Foot pain STUDENT 2022 - Tagged.pdf

Diagnosis and management of foot pain in the horse Dr Peter Milner Senior Lecturer in Equine Orthopaedics BEVA 2009 Learning outcomes • To integrate knowledge of the functional anatomy of the equine digit with conditions causing lameness localised to this area • To rationalise the use of the diff...

Diagnosis and management of foot pain in the horse Dr Peter Milner Senior Lecturer in Equine Orthopaedics BEVA 2009 Learning outcomes • To integrate knowledge of the functional anatomy of the equine digit with conditions causing lameness localised to this area • To rationalise the use of the different diagnostic tests for foot lameness in the horse • To explain the radiographic projections of the equine digit • To describe the management and outcome of different causes of foot pain in the horse • History Diagnostic approach to the horse with foot pain – Type of problem: acute or chronic, intermittent; uni- or bilateral lameness; shifting lameness; worse when worked/surface type; stumbling – Response to previous treatment/farriery • Clinical examination – Resting stance (weight shifting) – Foot balance/conformation; shoeing type and fitting; hoof capsule quality and distortions; shape and size of foot; – Presence of wounds/injuries; presence of effusion/swellings; heat/increased digital pulse; presence of scars – Hoof testers! • Dynamic examination • Local anaesthesia – see diagnostic anaesthesia lecture! Diagnostic imaging of the equine foot • Radiography – most common imaging technique used – Prepare foot well before taking the first radiograph!!! – Standard foot series (DP, LM, DPr-PaDiO (P3 and NB), PaPr-PaDiO) –see next slides • Ultrasound – Limited view through coronary band • Thermography – Surface temperature e.g. laminitis; subsolar abscessation • Nuclear scintigraphy – Rarely used now for foot lameness alone as superseded by MRI • MRI – Currently superior imaging technique for evaluation of foot – Limited availability but more frequently used Lateromedial projection • Horizontal beam • Foot on block/weightbearing – Otherwise will miss out sole – Foot at edge of block • Centre 1-2cm below coronary band, half way between dorsal hoof wall and heels • Look at heels – primary beam perpendicular • Do not collimate too tight! • Markers (dorsal hoof wall/frog) What can you assess on the lateromedial projection? • Phalangeal/solar angle • Relationship to dorsal hoof wall and sole/shoe • P3/P2/NB/DIP joint (P1/PIPJ) – Through DIPJ (look at DP if struggling!) • P3 extensor process – Variation • Navicular bone – Corticomedullary definition – Problem with side bone Horizontal dorsopalmar • Horse stood on blocks • Important that horse is standing straight! • Horizontal beam centred 2cm below coronary band and perpendicular to limb What can you assess on the dorsopalmar projection? • P3 margins – Relationship to hoof wall • Lateromedial balance with markers – Sidebone • DIPJ and PIP joint space • PIPJ joint margins • Navicular bone margins Dorsoproximal-palmarodistal oblique – P3 • Two versions – Upright-pedal • “Truer” image as beam perpendicular to the plate • Horse’s toe in a Hickman block – High coronary • Easier to perform with horse standing on tunnel containing a cassette • Angle down about 65o through coronary band • Slight elongation of foot Images from Butler et al 2005 Clinical Radiology of the Horse What can you assess on the dorsoproximalpalmarodistal oblique (P3) view? • P3 body, solar margin and wings – Crena versus lysis – Vascular channels versus fracture Dorsoproximal-palmarodistal oblique- navicular bone • Upright pedal (as below) or high coronary view • Collimate well • Centre 1-2cm above coronary band Images from Butler et al 2005 Clinical Radiology of the Horse What can you assess on the dorsoproximalpalmarodistal oblique (nav bone) view? Navicular bone • Proximal and distal borders • Lateral and medial wings DIPJ margins Palmar processes of P3 Palmaroproximal-palmarodistal oblique (“skyline” • Foot on cassette tunnel • Leg back/fetlock extended • Tube head under horse – vulnerable! • Centre between bulbs of heels; 45o • Look at LM view or foot conformation Images from Butler et al 2005 Clinical Radiology of the Horse What can you assess on the palmaroproximalpalmarodistal oblique (“skyline”) view? Articular surface of the navicular bone Synovial fossae Lateral/medial borders Flexor cortex and surface Palmar process of P3 Corticomedullary definition Normal variant in sagittal ridge Endosteal surface Conditions of the foot covered in this lecture • Distal interphalangeal joint and associated structures • Distal phalanx – Pedal bone fractures – Pedal osteitis (non-septic) • Navicular bone – Navicular bone fractures • Podotrochlear apparatus – Navicular disease • Deep digital flexor tendon Primary pain of the distal interphalangeal joint and associated structures • Include: – Synovitis/DJD/osteoarthritis/ osteochondral fragmentation – Joint trauma/subchondral bone pain – Collateral ligament desmitis – OCLL • Diagnosis – Clinical features • Uni- or bilateral lameness • DIPJ effusion (non-specific) – Lameness localised to the foot by diagnostic anaesthesia • Beware of lack of specificity of DIP block! – Diagnostic imaging • Radiography • Ultrasound – often unrewarding • MRI – collateral ligament desmitis Management of conditions of the distal interphalangeal joint • Synovitis/osteoarthritis/OC frag. – Intra-articular medication e.g. hyaluranon/corticosteroids, IRAP – NSAIDs – Remove fragment (if sign.) • Joint trauma/subchondral bone pain – Rest, NSAIDs • Collateral ligament desmitis – Rest – Farriery/shoeing (rolled toe) – Shockwave, intra-articular medication • OCLL – Intra-articular medication Pedal bone fractures • One of the more common fractures encountered in equine practice – But still relatively uncommon c.f. subsolar abscessation • Aetiology – Kicking wall; blunt trauma • Penetrating injury/hoof wall trauma • Signs – Acute foot pain (occ.chronic) – Increased digital pulse – Hoof tester +ve; percussion +ve • May not be specific – +/- DIPJ effusion Diagnosis of pedal bone fractures • Clinical signs relating to the foot • Local anaesthesia • Usually improves but may not fully block out • Radiography I • Standard views plus other obliques III to evaluate the “wings” of P3 • Fracture types described – Non-articular/articular, sagittal/ parasagittal, comminuted, extensor process, marginal • Occ. need advanced imaging (e.g. nuclear scintigraphy/MRI/CT) V II IV VI Management of pedal bone fractures • Conservative management – Immobilisation and rest using a bar shoe or hoof/foot cast • Fracture heals by fibrous union • Most foal P3 fractures heal without casting/shoeing (can lead to foot contraction) – Prognosis reduced if articular involvement • Surgical – Removal of fragment(s) e.g. extensor process fractures – Internal fixation e.g. sagittal articular fractures – PD neurectomy for non-healing wing fracture (type I and II) Pedal osteitis (non-septic) • Vague term covering radiographic changes in pedal bone in horses with chronic foot soreness • Often associated with foot imbalance • Diagnosis – Lameness localised to foot – Variable radiographic changes • Demineralisation/widening of vascular channels • Treatment • Correct foot imbalance/reduce abnormal stresses through foot Irregular margination to P3 and diffuse demineralisation Navicular bone fractures • Uncommon – Traumatic aetiology – Occasionally see bi- or tripartite navicular bones • Diagnosis – Moderate lameness • Diagnostic anaesthesia localised to foot – Radiography • Treatment – Conservative (heal by fibrous union) – Surgical repair difficult Navicular disease • Important cause of chronic bilateral forelimb lameness • Typical history of intermittent chronic forelimb lameness often worse on a hard surface and exacerbated in a circle • Horse may stumble, be unwilling to go forward, refuse jumps etc • Associated with low heel/long toe conformation Pathology associated with navicular disease • Age related – Thinning of fibrocartilage and roughening of DDFT • Defects in palmar surface fibrocartilage – Palmar cortex erosion and medullary lysis • DDFT damage – Surface fibrillation, core lesions, adhesions • Defects in palmar cortical bone – Replacement of normal medullary tissue with highly vascularised connective tissue • New bone formation along collateral sesamoidean ligament – Biomechanical adaptation • Degenerative changes around DIP/NB articulation Loss of fibrocartilage and subchondral bone necrosis Image from Blunden et al., 2006 Diagnosis • Clinical evaluation – History; signalment; age – Foot conformation – Hooftester+ve over frog not consistent finding • Dynamic evaluation – Land toe first • Start to point toe when landing – Lameness worse on hard, circle • Local anaesthesia – PD+ve; DIP+ve; NB+ve – May “switch” lameness or worsen lameness on other limb Radiographic abnormalities (in order of importance) • Medullary cyst formation • Flexor cortex erosion/ irregularities • Loss of corticomedullary definition – Endosteal sclerosis • Distal border fragmentation • Entheseophytes on lateral (or medial) border • Enlarged or increased number of synovial fossae (often over interpreted) Treatment options with navicular disease • Farriery – V. important as navicular disease is primary chronic degeneration due to abnormal biomechanical stress – Balance foot • Remove any hoof distortions and improve hoof-pastern axis – Reduce breakover by rolling toe/reducing leverage/improving centre of rotation of DIPJ – Engage frog with ground/shoe and improve heel support Management of navicular disease • Medical treatment – NSAID’s • Often mainstay of management with farriery – Intra-articular or intra-bursal medication • e.g. hyaluranon/corticosteroids – Bisphosphonates • Tiludronate; clodronate licenced • Significantly improved lameness but not resolved • Surgical management – Neurectomy • Around 75% sound after 1yr • Complications include: – Neuroma formation; incomplete desensitisation; reinnervation; DDFT rupture; navicular bone fracture; foot penetration; (hoof capsule slough) Diagnosis and management of primary DDFT lesions in the foot • Diagnosis – Mild-severe acute onset unilateral lameness – Clinical exam often unrewarding – Diagnostic analgesia • Most (but not all) positive to PDNB and NB – Radiography often NAD – MRI diagnosis • Management – Conservative • Rest; shoeing – Surgical • Debridement of lesion via navicular bursa