Symposium on the Management of Limb Fractures in Small Animals
Principles and Application of Plaster Casts R. Bruce Hahn, D.V.M.*
Although in the last decade, newer mechanically sound methods of internal fixation of fractures have been popularized,4 • 5 the surgeon must not lose sight of the importance of closed manipulative reduction and external fixation of selected fractures. Excellent stabilization of fractures below the elbow and stifle in small animals with properly applied plaster of Paris casts is possible to achieve and often obviates the disadvantages of operative infection and expensive surgical implants and procedures. While other methods of external fixation are available,3 plaster casts are readily accessible because the materials are easily stored, and in the experienced surgeon's hands they may be quickly applied and worn by the patient with little discomfort. Failures with such conservative treatment can usually be traced to inadequate plaster techniques. As Charnley has stated, "A good manipulative reduction is often allowed to slip during the clumsy application of plaster. The surgeon who aspires to skill in the conservative method must subject himself to a long apprenticeship in plastercraft." 1 INDICATIONS FOR USE External fixation of fractures requires adequate reduction and stability of the fracture. Plaster casts are no exception. While most surgeons prefer to use casts only on closed fractures, they may be applied following open reduction of either an open or closed fracture. However, if surgery is necessary for reduction, then internal fixation techniques 4 • 5 usually provide more rigid stabilization and earlier return of normal function. Long leg plaster casts are best suited to fractures below the elbow *Professor of Orthopedic Surgery, Department of Veterinary Clinical Sciences, Ohio State University College of Veterinary Medicine, Columbus, Ohio Veterinary Clinics of North America- Vol. 5, No.2, May 1975
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and stifle. The principle of immobilizing the joint above and below the fracture should be followed in most cases. Therefore fractures of the humerus and femur require a spica cast enclosing the shoulder or the hip as the case may be. Spicas are not well suited for animals because they are too restrictive and most animals are not able to arise without assistance. Incomplete (greenstick) fractures, transverse fractures of the shaft that can be reduced, closed, or spinal and oblique fractures that are relatively stable after reduction because of the serrated edges may be adequately immobilized with a properly applied cast. Fractures of the distal tarsal and carpal bones where motion is limited or more distal fractures of the metacarpals, metatarsals, and phalanges may also be stabilized with plaster. Plaster casts are not indicated for fractures of the olecranon or tuber calcis because of traction and subsequent displacement as a result of muscle pull. Comminuted shaft fractures where the periosteal sleeve is holding the fragments in good position may often be quite adequately immobilized with a plaster cast, especially in young animals where the rate of healing may be faster. Casts may be easily molded and positioned so as to correct for axial deformities or to compensate for anticipated growth plate problems, such as radial and ulnar fractures in growing dogs where the limb may be cast in varus to compensate for premature closure of the distal ulnar growth plate. Where additional change in axial alignment is necessary following application, the cast may be cut on one side and wedged into proper position and fixed with additional plaster. Full body casts are indicated in certain cases of spinal fractures or dislocation where open reduction and decompression is not necessary.
COMPOSITION AND MATERIALS Plaster of paris is manufactured from a solid crystalline material known as gypsum or calcium sulfate dihydrate. This material is pulverized to break up the crystals and then subjected to intense heat to drive out most of the inherent water of crystallization. When water is added to plaster the above reaction reverses. After the cast sets, the excess water must vaporize from the surface before the cast attains maximal strength; thus it is important not to stress a cast too early. Animals may be confined in the cage overnight to allow the cast to harden. This permits examination of the toes after 24 hours to assure there is no circulatory interference. The setting time of plaster is measured from the point at which the plaster is wetted to the point at which the cast becomes hard. This time
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is controlled by the type of plaster used- fast setting (five to eight minutes) or extra fast setting (two to four minutes), the temperature of the water (the warmer the water the faster the reaction), and the amount of water left in the plaster roll. In animals it is best to utilize general anesthesia and a slower setting plaster. This facilitates an easier and smoother application of the cast and allows time for molding. Cast strength necessary is dependent on the weight of the animal. The smallest possible amount of plaster should be used. Plaster splints incorporated into the several layers of the cast increase strength in the stress lines without greatly increasing the weight of the cast. Also resin-plaster bandages (e.g., Johnson and johnson's Zoroc*) are stronger and allow for a lighter cast with optimal strength. Casts that are overly thick are to be avoided, and the cast should be applied evenly and smoothly. The materials necessary for proper plaster cast application illustrated in Figure 1 are adhesive tape, cast padding,* stockinette, Zoroc plaster rolls,* and plaster splints.* The latter are impregnated more heavily with plaster of Paris to add additional strength in regions of stress. '{hese materials come in various widths for use according to the size of the limb.
TYPES OF CASTS AND THEIR APPLICATION While unpadded plaster casts were strongly advocated by Bohler in man,1 and by Jenny2 in animals, a lightly, evenly padded plaster is preferable in small animals. A layer of rolled cast padding* is interposed between the stockinette over the skin and the plaster, which is then firmly compressed against the limb by applying the wet plaster bandage under tension. The cast padding actually enhances the fixation of the fracture by compensating for slight tissue shrinkage after application of the cast. This type of cast appears to afford more comfort and avoids skin irritation. Application of excessive cast padding, however, will permit motion within the cast and may actually result in ulceration from a loose cast moving on a pressure point, e.g., the olecranon. Also secure conformation of the plaster to the tissues may be prevented with the overly padded cast. Bulk cotton should never be used for padding because its bulk presents difficulty in effecting even application. Palpation of the fracture and radiographic examination set the stage for cast application. The fracture must be subject to manipulative reduction and located where the cast will maximize immobilization. General anesthesia is usually necessary for adequate reduction and cast application, allowing time for the plaster to set before motion is *Johnson and Johnson, New Brunswick, New Jersey.
Figure l. The limb is exposed and the remainder of the body draped to protect the hair coat from excess plaster, with the tape strips in place. Note the plaster splints on the left and the stockinette, cast padding, and rolled plaster ready on the r igh t.
Figure 2. The stockinette rolled up over the limb.
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restored. The dog is covered with a paper drape to prevent soiling of the hair coat with dripping from the plaster during application. A strip of adhesive tape is fixed to the limb medially and laterally and the tape end is applied to a piece of tongue blade distal to the paw to facilitate separation later (Fig. 1). A stockinette is rolled up over the total limb (Fig. 2) and held by an assistant at either end. This will support the leg and permit fracture reduction and stabilization while the cast is being applied. The cast padding is then applied beginning at the toes (Fig. 3). A single roll, overlapping half of the width, is generally adequate. Pressure points such as the condyles may be padded with an extra piece or two. Beginning at the end of the second and fifth digits leaving the end of the second and aJl , of the third phalanges of the third and fourth digits exposed, the plaster of Paris (preferably resin-impregnated) is rolled up the leg overlapping half the width of the plaster. The roll of plaster remains in contact with the surface of the limb almost continuously and is pressed and pushed around the limb by the pressure of the surgeon's thenar eminence at the middle of the width of the bandage
Figure 3. The stre tched stockin ette holds the limb in normal position while the cast padding is app lied.
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firmly positiOning each turn of the plaster roll. At tapering parts of the limb the turns are made to lie evenly by taking small tucks and smoothing them into position. Above the elbow and the stifle the plaster roll is pulled very tight to prevent a loose cast in this conical fleshy area, thus preventing the "Wellington boot" effect at the top of the cast (Fig. 4). The cast should be applied high in the axilla or groin. The plaster splints are manufactured in 3, 4, and 5 inch widths. For small animals the narrowe r splint folded in h alf lengthwise to create a 6 to 8 sheet thickness should be precut to the correct length for the cast (Fig. 1). After applying the first roll of plaster, two splints, folded as shown on the left in Figure 1, are moistened and applied anteriorly and posteriorly (Fig. 5), a nd laminated manually to th e plaster below. Desired angulation of the involved j oints should be done at this time. Another roll of plaster is then applied, starting as before at the toes, very firmly around the limb molding each turn securely to the layers beneath (Fig. 6). Constant smoothing and pressing movements with the free hand are essential to lamination of all the plaster layers. In very large dogs a third layer of plaster may be rolled on for addi-
Figure 4. The plaster roll is applied firmly especially above the elbow o r stifle.
PLASTER CASTS
Figure 5. Application of the plaster splints is effected anteriorly and posteriorly to provide extra strength along the stress lines but with less bulk.
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Figure 6. The second toll of p laster is applied to bind the splints firmly to the first layer of plaster.
tiona! strength, bearing in mind that sufficient strength but not extr a weight is the goal. While the cast is setting, continuous molding movements with wet hands should be done to properly fit the cast to the limb and also to make any corrections in alignment, rotation, and joint angulation (Fig. 7). T he su rgeon can feel the cast begin to set. T he limb should then be held in the desired position until the cast has set sufficiently. After the plaster is firm the stockinette o n each end is turned back on the cast and trimmed to two inches in width. The two pieces of tape over the toes are separated and turned back over the stockinette on the cast. The excess tape is trimmed one to two inches long and secured to the cast with a plaster splint (Fig. 8). The stockinette at the proximal end is fixed to the cast in the same manner. Using additional warm water the surface of the cast should be rubbed so that it is smooth enough to accept the signatures of the family and inte rested friends (Fig. 9). While the animal is in the hospital it is best to cover the cast with stockinette to prevent soiling. This should be removed prior to disch arge from the hospital the following day. It
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Figure 7. The cast is molded to the limb with wet hands while h olding the limb in the desired position of reduction and function.
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Figure 8.
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A plaster strip incorporates th e ta pe a nd stockinette to the cast distally.
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Figure 9. Note the smooth surface of the finished cast, the high tight fit of the cast proximally, and the amount of toe protruding distally.
has been my practice not to send patients home the day of cast application. If the cast is too tight or otherwise does not fit properly, as evidenced by swollen toes, chewing, etc., it should be apparent by the following day and a new cast may be desirable. Post reduction and cast application radiographs should always be taken for evaluation and as a matter of record.
MANAGEMENT AND COMPLICATIONS Ambulation of the patient with a limb cast should not present a problem if the cast has been properly applied. A plastic cover should be
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placed over the cast when the cast is exposed to dampness. This is especially important in the first 48 hours while the plaster is "curing." The cast on an outpatient should be checked every two to three weeks especially in a young growing animal or when the owner is not conscientious about checking the cast. Palpation of the exposed toes signifies the overall limb circulation. The latter is extremely important because of the ever present possibility of swelling with subsequent circulatory impairment and eventual gangrene. Careful and regular observation easily prevents this disaster. If a cast becomes too loose from muscle atrophy or reduction of edema, it should be replaced, as should a broken cast. Animals that chew excessively at one or more points on a cast usually do so because it is uncomfortable or perhaps has loosened so that motion and subsequent ulceration is occurring. Such a cast should be removed and the limb recast. Periodic radiographic examination, first at two weeks postoperatively, the n every three to four weeks, should be done to assure that normal healing is progressing. A properly applied plaster cast should demonstrate an even thickness of the cast from e nd to end and it should conform closely to the limb throughout. Except for circulatory or other soft tissue problems or external mutilation or fracture , the cast should not be removed until the fracture is radiographically healed. Numerous cast changes coupled with manipulatory examination often lead to nonunion. Cast removal is facilitated
Figure 10. T his cast by is r e moved by making two lo n gitudinal cuts with an oscillating power saw.
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with a Stryker* oscillating cast cutter (Fig. 10). The cast should be split longitudinally on either side and the two half-shells carefully removed. Windowing of plaster casts generally is to be avoided because of the danger of edematous tissue herniating through the window. Limbs with open fractures or badly infected wounds are probably best treated locally and the fracture stabilized temporarily with a Robert Jones dressing, Schroeder-Thomas splint, Kirschner apparatus, or some other type of fixation. The cast may be applied when infection and drainage are under control. The plaster of Paris cast is a valuable adjunct to fracture treatment of lower limb injuries in animals. Materials are easily stored and readily accessible. Application of the cast can and should be done quickly not only to facilitate complete lamination of the plaster layers but also for the patient's welfare and conservation of the surgeon's time. *Johnson and Johnson, New Brunswick, New Jersey.
REFERENCES 1. Charnley, J.: The Closed Treatment of Common Fractures. Edition 3. Baltimore, Williams and Wilkins Co., 1963. 2. Jenny, J.: Personal communication. 3. Leonard, E. P.: Orthopedic Surgery of the Dog and Cat. Philadelphia, W. B. Saunders Co., 1971 4. Muller, M. E., Allgower, M., and Willenegger, H.: The Technique of Internal Fixation of Fractures. New York, Springer-Verlag, 1965. 5. Muller, M. E., Allgower, M., and Willenegger, H.: Manual of Internal Fixation. New York, Springer-Verlag, 1970.
Department of Veterinary Clinical Sciences Ohio State University College of Veterinary Medicine 1935 Coffey Road Columbus, Ohio 43210
Principles and Application of Plaster Casts R. Bruce Hahn, D.V.M.*
Although in the last decade, newer mechanically sound methods of internal fixation of fractures have been popularized,4 • 5 the surgeon must not lose sight of the importance of closed manipulative reduction and external fixation of selected fractures. Excellent stabilization of fractures below the elbow and stifle in small animals with properly applied plaster of Paris casts is possible to achieve and often obviates the disadvantages of operative infection and expensive surgical implants and procedures. While other methods of external fixation are available,3 plaster casts are readily accessible because the materials are easily stored, and in the experienced surgeon's hands they may be quickly applied and worn by the patient with little discomfort. Failures with such conservative treatment can usually be traced to inadequate plaster techniques. As Charnley has stated, "A good manipulative reduction is often allowed to slip during the clumsy application of plaster. The surgeon who aspires to skill in the conservative method must subject himself to a long apprenticeship in plastercraft." 1 INDICATIONS FOR USE External fixation of fractures requires adequate reduction and stability of the fracture. Plaster casts are no exception. While most surgeons prefer to use casts only on closed fractures, they may be applied following open reduction of either an open or closed fracture. However, if surgery is necessary for reduction, then internal fixation techniques 4 • 5 usually provide more rigid stabilization and earlier return of normal function. Long leg plaster casts are best suited to fractures below the elbow *Professor of Orthopedic Surgery, Department of Veterinary Clinical Sciences, Ohio State University College of Veterinary Medicine, Columbus, Ohio Veterinary Clinics of North America- Vol. 5, No.2, May 1975
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and stifle. The principle of immobilizing the joint above and below the fracture should be followed in most cases. Therefore fractures of the humerus and femur require a spica cast enclosing the shoulder or the hip as the case may be. Spicas are not well suited for animals because they are too restrictive and most animals are not able to arise without assistance. Incomplete (greenstick) fractures, transverse fractures of the shaft that can be reduced, closed, or spinal and oblique fractures that are relatively stable after reduction because of the serrated edges may be adequately immobilized with a properly applied cast. Fractures of the distal tarsal and carpal bones where motion is limited or more distal fractures of the metacarpals, metatarsals, and phalanges may also be stabilized with plaster. Plaster casts are not indicated for fractures of the olecranon or tuber calcis because of traction and subsequent displacement as a result of muscle pull. Comminuted shaft fractures where the periosteal sleeve is holding the fragments in good position may often be quite adequately immobilized with a plaster cast, especially in young animals where the rate of healing may be faster. Casts may be easily molded and positioned so as to correct for axial deformities or to compensate for anticipated growth plate problems, such as radial and ulnar fractures in growing dogs where the limb may be cast in varus to compensate for premature closure of the distal ulnar growth plate. Where additional change in axial alignment is necessary following application, the cast may be cut on one side and wedged into proper position and fixed with additional plaster. Full body casts are indicated in certain cases of spinal fractures or dislocation where open reduction and decompression is not necessary.
COMPOSITION AND MATERIALS Plaster of paris is manufactured from a solid crystalline material known as gypsum or calcium sulfate dihydrate. This material is pulverized to break up the crystals and then subjected to intense heat to drive out most of the inherent water of crystallization. When water is added to plaster the above reaction reverses. After the cast sets, the excess water must vaporize from the surface before the cast attains maximal strength; thus it is important not to stress a cast too early. Animals may be confined in the cage overnight to allow the cast to harden. This permits examination of the toes after 24 hours to assure there is no circulatory interference. The setting time of plaster is measured from the point at which the plaster is wetted to the point at which the cast becomes hard. This time
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is controlled by the type of plaster used- fast setting (five to eight minutes) or extra fast setting (two to four minutes), the temperature of the water (the warmer the water the faster the reaction), and the amount of water left in the plaster roll. In animals it is best to utilize general anesthesia and a slower setting plaster. This facilitates an easier and smoother application of the cast and allows time for molding. Cast strength necessary is dependent on the weight of the animal. The smallest possible amount of plaster should be used. Plaster splints incorporated into the several layers of the cast increase strength in the stress lines without greatly increasing the weight of the cast. Also resin-plaster bandages (e.g., Johnson and johnson's Zoroc*) are stronger and allow for a lighter cast with optimal strength. Casts that are overly thick are to be avoided, and the cast should be applied evenly and smoothly. The materials necessary for proper plaster cast application illustrated in Figure 1 are adhesive tape, cast padding,* stockinette, Zoroc plaster rolls,* and plaster splints.* The latter are impregnated more heavily with plaster of Paris to add additional strength in regions of stress. '{hese materials come in various widths for use according to the size of the limb.
TYPES OF CASTS AND THEIR APPLICATION While unpadded plaster casts were strongly advocated by Bohler in man,1 and by Jenny2 in animals, a lightly, evenly padded plaster is preferable in small animals. A layer of rolled cast padding* is interposed between the stockinette over the skin and the plaster, which is then firmly compressed against the limb by applying the wet plaster bandage under tension. The cast padding actually enhances the fixation of the fracture by compensating for slight tissue shrinkage after application of the cast. This type of cast appears to afford more comfort and avoids skin irritation. Application of excessive cast padding, however, will permit motion within the cast and may actually result in ulceration from a loose cast moving on a pressure point, e.g., the olecranon. Also secure conformation of the plaster to the tissues may be prevented with the overly padded cast. Bulk cotton should never be used for padding because its bulk presents difficulty in effecting even application. Palpation of the fracture and radiographic examination set the stage for cast application. The fracture must be subject to manipulative reduction and located where the cast will maximize immobilization. General anesthesia is usually necessary for adequate reduction and cast application, allowing time for the plaster to set before motion is *Johnson and Johnson, New Brunswick, New Jersey.
Figure l. The limb is exposed and the remainder of the body draped to protect the hair coat from excess plaster, with the tape strips in place. Note the plaster splints on the left and the stockinette, cast padding, and rolled plaster ready on the r igh t.
Figure 2. The stockinette rolled up over the limb.
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restored. The dog is covered with a paper drape to prevent soiling of the hair coat with dripping from the plaster during application. A strip of adhesive tape is fixed to the limb medially and laterally and the tape end is applied to a piece of tongue blade distal to the paw to facilitate separation later (Fig. 1). A stockinette is rolled up over the total limb (Fig. 2) and held by an assistant at either end. This will support the leg and permit fracture reduction and stabilization while the cast is being applied. The cast padding is then applied beginning at the toes (Fig. 3). A single roll, overlapping half of the width, is generally adequate. Pressure points such as the condyles may be padded with an extra piece or two. Beginning at the end of the second and fifth digits leaving the end of the second and aJl , of the third phalanges of the third and fourth digits exposed, the plaster of Paris (preferably resin-impregnated) is rolled up the leg overlapping half the width of the plaster. The roll of plaster remains in contact with the surface of the limb almost continuously and is pressed and pushed around the limb by the pressure of the surgeon's thenar eminence at the middle of the width of the bandage
Figure 3. The stre tched stockin ette holds the limb in normal position while the cast padding is app lied.
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firmly positiOning each turn of the plaster roll. At tapering parts of the limb the turns are made to lie evenly by taking small tucks and smoothing them into position. Above the elbow and the stifle the plaster roll is pulled very tight to prevent a loose cast in this conical fleshy area, thus preventing the "Wellington boot" effect at the top of the cast (Fig. 4). The cast should be applied high in the axilla or groin. The plaster splints are manufactured in 3, 4, and 5 inch widths. For small animals the narrowe r splint folded in h alf lengthwise to create a 6 to 8 sheet thickness should be precut to the correct length for the cast (Fig. 1). After applying the first roll of plaster, two splints, folded as shown on the left in Figure 1, are moistened and applied anteriorly and posteriorly (Fig. 5), a nd laminated manually to th e plaster below. Desired angulation of the involved j oints should be done at this time. Another roll of plaster is then applied, starting as before at the toes, very firmly around the limb molding each turn securely to the layers beneath (Fig. 6). Constant smoothing and pressing movements with the free hand are essential to lamination of all the plaster layers. In very large dogs a third layer of plaster may be rolled on for addi-
Figure 4. The plaster roll is applied firmly especially above the elbow o r stifle.
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Figure 5. Application of the plaster splints is effected anteriorly and posteriorly to provide extra strength along the stress lines but with less bulk.
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Figure 6. The second toll of p laster is applied to bind the splints firmly to the first layer of plaster.
tiona! strength, bearing in mind that sufficient strength but not extr a weight is the goal. While the cast is setting, continuous molding movements with wet hands should be done to properly fit the cast to the limb and also to make any corrections in alignment, rotation, and joint angulation (Fig. 7). T he su rgeon can feel the cast begin to set. T he limb should then be held in the desired position until the cast has set sufficiently. After the plaster is firm the stockinette o n each end is turned back on the cast and trimmed to two inches in width. The two pieces of tape over the toes are separated and turned back over the stockinette on the cast. The excess tape is trimmed one to two inches long and secured to the cast with a plaster splint (Fig. 8). The stockinette at the proximal end is fixed to the cast in the same manner. Using additional warm water the surface of the cast should be rubbed so that it is smooth enough to accept the signatures of the family and inte rested friends (Fig. 9). While the animal is in the hospital it is best to cover the cast with stockinette to prevent soiling. This should be removed prior to disch arge from the hospital the following day. It
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Figure 7. The cast is molded to the limb with wet hands while h olding the limb in the desired position of reduction and function.
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Figure 8.
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A plaster strip incorporates th e ta pe a nd stockinette to the cast distally.
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Figure 9. Note the smooth surface of the finished cast, the high tight fit of the cast proximally, and the amount of toe protruding distally.
has been my practice not to send patients home the day of cast application. If the cast is too tight or otherwise does not fit properly, as evidenced by swollen toes, chewing, etc., it should be apparent by the following day and a new cast may be desirable. Post reduction and cast application radiographs should always be taken for evaluation and as a matter of record.
MANAGEMENT AND COMPLICATIONS Ambulation of the patient with a limb cast should not present a problem if the cast has been properly applied. A plastic cover should be
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placed over the cast when the cast is exposed to dampness. This is especially important in the first 48 hours while the plaster is "curing." The cast on an outpatient should be checked every two to three weeks especially in a young growing animal or when the owner is not conscientious about checking the cast. Palpation of the exposed toes signifies the overall limb circulation. The latter is extremely important because of the ever present possibility of swelling with subsequent circulatory impairment and eventual gangrene. Careful and regular observation easily prevents this disaster. If a cast becomes too loose from muscle atrophy or reduction of edema, it should be replaced, as should a broken cast. Animals that chew excessively at one or more points on a cast usually do so because it is uncomfortable or perhaps has loosened so that motion and subsequent ulceration is occurring. Such a cast should be removed and the limb recast. Periodic radiographic examination, first at two weeks postoperatively, the n every three to four weeks, should be done to assure that normal healing is progressing. A properly applied plaster cast should demonstrate an even thickness of the cast from e nd to end and it should conform closely to the limb throughout. Except for circulatory or other soft tissue problems or external mutilation or fracture , the cast should not be removed until the fracture is radiographically healed. Numerous cast changes coupled with manipulatory examination often lead to nonunion. Cast removal is facilitated
Figure 10. T his cast by is r e moved by making two lo n gitudinal cuts with an oscillating power saw.
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with a Stryker* oscillating cast cutter (Fig. 10). The cast should be split longitudinally on either side and the two half-shells carefully removed. Windowing of plaster casts generally is to be avoided because of the danger of edematous tissue herniating through the window. Limbs with open fractures or badly infected wounds are probably best treated locally and the fracture stabilized temporarily with a Robert Jones dressing, Schroeder-Thomas splint, Kirschner apparatus, or some other type of fixation. The cast may be applied when infection and drainage are under control. The plaster of Paris cast is a valuable adjunct to fracture treatment of lower limb injuries in animals. Materials are easily stored and readily accessible. Application of the cast can and should be done quickly not only to facilitate complete lamination of the plaster layers but also for the patient's welfare and conservation of the surgeon's time. *Johnson and Johnson, New Brunswick, New Jersey.
REFERENCES 1. Charnley, J.: The Closed Treatment of Common Fractures. Edition 3. Baltimore, Williams and Wilkins Co., 1963. 2. Jenny, J.: Personal communication. 3. Leonard, E. P.: Orthopedic Surgery of the Dog and Cat. Philadelphia, W. B. Saunders Co., 1971 4. Muller, M. E., Allgower, M., and Willenegger, H.: The Technique of Internal Fixation of Fractures. New York, Springer-Verlag, 1965. 5. Muller, M. E., Allgower, M., and Willenegger, H.: Manual of Internal Fixation. New York, Springer-Verlag, 1970.
Department of Veterinary Clinical Sciences Ohio State University College of Veterinary Medicine 1935 Coffey Road Columbus, Ohio 43210
