Angular limb deformities and their treat-ment in foals and young horses constitutea significant part of the orthopedic prob-

lems that veterinarians must manage. This articlediscusses the clinical management and prognosisof these postural deformities.

TREATMENTThe absence of controlled studies has

impaired the accumulation of scientific dataguiding the management of angular limb defor-mities in foals (Table 1). The following man-agement recommendations are based on theliterature and our experience in treating foalswith angular limb deformities. Also, we use theterms mild, moderate, and severe angular defor-mities, which are defined as less than 10˚, 10˚ to

20˚, and greater than 20˚,respectively.1

Article #4

ABSTRACT:

CE

This article presents an overview of the clinical management of foals with angular limbdeformities. Both conservative and surgical treatment options exist; the choice of whichto use should be based on the type, severity, and location of the deformity as well as theage of the foal. Conservative measures include controlled exercise, rigid external limbsupport, and corrective hoof trimming. Surgical treatment modalities comprise tech-niques for manipulating physeal growth and, after physeal closure, various correctiveosteotomy or ostectomy methods.The prognosis is generally good if treatment is initi-ated well in advance of physeal closure.

Conservative TreatmentIn most foals born with mild to moderate

angular deformities, spontaneous resolutionoccurs within the first 2 to 4 weeks of life.2 Innewborn foals, periarticular laxity is the mostlikely cause, and these foals require no specialtreatment other than a short period of con-trolled exercise. In our opinion, mildly andmoderately affected foals should not be confinedto a stall because exercise is important for nor-mal muscular development and resolution of theangular deformity. The opposite treatment (i.e.,unlimited exercise) often leads to fatigue, whichexacerbates the deformity. Therefore, we suggestthat the mare and foal be placed in a small pad-dock (e.g., 15 × 15 m). Alternatively, the mareand foal may be kept in a large stall (e.g., 5 × 3m) and allowed frequent access to a small pad-dock for a few hours at a time to prevent exces-sive fatigue. There is a lack of scientific datadocumenting how much confinement thesefoals need, and these recommendations are

Angular Limb Deformities in Foals:Treatment and Prognosis*

Nicolai Jansson, DVM, PhD, DECVSSkara Equine HospitalSkara, Sweden

Norm G. Ducharme, DVM, MSc, DACVSCornell University

*A companion article on causeand diagnosis appeared in theJanuary 2005 issue (p. 48).

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Angular Limb Deformities in Foals:Treatment and Prognosis 135CE

based only on our experience.Foals with severe periarticular laxity and grave angular

deformities are unlikely to experience spontaneous cor-rection.2 These foals often need some form of externalsupport to straighten the limb in addition to stall andsmall paddock rest. A splint bandage or tube cast (i.e., acast that does not enclose the foot and fetlock) can beapplied to keep the limb straight and allow the periar-ticular tissues and collateral ligaments to strengthenwithin 2 to 4 weeks.2–4 By not incorporating the foot, asplint bandage or tube cast allows weightbearing, thuspreventing muscular atrophy and worsening of the con-

dition. However, treatment of periarticular laxity byrigid external support has been debated and, accordingto one author, may actually delay strengthening of theperiarticular structures.5 Because periarticular laxitymost often affects the carpus or tarsus, the splint band-age or cast should extend from the proximal radius ortibia to just above the fetlock joint. We use a transectedpolyvinylchloride pipe to create a hemispherical splintthat can be applied to the palmar aspect of the forelimbover roll cotton padding regardless of whether a valgusor varus deformity is being treated.

Because of the anatomy of the hindlimb, tarsal defor-mities can be best stabilized by applying a dorsal splint

that is bent to follow the dorsal contour of the limb.2

For splint bandaging, the foal should be sedated and lat-erally recumbent. After this, the deformity can be man-ually corrected and the splint applied to the limb.a

Splint bandages should be changed at least every 3 to 4days to check for skin pressure sores.3 However, ashorter bandage change interval is preferred.

In our experience, managing splint bandages is prob-lematic on many farms because of the help necessary inplacing a splint: someone to hold the mare, someone torestrain the foal, and someone to apply the splint. Thelabor required for splint application competes with the

demands of a breeding farm during the breeding season.To minimize these labor concerns, we have used snap-onsplints or tube casting. The snap-on splint is custom-made from padded fiberglass (Endurasplint 2, CarapaceInc., New Tazewell, TN; Figure 1). These splints haveenough strength for foals younger than 6 weeks of age.The foal should be sedated and laterally recumbent. Arectal sleeve should be placed over the limb to besplinted to protect it from contact with water andpolyurethane resin. The splint should be immersed inwater at a temperature of 69.8˚F to 73.4˚F (21˚C toaAuer JA: Personal communication, University of Zurich,Switzerland, 2003.

Table 1. Treatment Modalities for Foals with Angular Limb Deformities

Treatment Modality Angular Limb Deformity

Stall and/or small paddock rest All types

Rigid external support to the limb (e.g., splint Periarticular laxitybandage or tube cast) Cuboidal bone hypoplasia

Hypoplasia of the proximal aspect of the fourth metacarpal bone

Corrective hoof measures (e.g., trimming, Deformities originating in a long bone before cessation of physeal shoeing) growth

Surgical manipulation of physeal growth (growth Deformities originating in a long bone before cessation of physeal acceleration and/or growth retardation techniques) growth

Corrective ostectomy or osteotomy Deformities originating in a long bone after cessation of physealgrowth

Confinement to reduce axial compressive forces on the affected limb is an important part of managing angular limb deformities in foals.

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Angular Limb Deformities in Foals:Treatment and Prognosis136 CE

23˚C), and excess water should subsequently be squeezedout. The splint should be applied to the limb so that thefelt is against the skin and half of the circumference ofthe limb is covered. It should then be secured to the limbwith gauze and allowed to dry sufficiently to hold itsshape. The splint should be removed and allowed to setfor 5 to 7 minutes before reapplying it to the limb.Because the splint is padded and molded to the contourof the limb, it should be easy to place and only a singleroll of self-adhesive elastic bandage should be needed tosecure it, making it convenient for daily use. In a hospitalsetting, we recommend leaving the splint on for 12 hoursat a time to prevent pressure sores; the splint should beapplied at night while the foal is less active.

Another means of establishing external support to alimb is application of a tube cast, which is best done withthe patient under general anesthesia.4,6 Casts should bechanged at 10- to 14-day intervals to allow rapid growthof young foals.6,7 The main disadvantage of tube castingis the risk of developing skin pressure necrosis; this canbe somewhat reduced by cutting the cast into two half

shells immediately following application.7 The shells maythen be removed every 3 to 4 days to evaluate the skin.8

It should be noted that foals cope with rigid uni- orbilateral forelimb bandages or unilateral hindlimb band-ages without difficulty, whereas they need help rising ifboth hindlimbs require rigid external support.4

In foals born with angular deformities associated withcuboidal bone hypoplasia of the carpus and/or tarsus,treatment should be directed toward maintaining normalalignment of the affected limb and allowing the carti-laginous templates to ossify under even loading4–6,8,9 (Fig-ure 2). Except for very mild cases (<7˚), untreated foalsare at risk of developing permanent angular limb defor-

Figure 1. Endurasplint (Carapace Inc., New Tazewell,TN) is made of padded fiberglass and has the advantageof being molded to follow the contour of the limb,thereby reducing the risk of skin pressure sores.

Figure 2. Radiograph of the right carpus of a 1-day-oldmixed-breed foal with carpal valgus caused by carpalbone hypoplasia.

Note the rounded andincompletely ossified carpalbones as well as thehypoplastic proximal aspect ofthe fourth metacarpal bonecontributing to the valgusdeformity.

The foal was treated withexternal support to the limb,which allowed the carpal bonesand the proximal aspect of thefourth metacarpal bone toossify under even loading asseen on this radiograph taken 3 weeks later. (Courtesy of Dr.Tony Pease, Cornell University,Ithaca, NY)

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mity due to ossification of the cuboidal bones in awedge-shaped or collapsed configuration.2,3,7 It is there-fore very important that these foals be identified earlyand treated appropriately.2 In these foals, the requiredtreatment includes confinement and external support ofthe limb. The external support may be in the form ofsplint bandages or tube casts as previously discussed.Radiographs should be obtained at 14-day intervals todetermine the degree of cuboidal bone ossification.3

External support should be maintained until the ossifica-tion process is complete, which normally takes 2 to 4weeks. In some foals, it may take up to 2 months, whichstresses the importance of repeated radiographic evalua-tions.3 Foals with incomplete ossification of the proximalaspect of the fourth metacarpal bone should be treated inthe same way as foals with cuboidal bone hypoplasia.10

Angular limb deformities caused by asymmetric phy-

Orthotics

A. Weanling with carpal valgus and external rotationof the right forelimb. The brace should be secured overthe midradius and mid-third metacarpal bone. Note thestabilizing bar on the concave side (lateral aspect) of the limb.A hinge centered over the pivot point allows normal range offlexion of the carpus.

We have treated a select number of weanlings withangular deformities using orthotic devices (orthoses).Orthotics is the science that focuses on the design,manufacturing, application, and evaluation of orthoticdevices to assist in patient ambulation and correction ofvarious skeletal deformities. Using orthotic devices inchildren is well established and recommended for avariety of pediatric conditions.a–c In veterinary medicine,the use of orthotic devices has been extremely limited(excluding corrective shoeing and the standard splintsand casts described in this article). Use of an ankle–footorthosis in a dog with traumatic sciatic neuropathy hasbeen reported.d The orthotic devices that we have usedare custom-made to a given limb of a weanling. A moldis first made using a roll of cast material over astockinette to reproduce for the orthotist the relevantportion of the limb. The cast is cut and removed so thatthe custom-made device can be constructed to fit thelimb of the animal. To treat angular deformities, astabilizing stainless-steel bar should be placed on theconcave side of the deformity and pressure applied onthe convex side to help correct it (A). The foal shouldwear the device for progressively longer periods up to 12hr/day. The device should be removed at night. Furtherinvestigation into this technology is required before itsvalue and potential can be fully assessed.

aGenaze RR: Pronation: The orthotist’s view. Clin Podiatr Med Surg 17:481–503, 2000.bVankoski SJ, Michaud S, Dias L: External tibial torsion and the effectiveness of the solid ankle-foot orthoses. J Pediatr Orthop20:349–355, 2000.cWoolam PJ, Lomas B, Stallard J: A reciprocal walking orthosis hip joint for young paediatric patients with a variety of pathologicalconditions. Prosthet Orthot Int 25:47–52, 2001.d Levine JM, Fitch RB: Use of an ankle-foot orthosis in a dog with traumatic sciatic neuropathy. J Small Anim Pract 44:236–238, 2003.

seal or epiphyseal growth usually develop between 2weeks and 6 months of age; foals are rarely born withthis type of angular deformity. These foals should not betreated with external support because it almost invari-ably results in skin pressure sores without correction ofthe deformity.3–5 Mild deformities often respond well tostall or small paddock rest, whereas moderately affectedfoals need additional treatment in the form of correctivehoof trimming and, possibly, application of glue-onshoes.11,12 Confinement reduces the axial compressiveforces acting on the physeal and epiphyseal growth car-tilage, possibly correcting deformity by stimulating lon-gitudinal growth on the concave side of the limb.10

Contrary to this, excessive compressive forces as a resultof free pasture exercise reduce longitudinal growth onthe concave side. Free exercise may therefore delay cor-rection or even cause the deformity to worsen.6

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Angular Limb Deformities in Foals:Treatment and Prognosis138 CE

To further correct the deformity, the high side of thehoof wall can be frequently trimmed so that the foot islevel.3,7,13 The aim of hoof trimming is to correct the con-current rotational deformity. In foals with valgus deformi-ties, this is done by slightly rasping the outside hoof wall,which causes the inside hoof wall to contact the groundfirst during ambulation, thereby causing slight inwardrotation of the foot.3 Correspondingly, the inside hoofwall should be lowered in foals with varus deformities.3

The effect of corrective hoof trimming may be in-creased by placing a glue-on shoe with extension to theinside in foals with valgus deformities (outside in foalswith varus deformities).3,11,12 As an alternative to glue-onshoes, an extension can be molded directly onto thehoof using acrylic (minimal or nonhyperthermic poly-

mers should be used to prevent hoof damage); we donot feel that this is as safe as glue-on shoes becausemore stress can be applied to the hoof laminae (bybuilding onto or molding the hoof wall), possibly tear-ing a portion of the laminae. By forcing the foot into anabnormal position, corrective trimming and shoeingresult in torsional forces that may influence joints andperiarticular structures negatively and lead to concurrentangular deformities elsewhere.3,12 For example, a varusdeformity at the metacarpophalangeal joint could becreated during correction of a carpal valgus. Therefore,some authors do not recommend trimming and shoeingas outlined but prefer light rasping to balance the footand ensure normal breakover instead.14 However, in our

experience, the described methods for trimming andshoeing, if used judiciously and with frequent monitor-ing, can be applied with success.

Alternatively, trimming and shoeing to correct carpaland tarsal deformities could be done after closure of thedistal metacarpal or metatarsal growth plate. It isimportant not to extend the period of corrective trim-ming and shoeing for too long. Also, we recommendthat glue-on shoes not be left on for longer than 2weeks to avoid development of a contracted foot. Atleast 7 to 10 days of growth should be allowed to pass

before resetting the shoes. If confinement and, possibly,trimming and shoeing have not resulted in significantimprovement of the deformity within 4 to 6 weeks, sur-gical treatment should be attempted.3

Surgical TreatmentIn severely affected foals or those in which an angular

limb deformity is unresponsive to restricted exerciseand, possibly, corrective trimming and shoeing, surgicaltreatment should be administered. The surgical tech-niques to correct angular limb deformities in foals canbe divided into growth acceleration and retardation, theaim of which is to lead to correction by influencing thegrowth rate of the growth plate. Thus sufficient growth

Table 2. Period of Rapid Growth and Ageat Radiographic Closure of Some GrowthPlates in Horses6

Age atGrowth Period of RadiographicPlate Rapid Growth Physeal Closure

Distal radial 0–8 mo 22–36 mo

Distal tibial 0–6 mo 17–24 mo

Distal metacarpal/ 0–100 days 6–15 mometatarsal

Table 3. Age Limit Recommendations(for Optimal Results) for CorrectingAngular Limb Deformities by SurgicallyManipulating Physeal Growth

Technique andGrowth Plate Age Limit (mo)

Distal radial HCPTE: 4TPB: 12

Distal tibial HCPTE: 4TPB: 10

Distal metacarpal/metatarsal HCPTE: 2TPB: 3

HCPTE = hemicircumferential periosteal transection andelevation; TPB = transphyseal bridging.

Both conservative and surgical treatment options are available for managing angular limb deformities in foals.

potential should remain and surgery should be performed well before theend of the rapid growth phase. Restricted exercise until the angular limbdeformity is corrected is an important part of postoperative treatment. It isimportant to note that the period of rapid growth is different from the ageat radiographic evidence of physeal closure6,15 (Table 2). The age limits foroptimal results of surgical manipulation of physeal growth depend on thedegree and location of the deformity.15 Recommendations regarding theoptimal age for surgical treatment vary among authors.1,16,17 In general, foroptimal postoperative results, deformities caused by asymmetric growth atthe distal radial and distal tibial growth plates should be treated before 4months of age, whereas deformities at the distal growth plate of the thirdmetacarpal or metatarsal bones should be treated before 2 months of age(Table 3). These are only general guidelines because the degree of deformitygreatly influences the possibility of surgical correction. The earlier surgery isperformed, the faster correction occurs, which is often the rationale forchoosing surgical treatment well before the end of the rapid growth phase.3

However, according to a recent experimental study18 in which angular defor-mities were created by abaxial growth-plate retardation, surgically inducedgrowth acceleration was as effective in correcting carpal angular limb defor-mities as stall confinement alone. In that study, the cosmetic blemish leftafter surgery gave the visual impression that limbs that were operated on

were straighter than control limbs, but radiographic comparisons showedthere was no difference between limbs. Multiple conclusions can be extrap-olated from this study: Growth acceleration is of little value, and exerciserestriction is effective in treating angular limb deformities.

Since its introduction into equine surgery approximately 20 years ago,7,13,19

growth acceleration by hemicircumferential periosteal transection and eleva-tion (HCPTE) has gained widespread acceptance as the standard surgicaltechnique for correcting angular limb deformities.3,5,8,16,17,19–21 However, pre-vious clinical studies all lacked a control group and merely relied on thedegree of limb straightening as evidence of a positive effect of the proce-dure. This fact and the results of the experimental study already mentionedmay change the interpretation of the value of HCPTE in the future. Withthe patient under general anesthesia, HCPTE should be performed on theconcave aspect of the bone responsible for the deformity. A periosteal inci-sion shaped like an inverted T should be made proximal to the affectedgrowth plate followed by elevation of the periosteum to create two triangu-lar flaps (Figure 3). The periosteal incision and elevation stimulates longitu-dinal growth for approximately 2 months and can be repeated if correctionis incomplete.3 Overcorrection of the deformity has not been reported withthis technique. The exact mechanism by which HCPTE exerts its effectremains unknown. However, several mechanisms have been proposed,

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Surgical manipulation of physeal growth depends on residual growth potential.

including induction of mild metaphyseal ischemia,removal of periosteal compression across the growthplate, and creation of a so-called “internal splint” thatbraces the metaphyseal area and helps regulate itsgrowth.22,23

Postoperative exercise restriction to reduce the axialcompressive forces on the growth plate is an integralpart of treatment. HCPTE results in a cosmetic blemishthat may increase in size up to 2 months after surgeryand then progressively remodel in the following months.The result is that the carpus in the vast majority of year-lings that have undergone surgery bears no evidence ofthis. In our experience, the cosmetic results at themetacarpo- or metatarsophalangeal joint are not quite asgood, and yearlings that have had previous surgery occa-

sionally have detectable thickening at the surgery site.Growth retardation by temporary transphyseal bridg-

ing (TPB) was once the surgical treatment of choice forcorrecting angular limb deformities.24–27 Although thereare no controlled studies to document its effectiveness,there is little doubt that TPB is effective. The surgery isperformed with the patient under general anesthesiaand entails placing a growth-restraining implant acrossthe growth plate on the convex aspect of the bone (Fig-ure 4). The implant temporarily arrests longitudinalgrowth, allowing the concave aspect of the bone to con-tinue to grow, which eventually corrects the deformity.

The rate of correction following TPB has been re-ported.28 In general, carpal deformities that are treatedat 1 month of age can be expected to correct at a rate of

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Figure 3. HCPTE is performed on the lateral aspect ofthe distal radial growth plate to correct carpal valgus.Note the inverted T-shaped periosteal incision.This surgerystimulates longitudinal growth on the lateral side of the growthplate and has an effect for up to 2 months.

Figure 4. Postoperative radiograph showing atransphyseal implant that has been placed across thelateral aspect of the distal radial growth plate to treat acarpal varus. The implant temporarily slows longitudinal growthon the lateral side of the growth plate, thereby correcting thedeformity.

0.4˚ to 0.5˚ per day, which successively decreases to 0.05˚to 0.1˚ per day at 100 days of age.6 The correspondingimprovements for metacarpo- or metatarsophalangealdeformities are different from those just mentionedbecause of the relatively short growth phase of the distalmetacarpus or metatarsus: The rate of correction rapidlydeclines from approximately 0.3˚ to 0.4˚ per day at 2weeks of age to 0.1˚ per day at 80 days of age.28

Three techniques for TPB have been described3 (seebox above):

• Stapling

• Application of two screws and cerclage wire

• Application of two screws and a small bone plate

The main difference between these techniques andHCPTE is the need for a second surgery to remove theimplant once correction has been achieved. Timing isimportant because delayed removal results in overcor-rection of the deformity (Figure 5). In addition, the cos-metic results are generally inferior to those afterHCPTE. Although HCPTE has been regarded as thecurrent standard surgical treatment, its popularity isdeclining in light of recent studies.

TPB remains an effective therapy in managing foals withangular limb deformities. TPB can be performed in youngfoals with severe angular deformities, miniature foals, orfoals with significant limb deformity after the rapid growthphase is over.3 In these cases, growth acceleration and retar-dation techniques are often combined for faster and morecomplete correction of the deformity. TPB can be success-ful in treating carpal or tarsal angular limb deformities ingrowing horses 6 to 12 months of age. Similarly, the tech-nique can be used to correct distal metacarpal or metatarsaldeformities in foals 2 to 3 months of age. However, it is ourclinical impression that many warmblood and draft horsesmay have a slower growth profile; thus surgery may be use-ful even in slightly older foals.

Foals with angulation of the third metacarpal or meta-tarsal bone should first be treated with restricted exer-cise. If the deformity is severe or no improvement is seenin the first month of life, we perform periosteal strippingon the concave side of the deformity. With the patientunder general anesthesia, an I-shaped periosteal incisionis made and elevation is performed on the entire lengthof the angulated bone on the concave side. The hypothe-sis is that if surgery is performed at a young age, theresulting periosteal reaction will be followed by a naturalremodeling process that eventually leads to axial loadingof the affected bone because of bone resorption on theconvex side and preservation of newly formed bone onthe concave side. A similar principle has been applied tofoals younger than 2 months of age with bench kneeconformation.29 In that study, bench knee conformationwas corrected by a combination of HCPTE at the disto-lateral aspect of the radius and an I-shaped periostealincision and elevation on the medial aspect of the thirdmetacarpal bone. However, this approach has never beenevaluated in a controlled clinical study.

Correction of angular limb deformities after cessationof physeal growth necessitates a corrective ostectomy orosteotomy.30 Several types of corrective ostectomy andosteotomy techniques have been reported in theliterature3 (box on p. 144). Because corrective ostectomyor osteotomy requires substantially more skill, experience,and equipment, is associated with a higher postoperativerisk rate, and is more expensive, the technique is usuallyreserved for valuable animals with significant angularlimb deformity after physeal closure.

PROGNOSISSeveral studies have reported the response to both

nonsurgical and surgical treatment of foals with angular

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StaplingOne or more Vitallium (Dentsply Austenal, York, PA)staples should be inserted, with the staple legs placedequidistant on each side of the growth plate. The staplelegs should be parallel to the growth plate and the crossmember perpendicular to it. The staples should beplaced using special equipment (staple holder anddriver).

Screws and wiresA screw (cortex or fully threaded cancellous) should beplaced on each side of the growth plate. One or twoloops of 1.2-mm cerclage wire should be placed andtightened in a figure-of-eight pattern over the screwheads.

Screws and a small bone plateA 2.7-mm bone plate should be contoured to the shapeof the bone and placed perpendicular to the growth plateby a 3.5-mm cortex screw on each side of the growthplate. The screws should be inserted to producecompression across the growth plate.

Techniques for TemporaryTransphyseal Bridging

limb deformities. One study reported that in 81.5% offoals treated with HCTPE to correct angular deformi-ties, total limb straightening was achieved and 60% offoals went on to be used at their intended performancelevel.17 In a study that reported the results of transphy-seal bridging, 80% of foals with carpal deformities and27.3% of foals with metacarpo- or metatarsophalangealdeformities went on to a form of athletic use.31 The poorresults obtained in the foals treated for metacarpo- ormetatarsophalangeal deformities were attributed to thefact that several of these foals were operated on near orafter the end of the rapid growth phase of the distalthird metacarpal or metatarsal growth plate. Racing per-formance after HCPTE in Thoroughbreds has beenreported; treated foals had fewer starts at 2 years of ageand lower start percentile ranks.32 However, it is difficultto rely heavily on these comparison numbers becausemany foals that have undergone surgery for angular limb

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Figure 5. Preoperative radiograph of the right carpus of a 5-month-old standardbred foal with carpal valgus.

The foal was treated using TPB onthe medial aspect of the distalradial growth plate.

By 5 months after surgery, the foal had developed a carpalvarus.

A concurrent radiograph showedthat the implant had resulted inovercorrection of the valgusdeformity.TPB implants must beremoved once the deformity hasbeen corrected.

deformities are not declared as such in yearling sales. Astudy reporting the results of treatment in foals withtarsal valgus demonstrated that only 52.4% met theexpectations of their intended use, and these authorsconcluded that foals with tarsal valgus have a poorerprognosis for future athletic use than do foals withcarpal deformities.33 Another study showed that foalswith incomplete ossification of the tarsal bones andgreater than 30% collapse of the third and central tarsalbones had a poorer outcome than did similar foals withless than 30% collapse,34 thereby stressing the impor-tance of early recognition and treatment.

Conflicting results regarding the significance of thelocation of the pivot point and the presence of radi-ographic abnormalities in cases of carpal deformitieshave been published. According to one study, the moreradiographic abnormalities that are seen distal to thedistal radial physis and the more distal the location of

the pivot point is, the poorer is the prognosis.35 Inanother study, no such correlation could be made.36

Also, it has been demonstrated that surgical manipula-tion of distal radial physeal growth can cause changes inthe angles of all the carpal joints.37 Thus surgical manip-ulation of physeal growth may be successful in correct-ing angular limb deformities originating distal to thegrowth plate (e.g., epiphyseal deformities).

In summary, the prognosis for foals with angulardeformities is generally good with the exception of foalswith greater than 30% collapse of the third and centraltarsal bones. However, the age at which the foals arediagnosed and treated influences the prognosis. Defor-mities that are treated near or after the end of the rapidgrowth phase have a less favorable prognosis. Thisplaces the clinician in a dilemma. If treatment is delayeduntil the foal is 4 to 6 months of age, the prognosis for asuccessful outcome is decreased. On the other hand, iftreatment is done early, many foals may receive unneces-sary treatment. In Dr. Ducharme’s practice, which con-sists mainly of Thoroughbred racehorses, foals areevaluated within 2 weeks of birth and then every 2 to 3weeks thereafter. Significant angular limb deformity istreated with corrective trimming and shoeing in thehope that surgical treatment will be unnecessary. If anangular limb deformity involving the metacarpo- ormetatarsophalangeal joint shows no improvement

within 2 to 3 weeks, surgical intervention is considered.If no improvement is seen within 2 months for a carpalor tarsal angular limb deformity, surgery is considered.This approach tends to decrease the number of foalsthat require physeal bridging.

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16. Mitten LA, Bertone AL: Angular limb deformities in foals. JAVMA 204(5):717–720, 1994.

17. Bertone AL, Turner AS, Park RD: Periosteal transection and stripping fortreatment of angular limb deformities in foals: Clinical observations. JAVMA187(2):145–152, 1985.

18. Read EK, Read MR, Townsend HG, et al: Effect of hemi-circumferentialperiosteal transection and elevation in foals with experimentally inducedangular limb deformities. JAVMA 221(4):536–540, 2002.

19. Auer JA, Martens RJ: Periosteal transection and periosteal stripping for cor-rection of angular limb deformities in foals. Am J Vet Res 43(9):1530–1534,1982.

20. Auer JA: Periosteal transection of the proximal phalanx in foals with angular

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Closing wedge ostectomyA bone wedge should be removed from the horizontalplane in the physeal region of the affected bone. Fixationcan be achieved using one or two dynamic compressionplates.

Step ostectomy in the sagittal planeA vertical bone wedge, the point of which should belocated at the pivot point of the deformity, should beremoved from the center of the affected bone. Fixationcan be achieved by inserting lag screws and a bone plate.

Step osteotomy in the frontal planeA Z-shaped osteotomy in the frontal plane of theaffected bone should be performed. The distal horizontalcut should be located at the level of the pivot point ofthe deformity. Fixation can be achieved by inserting lagscrews and a bone plate.

Ostectomy and Osteotomy Techniquesfor Correcting Angular Limb DeformitiesAfter Cessation of Physeal Growth

limb deformities of the metacarpo/metatarsophalangeal area. JAVMA 187(5):496–499, 1985.

21. Jansson N: Angular limb deformities in 4 foals: Treatment by periosteal tran-section and stripping. Equine Vet Educ 7(2):70–74, 1995.

22. Mase CA: The anatomy and response to surgical manipulation of the distalradial growth plate in foals [master’s thesis]. University of Saskatchewan,1986.

23. Deppermann F, Dallek M, Meenen N, et al: The biomechanical significanceof the periosteum for the epiphyseal groove. Unfallchirurgie 15:165–173, 1989.

24. Heinze CD: Epiphyseal stapling. Proc 9th Annu Conv AAEP:203–216, 1963.

25. Heinze CD: Epiphyseal stapling: A surgical technique for correcting angularlimb deformities. Proc 15th Annu Conv AAEP:59–73, 1969.

26. Turner AS, Fretz PB: A comparison of surgical techniques and associatedcomplications of transphyseal bridging in foals. Proc 23rd Annu ConvAAEP:275–287, 1977.

27. Vaughan LC: Growth plate defects in foals. Vet Rec 98:165–168, 1976.

28. Fretz PB, Turner AS, Pharr J: Retrospective comparison of two surgical tech-niques for correction of angular deformities in foals. JAVMA 172(3):281–286,1978.

29. Auer JA: Beitrag zur frühdiagnose und behandlung einer speziellen stel-lungsanomalie beim pferd. Pferdeheilk 5(4):201–205, 1989.

30. Fretz PB, McIlwraith CW: Wedge osteotomy as a treatment for angulardeformity of the fetlock in horses. JAVMA 182(3):245–250, 1983.

31. Fretz PB, Donecker JM: Surgical correction of angular limb deformities infoals: A retrospective study. JAVMA 183(5):529–532, 1983.

32. Mitten LA, Bramlage LR, Embertsson RM: Racing performance after hemi-circumferential periosteal transection for angular limb deformities in thor-oughbreds: 199 cases (1987–1989). JAVMA 207(6):746–750, 1995.

33. Dutton DM, Watkins JP, Honnas CM, et al: Treatment response and athleticoutcome of foals with tarsal valgus deformities: 39 cases (1988–1997).JAVMA 215(10):1481–1484, 1999.

34. Dutton DM, Watkins JP, Walker MA, et al: Incomplete ossification of thetarsal bones in foals: 22 cases (1988–1996). JAVMA 213(11):1590–1594, 1998.

35. Pharr JW, Fretz PB: Radiographic findings in foals with angular limb defor-mities. JAVMA 179(8):812–817, 1981.

36. Bertone AL, Park RD, Turner AS: Periosteal transection and stripping fortreatment of angular limb deformities in foals: Radiographic observations.JAVMA 187(2):153–156, 1985.

37. Brauer TS, Booth TS, Riedesel E: Physeal growth retardation leads to correc-tion of intracarpal angular deviations as well as physeal valgus deformity.Equine Vet J 31(3):193–196, 1999.

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Angular Limb Deformities in Foals:Treatment and Prognosis 145CE

ARTICLE #4 CE TESTThis article qualifies for 2 contact hours of continuing education credit from the Auburn University College of Veterinary Medicine. Subscribers may purchase individual CE tests or sign up for our annual CE program.Those who wish to apply this credit to fulfill state relicensure requirements should consult their respective state authorities regarding the applicability of this program. To participate, fill out the test form inserted at the end of this issue or take CE tests online and get real-time scores at CompendiumVet.com.

CE

1. Which statement regarding management of con-genital angular limb deformities is correct?a. In most foals born with mild to moderate angular

limb deformities, spontaneous resolution is unlikely.b. In most foals born with mild to moderate angular

limb deformities, spontaneous resolution occurswithin 2 to 4 weeks of life.

c. In most foals born with angular limb deformities dueto carpal or tarsal bone hypoplasia, spontaneous res-olution occurs within 2 to 4 weeks of life.

d. In most foals born with angular limb deformities dueto carpal or tarsal bone hypoplasia, spontaneous res-olution occurs within 4 to 8 weeks of life.

2. To avoid development of a contracted foot in afoal, glue-on shoes should not be left on forlonger thana. 2 months.b. 3 months.c. 2 weeks.d. none of the above

3. To allow rapid growth in young foals, tube castsshould be changed at ______________ intervals.a. 3- to 4-day c. 3- to 4-weekb. 10- to 14-day d. 4- to 6-week

4. Corrective ostectomy or osteotomy isa. preferred in treating tarsal bone hypoplasia.b. preferred in treating severe carpal or tarsal bone

hypoplasia.c. generally performed before cessation of physeal growth.d. generally performed after cessation of physeal growth.

5. According to a recent experimental study,HCPTE wasa. more effective than stall confinement alone in cor-

recting carpal angular limb deformity.b. less effective than stall confinement alone in correct-

ing carpal angular limb deformity.c. as effective as stall confinement alone in correcting

carpal angular limb deformity.d. as effective as unlimited pasture exercise in correct-

ing carpal angular limb deformity.

6. Which statement regarding treatment of foalswith carpal bone hypoplasia is correct?a. Foals with carpal bone hypoplasia often require surgi-

cal treatment after an initial period of splint bandaging.b. Foals with valgus deformities caused by carpal bone

hypoplasia should be treated with confinement and byapplying a glue-on shoe with extension to the inside.

c. Foals with valgus deformities caused by carpal bonehypoplasia should be treated with confinement andby applying a glue-on shoe with extension to the out-side.

d. Foals with carpal bone hypoplasia should be treatedwith splint bandaging or tube casting.

7. A 6-week-old foal with a significant varus defor-mity caused by asymmetric growth at the distalmetatarsal growth plate in the left hindlimb isbest treated witha. splint bandaging and confinement.b. confinement.c. corrective trimming and, possibly, shoeing as well as

confinement.d. surgery, corrective trimming, and, possibly, shoeing as

well as confinement.

8. Which statement regarding HCPTE is true?a. HCPTE temporarily retards longitudinal growth on

the convex aspect of the deformity.b. HCPTE temporarily increases longitudinal growth on

the concave aspect of the deformity.c. Foals that have undergone HCPTE require a second

surgery to prevent overcorrection of the deformity.d. HCPTE exerts its effect for approximately 3 months.

9. Which statement regarding TPB is correct?a. TPB is primarily used in young foals with severe angu-

lar deformities, miniature foals, or foals with signifi-cant limb deformity after the rapid growth phase.

b. TPB is primarily used in foals with diaphyseal defor-mities.

c. Contrary to HCPTE, overcorrection has not beenreported after TPB.

d. TPB is primarily used in young foals with severe angu-lar deformities, miniature foals, or foals with diaphy-seal deformities.

10. Postoperative treatment of foals using HCPTEincludesa. free pasture exercise because it tends to increase the

rate of correction.b. confinement.c. splint bandaging.d. none of the above

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Angular Limb Deformities in Foals:Treatment and Prognosis146 CE