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Successful treatment of a horse with chronic, severe flexural deformity of the distal interphalangeal joint: A case report
..... ................. ?.? ................
%;: Reviewed
SUCCESSFULTREATMENTOF A HORSE WITH CHRONIC, SEVERE FLEXURALDEFORMITYOF THE DISTALINTERPHALANGEALJOINT:A case report Stacey Tarr, DVM; Doug Butler,PhD, CJF,FWCF; Robert K. Shideler DVM, ACT
Flexural deformities of the limbs of foals and young horses are relatively common entities presented to the equine practitioner. The more common areas of involvement include the distal interphalangeal, metacarpophalangeal, and(or) carpal joint areas. They may be classified as either congenital or acquired depending on the time of first appearance. Severity of deformity is graded as Type i if the cranial hoof wall does not pass the vertical, or Type II if it passes beyond the vertical, t The purpose of this ease presentation is to review initiating factors for acquired flexural deformity of the distal interphalangeal joint and the need to utilize professional capabilities of the veterinary surgeon and farrier. The etiology of acquired flexural deformity has been generally associated with nutritional imbalances occurring during the period of accelerated growth in the young horse (3 to 12 months of age). Excess energy and imbalance of rations are considered primary factors; 2,a accelerated compensatory growth rate following a change to a high nutritional plane has also been reported as a factor in this etiology.4 Calcium and phosphorous availability and ratio appear to be important contributions to flexural abnormalitiess and may have a significant relation to feed types, regional location and the effect of dietary protein on calcium hom~;ostasis,ms,6 It has also been reported as an hypothesis that rapid growth of long Authors' address: Animal Reproduction and BiotechnologyLaboratory, Equine Science Center, Colorado State University, Fort Collins, CO 80523.
Volume 13, Number 12, 1993
bones exceeds the ability of the check ligament to passively lengthen,s In the case of acquired flexural deformities involving the distal interphalangeal joint, the deep flexor tendon and carpal check ligament are thought to be involved in the deformity. One report cites a three-fold goal for trimming and shoeing to correct flexural deformity of the distal interphalangeal joint: 1) trimming the heels and lowering the hoof angle; 2) a toe extension to form a lever arm to force the heels to the ground; and 3) a toe extension to delay breakover, additionally forcing stretching and lengthening of the flexor tendons,r Elevating the toe when heel trimming is insufficient is also recommended to achieve proper hoof angle. This may be accomplished with half shoes, wedge pads or calks. The use of calks reduces some of the inherent disadvantages of an extended toe and shoe. Toe elevation is especially advantageous in conjunction with a carpal check ligament desmotomy when sufficient lowering of the heels cannot be accomplished. Corrective shoeing reinforces the results of successful surgery and helps prevent recurrence of the problem. 5 Changing the angle of the cranial hoof wall in its relationship to weightbearing surface (the ground) primarily affects only the distal phalangeal joint angle,a Therefore, any remedial alteration in hoof shape and angle, whether craniocaudal or latero-medial will affect angle change essentiallyonly in the distal phalanx. Monitoring the horse for pain and lameness will be necessary to assure that trimming and shoeing with angle changes have not been excessive and thus causing undue pressure of the deep flexor tendon on the
711
Figure 1. Hoof appearance at initial presentation.
Figure 3. RF hoof preparation prior to surgery.
Figure 2. Lateral radiograph RF, initial examination.
Figure 4. Post surgical radiograph
navicular bone or painful tension on the suspensory ligament. A retrospective study was done to determine the longterm results of desmotomy of the inferior (carpal) check ligament .9The horses were classified as acute (treatment prior to 1 year of age) and chronic (homes diagnosed and treated after 1 year of age). Twenty-fourof 26 horses treated from the acute group were free of lameness and were being used as athletes 9 months to 4 years later. Eleven of 14 chronic cases responded to treatment in the same manner. Corrective
shoeing was utilized in all cases as an adjunct to surgery. Nine to 18 months after surgery, 67.5% of the homes had a normal hoof wall appearance. A greater percentage of homes in the chronic group had a steeper than normal angle when compared to those in the acute group. The prognosis for achieving intended purpose of use was better in homes in the acute group than in the chronic (86% versus 78%, respectively). Correction of the acquired flexural deformity involving
712
JOURNAL OF EQUINE VETERINARY' SCIENCE
Figure 5. Post surgical calk placement.
Figure 7. Lateral radiograph after calk insertion into shoe.
Figure 6. Toe elevation with inserted calk. the distal interphalangeal joint therefore involves: 1) surgical intervention utilizing a carpal check desmotomy2.6,lo to release tension and pull associated with the deep digital flexor tendon; 2) corrective trimming and shoeing of the involved foot to assure normal distal interphalangeal joint angle is achieved and maintained; and 3) correction/alteration of nutritional intake to assure a properly balanced ration. A case is presented that represents an acquired flexural deformity of 2 1/2 years duration which required the combined efforts of the veterinary surgeon and the professional farrier to achieve correction.
A Case Report A three-year-old Quarter Horse gelding was presented with a"club foot" on the right front. The deformity in this case had been present from approximately 5 months of age, Although the deformity was obvious and the right front foot was smaller than the left, significant lameness was not apparent (Figure 1). The horse was in moderately good condition, weighed approximately 800 lbs, was trained to lead and relatively cooperative throughout the initial examination. Lateral radiographs were taken to determine position of Volume 13. Number 12. 1993
Figure 8. Hoof appearance 3 months after surgery. Calks have now been removed. the distal phalanx and angle of deformity (Figure 2). Angle of the hoof was 88* and angle measured from the initial radiographs showed a 17° deviation of the third phalanx from normal. Surgery for carpal check ligament transection was scheduled and initial hoof trimming was done. Approximately 3 cm was removed from the heel and an egg bar shoe was applied before surgery (Figure 3). This shoe type
713
was selected to give better support to the abnormal, excessively straight medial wall of the hoof, and to strengthen the shoe following drilling for calk inserts at the toe, as drill holes tend to weaken the shoe, allowing undesirable expansion at the heels. The horse was prepared for surgery and induced with 3 ml of xylazinea and 8 ml of ketamineb intravenously. The horse was placed in left lateral recumbency, and was intubated and placed on halothane anesthesia. Surgical preparation of the right foreleg was carried out from the carpus distal to the hoof. An incision was made on the lateral aspect of the leg, 6 cm distal to the carpus, cranial to the deep flexor tendon and caudal to the suspensory ligament. The carpal check ligament was identified and transected 2 cm to its tendon attachment. Manual extension of the distal interphalangeal joint created a gap of 15 mm in the check ligament. The incision was closed in two layers with the surgical procedure following the standard techniques presented by Turner and Mcllwraith 9 After-care included a sterile bandage and leg wrap, 2 grn phenylbutazone intravenously and 5 days of trimethoprim sulfac 12 - 960 gm tablets given orally twice daily. Postsurgical radiographs indicated little angle change in the distal interphalangeal joint (Figure 4). On day 5 after surgery, radiographs indicated no further improvement in the angle of the distal phalanx. The shoe was removed and two screwin calks were inserted into the toe area of the shoe, and a clip was drawn on the medial branch. The shoe was then replaced using the original nail holes (Figures 5 and 6). Calks were tungsten-centered and 1 cm in length when inserted. Lateral radiographs taken following this additional toe elevation, revealed an essentially normal angle to the distal phalanx (Figure 7). Fifteen minutes of hand-walking on an asphalt surface twice daily for ten days was initiated. The horse moved well, showed no pain nor lameness, and after removal of sutures on day 14, was discharged. Home care included regular foot cleaning, shoe resetting as needed and a training format for ranch work. Follow-up observation at 3 months showed marked improvement with no lameness and 55 ° hoof angle for both front feet (Figure 8). The horse was shod with standard shoes with the toes boriumplated, and returned for continuation of training.
REFERENCES 1. Stashak TS. Acquired flexural deformities. In: Adams Lameness in Horses. 4th ed. Philadelphia: Lea and Febiger, 454462, 1987. 2. Blaekwell RB. Response of acquired flexural deformity of the metacarpal phalangeal joint to desmotomy of the inferior check ligament. 28th Ann Proc AAEP 107-112, 1982. 3. McllwraithCW.Tendondisorderaofyounghoraes. In: Equine Medicine and Surgery. Santa Barbara; American Vet Publications, 1982. 4. Fackelman (~E. Equine flexural deformities of development origin. 26th Ann Proc AAEP97, 1980. 5. Adams OR. Lameness in Horses 2nd ed. Philadelphia: Lea and Febiger, 1966. 6. Owen JM. Abnormal flexion of the coronopedal joint or "contracted tendons" in unweaned foals. Equine Vet J7:40, 1975. 7. Metcalf S, Wagner PC, Balch-Burnett O. Corrective trimming and shoeing in the treatment of tendon disorders of young horses. Equine Prac 4:6, 1982. 8. Bushe T, Turner TA, Poulas PW, Harwell NW. The effect of hoof angle on coffin, pastern and fetlock joint angles. 33rdAnn Proc AAEP 729-737, 1987. 9. Wagner PC, Grant BD, Kaneps AJ, Watrous BJ. Long term results of desmotomy of the deep digital flexor tendon (distal check ligament) in horses. JAm VetMedAssoc187:12: 1351-1353, 1985. 10. Turner AS, Mcllwraith CW. Inferior check ligament desmotomy. In: Techniques in LargeAnimal Surgery. Philadelphia: Lea and Febiger, 124-127, 1982. 11. Mcllwraith CW, Fessler JF. Evaluation of inferior check ligament desmotomy for treatment of flexor tendon contracture in the horse. J Am Vet Med Assoc 172:293-298. 1978.
f
aRompun, Haver-MobayCorp., Shawnee,KS 66201. bKetaset, Fort Dodge Laboratories, Inc., Fort Dodge, IA 50501. cSMZ-TMP, BiocraftLaboratories, Inc., ElmwoodPark, NJ 07407.
r
+.p.p
+
-
MOVING? SEND YOUR NEW ADDRESS PLUS YOUR OLD ZIP CODE TO JOURNAL OF EQUINE VETERINARY SCIENCE, P.O. BOX 1209, WlLDOMAR, CA 92595 allow six weeks for change
++e-e-++++++ 714
J Two a.m. on a moonless night and my instructions are to turn right at the crossroads with the big red barn and drive until I see a brown house with a green roof and a white picket fence.
J
JOURNALOF EQUINEVETERINARYSCIENCE
%;: Reviewed
SUCCESSFULTREATMENTOF A HORSE WITH CHRONIC, SEVERE FLEXURALDEFORMITYOF THE DISTALINTERPHALANGEALJOINT:A case report Stacey Tarr, DVM; Doug Butler,PhD, CJF,FWCF; Robert K. Shideler DVM, ACT
Flexural deformities of the limbs of foals and young horses are relatively common entities presented to the equine practitioner. The more common areas of involvement include the distal interphalangeal, metacarpophalangeal, and(or) carpal joint areas. They may be classified as either congenital or acquired depending on the time of first appearance. Severity of deformity is graded as Type i if the cranial hoof wall does not pass the vertical, or Type II if it passes beyond the vertical, t The purpose of this ease presentation is to review initiating factors for acquired flexural deformity of the distal interphalangeal joint and the need to utilize professional capabilities of the veterinary surgeon and farrier. The etiology of acquired flexural deformity has been generally associated with nutritional imbalances occurring during the period of accelerated growth in the young horse (3 to 12 months of age). Excess energy and imbalance of rations are considered primary factors; 2,a accelerated compensatory growth rate following a change to a high nutritional plane has also been reported as a factor in this etiology.4 Calcium and phosphorous availability and ratio appear to be important contributions to flexural abnormalitiess and may have a significant relation to feed types, regional location and the effect of dietary protein on calcium hom~;ostasis,ms,6 It has also been reported as an hypothesis that rapid growth of long Authors' address: Animal Reproduction and BiotechnologyLaboratory, Equine Science Center, Colorado State University, Fort Collins, CO 80523.
Volume 13, Number 12, 1993
bones exceeds the ability of the check ligament to passively lengthen,s In the case of acquired flexural deformities involving the distal interphalangeal joint, the deep flexor tendon and carpal check ligament are thought to be involved in the deformity. One report cites a three-fold goal for trimming and shoeing to correct flexural deformity of the distal interphalangeal joint: 1) trimming the heels and lowering the hoof angle; 2) a toe extension to form a lever arm to force the heels to the ground; and 3) a toe extension to delay breakover, additionally forcing stretching and lengthening of the flexor tendons,r Elevating the toe when heel trimming is insufficient is also recommended to achieve proper hoof angle. This may be accomplished with half shoes, wedge pads or calks. The use of calks reduces some of the inherent disadvantages of an extended toe and shoe. Toe elevation is especially advantageous in conjunction with a carpal check ligament desmotomy when sufficient lowering of the heels cannot be accomplished. Corrective shoeing reinforces the results of successful surgery and helps prevent recurrence of the problem. 5 Changing the angle of the cranial hoof wall in its relationship to weightbearing surface (the ground) primarily affects only the distal phalangeal joint angle,a Therefore, any remedial alteration in hoof shape and angle, whether craniocaudal or latero-medial will affect angle change essentiallyonly in the distal phalanx. Monitoring the horse for pain and lameness will be necessary to assure that trimming and shoeing with angle changes have not been excessive and thus causing undue pressure of the deep flexor tendon on the
711
Figure 1. Hoof appearance at initial presentation.
Figure 3. RF hoof preparation prior to surgery.
Figure 2. Lateral radiograph RF, initial examination.
Figure 4. Post surgical radiograph
navicular bone or painful tension on the suspensory ligament. A retrospective study was done to determine the longterm results of desmotomy of the inferior (carpal) check ligament .9The horses were classified as acute (treatment prior to 1 year of age) and chronic (homes diagnosed and treated after 1 year of age). Twenty-fourof 26 horses treated from the acute group were free of lameness and were being used as athletes 9 months to 4 years later. Eleven of 14 chronic cases responded to treatment in the same manner. Corrective
shoeing was utilized in all cases as an adjunct to surgery. Nine to 18 months after surgery, 67.5% of the homes had a normal hoof wall appearance. A greater percentage of homes in the chronic group had a steeper than normal angle when compared to those in the acute group. The prognosis for achieving intended purpose of use was better in homes in the acute group than in the chronic (86% versus 78%, respectively). Correction of the acquired flexural deformity involving
712
JOURNAL OF EQUINE VETERINARY' SCIENCE
Figure 5. Post surgical calk placement.
Figure 7. Lateral radiograph after calk insertion into shoe.
Figure 6. Toe elevation with inserted calk. the distal interphalangeal joint therefore involves: 1) surgical intervention utilizing a carpal check desmotomy2.6,lo to release tension and pull associated with the deep digital flexor tendon; 2) corrective trimming and shoeing of the involved foot to assure normal distal interphalangeal joint angle is achieved and maintained; and 3) correction/alteration of nutritional intake to assure a properly balanced ration. A case is presented that represents an acquired flexural deformity of 2 1/2 years duration which required the combined efforts of the veterinary surgeon and the professional farrier to achieve correction.
A Case Report A three-year-old Quarter Horse gelding was presented with a"club foot" on the right front. The deformity in this case had been present from approximately 5 months of age, Although the deformity was obvious and the right front foot was smaller than the left, significant lameness was not apparent (Figure 1). The horse was in moderately good condition, weighed approximately 800 lbs, was trained to lead and relatively cooperative throughout the initial examination. Lateral radiographs were taken to determine position of Volume 13. Number 12. 1993
Figure 8. Hoof appearance 3 months after surgery. Calks have now been removed. the distal phalanx and angle of deformity (Figure 2). Angle of the hoof was 88* and angle measured from the initial radiographs showed a 17° deviation of the third phalanx from normal. Surgery for carpal check ligament transection was scheduled and initial hoof trimming was done. Approximately 3 cm was removed from the heel and an egg bar shoe was applied before surgery (Figure 3). This shoe type
713
was selected to give better support to the abnormal, excessively straight medial wall of the hoof, and to strengthen the shoe following drilling for calk inserts at the toe, as drill holes tend to weaken the shoe, allowing undesirable expansion at the heels. The horse was prepared for surgery and induced with 3 ml of xylazinea and 8 ml of ketamineb intravenously. The horse was placed in left lateral recumbency, and was intubated and placed on halothane anesthesia. Surgical preparation of the right foreleg was carried out from the carpus distal to the hoof. An incision was made on the lateral aspect of the leg, 6 cm distal to the carpus, cranial to the deep flexor tendon and caudal to the suspensory ligament. The carpal check ligament was identified and transected 2 cm to its tendon attachment. Manual extension of the distal interphalangeal joint created a gap of 15 mm in the check ligament. The incision was closed in two layers with the surgical procedure following the standard techniques presented by Turner and Mcllwraith 9 After-care included a sterile bandage and leg wrap, 2 grn phenylbutazone intravenously and 5 days of trimethoprim sulfac 12 - 960 gm tablets given orally twice daily. Postsurgical radiographs indicated little angle change in the distal interphalangeal joint (Figure 4). On day 5 after surgery, radiographs indicated no further improvement in the angle of the distal phalanx. The shoe was removed and two screwin calks were inserted into the toe area of the shoe, and a clip was drawn on the medial branch. The shoe was then replaced using the original nail holes (Figures 5 and 6). Calks were tungsten-centered and 1 cm in length when inserted. Lateral radiographs taken following this additional toe elevation, revealed an essentially normal angle to the distal phalanx (Figure 7). Fifteen minutes of hand-walking on an asphalt surface twice daily for ten days was initiated. The horse moved well, showed no pain nor lameness, and after removal of sutures on day 14, was discharged. Home care included regular foot cleaning, shoe resetting as needed and a training format for ranch work. Follow-up observation at 3 months showed marked improvement with no lameness and 55 ° hoof angle for both front feet (Figure 8). The horse was shod with standard shoes with the toes boriumplated, and returned for continuation of training.
REFERENCES 1. Stashak TS. Acquired flexural deformities. In: Adams Lameness in Horses. 4th ed. Philadelphia: Lea and Febiger, 454462, 1987. 2. Blaekwell RB. Response of acquired flexural deformity of the metacarpal phalangeal joint to desmotomy of the inferior check ligament. 28th Ann Proc AAEP 107-112, 1982. 3. McllwraithCW.Tendondisorderaofyounghoraes. In: Equine Medicine and Surgery. Santa Barbara; American Vet Publications, 1982. 4. Fackelman (~E. Equine flexural deformities of development origin. 26th Ann Proc AAEP97, 1980. 5. Adams OR. Lameness in Horses 2nd ed. Philadelphia: Lea and Febiger, 1966. 6. Owen JM. Abnormal flexion of the coronopedal joint or "contracted tendons" in unweaned foals. Equine Vet J7:40, 1975. 7. Metcalf S, Wagner PC, Balch-Burnett O. Corrective trimming and shoeing in the treatment of tendon disorders of young horses. Equine Prac 4:6, 1982. 8. Bushe T, Turner TA, Poulas PW, Harwell NW. The effect of hoof angle on coffin, pastern and fetlock joint angles. 33rdAnn Proc AAEP 729-737, 1987. 9. Wagner PC, Grant BD, Kaneps AJ, Watrous BJ. Long term results of desmotomy of the deep digital flexor tendon (distal check ligament) in horses. JAm VetMedAssoc187:12: 1351-1353, 1985. 10. Turner AS, Mcllwraith CW. Inferior check ligament desmotomy. In: Techniques in LargeAnimal Surgery. Philadelphia: Lea and Febiger, 124-127, 1982. 11. Mcllwraith CW, Fessler JF. Evaluation of inferior check ligament desmotomy for treatment of flexor tendon contracture in the horse. J Am Vet Med Assoc 172:293-298. 1978.
f
aRompun, Haver-MobayCorp., Shawnee,KS 66201. bKetaset, Fort Dodge Laboratories, Inc., Fort Dodge, IA 50501. cSMZ-TMP, BiocraftLaboratories, Inc., ElmwoodPark, NJ 07407.
r
+.p.p
+
-
MOVING? SEND YOUR NEW ADDRESS PLUS YOUR OLD ZIP CODE TO JOURNAL OF EQUINE VETERINARY SCIENCE, P.O. BOX 1209, WlLDOMAR, CA 92595 allow six weeks for change
++e-e-++++++ 714
J Two a.m. on a moonless night and my instructions are to turn right at the crossroads with the big red barn and drive until I see a brown house with a green roof and a white picket fence.
J
JOURNALOF EQUINEVETERINARYSCIENCE