Elbow and Forearm Injuries

1. THE 2-MINUTE KINEMATICS

Forearm fractures account for nearly 50% of all pediatric long bone fractures, possessing a bimodal age distribution peaking in children (6–15 years) and adults over 50. The most common mechanism of injury is a fall onto an outstretched hand (FOOSH), where forward momentum (e.g., falling from a bicycle) heavily influences the degree of displacement.

• Biomechanical Interdependence: The radius and ulna articulate both proximally and distally, allowing the radius to rotate around the ulna for pronation and supination; a fracture of one bone frequently leads to the dislocation of the other at the wrist or elbow.
• Elbow Dislocations: The second most common major joint dislocation, predominantly posterior, transmitting force from the wrist directly to the radial head.
• Supracondylar Fractures: Most common in children aged 5 to 10. Over 95% are extension-type injuries where the distal fragment is displaced posteriorly, while flexion-type injuries (<5%) displace anteriorly.

2. THE BEDSIDE ACTION PLAN

• Immediate Stabilization & Pain Control: Assess pain immediately and provide systemic analgesia. Make the patient strictly nil per os (NPO) in anticipation of procedural sedation or emergent surgical intervention. If a gross dislocation is obvious, immobilize the joint in the exact position it lies before sending the patient to radiology.
• Reduction Techniques: All elbow dislocations require immediate reduction to relieve pain and prevent neurovascular compromise; techniques include manual traction or the chair technique. Displaced supracondylar fractures should only be reduced in the ED if there is associated vascular compromise.
• Specific Splinting Applications:
• Forearm Shaft: Apply a sugar-tong forearm splint and arrange urgent referral within 7 days.
• Supracondylar (Type I/II): Splint or cast with the elbow flexed to 110-120 degrees to use the intact posterior periosteum as a tension band, unless swelling or circulatory obstruction prevents this, in which case 75-80 degrees in neutral rotation is used.
• Coronoid & Olecranon Fractures: Long arm posterior splint immobilization with the elbow in flexion. The forearm should be in supination for coronoid fractures and neutral for olecranon fractures.

3. THE DIAGNOSTIC GRID

• Targeted Physical Exam: Search for subtle puncture wounds that indicate an open fracture where the bone poked through and retracted. For olecranon fractures, test elbow extension against resistance; patients can falsely appear to have intact extension by simply allowing gravity to drop the forearm. Look for puckering, dimpling, or anterior bruising in supracondylar fractures, which signals the anteriorly displaced proximal fragment has penetrated the brachialis muscle.
• Mandatory Neurovascular Checks: Assess the 5 "Ps" (pain, pallor, pulselessness, paralysis, and paresthesias) before and after any manipulation.
• Median Nerve (Anterior Interosseous Branch): Test motor function via the "OK sign" against resistance; check sensation at the volar 2nd digit.
• Ulnar Nerve: Test motor function via finger spread (abduction) against resistance; check sensation at the 5th digit.
• Radial Nerve: Test motor function via the "thumbs up" sign; check sensation at the dorsal web space.
• Indications for CT/Angiography: Palpable radial pulses do not rule out a brachial artery injury. If a posterior elbow dislocation presents with a wide humerus-olecranon space, reduce the elbow and immediately obtain a CT angiography to evaluate for vascular injury. CT is also frequently required to diagnose coronoid fractures.

4. THE VISUAL BOARD

• Explicit X-Ray Interpretation: A true lateral and AP view of the elbow are essential to avoid missing subtle fractures, and imaging of the entire forearm is required to prevent missing concomitant distal fractures.
• Occult Fractures & Fat Pads: Evaluate for anterior and posterior fat pad signs. The appearance of an abnormal fat pad can indicate an occult fracture or joint effusion.
• The Benign X-Ray Trap: Even without definite radiographic findings, a child presenting with localized supracondylar tenderness must be treated as an occult fracture; apply a splint and refer for follow-up in 24-48 hours, as periosteal new bone formation may only become visible weeks later.

5. THE CLASSIFICATION MATRIX

• Gartland Classification (Supracondylar Fractures): Used to communicate the degree of cortical disruption and surgical urgency.
• Type I: Nondisplaced. Can be safely discharged with a splint.
• Type II: Minimally displaced. Treated with splinting or percutaneous pinning.
• Type III: Totally displaced. Requires emergent orthopedic consultation, admission, frequent neurovascular checks, and closed reduction with percutaneous pinning (or open reduction).
• The Terrible Triad: Complex elbow dislocations associated with both a coronoid fracture and a radial head fracture. This inherently unstable injury pattern requires surgical management.

6. THE DANGER ZONE

• Missed Compartment Syndrome: Severe forearm pain out of proportion to the injury, intense pain with passive extension of the fingers, and tense swelling signify developing compartment syndrome. The risk peaks at 24 to 48 hours post-injury when swelling is maximal. Note that the absence of some classic findings (like pulselessness) does not exclude the diagnosis.
• Cognitive Traps in Immobilization: Failing to reassess neurovascular status after splinting. If a patient develops a radial nerve palsy (e.g., inability to extend the thumb) after a humerus or forearm fracture is placed in a sling/splint, the splint must be removed to undo the offending manipulation, followed by admission for operative repair.
• Isolated Dislocation Fallacy: Because the radius and ulna function as a continuous ring, an isolated fracture of the radius or ulna should immediately trigger a hunt for a joint dislocation at the wrist or elbow.

7. MCQ MASTERCLASS

• Buzzword: "Nightstick fracture" = Isolated fracture of the ulna's middle third from direct trauma (e.g., blocking a blow).
• Buzzword: "Puckering or dimpling" of the anterior elbow = Supracondylar fracture with brachialis muscle penetration.
• Associated Nerve Injury (Monteggia): Proximal 1/3 ulna fracture with radial head dislocation. Classically associated with radial nerve injury.
• Associated Nerve Injury (Galeazzi): Distal 1/3 radius fracture with distal radioulnar joint (DRUJ) dislocation. Three times more common than Monteggia and associated with ulnar nerve injury.
• Common Exam Distractor: Describing fracture displacement using "anterior/posterior" for the distal forearm. Correction: Distal radius/ulna displacement must be precisely described as "volar" or "dorsal".

8. THE BOARDROOM SCRIPT

"I am consulting you for a [Patient Age]-year-old [Right/Left]-hand dominant patient who sustained a high-energy FOOSH injury resulting in a [Diagnosis, e.g., Type III Gartland supracondylar fracture / Galeazzi fracture-dislocation]. On examination, there is gross deformity with [dorsal/volar] displacement and [dorsal/volar] angulation. My mandatory neurovascular check reveals [intact/compromised] function, specifically noting [presence/absence] of radial nerve motor function via the thumbs-up sign, and a warm hand with capillary refill under 2 seconds. The compartment compartments are soft with no pain on passive finger extension. I have made the patient NPO, provided procedural sedation to perform a temporizing closed reduction, and applied a [sugar-tong / long-arm posterior] splint. Post-reduction X-rays show improved alignment and the neurovascular exam remains intact. The patient requires your urgent evaluation for definitive operative management."