Disorders of the Equine Elbow

Anatomy and Clinical Overview

- Joint Structure: A ginglymus (hinge) joint composed of the humerus, radius, and ulna.
- Support: Stabilized by medial and lateral collateral ligaments.
- Clinical Significance: Elbow lameness is uncommon; it is typically considered only if pain cannot be isolated to the distal limb.

Diagnostic Procedures

Physical Examination: Requires careful manipulation, including flexion, extension, and rotation.
Intrasynovial Anesthesia: Local anesthetic injection into the joint (after synoviocentesis via a lateral approach) is the best method for localization.
Imaging Modalities:
- Radiography: Limited to mediolateral (limb extended) and craniocaudal (weight-bearing) views.
- Ultrasonography: Ideal for inspecting the soft tissues, specifically the lateral and medial collateral ligaments and joint margins.
- Physiological Imaging: Scintigraphy and thermography are used to detect early pathological changes, particularly in stress fractures and ligament injuries.

Fractures of the Elbow Region

Olecranon Fractures (Ulna):

- Nature: The most common elbow injury in horses.
- Clinical Presentation: Characteristic "dropped-elbow," flexed-carpus, and non-weight-bearing lameness.
- Demographics: Most frequent in horses under 2 years old but can occur at any age.
- Treatment: Tension-band internal fixation is the preferred method; conservative stall rest (8 weeks) is only for nondisplaced, nonarticular fractures.

Distal Humeral Stress Fractures:

- 1. Target Population: Primarily Thoroughbred racehorses.
  2. Diagnosis: Often detected via scintigraphy, which is more sensitive than radiography for these lesions.
  3. Management: Tailored to the horse’s comfort, requiring a careful, staged return to exercise.

Developmental Orthopedic Disease (DOD)

Subchondral Cystlike Lesions (SCLs):
- Location: Most common in the proximal medial radius and the distal medial humeral condyle.
- Treatment: Initially conservative (rest and intra-articular medication) for 90 days.
- Surgery: Recommended if conservative management fails; requires an extra-articular approach because arthroscopic access to the radius is limited.

Soft Tissue and Degenerative Disorders

Olecranon Bursitis (Shoe Boil/Capped Elbow):
- Cause: Trauma from the shoe hitting the point of the elbow while the horse is lying down.
- Signs: Nonpainful swelling at the point of the elbow; becomes painful and causes lameness only if infected.
- Management: Use of a padded "donut" collar on the pastern to prevent further contact, fluid drainage, and improved bedding (avoiding sawdust).
Collateral Ligament Injury (Desmitis):
- Diagnosis: Identified through localized uptake on scintigraphy or architectural changes on ultrasonography.
- Therapies: Options include extracorporeal shock wave therapy and periligamentous injections of biologics like platelet-rich plasma (PRP).
Osteoarthritis (Degenerative Joint Disease):
- Presentation: Managed similarly to other joints; may present as lameness localized to the joint even when radiographic findings are inconclusive (potentially due to subchondral bone damage).

Disorders of the Equine Elbow

Anatomy and Clinical Overview

Joint Structure: A ginglymus (hinge) joint composed of the humerus, radius, and ulna.

Support: Stabilized by medial and lateral collateral ligaments.

Clinical Significance: Elbow lameness is uncommon; it is typically considered only if pain cannot be isolated to the distal limb.

Diagnostic Procedures

Physical Examination: Requires careful manipulation, including flexion, extension, and rotation.

Intrasynovial Anesthesia: Local anesthetic injection into the joint (after synoviocentesis via a lateral approach) is the best method for localization.

Imaging Modalities:

Radiography: Limited to mediolateral (limb extended) and craniocaudal (weight-bearing) views.

Ultrasonography: Ideal for inspecting the soft tissues, specifically the lateral and medial collateral ligaments and joint margins.

Physiological Imaging: Scintigraphy and thermography are used to detect early pathological changes, particularly in stress fractures and ligament injuries.

Fractures of the Elbow Region

Olecranon Fractures (Ulna):

Nature: The most common elbow injury in horses.

Clinical Presentation: Characteristic "dropped-elbow," flexed-carpus, and non-weight-bearing lameness.

Demographics: Most frequent in horses under 2 years old but can occur at any age.

Treatment: Tension-band internal fixation is the preferred method; conservative stall rest (8 weeks) is only for nondisplaced, nonarticular fractures.

Distal Humeral Stress Fractures:

Target Population: Primarily Thoroughbred racehorses.

Diagnosis: Often detected via scintigraphy, which is more sensitive than radiography for these lesions.

Management: Tailored to the horse’s comfort, requiring a careful, staged return to exercise.

Developmental Orthopedic Disease (DOD)

Subchondral Cystlike Lesions (SCLs):

Location: Most common in the proximal medial radius and the distal medial humeral condyle.

Treatment: Initially conservative (rest and intra-articular medication) for 90 days.

Surgery: Recommended if conservative management fails; requires an extra-articular approach because arthroscopic access to the radius is limited.

Soft Tissue and Degenerative Disorders

Olecranon Bursitis (Shoe Boil/Capped Elbow):

Cause: Trauma from the shoe hitting the point of the elbow while the horse is lying down.

Signs: Nonpainful swelling at the point of the elbow; becomes painful and causes lameness only if infected.

Management: Use of a padded "donut" collar on the pastern to prevent further contact, fluid drainage, and improved bedding (avoiding sawdust).

Collateral Ligament Injury (Desmitis):

Diagnosis: Identified through localized uptake on scintigraphy or architectural changes on ultrasonography.

Therapies: Options include extracorporeal shock wave therapy and periligamentous injections of biologics like platelet-rich plasma (PRP).

Osteoarthritis (Degenerative Joint Disease):

Presentation: Managed similarly to other joints; may present as lameness localized to the joint even when radiographic findings are inconclusive (potentially due to subchondral bone damage).