Upper Forelimb MOD 2021/22 PDF

Upper forelimb MOD 2021/22 Dr Peter Milner Senior Lecturer in Equine Orthopaedics BEVA 2009 Learning outcomes • To identify common pathological conditions affecting the upper forelimb (carpus to shoulder) • To formulate diagnostic and treatment plans for common pathological conditions affecting t...

Upper forelimb MOD 2021/22 Dr Peter Milner Senior Lecturer in Equine Orthopaedics BEVA 2009 Learning outcomes • To identify common pathological conditions affecting the upper forelimb (carpus to shoulder) • To formulate diagnostic and treatment plans for common pathological conditions affecting the upper forelimb (carpus to shoulder) • To describe overall prognosis for common pathological conditions affecting the upper forelimb Dorsal (left) carpus: bones and joints Radius Radius Radius ACB RC C2 RC IC C3 C3 UC RC IC C3 C4 UC C4 McIV McII Dorsomedial view IC McIII M Dorsal view L Dorsolateral view Dorsal (left) carpus: ligaments and tendons CDE ECR LDE LDE ECR CDE MCL MCL LCL LCL Dorsomedial view M Dorsal view L Dorsolateral view Investigation of problems of the carpus • Clinical examination – Pain/heat/soft tissue swelling – Reduced ROM, crepitus – Joint effusion (differentiate from extensor tendon sheath effusion dorsally) • Diagnostic anaesthesia – Carpal joint anaesthesia (RC and MC) – Median/ulnar nerve block • Radiography – DP, LM, DMPLO, DLPMO, flexed LM – Additional views to skyline carpal bones • Ultrasonography – Carpal and digital extensors and sheaths dorsally – Carpal sheath (SDFT/DDFT, ALSDFT) palmarly Carpal osteoarthritis • Degenerative joint disease affecting one or more of the carpal joints – Secondary to joint trauma, sepsis, fracture or softtissue injury (e.g. intercarpal ligament injury) – Poor conformation may predispose to carpal OA – Arabs predisposed to CMC OA • Clinical signs – Lameness; joint effusion; fibrosis; reduced ROM; positive to carpal flexion; crepitus • Diagnosis – Clinical signs; intra-articular anaesthesia – Radiography • Management – Intra-articular medication; NSAIDs – Arthrodesis in advanced cases (drilling of CMC) Osteochondral fragmentation • Also known as carpal “chip fracture” – May be fragmentation of an osteophyte (in OA) or fragmentation of the dorsal articular margin with training (racing breeds) • Sclerosis of subchondral bone may predispose pathology • Diagnostic anaesthesia and radiography • Management usually involved arthroscopic removal of the fragment(s) Carpal bone fractures • Include slab, frontal and comminuted fractures – Often present as acute single overload but may result from stress maladaptation (e.g. sclerosis from repetitive loading) • Diagnosis – Present as acute lameness + joint effusion with pain/crepitus on palpation – Radiography (inc. skyline views) • Nuclear scintigraphy • Management (slab and frontal) – Conservative • Incomplete f# – Surgical • Usually internal fixation via arthroscopy • Incomplete or complete f# Accessory carpal bone fractures • Trauma/single impact overload – Acute lameness with swelling/pain over the palmar carpus – Horse may stand with carpus semi-flexed – Antebrachiocarpal joint effusion and/or carpal sheath effusion • Diagnosis – Radiography (ultrasound) • Management – Conservative • Most cases heal by fibrosis – Surgical • Repair difficult (shallow/curved bone) • Remove any fragments in joint Carpal canal syndrome • Conditions leading to restriction or pain in the carpal sheath • Include: – Idiopathic tenosynovitis • Haemorrhage or secondary to other cause – Septic tenosynovitis • May or may not have a wound; seen secondary to elective tenoscopy – Tendinitis of the SDFT/DDFT (or muscle tears) – AL-SDFT (SCL) desmitis – Radial physeal exostosis • Bony extension from caudal radius to impinge on DDF muscle belly – Osteochondroma of the distal radius • Discrete separate centres of cartilage ossification – Accessory carpal bone (ACB) fracture • ACB forms lateral boundary of carpal sheath through carpus Carpal canal syndrome • Clinical signs – Carpal sheath effusion – Lameness/pain • Flexion often exacerbates lameness/pain – Puncture wound with sepsis • Diagnosis – Diagnostic anaesthesia (median/ulnar nerve block or carpal sheath anaesthesia) – Synoviocentesis – Radiography – Ultrasonography Management of carpal canal syndrome • Treat underlying cause: – Tenoscopic lavage (e.g. sepsis) – Removal of exostosis/osteochondroma via tenoscopy – Debridement of damaged tendon/ligament – Local anti-inflammatories into the carpal sheath Carpal subluxation • Usually trauma (e.g. high speed fall) – Often have additional carpal bone fractures • Horse is severely lame with marked swelling, carpal instability and overt anatomical derangement • Radiograph to determine level of luxation and presence of fractures • Management – Stabilise with full limb bandage plus splints (zone 3 external coaptation) – Euthanasia in many cases esp with fractures/carpal bone collapse – Surgical partial or complete arthrodesis possible Radial fractures • Usually due to external trauma (e.g. kick) esp. distomedial radius – Moderate swelling and lameness but can weightbear (incomplete fractures) • Check for wounds! – Open/complete fractures in adult horses usually euthanased • Conservative management – Most closed, incomplete fractures in adults managed conservatively – Full limb bandage plus caudal and lateral splint • Cross-tie but head down for feeding – Regular monitoring – can still displace! • Surgical – Internal fixation in foals Conservative management of incomplete radial fractures Complete, displaced transverse closed diaphyseal fracture in a foal managed by internal fixation Ulna fractures • Trauma/kick leading to the fracture of the proximal ulna (olecranon) • Acute lameness +/- wound with swelling/pain around elbow • Dropped elbow stance – (ddx radial nerve paralysis, triceps myopathy) • Radiography – Determine configuration and involvement of joint • (Synoviocentesis) Management of ulna fractures • First aid – Splint carpus as lost stay apparatus • Conservative – Often results in delayed or nonunion in adults • Surgical – Tension-band principal by converting distractive forces of triceps to compression – Plate fixation in adults (plate or wire/pins in foals) generally do well Fractures of the humerus and scapula • Usually acute trauma (kick, impact); also stress f# in racehorses • Presenting signs – Moderate to severe lameness with loss of limb function with complete fracture – Radiography can be difficult in this region Kick wound just above the elbow in this horse led to a complete fracture of distal humerus and nonweightbearing of limb • Management – Complete humeral fractures = euthanasia – Conservative e.g. deltoid tuberosity, scapula spine – Sporadic reports of surgical repair but difficult!!! Comminuted, complete, articular, displaced supraglenoid fracture Osteochondrosis of the elbow and shoulder • Elbow – Osseous cyst-like lesions in proximal radius – Conservative (intra-articular medication) or surgical (extraarticular drilling) • Shoulder – Osseous cyst-like lesions in the distal scapula (also proximal humerus) – OCD of the glenoid cavity Elbow OCLL Poor prognosis as often secondary joint disease present Shoulder OCD Shoulder dysplasia and subluxation • Seen in Shetland/Miniature breeds – Malalignment results in pain/instability • Subluxation can occur without dysplasia secondary to trauma • Moderate/severe lameness with pain on shoulder extension/abduction • Radiographic assessment – Abnormal alignment of scapulohumeral joint – Often secondary OA present • Reduction under GA possible but often recurs • Secondary OA managed conservatively • Shoulder arthrodesis a possibility but most cases euthanased Shoulder OA • Seen infrequently – Secondary to trauma, intra-articular fracture, osteochondrosis , sepsis – Shetland ponies /Miniature breeds predisposed • May be related to shoulder dysplasia • Affected horses/ponies generally moderately to severely lame – Diagnostic anaesthesia of the shoulder – Radiography • Palliative treatment; prognosis guarded Elbow OA • Unusual to get OA in the elbow in horses – Secondary to trauma, sepsis, OCLL • Can be difficult to diagnose – Diagnostic anaesthesia of the elbow joint difficult! – Radiography – (Nuclear scintigraphy) • Management – Intra-articular medication, NSAIDs – Guarded prognosis