CASE REPORT THE DIAGNOSIS AND TREATMENT OF AVULSION FRACTURE OF THE SUSTENTACULUM TALI IN A HORSE R. D. JoNEs* History On August 20, 1975 an 11 year old Palomino mare was presented to The Ohio State University Veterinary Hospital with a severe right hind limb lameness of one month's duration. The owners had been applying various liniments and occasional hydro-therapy to the right hind fetlock area, but no improvement was noticed. The mare was used as a barrel race horse. She had competed 24 hours previous to the owners noticing her to be slightly lame. The lameness quickly progressed to the point of non weight bearing on the affected
limb. On presentation to The Ohio State University, the mare would not use the right hind limb in ambulation, but would rest it on the ground when standing. The mare was in fair physical condition. An increased respiratory rate was attributed to pain. Some weight loss was evident and there was visible disuse atrophy of the right gluteal muscles. Pitting edema was present in the limb from the hock distally. The only area of increased heat was over the posterio-medial aspect of the hock region. Digital palpation of this site caused severe pain. This area would also pit with excessive palpation. No increased intensity was evident in the digital pulse. Thorough examination of the foot, fetlock and all areas distal to the hock was negative except for the edema. If the limb was gently flexed, the mare did not object, but any over flexion with torsional forces on the hock or any attempts to over extend the hock out behind the mare resulted in severe pain; enough for the mare to attempt to go down. The stifle and hip were normal on digital examination except for the atrophied gluteal muscles. Further digital examination of the posteriomedial hock, directly over the area of the
*Departnent of Veterinary Clinical Sciences, The Ohio State University, 1935 Coffey Road, Columbus, Ohio 43210. Present address: Department of Rural Practice, School of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee 37901. CAN. VET. JOUR., vol. 17, no. 11, November, 1976
FicuRE 1. APMLO view of right tarsus. Arrow indicates proliferative lesion on caudo-medial aspect of calcaneus.
proximal attachment of the tarso-metatarsal ligament-the bony sustentaculum tali of the calcaneus (2), produced excruciating pain. Routine anterio-posterior (AP), lateral and anterio-posterior, lateral-medial oblique (APLMO) radiographs of the hock were taken. As well, an anterio-posterior, medial-lateral oblique (APMLO) view was requested. The three routine hock radiographs revealed no significant lesion. The APMLO view revealed bony irregularity on the caudo-medial aspect of the calcaneus (Figure 1). A fifth radiograph was taken with the hock in a flexed, proximaldistad, "skyline" position as described by Farrow et al (1). A bony deficit was found in 87
CANADIAN VETERINARY JOURNAL
j
FIGURE 2. "Skyline" view of right tarsus. Arrow points to overlapping calcific density just lateral to bony deficit in sustentaculum tali. Note superimposition of chestnut over sustentaculum.
FIGuRE 3. APMLO view of right tarsus taken ten weeks postinjury. Arrow points to marked increase in bony proliferation over posterior-medial
the caudal aspect of the sustentaculum tali with an overlapping calcific density just lateral to it suggesting a chip fracture of the sustentaculum tali (Figure 2). A diagnosis of fracture of the sustentaculum tali was made. Because of the lack of response to one month's rest, the severity of the lameness, excessive mobility in the affected area, plus the owner's desire to use the horse only as an athlete, a guarded prognosis was given. A fair prognosis was given for use as a broodmare. Surgery was not attempted due to the severe heat and pain present. The owner was requested to rest the horse six more weeks. Cold hydrotherapy was recommended. The horse was returned for evaluation following six weeks in a box stall. The mare was less reluctant to bear weight, but was still severely lame. There was minimal heat at the fracture site. The area was still swollen and extremely painful. At this time, there was some distention of the tibiotarsal joint. As well, the proximal sheath of the deep digital flexor tendon was distended proximal to the cal-
caneus. An APMLO radiograph revealed a marked increase in bony proliferation on the posterior medial aspect of the calcaneus (Figure 3). The "skyline" view revealed the proliferation extending axially (Figure 4). Again, a grave prognosis for performance was given. Further rest in a box stall was advised. At reevaluation eight months after the initial onset of signs, the mare was still very lame.
calcaneus.
Discussion This is the second such fracture diagnosed by the author. Both horses were barrel race horses. Both were noticed to be lame the day following competition. It is feasible that this fracture is sustained during the race, likely during acceleration after a turn when maximum strain on the hock could result in either a torn ligament or an avulsion fracture. These cases point out the absolute necessity of a thorough and accurate physical examination of the affected limb of a lame horse. Only by painstaking digital palpation and manipulation of all the normal and abnormal areas of
288
AVULSION FRACTURE
FIGURE 5. Revised positioning of tube head and cassette for taking "skyline" view of tarsus.
FIGuRE 4. "Skyline" view of right tarsus ten weeks postinjury. Note extension of bony proliferation.
the limb can one unerringly pinpoint the significant lesion. As noted previously, the standard positioning for radiographic examination of a particular area may yield negative results. This must not bias the clinical evaluation and demonstrates the need for a clinical examination and a tentative diagnosis before the radiographic examination. The primary use of the radiographic examination should be to substantiate the clinical diagnosis. We have since revised our approach to radiographing the skyline view of the suscentaculum as described by Farrow et al. (1). We have essentially reversed the positioning of the tube head and cassette (Figure 5). This technique was developed for greater ease and safety to both the operator and patient. As well, this approach reveals much greater ana-
tomical detail and rarely results in superimposition of the chestnut in the critical area of the sustentaculum (Figures 2 and 4). Because of the author's experience with donor animals, surgical intervention has not been the treatment of choice for avulsion fractures of the sustentaculum tali due to the relative inaccessibility of the lesion without causing a tremendous amount of damage to ligaments during the approach. In this author's experience, surgical intervention of the hock joint from almost any approach inevitably results in a grossly fibrotic and enlarged joint area due to excessive peri articular fibrosis. This is due to the excessive mobility of the area plus the inability to maintain sufficient counterpressure on the surgery site postoperatively. This scarring and fibrosis is often excessive enough to cause a lameness, not necessarily due to pain, but rather due to mechanical interference with movement. Neither horse has become useably sound after prolonged stall rest. This is probably due to the fact that the deep digital flexor tendon is continually irritating (due to motion) the fracture site. This causes excessive callus formation, which in turn irritates the tendon. Based on the results of these two similar cases plus the generally poor results of extensive hock surgery, a grave prognosis for soundness should be given for avulsion fractures of the sustentaculum tali.
289
Summary One of two identical cases of avulsion fracture of the sustentaculum tali in barrel racing
CANADIAN VETERINARY JOURNAL
horses is described. History, physical and radiological examinations are discussed with particular emphasis on the thorough physical examination necessary to diagnose the fracture. The merits of prolonged rest versus surgical resection of the avulsed fragment are discussed. In either case, a grave prognosis for soundness is indicated.
avantages d'un repos prolong6 sur ceux de l'enlevement chirurgical du fragment d'os 16s6. Dans un cas comme dans l'autre, le pronostic demeure sombre. Acknowledgments The author wishes to thank Mr. Russ Benjamin, radiology technician for devising a safer "skyline" technique and Ms. Paula Modransky for her technical assistance.
Resume
L'auteur decrit l'un des deux cas identiques d'une fracture d'arrachement du sistentacullum References C. S., S. V. MCNEEL, J. P. MORGAN tali qui se produisirent chez des chevaux uti- 1. FARRow, and R. RESCH. Visualization of the tuber lises pour la course de barils. II commente calcis and sustentaculum in the horse. Calif. l'anamnese et les examens physiques et radioVet. 30: 14. 1976. logiques, en insistant sur la necessit6 d'un ex- 2. SIssoN, S. and J. D. GROSSMAN. Anatomy of amen physique minutieux pour diagnostiquer the Domestic Animals. 4th Edition. p. 242. Philadelphia: W. B. Saunders Company. 1969. ce genre de fracture. II commente aussi les
BOOK REVIEW The Veterinarian in America 1625-1975. J. F. Smithcors. Published by American Veterinary Publications, Wheaton, Illinois. 1975. 160 pages. Price $25.00. In 1963, Dr. Smithcors wrote "The American Veterinary Profession" on the occasion of the centennial of the American Veterinary Medical Association and immediately following the centennial of the Ontario Veterinary College. Dr. Smithcors noted in the preface to that book that "... the founding of these two institutions coincided with the ushering in of a century of unparalleled progress in veterinary medicine." It is perhaps appropriate then that Dr. Smithcors has re-issued some of this material in the form of the present book at about the time of the bicentennial celebrations of the United States. As is noted in the book, much of the text has come from Dr. Smithcors' previous book, but this should not discourage readers from purchasing this newer version. It is richly illustrated with line drawings and photographs of extremely interesting events, people, and places of the last 350 years. As is the case often with histories of the veterinary profession, certain themes are seen to have recurred time and time again. For example, the book notes that there was public concern about dogs
in communities as early as 1635, when the town of Salem, Massachusetts passed an ordinance requiring that dogs be "tied up in the daytime and that if any dogs spoil the fish they also shall either be sent away or killed." One is tempted to conclude that there is very little new in the world! Dr. Smithcors also notes the lengthy history of the Ontario Veterinary College and points out that in 1934 graduates of that institution accounted for more than 20% of the total veterinarians in the United States and Canada. Critics might argue that Canada's rich veterinary history (so ably studied by Mitchell, Barker, Love and others) should not have been left out of a book referring to "America," but such inclusions must await the future. The illustrations alone should make this book of interest to nearly every veterinarian and it is bound in a special binding which makes it an attractive gift as well. There are a few typographical errors, but these are not serious. I highly recommend the book to all veterinarians. If it were not for Dr. Smithcors' interest in the history of the profession, very little collation and synthesis would have occurred. Future books on the history of the profession will owe a debt to the pioneering work and stimulus of this author. F. M. Loew.
290
limb. On presentation to The Ohio State University, the mare would not use the right hind limb in ambulation, but would rest it on the ground when standing. The mare was in fair physical condition. An increased respiratory rate was attributed to pain. Some weight loss was evident and there was visible disuse atrophy of the right gluteal muscles. Pitting edema was present in the limb from the hock distally. The only area of increased heat was over the posterio-medial aspect of the hock region. Digital palpation of this site caused severe pain. This area would also pit with excessive palpation. No increased intensity was evident in the digital pulse. Thorough examination of the foot, fetlock and all areas distal to the hock was negative except for the edema. If the limb was gently flexed, the mare did not object, but any over flexion with torsional forces on the hock or any attempts to over extend the hock out behind the mare resulted in severe pain; enough for the mare to attempt to go down. The stifle and hip were normal on digital examination except for the atrophied gluteal muscles. Further digital examination of the posteriomedial hock, directly over the area of the
*Departnent of Veterinary Clinical Sciences, The Ohio State University, 1935 Coffey Road, Columbus, Ohio 43210. Present address: Department of Rural Practice, School of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee 37901. CAN. VET. JOUR., vol. 17, no. 11, November, 1976
FicuRE 1. APMLO view of right tarsus. Arrow indicates proliferative lesion on caudo-medial aspect of calcaneus.
proximal attachment of the tarso-metatarsal ligament-the bony sustentaculum tali of the calcaneus (2), produced excruciating pain. Routine anterio-posterior (AP), lateral and anterio-posterior, lateral-medial oblique (APLMO) radiographs of the hock were taken. As well, an anterio-posterior, medial-lateral oblique (APMLO) view was requested. The three routine hock radiographs revealed no significant lesion. The APMLO view revealed bony irregularity on the caudo-medial aspect of the calcaneus (Figure 1). A fifth radiograph was taken with the hock in a flexed, proximaldistad, "skyline" position as described by Farrow et al (1). A bony deficit was found in 87
CANADIAN VETERINARY JOURNAL
j
FIGURE 2. "Skyline" view of right tarsus. Arrow points to overlapping calcific density just lateral to bony deficit in sustentaculum tali. Note superimposition of chestnut over sustentaculum.
FIGuRE 3. APMLO view of right tarsus taken ten weeks postinjury. Arrow points to marked increase in bony proliferation over posterior-medial
the caudal aspect of the sustentaculum tali with an overlapping calcific density just lateral to it suggesting a chip fracture of the sustentaculum tali (Figure 2). A diagnosis of fracture of the sustentaculum tali was made. Because of the lack of response to one month's rest, the severity of the lameness, excessive mobility in the affected area, plus the owner's desire to use the horse only as an athlete, a guarded prognosis was given. A fair prognosis was given for use as a broodmare. Surgery was not attempted due to the severe heat and pain present. The owner was requested to rest the horse six more weeks. Cold hydrotherapy was recommended. The horse was returned for evaluation following six weeks in a box stall. The mare was less reluctant to bear weight, but was still severely lame. There was minimal heat at the fracture site. The area was still swollen and extremely painful. At this time, there was some distention of the tibiotarsal joint. As well, the proximal sheath of the deep digital flexor tendon was distended proximal to the cal-
caneus. An APMLO radiograph revealed a marked increase in bony proliferation on the posterior medial aspect of the calcaneus (Figure 3). The "skyline" view revealed the proliferation extending axially (Figure 4). Again, a grave prognosis for performance was given. Further rest in a box stall was advised. At reevaluation eight months after the initial onset of signs, the mare was still very lame.
calcaneus.
Discussion This is the second such fracture diagnosed by the author. Both horses were barrel race horses. Both were noticed to be lame the day following competition. It is feasible that this fracture is sustained during the race, likely during acceleration after a turn when maximum strain on the hock could result in either a torn ligament or an avulsion fracture. These cases point out the absolute necessity of a thorough and accurate physical examination of the affected limb of a lame horse. Only by painstaking digital palpation and manipulation of all the normal and abnormal areas of
288
AVULSION FRACTURE
FIGURE 5. Revised positioning of tube head and cassette for taking "skyline" view of tarsus.
FIGuRE 4. "Skyline" view of right tarsus ten weeks postinjury. Note extension of bony proliferation.
the limb can one unerringly pinpoint the significant lesion. As noted previously, the standard positioning for radiographic examination of a particular area may yield negative results. This must not bias the clinical evaluation and demonstrates the need for a clinical examination and a tentative diagnosis before the radiographic examination. The primary use of the radiographic examination should be to substantiate the clinical diagnosis. We have since revised our approach to radiographing the skyline view of the suscentaculum as described by Farrow et al. (1). We have essentially reversed the positioning of the tube head and cassette (Figure 5). This technique was developed for greater ease and safety to both the operator and patient. As well, this approach reveals much greater ana-
tomical detail and rarely results in superimposition of the chestnut in the critical area of the sustentaculum (Figures 2 and 4). Because of the author's experience with donor animals, surgical intervention has not been the treatment of choice for avulsion fractures of the sustentaculum tali due to the relative inaccessibility of the lesion without causing a tremendous amount of damage to ligaments during the approach. In this author's experience, surgical intervention of the hock joint from almost any approach inevitably results in a grossly fibrotic and enlarged joint area due to excessive peri articular fibrosis. This is due to the excessive mobility of the area plus the inability to maintain sufficient counterpressure on the surgery site postoperatively. This scarring and fibrosis is often excessive enough to cause a lameness, not necessarily due to pain, but rather due to mechanical interference with movement. Neither horse has become useably sound after prolonged stall rest. This is probably due to the fact that the deep digital flexor tendon is continually irritating (due to motion) the fracture site. This causes excessive callus formation, which in turn irritates the tendon. Based on the results of these two similar cases plus the generally poor results of extensive hock surgery, a grave prognosis for soundness should be given for avulsion fractures of the sustentaculum tali.
289
Summary One of two identical cases of avulsion fracture of the sustentaculum tali in barrel racing
CANADIAN VETERINARY JOURNAL
horses is described. History, physical and radiological examinations are discussed with particular emphasis on the thorough physical examination necessary to diagnose the fracture. The merits of prolonged rest versus surgical resection of the avulsed fragment are discussed. In either case, a grave prognosis for soundness is indicated.
avantages d'un repos prolong6 sur ceux de l'enlevement chirurgical du fragment d'os 16s6. Dans un cas comme dans l'autre, le pronostic demeure sombre. Acknowledgments The author wishes to thank Mr. Russ Benjamin, radiology technician for devising a safer "skyline" technique and Ms. Paula Modransky for her technical assistance.
Resume
L'auteur decrit l'un des deux cas identiques d'une fracture d'arrachement du sistentacullum References C. S., S. V. MCNEEL, J. P. MORGAN tali qui se produisirent chez des chevaux uti- 1. FARRow, and R. RESCH. Visualization of the tuber lises pour la course de barils. II commente calcis and sustentaculum in the horse. Calif. l'anamnese et les examens physiques et radioVet. 30: 14. 1976. logiques, en insistant sur la necessit6 d'un ex- 2. SIssoN, S. and J. D. GROSSMAN. Anatomy of amen physique minutieux pour diagnostiquer the Domestic Animals. 4th Edition. p. 242. Philadelphia: W. B. Saunders Company. 1969. ce genre de fracture. II commente aussi les
BOOK REVIEW The Veterinarian in America 1625-1975. J. F. Smithcors. Published by American Veterinary Publications, Wheaton, Illinois. 1975. 160 pages. Price $25.00. In 1963, Dr. Smithcors wrote "The American Veterinary Profession" on the occasion of the centennial of the American Veterinary Medical Association and immediately following the centennial of the Ontario Veterinary College. Dr. Smithcors noted in the preface to that book that "... the founding of these two institutions coincided with the ushering in of a century of unparalleled progress in veterinary medicine." It is perhaps appropriate then that Dr. Smithcors has re-issued some of this material in the form of the present book at about the time of the bicentennial celebrations of the United States. As is noted in the book, much of the text has come from Dr. Smithcors' previous book, but this should not discourage readers from purchasing this newer version. It is richly illustrated with line drawings and photographs of extremely interesting events, people, and places of the last 350 years. As is the case often with histories of the veterinary profession, certain themes are seen to have recurred time and time again. For example, the book notes that there was public concern about dogs
in communities as early as 1635, when the town of Salem, Massachusetts passed an ordinance requiring that dogs be "tied up in the daytime and that if any dogs spoil the fish they also shall either be sent away or killed." One is tempted to conclude that there is very little new in the world! Dr. Smithcors also notes the lengthy history of the Ontario Veterinary College and points out that in 1934 graduates of that institution accounted for more than 20% of the total veterinarians in the United States and Canada. Critics might argue that Canada's rich veterinary history (so ably studied by Mitchell, Barker, Love and others) should not have been left out of a book referring to "America," but such inclusions must await the future. The illustrations alone should make this book of interest to nearly every veterinarian and it is bound in a special binding which makes it an attractive gift as well. There are a few typographical errors, but these are not serious. I highly recommend the book to all veterinarians. If it were not for Dr. Smithcors' interest in the history of the profession, very little collation and synthesis would have occurred. Future books on the history of the profession will owe a debt to the pioneering work and stimulus of this author. F. M. Loew.
290
