Preanesthesic induction.

6.  General anesthesia with sevoflurane.

7.  Routine preparation of the surgical area.

8.  Surgical boarding and fracture healing using the planning implants.

9.  Routine surgical close and restore antibiotic therapy for 7 days.

10.  Preoperative radiograph.

11.  Suture removal in 10 days.

12.  Complete orthopedic exam for control each 15 days.

13.  Each month postoperative control radiographic exam until the clinic or radiographic close of fracture line is seen.

14.  Surgery for implants remove.

RESULTS

The six surgeries for fracture healing of long bones with intramedullary pin and orthopedic staple with clamps achieve healing in a period of 2.7 months therefore they have been placed.

The six surgeries for fracture healing of long bones with intramedullary pin and antirotational plate achieve healing in a period of 2.6 months therefore they have been placed.

The six surgeries for fracture healing of comminuted fracture or with a absence of bone in long bones with the double internal skeletal fixation achieve clinic union in a period of 95 days therefore they have been placed. In any of the cases the implants were seen upset.

DISCUSSION

If we compare the different auxiliary implants that we used (orthopedic staple with clamps and antirotational plate) for the intramedullary pin, with the cerclage wire, hemicerclage wire, screws, Kirschner needle , to counteract the rotation forces in simple fractures, results superior the greater stability obtained with this two implants in dogs of small and medium size with fractures in which extremes are in contact, because the implants act as a miniplate and cerclage for the presence of clamps.

The double internal skeletal fixation is recommended for heavier dogs with comminuted fractures and with bone absence, that's why we compared him with the external skeletal fixation plates and interlocking nail, having over this traditional implant the significant advantage because it gives more rigidity and stability of the fracture area because it is a combination of implants that acts in conjunct an tightly join, so we can say that it is the implant that achieve the best neutralization of all the forces that acts over the fracture line.

CONCLUSION

For the excellent results obtained in the healing of the 18 treated fractures with the three methods that we described, we can conclude that it is recommendable the use of these methodologies and implants for the osteosynthesis in the different diaphyseal fractures of long bones.

References

1.  Brinker, W.O., Piermattei, D.L. y Flo, G.L.: Ortopedia y reparación de fracturas de Pequeños Animales. McGraw-Hill-Interamericana , Spain; 1999.

2.  Brinker, W.O. y Flo, G.L.: Principles and application of external skeletal fixation. Vet. Clin. North Am.

3.  Hulse, D.A y Aron, D.N.: Advances in small animal orthopedics. Compendium 16:831-832, 1994.

4.  Palmer, R.H. y Hulse, D.A.: Principles of bone healing and biomechanics of external skeletal fixation. Vet. Clin. North Am. Small Anim. Pract. 22:45-68, 1992.