Exam 1: Equine Juvenile Orthopedics

angular limb deformity

• deviation of the appendicular skeleton in the frontal plane

• abnormal angulation refers to the direction of deviation of the limb distal to the involved area or joint in relation to the midline

Valgus

abnormal angulation AWAY from midline

knock knee, angle is OUT

Varus

abnormal angulation towards midline

bow legged

angle is IN

conservative treatment angular limb deformities 

• stall rest 

• splints and tube casts 

  • corrective hoof trimming 

surgical treatments angular limb deformities

• growth acceleration = periosteal transection and stripping

• growth slowing = transphyseal bridging

• corrective osteotomies/ostoectomy

stall rest for angular limb deformities

• cuboidal bone hypoplasia = 4-6 weeks, repeat radiographs at 2 week intervals

• periarticular laxity and normal cuboidal bone ossification = 15 min controlled exercise, swimming if possible

• physeal and diaphyseal growth disturbances= 4-6 weeks, surgery if no improvement

hoof trimming for valgus 

• trim lateral, causing inside of the foot the contact the ground first during the procress of placing weight and rotates medially 

• do not trim heel bulb 

hoof trimming varus

trim medial

do not trim heel bulb

periosteal elevation

• causes growth acceleration

• performed on the short side concave aspect of bone

• repeatable

• good cosmetic results

• no overcorrection possible

• commonly performed laterally in carpal valgus

periosteal elevation postop care 

• light bandages for 10-12 days 

• stall rest 4-6 weeks 

• corrective hoof trimming every 2 weeks 

• observatio/rads 

sites for transphyseal bridging

• distal radius

• distal tibia

• distal mc III,Mt II

techniques for transphyseal bridging

• transphyseal staples

• transphyseal screws

• screws and figure 8 cerclage wires

• screws and small bone plates

use of transphyseal screw 

• most common technique 

• single cortical screw placed THROUGH physis 

• performed on distal radius, tibia, distal MC/Mt 3 

  

use of staple for transphyseal bridging

• commonly used in the carpus

• single staple screw placed across physis

  

transphyseal bridging using screw and wire

• commonly used in the carpus

• two scres placed on either side of the physis, held with a figure 8 cerclage wire across physis

  

transphyseal screw and plate

• commonly used in the carpus

• used for more severe angulation

  

transphyseal bridging post operative care

• light bandages for 10-12 days

• stall rest for 6 weeks

• corrective hood trimming every 2 weeks

• with all types of implants monitor foals daily to determine extent of change

• lack of minitoring can lead to over-correction

• screw removal 2-4 wks post implantation or when limb is at the desirable position

• some screws can be reset or replaced if not enough change in 4 weeks

corrective osteotomy techniques 

• foals with closed growth plates and severe diaphyseal deformities 

• metaphyseal/diaphyseal deformities 

• prolonged recovery and higher cost 

• horizontal wedge, step sagittal, rotational, frontal 

wedge ostectomy

step ostectomy saggital 

step ostectomy rotational

step ostectomy frontal

prognosis for angular limb deformities

• periosteal transection = limb straightening achieved in 60%

• transphyseal bridge = 80% of carpal and 27% of fetlock successful

• trasal valgus= 52%

• incomplete ossification >30%

  • early recognition is key

flexural deformity 

• deviation of a limb in the sagittal plane 

• persistent hyperflexion or hyperextention of a joint 

• classified according to joint involved and age of onset 

• most often observed in forelimbs 

  • usually bilateral unless pain associated 

conservative management flexural deformity of the DIP joint

• restrict protein and caloric intake, balanced trace minerals

• increased exercise

• corrective trimming reducing heel length

• extended toe shoe or acrylic

etiology flexural deformity of DIP joint

• contracture of DDF tendon, club foot

• multifactorial

• rapidly growing foals 2-8mo

• rarely present at birth

• high plane of nutrition

  • functional shortening of DDF muscle tendon unit

flexural deformity of DIP inferior check ligament desmotomy 

• all stage II or stage I with no response to conservative tx 

• lengthening of DDF musculo-tendionous unit

• infections, scarring, recurrence

• 87% of horses treated athletically sound 

flexureal deformity of DIP deep digital flexor tenotomy

• severe stage II deformities

• cases unnresponsive to ICL desmotomy

• salvage procedure, corrective shoeing to prevent DIP subluxation

flexural deformity DIP prognosis

• ICL desmotomy= good for stage I, guarded to fair for stage II, minimal scarring if <1yr

• DDF tenotomy- poor for athletic soundness

congenital flexural deformity of metacarpophalangeal joint 

• contracture of SDF tendon, flexural deformity of the fetlock 

• unequal lengthening of SDF muscle tendon unit and bones of limb 

• DDF tendon and suspensory appear to be involved in some cases 

flexural deformity of metacarpophalangeal joint- congenital- conservative management

• exercise or physical therapy

• light weight bandages

• splits or casts

• oxytestracycline- binds Ca which is used by myofibroblasts involved in contraction

flexural deformity of the metacarpophalangeal- congenital- surgical management

• cases unresponsive to conservative therapy

• SCL desmotomy

• ICL desmotomy

• transection of SDF tendon

• transection of suspensory ligament

SCL desmotomy post op care and px 

• reduced/controlled activity until deformity corrected

• bandages for 12-15 days 

• cast or splint for 10-14 days 

• good px if limb can be straightened manually, better than carpus 

flexural deformity of metacarpophalangeal- acquired- etiology

• multifactorial

• high energy/protein diet

• quarter horses

• excessive or lack of exercise

• pain = physitis in distal radius, OCD in shoulder or fetlock, fractures ect

flexural deformity of metacarpophalangeal- acquired- diagnosis

• horses between 8 and 18mo

• rapidly growing horses

• mostly forelimbs, hindlimbs can also be affected

• palpation of involved structures

• rads showing changes in fetlock and distal interphalangeal joints

flexural deformity of metacarpophalangeal- acquired- conservative management 

• corrective shoeing with elevated heel and toe extension- loads SDF and suspensory but little value if ddf also involved 

• reduce protein and energy intake, balance trace minerals 

  • NSAIDs

  • bandages, splints, casts- heel to proximal cannon bone or higher

flexural deformity of metacarpophalangeal- acquired- surgical management 

• moderate to severe cases unresponsive to conservative 

• SCL desmotomy if SDF only affected structure 

• SCL and ICL desmotomy of SDF and DDf affected 

• salvage= SDF tenotomy, suspensory desmotomy, DDF tenotomy 

flexural deformity of metacarpophalangeal- acquired- complications and prognosis

• pressure sores, recurrence, failure to respond

• px good if fetlock angle can be corrected manually

  • px poor if suspensory involved or joint capsule contracted

flexural deformity of the carpus- etiology

• usually bilateral, almost always congenital

• uterine malpositioning

• teratogenic factors first 3 months= toxic weeds, viral infections

• palmar ligament, palmar carpal joint capsule restricting carpal extension

flexural deformity of the carpus-treatment 

• exercise 

• physical therapy 

• casts, bandaging and splinting (PCV splints, sleeve casts if manually correctable, monitor for slipping, rotation, pressure sores)

• oxytetracycline 

• surgery to release palmar carpal capsule in severe cases unresponsive to splinting 

ruptured common digital extensor tendon

• common congenital disorder, not truly a flexural deformity

• swelling in the tendon sheath at dorsolateral aspect of carpus

• rupture of CDE often secondary to carpal flexural deformity

• bowlegged and “over the knees” stance

flexor tendon laxity etiology

• unknown

• known factors include systemic disease, lack of exercise, pre/dysmaturity, secondary to bandaging and casting

• mainly hind limbs but may involve all 4

• foot rocks back and heel on heel, toe off ground

• abrasions palmar/plantar on pastern and fetlock

flexor tendon laxity- treatment 

• corrective hoof trimming 

• heel extensions 

• forced controlled exercise 

• light bandaging- excessive will make worse!! 

osteochondrosis

• failure of endochondral ossificaton causing thickening or retention of growth plates

• diagnosis when defective cartilage growth in the articular-epiphyseal complex is found

sites of osteochondrosis

• stifle, tarsus, fetlock, shoulder

• physitis

• cervical vertebral malformation aka wobblers

osteochondrosis prognosis varies due to ? 

• location of lesion 

• duration of lesion 

• severity of lesion 

• concurrent DJD 

• owner compliance 

etiologies of stifle osteochondrosis

• OCD in lateral trochlear ridge, medial trochlear ridge, lateral facet of patella

  • cysts in medical femoral condyle, patella

treatment stifle osteochondrosis

• arthroscopic debridement

• 60% athletic function

treatment stifle subchondral bone cyst 

• arthroscopic guided injection of steroids 

• packing with bone cement and stem cells 

• arthroscopic currettage 

locations for tarsal OCD

• distal intermediate ridge of the tibia (DIRT)

• lateral trochlear ridge of the talus

• medial malleous of tibia

• medial trocheal ridge of the talus

treatment of lateral trochlear ridge OCD

• arthroscopic debridement

  • good prognosis

fetlock osteochondrosis 

• OCD of dorsal distal MC3- stagittal ridge 

• P1 osteochondral fragments- dorsal, palmar/plantar 

types of sagittal ridge fetlock osteochondrosis

• 1= defect or flattening, can attempt conservative treatment

• 2= defect or flattening with fragmentation

• 3= defect or flattening with or without fragmentation, loose bodies

P1 fragments fetlock osteochondrosis

• dorsal are not usually OCD but traumatic

• Palmar/plantar may be OCD lesions

• axial fragments can cause lameness and need to be removed

• abaxial fragments are not always signfificant

treatment fetlock osteochondrosis 

• arthroscopic debridement for proximal P1 chips, MC3 sagittal ridge lesions, palmar/plantar P1 fragmentgs 

  • \

treatment fetlock sobchondral bone cysts

• found i P1, MC3

• curettage ± stem cells, bone graft, injection of steroids

causes of shoulder osteochondrosis

• glenoid or humeral head subchondral bone cysts- treat if lame, depends on location

• OCD of humeral head or glenoid- guarded to poor px

osteochondrosis post surgical care 

• stall rest and hand walking → increased hand walking → round pen turn out → small paddoc 

• swimming 

• 60 days to 6 months off before resuming work 

• NSAIDs

• intraarticular steroids

• hyaluronic acid

• PSGAGS

• oral supplemets