BRAN500 Pathology: Elbow Trauma and Clinical Conditions

Epidemiology and Anatomy of Elbow Fractures

• Fractures and dislocations involving the elbow constitute approximately $6\%$ of all fractures.

• There is a distinct age-based distribution in the types of elbow injuries observed:

  • Adults: Primarily involve fractures of the radial head, radial neck, and the olecranon.

  • Children: More commonly involve the supracondylar area or the epicondyles.

Olecranon Fractures

• Prevalence: It is the second most common elbow fracture in adults, surpassed only by fractures of the radial head and neck.

• Etiology (Causes):

  • Acute Trauma:

    1. Direct Blow: A fall or impact directly onto the olecranon. This mechanism is more frequently seen in the elderly population.

    2. Distraction: Extension against resistance.

    3. Avulsion: Specifically of the triceps tendon, often resulting from sudden contraction of the triceps muscle.

  • Repetitive Trauma:

    1. Repetitive abutment of the olecranon into the olecranon fossa.

    2. Triceps traction used to arrest forward motion during throwing activities.

    3. Valgus stress, commonly seen in overhead throwing athletes.

• Anatomical and Pathological Features:

  • Fracture lines may be transverse, oblique, or comminuted.

  • Triceps muscle traction significantly influences the degree of fracture displacement.

  • Classification by Articular Involvement:

    1. Extra-articular: Rare.

    2. Intra-articular: The most common form.

    3. Intra-articular with Association: Often accompanied by radial head fractures or dislocations.

• Imaging Findings:

  • X-ray: The lateral projection is the definitive view for visualizing the fracture line.

  • Fracture Appearance: Presents as a lucent (low density) or sclerotic (high density) line across the olecranon.

  • Avulsion Indicators: A small fracture with displacement located near the proximal tip usually indicates an avulsion fracture at the triceps insertion point.

  • Advanced Imaging: MRI and CT scans are utilized to evaluate the degree of comminution and to identify potential associated triceps injury.

  • Bursal Involvement: Swelling of the olecranon bursa is a common finding.

• Clinical Presentation:

  • Localized pain and swelling over the olecranon.

  • Limitations in elbow extension capacity.

  • Most frequent in adults; significantly less common in pediatric patients due to their limited muscular strength.

• Treatment Protocols:

  • Conservative: Indicated if the fracture is non-displaced. Involves rest and temporary splinting.

  • Operative: Required if the displacement of fragments exceeds $2\,mm$. Typically involves surgical internal fixation.

• Complications:

  • Decreased range of motion (ROM), specifically a loss of $5^{\circ}$ to $15^{\circ}$ of normal extension.

  • Early-onset osteoarthritis.

  • Heterotopic ossification.

  • Ulnar nerve paresthesia.

  • Nonunion of fracture fragments.

  • Infection at the site.

Radial Head and Neck Fractures

• Prevalence: These are the most frequent fractures occurring at the elbow joint.

• Mechanism of Injury: Typically caused by a Fall On Outstretched Hand (FOOSH), resulting in the impaction of the radial head into the capitulum.

• Symptomatology:

  • Pain located on the lateral (outer) aspect of the elbow.

  • Swelling surrounding the elbow joint.

  • Limited range of motion in flexion and extension (bending and straightening).

  • Difficulty with forearm rotation (supination and pronation/turning the palm up or down).

• Classification (Mason Types):

  • Type I: Non-displaced fractures featuring minimal cracks. Treatment usually involves a sling or splint.

  • Type II: Displaced fractures involving larger bone fragments. These may necessitate surgical intervention.

  • Type III: Severely displaced, comminuted fractures with multiple bone fragments. These frequently require surgical repair.

Epicondylar Fractures

• Prevalence: Highly common, particularly among children.

• Mechanisms of Injury:

  • Sudden Muscle Contraction: A sudden pull on the flexor-pronator muscle group, leading to the avulsion of the medial epicondyle.

  • Direct Trauma: Direct impact to the site.

  • Elbow Dislocation: Force transmitted through the ulnar collateral ligament (UCL).

• Symptoms:

  • Pain and swelling localized around the medial/lateral aspects of the elbow.

  • Difficulty with joint movement.

  • Potential physical deformity if significant displacement is present.

• Treatment:

  • Non-operative: The majority of these fractures are managed with immobilization.

  • Operative: Surgery is indicated in cases of significant displacement or if a fracture fragment becomes entrapped within the joint space.

Lateral Epicondylitis (Tennis Elbow)

• Definition: Pain situated at the common extensor tendon insertion site on the lateral elbow.

• Pathology: Chronic tendonitis affecting the Extensor Carpi Radialis Brevis (ECRB) muscle.

• Etiology: Resulting from repetitive wrist extension.

CRITOL: Elbow Fracture Characteristics

• Capitellum: Caused by direct trauma or FOOSH; significantly impacts the stability and movement of the elbow joint.

• Radial Head: Common injury resulting from FOOSH; impacts forearm rotation and joint stability.

• Internal (Medial) Epicondyle: Often occurs as an avulsion fracture; very common in children and frequently associated with elbow dislocations.

• Trochlea: Less common injury; caused by direct trauma or severe dislocation; primarily affects the hinge-like movement of the joint.

• Olecranon: Caused by direct trauma or a fall onto a flexed elbow; impairs elbow extension and is often linked to injuries of the triceps tendon.

• Lateral Epicondyle: Not a common fracture site; typically caused by direct trauma; affects the attachment points of the forearm extensor muscles.