of blood supply to the bone may occur due to the exposure necessary for open reduction and implant placement. Proper evaluation of soft tissue viability will influence the outcome of postoperative complications, such as infection and wound dehiscence. Adequate first aid and preoperative care are essential for the preservation of the remaining blood supply following injury.
Whenever possible, internal fixation using lag screws should be accomplished under radiographic control through stab incisions to minimize additional soft tissue compromise. This is usually performed for nondisplaced fractures. Sometimes additional stab incisions can be used for the insertion of screws even when open approaches are used for visualization and reduction. As an alternative to expansion of the primary incision, this technique serves to limit the necessary exposure. Soft tissues should always be protected during drilling and tapping by the use of drill guides and tap sleeves.
The need for open reduction and internal fixation must be balanced by its risks. Experience with this paradox in the horse will help define each surgeon's abilities and limitations.
Avascular tissue will be at a higher risk for necrosis and infection.
Anesthetic recovery can be a critical time.
The need for open reduction and internal fixation must be balanced by its risks.
1.6 Functional rehabilitation
As stressed in this chapter, anatomic reconstruction, stable internal fixation with good soft tissue evaluation, and careful surgical handling should permit early weight bearing with pre-
servation of joint function. To accomplish these goals, external casts or splints must sometimes be used in the postoperative period or at least during recovery from anesthesia. Anesthetic recovery can be a critical time in the early treatment of a horse with a fracture, and protection of the animal and the reconstructed fracture is of paramount importance. Casts are often used to help ensure a safe recovery. Concern for preservation of the animal and its operated extremity has resulted in specialized recovery techniques such as the raft/pool recovery system.
Healing of bone itself does not ensure full functional rehabilitation. Failure of bone healing, however, does ensure failure of functional rehabilitation. Therefore, healing of bone is the first criterion for the rehabilitation of an afflicted animal.
Success in fracture treatment is measured according to expectations. Some injuries are so severe that they are lifethreatening. In such cases, just saving an animal's life to allow it to be pasture sound may be a success. In other cases, the animal will be expected to perform at levels equal to or surpassing those of its former status. Here, fracture fixation and bone healing constitute only a small part of the total rehabilitation process. Further efforts will be required to bring the horse back to its former athletic prowess. Truly successful fracture treatment must involve the whole animal and reach beyond the gains made in the operating theatre.
Success in fracture treatment is measured against preoperative expectations.
1.7 References
1. Nunamaker DM, Richardson DW, Butterweck DM (1991) Mechanical and biological effects of plate luting. J Orthop Trauma; 5:138–145.
2. Young DR, Richardson DW, Nunamaker DM, et al. (1989) Use of dynamic compression plates for treatment of tibia diaphyseal fractures in foals: Nine cases (1980–1987). J Am Vet Med Assoc; 194:1755.
3. Nunamaker DM, Richardson DW, Butterweck DM, et al. (1986) A new external skeletal fixation device that allows immediate full weightbearing: Application in the horse. Vet Surg; 15:345.
4. Nunamaker DM, Richardson DW (1992) External skeletal fixation in the horse. Proc 37th Annual Convention of Am Assoc Equine Pract; 549.
5. Perren SM (1979) Physical and biological aspects of fracture healing with special reference to internal fixation. Clinical Orthop; 138:175.
6. Cheal EJ, Mansmann KA, DiGioia III AM, et al. (1991) Role of interfragmentary strain in fracture healing: ovine model of a healing osteotomy. J Orthop Res; 9:131–142.
1.7.1 Online references
See online references on the PEOS internet home page for this chapter: http://www.aopublishing.org/PEOS/01.htm
David M. Nunamaker
2.1.1 Drilling and tapping holes in bone
2.5 Mechanics of plate fixation
2.5.1 Contouring and prebending
