{"id":20677,"date":"2020-04-17T19:12:35","date_gmt":"2020-04-17T19:12:35","guid":{"rendered":"https:\/\/todaysveterinarypractice.com\/?p=20677"},"modified":"2024-07-02T17:23:48","modified_gmt":"2024-07-02T17:23:48","slug":"definitive-treatment-of-limb-fractures-with-splints-or-casts","status":"publish","type":"post","link":"https:\/\/navc.sitepreview.app\/todaysveterinarypractice.com\/emergency-medicine-critical-care\/definitive-treatment-of-limb-fractures-with-splints-or-casts\/","title":{"rendered":"Definitive Treatment of Limb Fractures With Splints or Casts"},"content":{"rendered":"

Dramatic technologic advances in fracture fixation offer veterinarians a wider array of surgical fixation systems than ever before; however, a definitive treatment role remains for splints and casts for selected fractures. As a profession, veterinarians must preserve their knowledge and skills in the \u201cart\u201d of effective utilization of splints and casts for these fractures, referred to in this article as coaptation<\/i>. The keys to successful use of coaptation as a definitive fracture treatment are case selection, the techniques of fracture reduction and cast application, and proper post-application care and monitoring.<\/span><\/p>\n

Case Selection<\/h2>\n

TABLE 1<\/b><\/span> summarizes important mechanical and biologic factors when considering coaptation for the definitive treatment of long bone fractures. <\/span><\/p>\n

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Indications<\/h3>\n

Depending on the fracture configuration and location, the fracture zone may experience any of 5\u00a0disruptive forces: bending, rotation, compression, shear, and tension. Properly applied splints and casts are capable of providing some resistance to bending forces and somewhat less resistance to rotational forces. Since they are not capable of resisting compression, shear, or tensile forces, they are unsuitable for treatment of fractures for which these disruptive forces are significant. In brief, coaptation is best used for treatment of fractures distal to the elbow\/stifle that are subjected only to moderate bending and mild rotational forces. <\/span><\/p>\n

Incomplete (\u201cgreenstick\u201d) fractures in the crus or antebrachium; fractures with an intact adjacent bone, such as tibial fracture with an intact fibula (<\/span>FIGURE 1<\/b><\/span>); and fractures of 1 or 2 of the 4 metacarpal\/metatarsal bones tend to be the best candidates for cast\/splint treatment. An intact bone adjacent to a fractured bone functions as an internal anatomic splint. Incomplete fractures and preservation of an intact adjacent bone are most common in animals aged <6 months owing to the relatively compliant nature of their collagen-rich bone compared with the more mineral-rich bone of adult animals. Some transverse fractures in which >50% reduction can be achieved in both orthogonal radiographic views may also be candidates for casting; the restored bony column should be capable of resisting axial collapse while the cast resists bending and rotational forces.<\/span><\/p>\n

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Figure 1. Incomplete tibial fracture with an intact fibula in a growing dog may be an ideal case for coaptation.<\/p><\/div>\n

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Figure 1. Incomplete tibial fracture with an intact fibula in a growing dog may be an ideal case for coaptation.<\/p><\/div>\n

Contraindications<\/h2>\n

Coaptation should never be used for definitive treatment of fractures proximal to the elbow\/stifle, as it is not possible to span the joint above the fracture; thus, disruptive bending forces cannot be controlled. It is not recommended for fracture configurations in which <\/span>the bone itself is incapable of resisting axial compression; these include complete oblique or spiral fractures, comminuted fractures, and transverse fractures in which <50% reduction is present in one or more <\/span>orthogonal radiographic views. Coaptation is unsuitable for treatment of fractures at the insertion site of muscle-tendon units, due to the strong tensile forces acting on them; these so-called traction apophyses <\/span>include the tibial tuberosity, tuber calcis, and olecranon.<\/p>\n

Coaptation is prone to complication and should be avoided in scenarios where mechanical overloading is a concern; this includes animals with multi-limb dysfunction and pets in which activity restriction is unlikely due to patient temperament and\/or anticipated client noncompliance. Cast\/splint application should also be avoided in fracture scenarios in which delayed healing is predictable, regardless of mechanical factors, as the risk of complications with coaptation increases with treatment duration.<\/span><\/p>\n

Before anesthesia and attempted fracture reduction, owners should be informed that surgical treatment will be recommended (and may involve referral) if >50% reduction of a transverse fracture cannot be achieved in both orthogonal radiographic views. If the owner refuses surgical treatment despite inadequate fracture reduction, clarify that coaptation is their choice but is not the recommended treatment. <\/span><\/p>\n

Complication Factors<\/h3>\n

Soft tissue complications can be mild, moderate, or severe. Total soft tissue complication rates can be as high as 63% of cases, and the cost of treating them can be up to 121% of the original procedure cost.1,2<\/sup> Since the likelihood of soft tissue complications increases with treatment duration, coaptation may not be the best treatment when the estimated healing time exceeds 4 to 6 weeks; this may include animals older than a young adult (age \u22653 years), patients with moderate\/severe regional soft tissue injury (including open fractures), and anatomic regions with poor regional blood supply to bone. <\/span><\/p>\n

Poor vascular density of the distal radius\/ulna in small breeds of dogs may contribute to the reported 75% rate of nonunion and malalignment in such fractures treated with coaptation.3,4<\/sup> Therefore, even when >50% reduction of transverse fractures of the distal radius\/ulna is achievable, coaptation is not<\/i> the treatment of choice in these patients. Articular fractures require rigid fixation and maintenance of perfect anatomic reduction in order to maximize restoration of limb function; coaptation is not<\/i> recommended for treatment of these fractures because of its inability to satisfy these treatment requirements. Additionally, the thin skin and bony prominences of sighthound breeds make them particularly prone to soft tissue complications. <\/span><\/p>\n

Additional Considerations for Growing Animals<\/h3>\n

Rapidly healing fractures are most suitable for cast\/splint treatment, and fracture healing is most rapid in young, healthy animals with only minor disruption of regional soft tissue health. However, casting duration should be kept to a minimum in animals aged <6 months due to the bones of young animals shaping and developing in response to the forces placed on them. Casts do not permit normal physiological weight-bearing forces in the limb and can therefore interfere with normal bony shaping and development, leading to issues such as patellar luxation (due to shallow trochlear groove development) and hip dysplasia (due to poor development of acetabular depth). <\/span><\/p>\n

Casts should be molded such that normal limb contours are preserved. Cast application with the limb held in firm traction is a common error that causes the limb to be too extended; it is especially important to avoid this in the hindlimbs of growing animals. <\/span><\/p>\n

Closed Fracture Reduction Techniques for Use With Coaptation<\/h2>\n

Greenstick fractures and fractures with an intact adjacent bone are often minimally displaced and may not require specific reduction techniques. In contrast, complete transverse fractures are frequently displaced with angulation and may be overridden. If significant soft tissue swelling is present, initial temporary immobilization with a Robert Jones bandage for the first 24 hours can facilitate fracture reduction and improve subsequent cast conformation. When the configuration and displacement of the fracture require closed reduction, general anesthesia is typically required. While limb traction via suspension of the limb (to the point of gentle regional trunk elevation) can help fatigue the patient\u2019s muscles and stretch regional periosteum\/soft callus, it is seldom sufficient, by itself, to permit adequate fracture reduction. For a step-by-step description of coaptation for temporary first aid immobilization, including placement of a Robert Jones bandage, please see part 1 of this article at <\/span>todaysveterinarypractice.com\/temporary-immobilization-of-limb-fractures<\/span><\/a>.<\/span><\/p>\n

When angulation is present, the periosteum is often completely disrupted on the convex side of the angulated limb, but it may be preserved on the concave side of the limb. Frequently, the direction of angulation is caused by muscular dominance on the concave side; for example, valgus angulation of complete tibia\/fibula fractures is common because the muscles on the tibia\u2019s lateral side are dominant (FIGURE<\/b><\/span><\/span>\u00a02<\/b><\/span>).<\/span><\/p>\n

\"FigureFigure 2. (A) Normal relationship of muscle and intact bone in canine lower leg (cranial view).<\/span><\/a><\/div>
\"FigureFigure 2. (B) In the case of fracture, bony angulation is often in the direction of muscular dominance. Taut musculature and intact periosteum on the concave side of the angulation must be overcome to accomplish fracture reduction and alignment.<\/span><\/a><\/div>
\"FigureFigure 2. (C) Increasing the bony angulation to relax the tension in the soft tissues allows the fracture ends to be brought into contact with each other.<\/span><\/a><\/div>
\"FigureFigure 2. (D) The cortical contact of the fractured ends at the concave surface works as a hinge about which steady 4-point bending in the direction of the arrows can be used to slowly improve angulation as the musculature is stretched.<\/span><\/a><\/div>
\"FigureFigure 2. (E) The 4-point bending process is continued slowly to progressively restore fracture reduction until (F) bony alignment is achieved.<\/span><\/a><\/div>
\"FigureFigure 2. (F) Bony alignment is achieved. Illustrations: Kip Carter (6)<\/span><\/a><\/div>
<\/div><\/div>\n

Lateral muscle spasm and lateral bridging periosteal sleeve prevent pure longitudinal limb traction from achieving fracture alignment. Tension in these lateral bridging tissues can, first, be relaxed by exaggerating the angulation toward the concave side, often to 90\u00b0 or more (\u201cyou must make the fracture worse before you make it better<\/i>\u201d). The fractured bone ends can then be manipulated until they come in contact with one another. The cortical contact of the fractured ends at the concave margin serves as a hinge about which slow, progressive, 4-point bending using the bone segments as levers to stretch the contracted soft tissues gradually restores bony alignment (FIGURE<\/b><\/span><\/span>\u00a02<\/b><\/span>).<\/span><\/p>\n

Cast Application Technique for Definitive Fracture Treatment<\/h2>\n

The patient is typically under general anesthesia if closed reduction techniques are used; sedation may be feasible in instances of incomplete fracture or fracture with intact adjacent bone because these fractures are inherently more stable and often well reduced, and the patient is typically more comfortable. <\/span><\/p>\n

At least one assistant is necessary to support the limb. For relatively unstable complete fractures, one assistant may be required for limb support and another for traction on the stirrups and bandaging assistance. Most fractures tend to deviate toward valgus angulation because the fracture zone is mistakenly allowed to sag medially while upward tension is mistakenly applied to the stirrups. The assistant must be trained to always support the fracture zone and avoid upward deviation of the distal limb segment throughout the casting process.<\/span><\/p>\n

The following step-by-step description assumes that a cast is being applied to a relatively unstable complete fracture that has been reduced as illustrated in FIGURE<\/b><\/span><\/span>\u00a02<\/b><\/span>. (Supplies needed for the cast application are listed in <\/span>BOX 1<\/b><\/span>.)<\/span><\/p>\n

BOX 1 Casting Supplies<\/div>
<\/p>\n