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or fracture of the first carpal bone in thoroughbred horses and its surgical resolution
WORLDEOO,.E VETER,..
.SSOC,..,O.
PRESENTEDATTHE WORLDVETERINARYCONGRESS,RIO DE JANEIRO,BRA2IL, AUGUST1991.
LUXATIONAND/OR FRACTUREOF THE FIRSTCARPALBONE IN THOROUGHBREDHORSESAND ITS SURGICALRESOLUTION C. A. Carabajal, DVM
SUMMARY
A syndrome involving luxation and/or fracture of the first carpal bone is described. Affected horses have a grade 13 lameness, which responds to intra-articular anesthesia of the intercarpal joint. Medical treatment has not be successful in relieving lameness, and the treatment of choice is surgical removal of the first carpal bone.
INTRODUCTION
The majority of Thoroughbred race horses suffer pain in some part of their limbs as a consequence of daily exercise. Prompt diagnosis and treatment are important to get the horses back to training and racing as soon as possible. We have studied a syndrome in a number of Thoroughbred horses with a grade 1-3 lameness of one or both front limbs. Our initial diagnostic and therapeutic efforts with this condition were unsatisfactory, producing only a temporary clinical improvement. It was recognized that neither the diagnosis or treatment was satisfactory,which prompted us to investigate the problem in more detail. This paper presents the results of our further investigations of this problem. Clinical s i g n s a n d d i a g n o s i s
The clinical signs include a reluctance to trot, with affected horses preferring to gallop from the outset. Sometimes the horse stumbles, and may even fall. The jockey Author's address: Piso 3, Depto C, San Isidro CP: 1642, Buenos Aires.
Argentina.
Volume 12, Number 6, 1992
reports that the horse walks with difficulty and reacts as if the limb is acutely painful just before stumbling. Clinical examinations, including observation, palpation, percussion, and flexion tests do not show any abnormality. There is no response to local or regional anesthesia, except when the anesthetic is injected into the intercarpal joint. The injection of 5 to 8 co of 2% lidocaine resulted in a disappearance of the lameness within approximately 5 minutes. Radiological studies do not reveal the presence of bone chips or fractures of the carpal bones. However, the anterioposteriolateral oblique (APLO) showed the presence of a luxated or fractured first carpal bone. Normally, the first carpal bone is approximately the size of a pear and is located in the medial collateral ligament, palmar to the second carpal bone. The luxated first carpal bone lies in a more distal location. There is a strong correlation between lameness of the affected limb, the presence of a luxated or fractured first carpal bone, and a favorable response to the injection of local anesthetic into the intercarpal joint. This led us to the conclusion that the first carpal bone may be the cause of lameness. Treatment
In our experience, surgical resection of the first carpal bone is the treatment of choice. The patient is positioned in lateral recumbency, with the affected limb down. A skin incision is made extending from the second carpal bone to the level of the proximal epiphysis of the metacarpal bone. The incision is 3 to 5 cm in length. The subcutaneous fascia is incised to expose the underlying intercarpal ligaments and the in'st carpal bone. The first carpal bone is dissected free of the surrounding ligaments, taking care not to damage the vessels or tendon sheaths in the
393
wo,,D EouI.E WrE.I.A,V ASSOClArIO. PRESENTEDATTHEWORLDVETERINARYCONGRESS,RIODEJANEIRO,BRAZIL,AUGUST1991.
area. After removal of the first carpal bone, the incision is dosed using an interrupted or continuous suture pattern with the incised edges firmly opposed. Following surgery horses are rested for a period of 3 months.
RESULTS As of August 1991, we have operated on 12 horses. In six cases the procedure was bilateral, giving a total of 18 first carpal bones resected. Eleven horses returned to training without showing any further signs of lameness. Seven of them have won good quality races since surgery. One horse failed to return to soundness after surgery. The failure was due to the horse being treated with corticosteroids during the postoperative period at the farm.
medial collateral ligament of the carpus, palmar to the second carpal bone. In about 50% of the horses, the f'Lrstcarpal bone is entirely absent. It is often present on one side only. In the majority of cases, the fLrst carpal bone does not have any articulations, but sometimes it articulates with the second carpal bone, and rarely with the second metacarpal bone also.1 In our series, the fLrStcarpal bone was present unilaterally in 3 horses. Both the size and shape varied; some horses had a large f'Lrstcarpal bone in one limb and a small one in the other limb. Lameness was present only when the first carpal bone was luxated and/or fractured. When the bone was luxated, it generally moved distally.
REFERENCE 1. Getty R: Sisson and Grossman's The Anatomy of the DomesticAnimals. WB Saunders:Philadelphia, 1975.
DISCUSSION The first carpal bone is a small inconstant bone, about the size and shape of a pea. It is embedded in the distal part of the
SPORTS MEDICINE FOR THE RACEHORSE S e c o n d Edition By Dr. William E. Jones, DVM, PhD
The revised edition of Sports Medicine for the Racehorse contains basic and up-to-date information in the emerging equine sports medicine field, but scientific race training is the major emphasis of the book.
Chapters are included on: • Equine Sports Medicine , • Scientific Training • Conditioning • Nutrition • Lameness • Profiling • Physical Therapy • Drugging 394
JOURNAL OF EQUINE VETERINARY SCIENCE
.SSOC,..,O.
PRESENTEDATTHE WORLDVETERINARYCONGRESS,RIO DE JANEIRO,BRA2IL, AUGUST1991.
LUXATIONAND/OR FRACTUREOF THE FIRSTCARPALBONE IN THOROUGHBREDHORSESAND ITS SURGICALRESOLUTION C. A. Carabajal, DVM
SUMMARY
A syndrome involving luxation and/or fracture of the first carpal bone is described. Affected horses have a grade 13 lameness, which responds to intra-articular anesthesia of the intercarpal joint. Medical treatment has not be successful in relieving lameness, and the treatment of choice is surgical removal of the first carpal bone.
INTRODUCTION
The majority of Thoroughbred race horses suffer pain in some part of their limbs as a consequence of daily exercise. Prompt diagnosis and treatment are important to get the horses back to training and racing as soon as possible. We have studied a syndrome in a number of Thoroughbred horses with a grade 1-3 lameness of one or both front limbs. Our initial diagnostic and therapeutic efforts with this condition were unsatisfactory, producing only a temporary clinical improvement. It was recognized that neither the diagnosis or treatment was satisfactory,which prompted us to investigate the problem in more detail. This paper presents the results of our further investigations of this problem. Clinical s i g n s a n d d i a g n o s i s
The clinical signs include a reluctance to trot, with affected horses preferring to gallop from the outset. Sometimes the horse stumbles, and may even fall. The jockey Author's address: Piso 3, Depto C, San Isidro CP: 1642, Buenos Aires.
Argentina.
Volume 12, Number 6, 1992
reports that the horse walks with difficulty and reacts as if the limb is acutely painful just before stumbling. Clinical examinations, including observation, palpation, percussion, and flexion tests do not show any abnormality. There is no response to local or regional anesthesia, except when the anesthetic is injected into the intercarpal joint. The injection of 5 to 8 co of 2% lidocaine resulted in a disappearance of the lameness within approximately 5 minutes. Radiological studies do not reveal the presence of bone chips or fractures of the carpal bones. However, the anterioposteriolateral oblique (APLO) showed the presence of a luxated or fractured first carpal bone. Normally, the first carpal bone is approximately the size of a pear and is located in the medial collateral ligament, palmar to the second carpal bone. The luxated first carpal bone lies in a more distal location. There is a strong correlation between lameness of the affected limb, the presence of a luxated or fractured first carpal bone, and a favorable response to the injection of local anesthetic into the intercarpal joint. This led us to the conclusion that the first carpal bone may be the cause of lameness. Treatment
In our experience, surgical resection of the first carpal bone is the treatment of choice. The patient is positioned in lateral recumbency, with the affected limb down. A skin incision is made extending from the second carpal bone to the level of the proximal epiphysis of the metacarpal bone. The incision is 3 to 5 cm in length. The subcutaneous fascia is incised to expose the underlying intercarpal ligaments and the in'st carpal bone. The first carpal bone is dissected free of the surrounding ligaments, taking care not to damage the vessels or tendon sheaths in the
393
wo,,D EouI.E WrE.I.A,V ASSOClArIO. PRESENTEDATTHEWORLDVETERINARYCONGRESS,RIODEJANEIRO,BRAZIL,AUGUST1991.
area. After removal of the first carpal bone, the incision is dosed using an interrupted or continuous suture pattern with the incised edges firmly opposed. Following surgery horses are rested for a period of 3 months.
RESULTS As of August 1991, we have operated on 12 horses. In six cases the procedure was bilateral, giving a total of 18 first carpal bones resected. Eleven horses returned to training without showing any further signs of lameness. Seven of them have won good quality races since surgery. One horse failed to return to soundness after surgery. The failure was due to the horse being treated with corticosteroids during the postoperative period at the farm.
medial collateral ligament of the carpus, palmar to the second carpal bone. In about 50% of the horses, the f'Lrstcarpal bone is entirely absent. It is often present on one side only. In the majority of cases, the fLrst carpal bone does not have any articulations, but sometimes it articulates with the second carpal bone, and rarely with the second metacarpal bone also.1 In our series, the fLrStcarpal bone was present unilaterally in 3 horses. Both the size and shape varied; some horses had a large f'Lrstcarpal bone in one limb and a small one in the other limb. Lameness was present only when the first carpal bone was luxated and/or fractured. When the bone was luxated, it generally moved distally.
REFERENCE 1. Getty R: Sisson and Grossman's The Anatomy of the DomesticAnimals. WB Saunders:Philadelphia, 1975.
DISCUSSION The first carpal bone is a small inconstant bone, about the size and shape of a pea. It is embedded in the distal part of the
SPORTS MEDICINE FOR THE RACEHORSE S e c o n d Edition By Dr. William E. Jones, DVM, PhD
The revised edition of Sports Medicine for the Racehorse contains basic and up-to-date information in the emerging equine sports medicine field, but scientific race training is the major emphasis of the book.
Chapters are included on: • Equine Sports Medicine , • Scientific Training • Conditioning • Nutrition • Lameness • Profiling • Physical Therapy • Drugging 394
JOURNAL OF EQUINE VETERINARY SCIENCE