Hindlimb Lameness in Horses PDF

Hind Limb Lameness in Horses Chris Byron Objectives – Hindlimb Lameness 1 & 2 1. Apply basic diagnostic techniques to hind limb problems 2. Understand basic equine anatomy of the hock and stifle as it pertains to common lameness conditions 3. Be familiar with terminology for common hindlimb conditio...

Hind Limb Lameness in Horses Chris Byron Objectives – Hindlimb Lameness 1 & 2 1. Apply basic diagnostic techniques to hind limb problems 2. Understand basic equine anatomy of the hock and stifle as it pertains to common lameness conditions 3. Be familiar with terminology for common hindlimb conditions 4. Recognize common sites for OCD 5. Understand treatments discussed 6. Be familiar with the prognosis for the conditions discussed Outline – Hindlimb Lameness 1 & 2 1. Brief review of diagnostics used 2. Conditions of the tarsus 3. Conditions of the stifle 4. Conditions of the pelvis 5. Be familiar with the prognosis for the conditions discussed Diagnosis – Physical Exam Diagnosis – Lameness Exam Flexion tests Regional anesthesia Diagnosis - Radiography osteochondrosis luxations and fractures Diagnosis Ultrasonography Synoviocentesis t t n 000 Lesion on lateral trochlear ridge (LTR) of the talus Pelvic fractures Normal cytology culture / sensitivity Tarsus (hock) Anatomy–Tarsus n n n Numerous articulations 4 synovial compartments Numerous ligaments Lateral Dorsal Medial Radiographs of the Tarsus Lateromedial Dorsopalmar DLPLMO DMPLLO Synovial Effusions Tarsocrural Joint Effusion Many causes n Idiopathic (unknown cause) n Synovitis/capsulitis n Conformation n Osteochondrosis n Fracture n Desmitis n Septic arthritis aka “Bog Spavin” Calcaneal Bursitis aka “Capped Hock” Synovitis of Tarsal Sheath n Idiopathic effusion of tarsal sheath n Swelling cranial to point of hock n Typically asymptomatic n Requires no treatment aka “Thoroughpin” Treatment Depends on the cause: n Nothing n Cryotherapy (icing) n Rest n IA medications t t t n n Hyaluronic acid IRAP serum Corticosteroids Arthroscopic surgery (diagnosis & treatment) Antimicrobials & lavage (if septic) Osteoarthritis Osteoarthritis (OA) **tarsometatarsal & distal intertarsal joints** n n Tibiotarsal & proximal intertarsal NOT (usually) involved Etiology (specific to TMT/DIT joints) t t t “wear & tear” repeated compression & rotation poor conformation ü sickle hocks ü upright hocks aka “Bone Spavin” Normal Upright Sickle Therapeutic Goal **tarsometatarsal & distal intertarsal joints** n n Pain relief / Soundness Not cartilage preservation WHY??? n Low motion joints n Slow disease progression n Joint fusion desirable Medical Treatment **tarsometatarsal & distal intertarsal joints** n n n n n n n Corrective shoeing/trimming NSAIDs IA corticosteroids Hyaluronic acid PSGAG Nutraceuticals Continued work Arthrodesis Surgical n Drill across joint space n Create “spot welds” Shoemaker, Am J Vet Res, 2006 Chemical n 70% ethyl alcohol n Neurolytic n Protein destruction ü ü light riding – 30 days full work – 5-12 months Ligament Injuries Ligament Injuries Normal 2 1 1 Fragment Medial 2 Enlarged and anechoic Ligament Injuries Plantar Ligament aka “Curb” Medial Tarsal Luxation n n Usually due to trauma Diagnosis ¢ clinical signs p p p ¢ radiographs p n ± stressed views Treatment ¢ ¢ n acute severe lameness soft tissue swelling instability full limb cast (foot to stifle) internal fixation if fractures Prognosis ¢ ¢ fair to poor (pasture soundness) depends on degree of ligament damage and presence of fractures Stifle Anatomy–Stifle n n 3 bones 3 synovial compartments t t t n n n n femoropatellar lateral femorotibial medial femorotibial Collateral ligaments Patellar ligaments (3) Menisci (2: medial, lateral) Cruciate ligaments (2: cranial, caudal Radiographs of the Stifle Lateral CdLat-CrMed Caudocranial Stifle Joint Effusion Many causes n n n n n n Idiopathic Synovitis/capsulitis Osteochondrosis Fracture Soft tissue injury Septic arthritis Osteoarthritis n n n n n n Chronic use Trauma Meniscal tear Cruciate tear Joint instability Untreated OCD meniscus Prognosis – OA in general Depends on: n n n n n n Severity of cartilage damage Severity of bony remodeling Joint(s) involved ± Concurrent soft tissue injury Progression of the changes Intended use Osteochondrosis – General n Synovial effusion n Variable degree of lameness n Young animals ( Reiners, Proc AAEP 2005 100% success => Tnibar, Vet Surg 2002 ** Surgical treatment of choice ** n n standing, sedated horse local anesthetic Long-term outcome ~73% => James, JEVS 2014 Prognosis – Patellar Fixation n n n In general very good – depends on … Response to conservative therapy Response to MPL splitting t n can be performed a second time MPL desmotomy (cutting the entire ligament) t t last ditch option if above do not work ultimately results in development of OA due to resulting joint instability “Mechanical” Gait Abnormalities: Stringhalt Stringhalt (Equine Reflex Hypertonia) n 3 forms ¢ classic form (neurogenic/idiopathic) ü ¢ Australian form (neurogenic/dandelion ingestion) ü ¢ Bilateral Traumatic ü n often unilateral Unilateral Characteristic gait ¢ ¢ ¢ observed at the walk or trot involuntary and exaggerated flexion of one or both hind limbs limb jerked toward abdomen in cranial phase of stride Stringhalt – Diagnosis n Observation of characteristic gait ¢ n differentiate from upward patellar fixation Presence of toxic dandelions and evidence of lack of other forage Stringhalt – Treatment and Prognosis n Prevent ingestion of dandelions ¢ ¢ n herbicides + provide adequate forage fair prognosis (50-78% spontaneous recovery) Lateral digital extensor myotenectomy ¢ ¢ guarded to favorable prognosis response to surgery varies “Mechanical” Gait Abnormalities: Shivers Shivers n n Gradually progressive, chronic neuromuscular disease Clinical signs ¢ ¢ ¢ ¢ n Diagnosis – clinical signs ¢ ¢ n n gait abnormalities when backing up or when farrier working on hind feet trembling of the tail while held erect trembling of the thigh muscles flexed and trembling hind differentiate from stringhalt many breeds, esp. draft horses Treatment – none Prognosis – variable “Mechanical” Gait Abnormalities: Fibrotic Myopathy Fibrotic Myopathy - Diagnosis n n n Traumatic etiology palpable fibrosis of semitendinosus (± semimembranosus) muscle(s) Characteristic gait ¢ ¢ ¢ best observed at the walk abrupt cessation of cranial phase of stride of affected limb foot suddenly jerked caudally just before it hits the ground Fibrotic Myopathy – Treatment and Prognosis n Semitendinosus tenotomy ¢ ¢ most horses improve following surgery few surgical complications Traumatic Musculotendinous Injuries Ruptured Gastrocnemius Muscle n Diagnosis ¢ clinical signs ü ü ü ü ¢ n ultrasound and radiographs Treatment ¢ n vary depending if partial or complete rupture acute lameness partial or complete inability to fix stay apparatus point of hock dropped stall rest and stabilization Prognosis ¢ ¢ foals – favorable adults – poor for complete ruptures Ruptured Peroneus Tertius Muscle n Diagnosis ¢ clinical signs ü ü ¢ n ultrasound and radiographs Treatment ¢ ¢ n ability to extend tarsus while stifle flexed dimple in common calcaneal tendon stall rest – 6 weeks controlled exercise – 3 months Prognosis ¢ ¢ favorable (78% returned to previous exercise; 21% euthanatized) adults with proximal avulsion – guarded Questions? References n n n n Equine Surgery. Auer & Stick, 2012. Chapters 97 and 99 Diagnosis and Management of Lameness in the Horse. Ross and Dyson, 2003. Part IV: The Hindlimb. Chapters 45 and 47 Equine Sports Medicine and Surgery. Hinchcliff et al, 2004. Chapter 19 Adams’ Lameness in Horses. Stashak, 2002. Chapters 2 and 8 (parts X and XII) References n n n Vilar et al. Systematic exploration of the equine tarsus by ultrasonography. Anat Histol Embrol 2008;37:338-343 Byron CR. Collateral ligament injuries in horses. Equine Vet Educ 2016;Epub Raes EV. Ultrasonographic findings in 100 horses with tarsal region disorders. Vet J 2010;186:201-209 A - Tibia B - Calcaneus C - Central tarsal bone D - Third tarsal bone E - Fourth tarsal bone F - Third metatarsal bone G - Fourth metatarsal bone H - Second metatarsal bone I - Tarsocrural joint J - Talocalcaneal- centroquatral joint (proximal intertarsal) K - Centrodistal joint (distal intertarsal) L - Tarsometarsal joint M - Talocalcaneal joint N - Second metatarsal bone 1 - Medial trochlear tali 2 - Medial malleolus 3 - Lateral malleolus 4 - Lateral trochlear tali 5 - Sustentaculum tali 6 - Distal intermediate ridge of tibia