Eq2-mid2- angular limb deformities Flashcards
Perinatal deformities
- cuboidal bone ossification
- about 260 days gestation
- ossification centers: distal radial, tibial epiphysis, carpal and tarsal bones
- ulnar styloid process - last ossification center - ossification progress toward the periphery
Causes of incomplete ossification
- shortened gestation - abnormal uterine position - placental insufficiency, placentitis - metabolic diseases - colic and shock
Grading of Incomplete ossification
- Grade 1: some cuboidal bones of carpus and tarsus have no evidence of ossification - Grade 2: All cuboidal bones have some evidence of ossification - Grade 3: All cuboidal bones are ossified, but small and rounded edges are present. Joint spaces are wide, proximal physes of McIII/MtIII are closed - Grade 4: Cuboidal bones are shaped
Treatment of incomplete ossification
- stall rest: straight limb and incomplete ossification - Exercise on the wekened partially ossified carpal and tarsal bones - abnormal ossification - radiological examination every 2 weeks - splint and cast - splint not below end of fetlock: If the hoof is incorporated in the cast, it will weaken the flexor- and extensor-tendon - splint should be changed every 3 to 4 days, cast evere 10-14 day - if the cast stays on for too long it will lead to flaccid flexor carpi ulnaris and ulnaris lat. (- back at the knee?)
Acquired deformities
Acquired ALDs are results of disproportionate bone growth Rapid bone growth: - Proximal P1: 0-2 months - Distal Mc/Mt: 0-2months - Distal radius: 0-6months - Distal tibia: 0-4 months Developmental factors, genetic predisposition, dietary imbalance, trauma, excersice, physeal dysplasia, heavy birth weigh etc.
Treatment of Acquired deformities
- Carpal deviation up to 4 degrees are normal - Foals have a natural growth correction - 50% have moderate or severe forelimb deformities - more heavily loaded side of bone (concave): grows faster - Less heavily loaded side (convex): grow slower
Non-surgical techniques of Acquired deformities
- Stall rest and controlled exercise - Disproportionate growth at level of physis greater than 10 degrees - stall rested and exercised in controlled fashion (4-6 weeks) - foot manipulation - balancing the force on the growth plate - more effective in fetlock deviation than in carpal
Foot manipulation
- mild fetlock deformities: controlled exercise and hoof trimming - should be repeated every 2 to 4 weeks - Valgus: outside hoof is lowered - Varus, pigeon toe in conformation: inside hoof wall is lowered - trimming or foot extension shoes - Valgus: extension placed on medial aspect of hoof - Varus: extension placed on lateral aspect of hoof
Surgical techniques of acquired deformities
HCPTE (hemicircumferential periosteal transsection and elevation): - growth acceleration - foal after 2 weeks of age - ALD more than 10 degrees - Periosteal transection has its effect 2 months of age - the surgery performed on concave aspect of the limb - valgus-lateral, varus-medial
Technique of HCPTE in distal radius
- horse in lateral recumbency - Valgus: 3cm vertical incision between common and lateral digital extensor tendon, 4-5 cm proximal to the distal radial physis - Inverted T shaped incision in periosteum, elevate flaps - 20% of foals rudimentary ulna is ossified, can be removed with rongeurs - additionally foot manipulation may be used
Technique of HCPTE-distal McIII/MtIII and P1
- concave most distal aspect of metaphysis of McIII/MtIII - before 3 months of age after that limited growth at distal physis - P1-level of extensor branch of suspensory ligament - periosteal incision are T-shaped, the horizontal incision 1 cm distal to the physis
Bench knees
- valgus deformity at distal radius and varus deformity of proximal third of McIII - if this conformation diagnosed the first 2 months: periostal elevation - distal lateral radius and medial distal McIII - Periostal stripping over total length of Mc/Mt
Technique in Growth retardation
- increase static compression at the physis - implants applied at convex surface - bridge the physis temporarily - cerclage wire - single transphyseal screw - distal McIII/MtIII, distal radial/tibialphysis - dorsal recumbency - 10mm proximal to the physis - 4.5 cortex screw : 3,2 mml drill sleeve in 70 degrees to the physis
combination of growth acceleration and retardation
- faster and more complete correction - the advantage of using implants is that they can stay in place as long as they are needed
Implant removal
- prevent overcorrection of the deformity - monthly radiological examination - implant removal before complete limb straightening Complications: - surgical site infection - septic physitis
Flexural limb deformities
- persistent hyperflexion: contracted tendons - tendon units not contracted - relative to short
Congenital flexural deformities
- congenital factors - teratogenic agents - intrauterine positioning - genetic predisposition
Digital hyperextension deformities
- newborn foal: mild degree of digital hyperextension - flaccidity of the flexor muscles - usually corrects itself within few weeks
Treatment of digital hyperextension deformities
- mild digital hyperextension: dont need treatment - minimal trimming of feet - moderate exercise: strengthen musculotendinous unit - Farriery: palmar/planter extension (Dallmer cuff shoes), helps maintain the hoof sole on the ground - light bandaging: minimize the skin trauma - splint bandage and cast incorporating the foot: contraindicated - mild deformity resolve spontaneously
Ruptured common digital extensor tendon
- common congenital disorders - characteristic swelling in tendon sheath dorso-lat aspect of carpus - recognised soon after birth - secondary after flexura deformity - tendon defect palpable in tendon sheath - ultrasound
Ruptured common digital extensor tendon - clinical signs and treatment
clinica signs: - characteristic swelling at the carpus - during walk knuckles at the fetlock joint frequently - in severe cases may not be able to stand treatment: - well-padded splint bandage change in 3-5 days, for 2-4 weeks
Flexura deformities - treatment
Exercise: - moderate exercise: the foal should not be allowed to be over tired Treatment: intravenous oxytetracycline - 3g oxytetracycline in 500 ml saline - the treatment may be repeated 2 times in first week - decrease in matrix metalloproteinase 1 (MMP-1) - inhibits tractional structuring of collagen fibrils
Farriery (hovslager?) - toe extension
- dorsal hoof extension - suffering flexura deformity DIP, MCP/MTP joints - hoof acrylic used
Farriery (hovslager?) - splint/cast
- usefull for MCP/MTP, carpal region - DIP joint - half limb cast not effective - splint - PVC pipe, iberglass - pressure sores - sedation
