Lameness of the Elbow and Shoulder
Basic Information
Definition
Injuries and lameness associated with the upper forelimb, cubital joint, or scapulohumeral joint
Clinical Presentation
History, Chief Complaint
• Acute, severe lameness of the elbow or shoulder region may be associated with a fall or crashing into a solid object. The horse will shift weight to the opposite limb and will often stand with the carpus slightly flexed.
• In motion, the horse may have a shortened anterior phase to the stride, especially if the biceps tendon or bicipital bursa is affected.
• Upper forelimb fractures usually result in non–weight-bearing lameness. If nerve injury has occurred, the primary complaint may be muscle atrophy over the shoulder, abduction of the shoulder during weight bearing, or dropped elbow.
Physical Exam Findings
• Mild upper forelimb lameness may be difficult to localize. Horses with fractures and luxations will not bear weight on the affected limb, will have localized swelling, and often stand with the carpus partially flexed. If the olecranon is displaced or the radial nerve is damaged, the horse will have a dropped elbow.
• Manipulation of the fracture will cause significant pain and may have auscultable and palpable crepitus.
• Stress fractures or enostoses may have no outward signs whatsoever except for acute lameness.
• Soft tissue injuries may have only a shortened anterior phase to the stride because swelling of the affected tissue is often not observed.
• Nerve injuries may result in abaxial displacement of the shoulder at the walk (“Sweeney shoulder”), dropped elbow, or muscle atrophy. Horses with septic arthritis will usually not bear weight on the affected limb.
Diagnosis
Differential Diagnosis
• Osteoarthritis: Usually a mild but progressive lameness that is relieved with intraarticular anesthesia
• Fractures: Olecranon, proximal radius, humerus, scapula
• Luxations: Elbow luxations are usually associated with proximal fractures of the radius; shoulder luxations are very rare
• Osteochondrosis: Very uncommon in the elbow but is recognized infrequently in the shoulder, particularly the glenoid fossa
• Osseous cyst: May be found in the proximal radius and rarely in the distal humerus
• Stress fracture: Common in racehorses and may be found in the proximal caudal, distal cranial, or caudal aspects of the humerus
• Enostosis (stress reaction, bone islands): Usually only recognized after scintigraphy and high-detail radiography
• Collateral ligament desmitis of the elbow: Usually associated with trauma
• Bicipital bursitis: May be caused by blunt force trauma or strain of the overlying tendon
• Nerve injury to the suprascapular nerve, brachial plexus, or radial nerve