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Equine femoral fracture repair: A case report
EQUINE FEMORAL FRACTURE REPAIR: A CASE REPORT C.H. Boulton, DVM and M.J. Dallman, DVM, PhD
SUMMARY A case report of successful femoral fracture repair in a foal is presented. The repair utilized a single DCP plate (Dynamic Compression Plate) and two additional screws placed in lag fashion.
presence of a closed, two piece, long oblique midshaft fracture with cranial and dorsolateral displacement (Figure 1).
INTRODUCTION One of the largest nemeses in equine veterinary surgery is the long bone fracture. Although significant achievements have been made through the advancement of internal fixation, the stress placed upon the repaired bone by muscular activity and movement often exceed the limits of our t e c h n o l o g y and strength of o u r implants. If advancements in fracture repair are to be made, the limits and strengths of available implants must be meticulously explored. The following case illustrates a compromise of currently proposed technical guidelines which still resulted in successful fracture repair. Case History and Findings
During the summer of 1981 a 10 year old Arabian mare and 5 week old (60 kg) filly were referred to the U MC Middlebush Equine Center. The filly had been nonweightbearing in the right rear leg for 2 days. The referring veterinarian suspected a femoral fracture. Physical examination revealed an intact integument with tense soft tissue swelling of the right quadriceps femoris muscle. Upon manipulation, crepitation and rotary instability were noted in the femoral area. Vital signs, appetite, and attitude were judged to be within normal limits. The foal could rise and nurse unassisted, but knuckling of the fetlock was noticed with repeated attempts to use the leg. No neurologic deficits in skin sensation were noted. Radiographs of the right femur confirmed the Authors' address: College of Veterinary Medicine Department of Veterinary Medicine and Surgery University of Missouri-Columbia Columbia, MO 65211 60
Figure 1. Admitting radiograph illustrates midshaft fracture of the right femur. The proximal fragment is longest on the caudal and lateral aspect. Notice that the fracture extends through the nutrient foramen. EQUINE VETERINARY SCIENCE
The owners were apprised of these findings and informed of the possible treatments. A decision to attempt repair through internal fixation was reached based upon the value of the filly and predicted use.
Surgical T e c h n i q u e s Prior to surgery the surgical site was clipped and scrubbed with povidone-iodine soap a and the filly was started on !.76 m g / k g of gentomycin b I M T I D and 20,000 I U / K g of procaine penicillin c BID. Tetanus prophylaxis was provided with tetanus t o x o i d and antitoxin. Anesthesia was induced with a halothaneo x y g e n c o m b i n a t i o n d e l i v e r e d via f a c e m a s k a n d continued t h r o u g h endotracheal intubation. Positivepressure ventilation was provided with a h u m a n gas a n e s t h e t i c unit d a n d m a n u a l c o m p r e s s i o n o f the rebreathing bag. The horse was positioned in left lateral recumbency. Padding and support of the recumbent horse was achieved with a partially inflated rubber air bag. The surgical site was scrubbed with povidone-iodine soap, sprayed with alcohol, and then sprayed with povidone solution. Aseptic technique was utilized. The body and limb were draped with water-resistant paper drapes, e A 35 cm curvilinear skin incision was made along the lateral aspect of the femur, as described by Milne and Turner, 5 and was followed by a facial incision between the biceps femoris and superficial gluteal muscles proximally and the biceps femoris and tensor fasciae latae muscles distally. Further exposure was achieved by severing the femoral a t t a c h m e n t of the superficial gluteal muscle at the trochanteric tertius and partially elevating the origin of the gastrocnemius muscle. The fracture was reduced by toggling the fragments while exerting a distracting rotary force on the distal leg. Reduction was maintained with verbrugge forceps and two l m m cerclage wires until a more rigid fixation could be completed. A broad 8 hole Dynamic C o m p r e s s i o n Plate ( D C P ) f was placed on the cranio-lateral tension s u r f a c e o f the f e m u r a n d a p p l i e d by t h e A S I F ( A s s o c i a t i o n for the S t u d y of I n t e r n a l F i x a t i o n ) compression system.~ 6 Additionally, two A S I F cortical screws were placed in lag fashion through the cranial and caudal cortices to provide interfragmentary compression utilizing H o h m a n retracters to protect the lateral and anterior musculature (Figures 2 and 3). A continuous suction drain g was inserted and the a Prepodyne Solution and Scrub. West Chemical Products Inc., 8 Fycer St., Lynbrook, NY 11563. bGentocin®. Schering Corporation, Kenilworth, NJ 07033. CProcaine Penicillin G. Pfizer, Inc., New York, NY 10017. dHeidbrink®. Kinet-O-Meter® Model 2128. Ohio Chemical and Surgical Equipment Co., Madison, Wisconsin, equipped with a Fluotec 3 Vaporizer. Distributed by Fraser Sweatman, Inc., NY 14086. eDrape fabric. Cleveland Cotton Products, Box 6500, Cleveland, OH 44101. fSynthes®. L T D (USA), 997 Old Eagle School Road, Wayne, PA 19087. ~Redivacette System No. 623518. Orthopedic Equipment Inc., Bourbon, IN 46504. Volume 3, Number 2
Figure 2. Twelve days postoperative lateral radiograph illustrating fixation.
lateral femoral fascia was sutured with O polyglycolic acid suture" in a horizontal mattress pattern. The subcutaneous tissue was apposed with a continuous pattern of O polyglycolic acid and the skin was closed in an alternating pattern of vertical mattress and simple interrupted sutures of #l teflon impregnated braided polyester) The surgical site was then covered with a sterile bandage which was maintained until suture removal. No additional (external) support was added to the fixation. Both the mare and foal were confined to a boxstall postoperatively. Six hours after recovery, the foal was placing a small a m o u n t of weight u p o n the leg and 24 hours postoperatively, the foal was nursing and walking stiffly upon the leg. By 48 hours after surgery, the foal exhibited only slight lameness. Postoperative management consisted of confinement, monitoring of vital signs, prophylactic antibiotic therapy, monitoring of the suction drain, and culture of the drainage material. Drainage f r o m the surgical site was substantially reduced at 48 hours after surgery and the drain was removed at 72 hDexon®. Davis & Geck, Inc., Manati, Puerto Rico 00701 USA iTevdekll® Code #79-556. DeKnatel Division of Howmedica, Inc., Queens Village NY 11429.
61
Figure 3. Twelve days postoperative standing craniocaudal radiograph.
Figure 4. Six months postoperative lateral radiograph immediately prior to plate removal.
hours. On the 10th postoperative day alternate skin sutures were removed. The remainder were removed on the 12th day. At 12 and 28 days the repair was reassessed radiographically; no adverse findings were noticed. The foal was walking soundly and subsequently released at 28 days postoperatively. Discharge instructions consisted of 30 days continuous stall confinement followed by 30 to 60 days of limited exercise in a small paddock, which was to be g r a d u a l l y i n c r e a s e d with t i m e . A d d i t i o n a l recommendations called for a return in 6 months for reevaluation and possible removal of the fixation device.
revealed complete healing with minimal callus (Figure 4). Preparation of the surgical site was identical to the previous surgery. The anesthetic induction differed in that 1.1 mg/Kg xylazinei IV, followed by 2.2 m g / K g ketamine HCL k IV was administered. The lateral approach to the femur was repeated with minimal difficulty. Exposure allowed removal of the plate and proximal compression screw. The more distal screw was covered by callus preventing uncomplicated removal of the screw. A decision was made to not remove it or the cerclage wires. The surgical site was closed and drained as before. Drainage was considerably less than at the initial surgery a n d the a p p a r a t u s was r e m o v e d at 48 h o u r s postoperatively. The foal was w a l k i n g on the leg i m m e d i a t e l y postoperatively and was judged to ambulate normally 13 days later when skin sutures were removed. The foal was discharged and the owners were instructed to limit exercise to a small paddock for 30 days, to increase the
Plate Removal Re-evaluation of the foal 6 months after surgery revealed a sound gait at walk, trot, and lope. Growth of the foal was considerably below expectations. The poor growth was attributed to the stress of the fracture but more importantly to heavy parasitism, confirmed through coprology, and poor nutrition. Radiography of the fractured femur
62
JRompun®100 mg/ml. Haver-Lockhart, Bayvet Division, Cutter Laboratories, Inc. kVetalar® 100 mg/ml. Parke, Davis & Co., Detroit, MI 48232. EQUINE VETERINARY SCIENCE
nutritional plane of the foal, and to institute a regular d e w o r m i n g p r o g r a m . N o n o t i c e a b l e a t r o p h y or assymmetry was noted u p o n discharge or has been reported in the past 6 months. Subsequent g r o w t h of the foal was judged to be n o r m a l by the owner.
DISCUSSION Successful internal fixation of midshaft femoral fractures in the equine has been reported only four times in the American literature, 8 10 12 15 although the fracture is recognized to be relatively common. 2 3 4 Previous methods of repair have involved some form of external fixation a n d / o r stall confinement. 2 3 4 9 They have met with limited success when post~fracture athletic ability and conformation have been evaluated. Repair, utilizing internal fixation with intermedullary pins, has been reported once in a pony, 8 and once in a 7 day old foal, l° but generally there have been problems with migration and instability. 2 Successful repair of femoral fractures in the horse with rigid internal fixation of femoral fractures in the adult tends to present problems which exceed the strength of present implants while those of the foal offer more than an adequate challenge for most fixation devices. The suggestions of Turner ~3 and others for the use of a double plating technique for equine long bone fractures is sound advice. No such fracture should be approached without adequate planning to accomplish this goal, but the judgement of the surgeon during the procedure may circumvent the extra time and stress to the patient if careful evaluation of the fixation occurs at the completion of the first plate application. This evaluation must include a thorough and exact evaluation of the stability which has been achieved, and further, must anticipate the dynamic biomechanical forces to which the repair will be subjected. Knowledge of the types of instability which the fracture itself generates is important. It is doubtful that a single plate technique combined with intrafragmentary compression screws would offer sufficient stability to a transverse fracture of the femur, but it may be adequate for the long oblique fracture as illustrated in this patient. In this case, two of the screws holding the plate to the bone also crossed the fracture enabling the surgeons to accomplish interfragmentary compression of the fracture via the D C P plate and via the screws. The addition of two more screws placed in lag fashion through the cranial cortex and across the fracture added to the stability. The light weight and quiet attitude of the foal combined with the rigidity of the repair led to good bone healing. The presence of boney callus suggests that primary bone healing, which is the goal of the A S I F technique of plate application, did not occur, but sufficient stabilization was afforded to result in healing. Comparison with other reports does not indicate that any greater instability occurred at this fracture site than in other successful repairs. Critique of the repair suggests that it would have been preferrable to use a 10 or 12 hole D C P plate in place of the 8 hole plate. It has been reported that short plates may act as Volume 3, Number 2
stress inducers by concentrating forces of weightbearing at the ends of the plate rather than passing them to the ends o f the bone which are designed to handle those forces. 14 The use of a continuous suction drain was judged to be beneficial as evidenced by the uncomplicated healing of bone and skin. The presence of large seromas is known to delay healing and predispose fractures to infection. 16 The absence of a seroma and the constant microbial surveillance of the fracture offered by the culturing of suction products are important postoperative considerations. However, a s u c t i o n d r a i n c a n be a n e x c e e d i n g l y e x p e n s i v e consideration if adequate precautions are not taken to prevent contamination of the drain and retrograde infection of the fracture. Antimicrobial therapy was initiated prior to surgical intervention to obtain bacteriocidal levels of antibiotic within the surgical site and the postoperative hematoma. Due to the heavy environmental contamination of both gram (+) and gram (-) bacteria accompanying any stall environment, we chose to use broad spectrum antibiotics with proven efficacy against the most c o m m o n nosocomial bacteria in our hospital population. Removal of fixation devices after healing is indicated but not essential, r5 Those animals which are destined for an athletic career are susceptible to stress protection and possible refracture of the involved b o n e ) l Animals which are destined for the more sedentary life of the breeding farm may survive well without removal of the fixation devices. Removal was indicated in this case, due to the shortness of this plate. The most opportune time for plate removal in the horse is unknown and varies with respect to the rate of healing and the nature of the fracture itself. The only published guidelines available in the veterinary literature are those for small animals where a rough guideline of 6 months is made 7 if radiographic evidence of complete healing is present. The success of the veterinary surgeon in repair of equine l o n g b o n e f r a c t u r e s is d e p e n d e n t u p o n a d e q u a t e preparation and application of current techniques. Double plating of all long bone fractures in the horse is currently indicated with the realization that, in limited cases, exceptions to this general rule can be successfully made.
REFERENCES I. Allgower M., Mattler P., Perren S.M., Ruedi T.: The Dynamk" Compression Plate (DCP). Springer-Verlag, Berlin, Germany, 1973. 2. FesslerJ.F., Amstutz, H.E.: In Large AnimalSurgery Edited by F.W. Oheme and J.E. Prier. The Williams and Wilkins Company, Baltimore, MD, 1974 pp 321-24. 3. Lundvall R.L.: Observations on the Treatment of Fractures of the Long Bones in Large Animals. JA VMA 137:308-312, 1960. 4. Lundvall R.L.: In Equine Medicine and Surgery. Edited by E.J. Catcott and J.F. Smithcors. American Vet Publications Inc., Wheaton, ! L 1972, pp 877-878. 5. Milne D.W., Turner A.S.: An Atlas of Surgical Approaches to the Bones of the Horse. W.B. Saunders Co, Philadelphia, PA 1979,pp 154-59. 6. Mueller M.E., Allgower M., Willenegger H.: Manual of Internal Fixation. Springer-Verlag Publishers, Berlin, Germany, 1970. 7. Noser G.A., Brinker W.O., Little R.W., LammerdingJ.J.: Effectof Time on Strength of Healing Bone with Bone Plate Fixation. JAA HA 13:559-561, 1977. 63
8. Pettit G.D., Wheat J.D.: Fracture of the Femur in a Shetland Pony. JA VMA 138(1): 13-14, 1961. 9. Reichel E.C.: Treatment of Fractures of the Long Bones in Large Animals. JA VMA 129:8-15, 1956. 10. Stick J.A., Derksen F.J.: Intramedullary Pinning of a Fractured Femur in a Foal. JA VMA 176(7):627-629, 1980. 11. Tonino A.J., Davidson C.L., Klopper P.J., Linclau L.A.: Protection From Stress in Bone and Its Effects. J Bone and Joint Surgeo'. 58-B(I): 107-113, 1976. 12. Turner A.S.: Surgical Repair of a Fractured Femur ina Foal: A Case
64
Report. J Eq Meal & Surg 1:180-185, 1977. 13. Turner A.S., Bramlage L.R.: 12th Annual Basic Course Internal Fixation of Fractures and Non-Unions. Columbus, Ohio, March 1981. 14. Turner A.S., Milne D.W., Gabel A.A.: The Use of the Dynamic Compression Plate for Treatment of Equine Long-Bone Fractures. JA VMA 168:309-315, 1976. 15. Valdex H., Morris D.L., Auer J.A.: Compression Plating of Long Bone Fractures in Foals. J Vet Orth I(I): 10 18, 1979. 16. Waugh T.R., Stinchfield F.E.: Suction Drainage of Orthopaedic Wounds. J of Bone and Joint Surgery 43(7): 939-945, 1961.
EQUINE VETERINARY SCIENCE
SUMMARY A case report of successful femoral fracture repair in a foal is presented. The repair utilized a single DCP plate (Dynamic Compression Plate) and two additional screws placed in lag fashion.
presence of a closed, two piece, long oblique midshaft fracture with cranial and dorsolateral displacement (Figure 1).
INTRODUCTION One of the largest nemeses in equine veterinary surgery is the long bone fracture. Although significant achievements have been made through the advancement of internal fixation, the stress placed upon the repaired bone by muscular activity and movement often exceed the limits of our t e c h n o l o g y and strength of o u r implants. If advancements in fracture repair are to be made, the limits and strengths of available implants must be meticulously explored. The following case illustrates a compromise of currently proposed technical guidelines which still resulted in successful fracture repair. Case History and Findings
During the summer of 1981 a 10 year old Arabian mare and 5 week old (60 kg) filly were referred to the U MC Middlebush Equine Center. The filly had been nonweightbearing in the right rear leg for 2 days. The referring veterinarian suspected a femoral fracture. Physical examination revealed an intact integument with tense soft tissue swelling of the right quadriceps femoris muscle. Upon manipulation, crepitation and rotary instability were noted in the femoral area. Vital signs, appetite, and attitude were judged to be within normal limits. The foal could rise and nurse unassisted, but knuckling of the fetlock was noticed with repeated attempts to use the leg. No neurologic deficits in skin sensation were noted. Radiographs of the right femur confirmed the Authors' address: College of Veterinary Medicine Department of Veterinary Medicine and Surgery University of Missouri-Columbia Columbia, MO 65211 60
Figure 1. Admitting radiograph illustrates midshaft fracture of the right femur. The proximal fragment is longest on the caudal and lateral aspect. Notice that the fracture extends through the nutrient foramen. EQUINE VETERINARY SCIENCE
The owners were apprised of these findings and informed of the possible treatments. A decision to attempt repair through internal fixation was reached based upon the value of the filly and predicted use.
Surgical T e c h n i q u e s Prior to surgery the surgical site was clipped and scrubbed with povidone-iodine soap a and the filly was started on !.76 m g / k g of gentomycin b I M T I D and 20,000 I U / K g of procaine penicillin c BID. Tetanus prophylaxis was provided with tetanus t o x o i d and antitoxin. Anesthesia was induced with a halothaneo x y g e n c o m b i n a t i o n d e l i v e r e d via f a c e m a s k a n d continued t h r o u g h endotracheal intubation. Positivepressure ventilation was provided with a h u m a n gas a n e s t h e t i c unit d a n d m a n u a l c o m p r e s s i o n o f the rebreathing bag. The horse was positioned in left lateral recumbency. Padding and support of the recumbent horse was achieved with a partially inflated rubber air bag. The surgical site was scrubbed with povidone-iodine soap, sprayed with alcohol, and then sprayed with povidone solution. Aseptic technique was utilized. The body and limb were draped with water-resistant paper drapes, e A 35 cm curvilinear skin incision was made along the lateral aspect of the femur, as described by Milne and Turner, 5 and was followed by a facial incision between the biceps femoris and superficial gluteal muscles proximally and the biceps femoris and tensor fasciae latae muscles distally. Further exposure was achieved by severing the femoral a t t a c h m e n t of the superficial gluteal muscle at the trochanteric tertius and partially elevating the origin of the gastrocnemius muscle. The fracture was reduced by toggling the fragments while exerting a distracting rotary force on the distal leg. Reduction was maintained with verbrugge forceps and two l m m cerclage wires until a more rigid fixation could be completed. A broad 8 hole Dynamic C o m p r e s s i o n Plate ( D C P ) f was placed on the cranio-lateral tension s u r f a c e o f the f e m u r a n d a p p l i e d by t h e A S I F ( A s s o c i a t i o n for the S t u d y of I n t e r n a l F i x a t i o n ) compression system.~ 6 Additionally, two A S I F cortical screws were placed in lag fashion through the cranial and caudal cortices to provide interfragmentary compression utilizing H o h m a n retracters to protect the lateral and anterior musculature (Figures 2 and 3). A continuous suction drain g was inserted and the a Prepodyne Solution and Scrub. West Chemical Products Inc., 8 Fycer St., Lynbrook, NY 11563. bGentocin®. Schering Corporation, Kenilworth, NJ 07033. CProcaine Penicillin G. Pfizer, Inc., New York, NY 10017. dHeidbrink®. Kinet-O-Meter® Model 2128. Ohio Chemical and Surgical Equipment Co., Madison, Wisconsin, equipped with a Fluotec 3 Vaporizer. Distributed by Fraser Sweatman, Inc., NY 14086. eDrape fabric. Cleveland Cotton Products, Box 6500, Cleveland, OH 44101. fSynthes®. L T D (USA), 997 Old Eagle School Road, Wayne, PA 19087. ~Redivacette System No. 623518. Orthopedic Equipment Inc., Bourbon, IN 46504. Volume 3, Number 2
Figure 2. Twelve days postoperative lateral radiograph illustrating fixation.
lateral femoral fascia was sutured with O polyglycolic acid suture" in a horizontal mattress pattern. The subcutaneous tissue was apposed with a continuous pattern of O polyglycolic acid and the skin was closed in an alternating pattern of vertical mattress and simple interrupted sutures of #l teflon impregnated braided polyester) The surgical site was then covered with a sterile bandage which was maintained until suture removal. No additional (external) support was added to the fixation. Both the mare and foal were confined to a boxstall postoperatively. Six hours after recovery, the foal was placing a small a m o u n t of weight u p o n the leg and 24 hours postoperatively, the foal was nursing and walking stiffly upon the leg. By 48 hours after surgery, the foal exhibited only slight lameness. Postoperative management consisted of confinement, monitoring of vital signs, prophylactic antibiotic therapy, monitoring of the suction drain, and culture of the drainage material. Drainage f r o m the surgical site was substantially reduced at 48 hours after surgery and the drain was removed at 72 hDexon®. Davis & Geck, Inc., Manati, Puerto Rico 00701 USA iTevdekll® Code #79-556. DeKnatel Division of Howmedica, Inc., Queens Village NY 11429.
61
Figure 3. Twelve days postoperative standing craniocaudal radiograph.
Figure 4. Six months postoperative lateral radiograph immediately prior to plate removal.
hours. On the 10th postoperative day alternate skin sutures were removed. The remainder were removed on the 12th day. At 12 and 28 days the repair was reassessed radiographically; no adverse findings were noticed. The foal was walking soundly and subsequently released at 28 days postoperatively. Discharge instructions consisted of 30 days continuous stall confinement followed by 30 to 60 days of limited exercise in a small paddock, which was to be g r a d u a l l y i n c r e a s e d with t i m e . A d d i t i o n a l recommendations called for a return in 6 months for reevaluation and possible removal of the fixation device.
revealed complete healing with minimal callus (Figure 4). Preparation of the surgical site was identical to the previous surgery. The anesthetic induction differed in that 1.1 mg/Kg xylazinei IV, followed by 2.2 m g / K g ketamine HCL k IV was administered. The lateral approach to the femur was repeated with minimal difficulty. Exposure allowed removal of the plate and proximal compression screw. The more distal screw was covered by callus preventing uncomplicated removal of the screw. A decision was made to not remove it or the cerclage wires. The surgical site was closed and drained as before. Drainage was considerably less than at the initial surgery a n d the a p p a r a t u s was r e m o v e d at 48 h o u r s postoperatively. The foal was w a l k i n g on the leg i m m e d i a t e l y postoperatively and was judged to ambulate normally 13 days later when skin sutures were removed. The foal was discharged and the owners were instructed to limit exercise to a small paddock for 30 days, to increase the
Plate Removal Re-evaluation of the foal 6 months after surgery revealed a sound gait at walk, trot, and lope. Growth of the foal was considerably below expectations. The poor growth was attributed to the stress of the fracture but more importantly to heavy parasitism, confirmed through coprology, and poor nutrition. Radiography of the fractured femur
62
JRompun®100 mg/ml. Haver-Lockhart, Bayvet Division, Cutter Laboratories, Inc. kVetalar® 100 mg/ml. Parke, Davis & Co., Detroit, MI 48232. EQUINE VETERINARY SCIENCE
nutritional plane of the foal, and to institute a regular d e w o r m i n g p r o g r a m . N o n o t i c e a b l e a t r o p h y or assymmetry was noted u p o n discharge or has been reported in the past 6 months. Subsequent g r o w t h of the foal was judged to be n o r m a l by the owner.
DISCUSSION Successful internal fixation of midshaft femoral fractures in the equine has been reported only four times in the American literature, 8 10 12 15 although the fracture is recognized to be relatively common. 2 3 4 Previous methods of repair have involved some form of external fixation a n d / o r stall confinement. 2 3 4 9 They have met with limited success when post~fracture athletic ability and conformation have been evaluated. Repair, utilizing internal fixation with intermedullary pins, has been reported once in a pony, 8 and once in a 7 day old foal, l° but generally there have been problems with migration and instability. 2 Successful repair of femoral fractures in the horse with rigid internal fixation of femoral fractures in the adult tends to present problems which exceed the strength of present implants while those of the foal offer more than an adequate challenge for most fixation devices. The suggestions of Turner ~3 and others for the use of a double plating technique for equine long bone fractures is sound advice. No such fracture should be approached without adequate planning to accomplish this goal, but the judgement of the surgeon during the procedure may circumvent the extra time and stress to the patient if careful evaluation of the fixation occurs at the completion of the first plate application. This evaluation must include a thorough and exact evaluation of the stability which has been achieved, and further, must anticipate the dynamic biomechanical forces to which the repair will be subjected. Knowledge of the types of instability which the fracture itself generates is important. It is doubtful that a single plate technique combined with intrafragmentary compression screws would offer sufficient stability to a transverse fracture of the femur, but it may be adequate for the long oblique fracture as illustrated in this patient. In this case, two of the screws holding the plate to the bone also crossed the fracture enabling the surgeons to accomplish interfragmentary compression of the fracture via the D C P plate and via the screws. The addition of two more screws placed in lag fashion through the cranial cortex and across the fracture added to the stability. The light weight and quiet attitude of the foal combined with the rigidity of the repair led to good bone healing. The presence of boney callus suggests that primary bone healing, which is the goal of the A S I F technique of plate application, did not occur, but sufficient stabilization was afforded to result in healing. Comparison with other reports does not indicate that any greater instability occurred at this fracture site than in other successful repairs. Critique of the repair suggests that it would have been preferrable to use a 10 or 12 hole D C P plate in place of the 8 hole plate. It has been reported that short plates may act as Volume 3, Number 2
stress inducers by concentrating forces of weightbearing at the ends of the plate rather than passing them to the ends o f the bone which are designed to handle those forces. 14 The use of a continuous suction drain was judged to be beneficial as evidenced by the uncomplicated healing of bone and skin. The presence of large seromas is known to delay healing and predispose fractures to infection. 16 The absence of a seroma and the constant microbial surveillance of the fracture offered by the culturing of suction products are important postoperative considerations. However, a s u c t i o n d r a i n c a n be a n e x c e e d i n g l y e x p e n s i v e consideration if adequate precautions are not taken to prevent contamination of the drain and retrograde infection of the fracture. Antimicrobial therapy was initiated prior to surgical intervention to obtain bacteriocidal levels of antibiotic within the surgical site and the postoperative hematoma. Due to the heavy environmental contamination of both gram (+) and gram (-) bacteria accompanying any stall environment, we chose to use broad spectrum antibiotics with proven efficacy against the most c o m m o n nosocomial bacteria in our hospital population. Removal of fixation devices after healing is indicated but not essential, r5 Those animals which are destined for an athletic career are susceptible to stress protection and possible refracture of the involved b o n e ) l Animals which are destined for the more sedentary life of the breeding farm may survive well without removal of the fixation devices. Removal was indicated in this case, due to the shortness of this plate. The most opportune time for plate removal in the horse is unknown and varies with respect to the rate of healing and the nature of the fracture itself. The only published guidelines available in the veterinary literature are those for small animals where a rough guideline of 6 months is made 7 if radiographic evidence of complete healing is present. The success of the veterinary surgeon in repair of equine l o n g b o n e f r a c t u r e s is d e p e n d e n t u p o n a d e q u a t e preparation and application of current techniques. Double plating of all long bone fractures in the horse is currently indicated with the realization that, in limited cases, exceptions to this general rule can be successfully made.
REFERENCES I. Allgower M., Mattler P., Perren S.M., Ruedi T.: The Dynamk" Compression Plate (DCP). Springer-Verlag, Berlin, Germany, 1973. 2. FesslerJ.F., Amstutz, H.E.: In Large AnimalSurgery Edited by F.W. Oheme and J.E. Prier. The Williams and Wilkins Company, Baltimore, MD, 1974 pp 321-24. 3. Lundvall R.L.: Observations on the Treatment of Fractures of the Long Bones in Large Animals. JA VMA 137:308-312, 1960. 4. Lundvall R.L.: In Equine Medicine and Surgery. Edited by E.J. Catcott and J.F. Smithcors. American Vet Publications Inc., Wheaton, ! L 1972, pp 877-878. 5. Milne D.W., Turner A.S.: An Atlas of Surgical Approaches to the Bones of the Horse. W.B. Saunders Co, Philadelphia, PA 1979,pp 154-59. 6. Mueller M.E., Allgower M., Willenegger H.: Manual of Internal Fixation. Springer-Verlag Publishers, Berlin, Germany, 1970. 7. Noser G.A., Brinker W.O., Little R.W., LammerdingJ.J.: Effectof Time on Strength of Healing Bone with Bone Plate Fixation. JAA HA 13:559-561, 1977. 63
8. Pettit G.D., Wheat J.D.: Fracture of the Femur in a Shetland Pony. JA VMA 138(1): 13-14, 1961. 9. Reichel E.C.: Treatment of Fractures of the Long Bones in Large Animals. JA VMA 129:8-15, 1956. 10. Stick J.A., Derksen F.J.: Intramedullary Pinning of a Fractured Femur in a Foal. JA VMA 176(7):627-629, 1980. 11. Tonino A.J., Davidson C.L., Klopper P.J., Linclau L.A.: Protection From Stress in Bone and Its Effects. J Bone and Joint Surgeo'. 58-B(I): 107-113, 1976. 12. Turner A.S.: Surgical Repair of a Fractured Femur ina Foal: A Case
64
Report. J Eq Meal & Surg 1:180-185, 1977. 13. Turner A.S., Bramlage L.R.: 12th Annual Basic Course Internal Fixation of Fractures and Non-Unions. Columbus, Ohio, March 1981. 14. Turner A.S., Milne D.W., Gabel A.A.: The Use of the Dynamic Compression Plate for Treatment of Equine Long-Bone Fractures. JA VMA 168:309-315, 1976. 15. Valdex H., Morris D.L., Auer J.A.: Compression Plating of Long Bone Fractures in Foals. J Vet Orth I(I): 10 18, 1979. 16. Waugh T.R., Stinchfield F.E.: Suction Drainage of Orthopaedic Wounds. J of Bone and Joint Surgery 43(7): 939-945, 1961.
EQUINE VETERINARY SCIENCE