Farriery for the foal: A review part 2: Therapeutic farriery

The extensive nature of this topic warrants this review paper to be divided into two parts: ‘Basic trimming in foals’ and ‘Therapeutic farriery in foals’. Management of the feet and limbs during this juvenile period will often dictate the success of the foal as a sales yearling or mature sound athlete. Overall hoof care in the foal is often a joint venture between the veterinarian and the farrier. The orthopaedic disorders discussed in this paper that require input from the two professions are flexural limb deformities (FLD) and angular limb deformities (ALD). The concept of protecting the foot from the deleterious effects of mal-loading created by many FLDs and ALDs is just as important as using the symptomatology as an instrument to correct the deformity. This paper presents a review of the current information regarding the farriery for these two limb deformities while dispelling some of the anecdotal methodology, such as the use of toe extensions to treat flexural deformities, that presently exists. Considering the deficiency of information in the literature, segments of this text will be based on the author's extensive clinical practice, comprehensive clinical records and comparisons of case outcomes.     

Congenital bilateral aplasia of the metacarpophalangeal joints in a foal

A 2‐day‐old Warmblood filly was presented for examination of an angular limb deformity of the left front limb and an upright conformation of both metacarpophalangeal joints. Radiological examination revealed bilateral absence of the metacarpophalangeal joint space with fusion of the third metacarpal bone and first phalanx (synostosis). No treatment was undertaken. The filly was readmitted to the clinic 10 weeks later for bilateral front limb lameness. On radiological examination, the synostosis of the front metacarpophalangeal joints was still present. Physitis of the distal growth plate of the right third metacarpal bone and proximal growth plate of the right proximal phalanx, and an avulsion fracture of the palmaromedial and proximal aspect of the left middle phalanx, with a cystic like lesion on the medial aspect of distal first phalanx and proximal middle phalanx were diagnosed. Given the poor prognosis, the foal was subjected to euthanasia. Post mortem examination confirmed the absence of the metacarpophalangeal joint space with a trabecular bony union between the third metacarpal bone and the first phalanx. A rudimentary joint capsule was present at the level of the absent joints as well as a small zone of articular cartilage, which invaginated over a short distance into the dorsal trabecular bone on the right front limb. On the medial aspect of the left proximal interphalangeal joint, a focal defect of articular cartilage with exposure of subchondral bone was observed. This is the first case report of a foal born with congenital aplasia of both metacarpophalangeal joints. Congenital malformations should be considered as differential diagnosis in lame foals or foals born with angular or flexural limb deformities.     

Periosteal transection of the proximal phalanx in foals with angular limb deformities of the metacarpo/metatarsophalangeal area

Bilateral angular limb deformities of the metacarpo/metatarsophalangeal regions in 2 foals are discussed. Periosteal transection was used to correct the deformity in both foals. In one foal, only the right forelimb was treated because the deformity in the left forelimb did not appear to warrant surgery. Subsequently, an angular limb deformity, which could have been prevented, developed in the left forelimb. A third foal developed a deformity in the proximal phalanx after periosteal transection of the distal third metatarsal bone.     

Management of bilateral flexural deformity of the metacarpophalangeal joints in three alpaca crias

Three neonatal alpacas were treated for MCP flexural deformities. Two crias responded well to conservative therapy using splints made from fibreglass cast material. One cria with severe deformity failed to respond to conservative treatment but recovered satisfactorily after transection of the suspensory ligament in both legs. It seems that mild cases of flexural deformity of the MCP joint in alpaca crias respond well to conservative therapy but that surgical correction may be required in more severe cases. Sequential transection of the structures limiting extension of the MCP joint may result in fewer complications than previously reported techniques.     

Oxytetracycline associated acute kidney injury in a neonatal foal

A 3-day-old Australian Stock Horse filly presented with fulminant acute kidney injury after receiving 4 g of intravenous oxytetracycline at 24 and 48 h of age for medical management of flexural deformities. The filly’s clinical status initially improved, but worsening azotaemia prompted euthanasia after 55 h of supportive care. Necropsy confirmed proximal tubular necrosis. Nephropathy in association with oxytetracycline administration has been rarely reported. This case describes severe nephropathy in an apparently normal foal and highlights the need for thorough case evaluation prior to use of high-dose oxytetracycline therapy for correction of flexural deformities in foals.     

Single transphyseal screws for the correction of moderate to severe angular limb deformities in 28 Thoroughbred foals

This study reports on the effective use of a single transphyseal screw for the treatment of moderate to severe angular limb deformities (ALDs) of the fetlocks and carpi of 28 young Thoroughbred foals. The objective was to evaluate the surgical management of foals with moderate to severe ALDs treated with single transphyseal screws. Evaluation of medical records of 28 Thoroughbred foals treated with single transphyseal screws placed across the distal radial, metacarpal and metatarsal physes was undertaken. The angle of joint deviation was measured prior to implantation and at removal of the implants, and the degree of improvement was calculated. A total of 39 screws were placed: 24 in the distal metacarpus or metatarsus and 15 in the distal radial physis. Varus or valgus deformities in the fetlock improved by 4–5° over a period of 15–30 days. Varus or valgus deformities in the carpi improved by 8–11° in 11–56 days. One case failed to improve adequately due to implant infection. Single transphyseal screws were effective in treating moderate to severe varus and valgus ALD of the fetlocks and carpi in young Thoroughbred foals. Further investigation into their use in the distal radius in young foals is needed. While single transphyseal screws are almost exclusively used by some clinics in the distal metatarsal and metacarpal physes, many clinicians do not use them in the distal radial physis of young foals due to fear of over‐correction, physitis and metaphyseal collapse. This was not observed in any of our cases.     

Femoral head excision after coxofemoral luxation in an Arab filly: Four years follow‐up

A foal with a cranio‐dorsal coxofemoral luxation was treated with a prosthetic capsulorraphy technique after open reduction. After reluxation a femoral head ostectomy was performed for salvage purposes. The filly was discharged with minimal lameness and was using the limb properly after 51 days of hospitalisation. Four years later the filly is still doing well as a breeding mare, with an acceptable quality of life despite angular deformities in the contralateral limb.     

Complications after two transphyseal bridging techniques for treatment of angular limb deformities of the distal radius in 568 Thoroughbred yearlings

Reasons for performing study: Surgical correction of carpal angular limb deformities by growth retardation is commonly undertaken with a screws and tension band wire loop technique (S&W) or a single transphyseal screw (STS). This study compares complications after S&W and STS bridging in the distal radius of Thoroughbred yearlings. Objective: To compare the prevalence of complications serious enough to require follow‐up radiographs following either S&W or STS surgery for growth manipulation in the distal radius of Thoroughbred yearlings. Methods: Medical records and radiographs from Thoroughbred yearlings (age range 261–457 days) treated for carpal angular limb deformities at a single hospital over 2 years were reviewed. Each of the techniques was used exclusively during a single year. The complication threshold criterion for inclusion was the need for nonroutine radiographs of the operated site anytime after implant insertion or removal. Results: Of 568 horses, 253 received S&W and 315 received STS. Horses were of similar age at the time of surgery for STS and S&W. Single transphyseal screws were left in place for a significantly shorter amount of time (16 days). Sex, the limb(s) treated and medial vs. lateral placement were not significantly different between techniques. Complications included physitis post implant removal, metaphyseal collapse post implant removal, infection, overcorrection and seroma formation severe enough to require radiography. Physitis and metaphyseal collapse occurred significantly more frequently with STS compared with S&W. Infection, overcorrection and seromas were not significantly different between techniques. Conclusion: The STS and S&W techniques are both viable treatment options for correction of carpal angular limb deformities. However, horses treated with the STS technique have a significantly increased risk of developing physitis or metaphyseal collapse. Potential relevance: Horses treated with STS bridging have a significantly increased risk of developing the post correction complications of moderate to severe physitis and metaphyseal collapse compared with horses treated with S&W bridging.     

Facilitated ankylosis of a juvenile,flexurally deformed,open, luxated and infected metacarpophalangeal joint using an alternative approach

A 4‐day‐old Arabian filly was referred for severe lameness due to a flexurally deformed, open, luxated and infected metacarpophalangeal joint. Arthrodesis was indicated as progressive cartilage destruction and osteomyelitis developed. An alternative arthrodesis technique was employed, which consisted of a loop of cerclage wire running through predrilled holes in a lateromedial direction and dorsal to the central axis of the third metacarpal bone and proximal phalanx, in combination with external coaptation using a half‐limb transfixation cast. Ankylosis was radiographically confirmed after 4 weeks. The foal was discharged from the hospital with a grade 1 out of 5 lameness and a 6–7° valgus deviation of the ankylosed metacarpophalangeal joint. At telephone follow‐up after 18 months, the owner reported persistence of the valgus deviation, soundness at walk, and a slight gait irregularity at trot. The described cerclage wire arthrodesis technique is a relatively simple method for attaining ankylosis that could be considered in similar cases.     

Volvulus of the large colon in a neonatal foal

A one‐day‐old Thoroughbred colt foal was presented for assessment of abdominal pain and reduced urine output. Physical examination of the foal revealed marked abdominal distension, mild tachycardia, tachypnoea and congested mucous membranes. A marked anechoic peritoneal effusion, intestinal hypomotility and mural thickening of the large colon were detected sonographically. Serosanguinous fluid was obtained by abdominocentesis. After haemodynamic stabilisation, the foal underwent general anaesthesia and exploratory laparotomy and a 720° volvulus of the large colon at the sternal and diaphragmatic flexures was identified. After correction of the volvulus, the intraoperative findings were consistent with nonviability of the affected portion of the colon. The owner declined partial colon resection and elected for euthanasia of the foal. Although rare in neonatal foals, large colon volvulus should be considered in foals with signs of abdominal pain, abdominal distension and ultrasonographic findings of colonic mural thickening and luminal distension.     

Foot management in the foal and weanling.

Foot management and hoof care of foals, weanlings, and yearlings tends to be considered a specialist job. Many farriers and veterinary surgeons have little exposure to young and growing stock. Nevertheless, a variety of angular and flexural limb deformities can benefit from simple podiatry techniques, which can be performed provided that a few basic rules are followed. The combined skills of the farrier and veterinary surgeon offer many young horses with angular or flexural limb deformities a chance of a future athletic career.     

Long-term effects of desmotomy of the accessory ligament of the deep digital flexor muscle in standardbreds: 23 cases (1979-1989).

Desmotomy of the accessory ligament of the deep digital flexor muscle (inferior check desmotomy) permitted Standardbred foals affected with flexural deformities to reach their full athletic potential. Long-term effects of inferior check desmotomy were examined in 23 Standardbreds over a 10-year period. Six of 11 foals that were treated surgically either raced 6 times and obtained a race record or were training sound (if yearlings). All 12 horses with flexural deformity that did not receive an inferior check desmotomy had an unfavorable outcome (no race record). Foals that had surgery performed at a younger age apparently had a better chance of racing or training sound because no foals treated surgically after 8 months of age had a favorable outcome and only 1 foal that was older than 5 months at the time of surgery had a favorable outcome. In 5 foals that had surgery with an unsuccessful outcome, 3 were greater than or equal to 1 year old at the time of surgery and were lame when training was started on the limb(s) with the desmotomy.     

The use of an absorbable bone screw as a transphyseal bridge for the correction of fetlock varus deviations in six foals

This report describes and evaluates the use of a single‐positional absorbable screw (Smart Screw) ¹ as a temporary transphyseal bridge of the lateral aspect of the distal metacarpus in 6 foals with fetlock varus deformities. Using radiographic and visual assessments, an improvement in the severity of the deviation was identified in all cases. There were no complications encountered during screw placement or post operatively. The use of absorbable screws in the treatment of angular limb deformities in foals has potential and offers several advantages over the use of traditional stainless steel implants.     

Correction of angular limb deformities in foals: A review

Angular limb deformities may result in permanent impairment of the foal, if not corrected early. Due to the simplicity of the approach and the effectiveness of hemicircumferential transection and periosteal stripping, the general practitioner can benefit from this technique. In most cases where this procedure is applicable, correction of the angular limb deformity is achieved. Overcorrection does not appear to be a problem.     

Surgical repair of fractures of the lateral and medial tibial malleoli in a yearling Arabian filly

A yearling Arabian filly presented with a history of acute hindlimb lameness, marked tarsocrural effusion and associated soft tissue swelling and was diagnosed with fractures of both the lateral and medial malleoli of the distal aspect of the tibia. The fractures were repaired using a combination of cortical bone screws placed in lag fashion and a tension band wire. A full limb cast bandage was placed for recovery from general anaesthesia and the early post operative period. Despite radiographic development of osteoarthritis, 21 months after surgery the filly was clinically sound and racing successfully.     

Coxofemoral luxation in two foals wearing hindlimb casts

Two foals wearing hindlimb casts developed coxofemoral luxations 6 days and 9 days after the casts were applied. One foal had a cast on one hindlimb up to the proximal portion of the tibia and the other foal had tube casts on all 4 limbs. Although the incidents that resulted in the luxations were not observed, they probably occurred during awkward attempts to stand or from being pushed by the mare, with the affected limb being caught under the body in a forward extended and adducted position.     

Bilateral distal radial epiphysectomy and pancarpal arthrodesis for correction of complex carpal deformities in an American Miniature horse

A 9‐day‐old American Miniature horse was referred for evaluation and treatment of congenital bilateral carpal deformities. Clinical examination revealed a combination of flexural, angular and rotational deformities affecting both carpi. Radiographic evaluation of both forelimbs revealed malformation of the distal radial epiphysis accompanied by flexural contracture and external rotation of the limb distal to the antebrachial carpal joint. Conservative therapy was attempted with splints and bandages and failed to result in improvement. Surgical intervention was elected and a bilateral distal radial epiphysectomy and pancarpal arthrodesis performed. Fourteen months later the mare was turned out to pasture and ambulating well.     

Diseases in neonatal foals. Part 1: The 30 day incidence of disease and the effect of prophylactic antimicrobial drug treatment during the first three days post partum

Reasons for performing study: Neonatal diseases have been grouped and analysed but up‐to‐date statistically significant information about the incidence and prevalence of diseases in foals is limited. Since the 1950s it has been a common management practice to administer a 3 day course of antimicrobial drugs to neonatal foals. This was shown to significantly reduce the incidence of infections (Platt 1977). Since then management practices have improved and it is widely believed that prophylactic antimicrobial drugs are no longer necessary in foal rearing. Objectives: To determine the 30 day incidences or prevalences (depending on case definition) of various diseases and conditions in the neonatal foal and ascertain the influence of a prophylactic 3 day treatment on the frequency of infections. Methods: The population consisted of Thoroughbred foals born on stud farms in the Newmarket (UK) area in 2005 (n = 1031). Depending on the stud farm's practice in the use of prophylactic antimicrobial drugs, 2 groups of newborn foals (treated and untreated) were identified and followed for 30 days. Results: The 30 day incidences of infectious diseases under study were between 0.2% (osteomyelitis) and 5.85% (systemic disease with diarrhoea). The overall incidence for ‘total infectious diseases’ was 8.27%. The most commonly observed noninfectious condition was limb deformities (12.11% of all foals). There was no significant difference in the incidence of infectious diseases between the 2 groups. Conclusion: Infectious diseases are still an important problem in neonatal foals requiring further investigation as to which factors other than antimicrobial prophylaxis are relevant for disease prevention. Potential relevance: The results provide an up‐to‐date overview about the frequencies of various neonatal foal diseases. They do not support the traditional prophylactic use of antimicrobials to prevent infectious diseases in healthy newborn foals. However, it should be noted that this study was not a randomised controlled trial and therefore does not provide the strongest possible evidence for this conclusion.     

Effect of hemi-circumferential periosteal transection and elevation in foals with experimentally induced angular limb deformities

OBJECTIVE: To evaluate the effect of hemi-circumferential periosteal transection and elevation (HCPTE) in foals with, experimentally induced angular limb deformities. DESIGN: Prospective study. ANIMALS: 10 healthy foals. PROCEDURE: When foals were 30 days old, transphyseal bridge implants were placed on the lateral aspects of both distal radial physes. At 90 days of age (or when 15 degrees of angulation had developed), implants were removed, and HCPTE was performed on 1 limb. Foals were confined in small pens after surgery; the front feet of the foals were rasped weekly to maintain medial-to-lateral hoof wall balance. Dorsopalmar radiographic projections of the carpi were obtained before HCPTE and 2, 4, 6, 8, and 48 weeks later. RESULTS: At the time of transphyseal bridge removal and HCPTE, both treated and control limbs were observed to have a significantly greater carpal valgus, compared with the initial degree of angulation at 30 days of age. Following HCPTE or sham surgery, all limbs straightened over the subsequent 2 months of the study. Median angulation was not significantly different between treated and control limbs at any time during the study. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in foals with experimentally induced limb deformities, HCPTE was no more effective than stall confinement and hoof trimming alone for correction of the deformity.     

In Vivo Evaluation of Intramedullary Interlocking Nail Fixation of Transverse Femoral Osteotomies in Foals

Objective—To evaluate an intramedullary interlocking nail for stabilization of transverse femoral osteotomies in foals.
Study Design—A transverse osteotomy and restabilization with an intramedullary interlocking nail was performed on the right femur in three foals and the left femur in three foals. Animals—Six foals weighing 149 to 207 kg.
Methods—The femur was destabilized with a transverse middiaphyseal osteotomy and repaired with a 0.5-in (12.7 mm) interlocking nail. The implanted femurs were radiographed monthly until completion of the study 6 months after surgery. At the completion of the study, all foals were observed for evidence of lameness, gluteal thickness was determined by ultrasonographic measurement, and a necropsy was performed.
Results—Healing was satisfactory in all foals. Five of the six had osseous bridging of the osteotomy apparent radiographically by 3 to 4 months. The sixth foal had postoperative infection but was healed radiographically in 5 months. There was a mean decrease in gluteal muscle thickness of 6.6 mm ( P = .04) in the operated limb of the five foals that healed without complication. Two foals were lame at the completion of the project; one foal with varus deformities of the contralateral limb was mechanically lame, and another was grade 2/5 lame on the operated limb. On necropsy, there was circumferential enlargement of the diaphysis of all operated limbs with the majority of the callus at the cranial and medial aspects of the cortex. All nails were solid within the medullary cavity.
Conclusions —The intramedullary interlocking nail provided adequate stabilization for repair of the transverse osteotomy.
Clinical Relevance —Further investigation is warranted before use for stabilization of spontaneously occurring fracture configurations.