Thoracic+limb+lameness+Part+I+OL+2023 copy.pptx

Thoracic Lameness Part One Learning Objectives • List differentials for lameness localizing to the carpus, elbow, and shoulder regions of the forelimbs • Describe the etiopathology, diagnosis, treatment and outcome of carpal hyperextension injury, elbow dysplasia, incomplete ossification of the hu...

Thoracic Lameness Part One Learning Objectives • List differentials for lameness localizing to the carpus, elbow, and shoulder regions of the forelimbs • Describe the etiopathology, diagnosis, treatment and outcome of carpal hyperextension injury, elbow dysplasia, incomplete ossification of the humeral condyle, elbow luxation, shoulder luxation/instability, and biceps/supraspinatus tendinopathy • Define the components of elbow dysplasia Conditions of the Carpus and Metacarpals Juvenile Adult • Puppy carpal laxity syndrome • Dysostoses • Carpal hyperextension injury • Carpal laxity • Fracture/luxation • Sesamoid disease • Angular limb deformities • Incomplete ossification of the radial carpal bone (Boxer) • Abductor pollicus longus tenosynovitis • Arthritis • Neoplasia • Joint or long bone Carpus • Surgical anatomy • • • • • Hinge joint Radiocarpal bone Ulna carpal bone Accessory carpal bone Numbered carpal bones • Ligaments • Short intercarpal ligaments • Palmar fibrocartilage • Collateral ligaments Hyperextension Injury • Damage to the flexor retinaculum and palmar fibrocartilage • Loss of palmar support • Hyperextension of the carpus • Level of the radiocarpal, intercarpal and/or carpometacarpal joint Radiocarpal Joint Intercarpal Joint Carpometacarpal Joint Hyperextension Injury • Clinical presentation • • • • Variable lameness Soft tissue swelling (acute) Joint effusion Hyperextended stance Hyperextension Injury • Diagnostics • Radiographs • Orthogonal and stressed views • Medial and lateral stressed to look for concurrent collateral damage Hyperextension Injury • Conservative management • Splint and rest • Poor outcome • Long term carpal support • For poor surgical candidates • Partial carpal arthrodesis • Normal radiocarpal joint • Preserves motion of the carpus Orthovet Brace Hyperextension Injury • Arthrodesis • Permanent fusion of a joint • Can be partial – not all bones are fused • Or full – all bones in the joint are fused • Partial carpal arthrodesis • Need a normal radiocarpal joint • Trauma needs to be confined to intercarpal and/or carpometacarpal joints • Fuses the intercarpal and carpometacarpal joints • Normally very little motion in these joints anyway • Preserves motion of the carpus Hyperextension Injury - Surgery • Pancarpal arthrodesis • Fusion of all joints that make up the carpus • Principles of arthrodesis • • • • Complete removal of cartilage Rigid fixation Bone graft Anatomic alignment • 10-12o extension • Splint post op • Complication rate up to 50% • Educate clients on expectations 12 o Hyperextension Injury – After Care • Pain relief • NSAID + adjunctive x 7-10 d • Palmar splint • Change every 1-2 weeks • Monitor for bandage sores • Strict confinement • Radiographs at 8 weeks • Every 2-4 thereafter until clinical union • Takes 12-16 weeks on average to fuse Hyperextension Injury 3.5mm screws • Potential complications • • • • • • • Screw loosening Implant breakage Metacarpal fracture Non healing Infection Physiologic tourniquet Bandaging complications Screw for radiocarpal bone 2.7mm screws Pre-contoured 10-12 degrees Hybrid Pancarpal Arthrodesis Plate Conditions of the Elbow Juvenile Adult • Elbow dysplasia • Incomplete ossification of the humeral condyle • Flexor tendon enthesopathy • Traumatic luxation • Fracture • Neoplasia • Fragmented medial coronoid process • Osteochondrosis/ osteochondritis dissecans • Ununited anconeal process • Incongruity • Ununited medial epicondyle • Congenital luxation • Joint or long bone Elbow Dysplasia • Surgical anatomy Anconeal process • Three joints • Humeroradial • Humeroulnar • Proximal Radioulnar • Collateral ligaments • Radial, ulna, and median nerve • Important landmarks • Medial Coronoid Process • Anconeal Process Medial coronoid process Elbow Dysplasia • Components • Fragmented medial coronoid process (FCP) • Radio-ulna incongruence • Osteochondritis Dissecans • Ununited anconeal process (UAP) • Medial compartment disease/DJD • Flexor tendon enthesopathy • Ununited epicondyle Elbow Dysplasia • Clinical presentation • Large- and giant- breed, fast growing dogs • Onset of lameness at 5-7 months • Or mature dogs with secondary OA • Variable degrees of lameness • Worse with prolonged rest • Worse with exercise • Elbow effusion • Pain on hyperextension and flexion • Decreased ROM, crepitus, palpable thickening Elbow Dysplasia • Diagnostics • Radiographs • Standard lateral and craniocaudal views • Flexed lateral • CT scan • More sensitive • MRI • Ultrasound Elbow Dysplasia Fragmented Medial Coronoid Process (MCP) • Fissure or fragment of the MCP • Kissing lesion on the opposing surface of the humerus • Theories on causes • • • • Osteochondrosis Dessicans Asynchronous growth Osteonecrosis Trauma Fragmented Medial Coronoid Process • Diagnosis • Radiographs • CT scan Fragmented Medial Coronoid Process • Conservative management • Treat how we would treat osteoarthritis • Fragment retrieval • Arthroscopic or open • Subtotal coronoidectomy • Biggest benefit with low to moderate OA • Assess the rest of the joint Fragmented Medial Coronoid Process • Surgical Complications • Post-operative lameness (5%) • Swelling (2%) • Infection (0.2%) • Significant pain (2.8%) • Neuropraxia (0.2%) • Increased long term lameness (7%) % based on a study by Perry et al, which looked at 750 dogs treated with arthroscopy Perry, K. L. & Li, L. A retrospective study of the short-term complication rate following 750 elective elbow arthroscopies. Veterinary and Comparative Orthopaedics and Traumatology 27, 68–73 (2014). Osteochondritis Dissecans (OCD) • Diagnosis • Radiographs • Radiolucent subchondral defect • Radiograph both sides • CT scan • Arthroscopy • DDX kissing lesion – requires histology Osteochondritis Dissecans (OCD) • Flap removal • Arthroscopic or open • Principles • Remove flap • Debride to bleeding subchondral bone • Make the edges perpendicular • More in juvenile orthopedic diseases lecture Medial Compartment Disease • Moderate to severe cartilage erosion • Secondary to other components of elbow dysplasia • Diagnosis • Radiographs • Signs of osteoarthritis • Arthroscopy Medial Compartment Disease • Modified Outerbridge Scale i. Chondromalacia ii. Partial thickness fibrillation and fissuring iii. Full thickness fissuring iv. Full thickness cartilage loss v. Ebernated cartilage (I do not expect you to ID these from pictures, just know the scoring exists and what each score means Medial Compartment Disease • Arthroscopy • Assessment and grading • Abrasion arthroplasty • Make the underlying bone bleed • Stimulates fibrocartilage formation Medial Compartment Disease • Shift the weight to the lateral side of the joint • Sliding Humeral Osteotomy • Fallen out of favor • Proximal Abducting Ulna Osteotomy (PAUL) Sliding Humeral Osteotomy PAU L Medial Compartment Disease • Replace the damaged cartilage with something • Resurfacing • Synthetic • Autogenous • Partial and total elbow replacement Radial-Ulna Incongruence • Step between the radius and ulna at the elbow joint surface • Radius too short • Radius too long • Diagnosis • Radiographs • Difference > 4mm • CT scan • Arthroscopy Radial-Ulna Incongruence • Occurs due to unequal bone growth • Either ulna growth • Premature closure: distal physis • ”Radius too long” • Pressure on the anconeal process • Or radius growth • Premature closure: distal physis • “Radius too short” • Pressure on the coronoid Millers anatomy Radial-Ulna Incongruence • Proximal ulna segmental ostectomy • Bi-oblique • +/- IM pin Radial-Ulna Incongruence • Complications of ulna osteotomy • Non healing • Implant breakage/migration • Premature fusion • Synostosis Ununited Anconeal Process (UAP) • Separate center of ossification • Starts at 11-12 weeks • Complete by 16-20 weeks • 20-25% bilateral • Diagnosis • Flexed elbow radiographs • Over 6 months old Ununited Anconeal Process (UAP) • Fragment removal • Caudolateral approach to the elbow • Dec range of motion, increased OA • Try to get it to heal • Proximal segmental ostectomy • Decreases pressure on the anconeal process to allow union • Screw in lag fashion Elbow Dysplasia Prognosis • Depends on degree of joint damage • Earlier intervention is better? • Regardless OA will progress Elbow Dysplasia Prognosis • Medial Coronoid Disease • Meyer-Lindenburg 2003 • 238 cases of arthroscopy • 60% no lameness • 30% temporary lameness • 10% consistent lameness • Meta-analysis (Evan 2008) • 85% Good to excellent outcome with arthroscopy • 63% with conservative Elbow Dysplasia Prognosis • Medial Coronoid Disease • Dempsey 2019 • No difference between arthroscopy and conservative management • Retrospective owner questioneer > 12 months post-op • Burton 2011 • Gait analysis over 52 months • Initially arthroscopy dogs were more lame • By 52 months, no difference Elbow Dysplasia Prognosis • Ununited Anconeal Process • Small study sizes and few studies • Excision • 90% owner satisfaction • 70% clinical improvement • 50% lameness free • Ulna ostectomy • Variable union rates 21-71% • Screw placement • Union at 2-6 months in 6/10 dogs Questions? Rangitoto and Auckland Harbor, New Zealand Rangitoto Island Auckland, New Zealand