267. Injuries to the Elbow and Forearm

Anatomy

Radial nerve: transverses lateral epicondyle. Motor: wrist and finger (posterior interosseus nerve branch) extension. Sensory: dorsal aspect of hand from thumb to middle of ring finger. Test: extend wrist and fingers against resistance, sensation to dorsal thumb webbing.

Median nerve: down the middle. Motor: wrist/finger flexion. Sensory: volar aspect of hand from thumb to middle of ring finger.Test: OK sign with thumb/index finger assesses anterior interosseous branch, Thumb’s up (abduction) assesses recurrent branch; sensation to tip of index finger.

Ulnar nerve:’funny bone;’ wraps around lateral epicondyle. Motor: intrinsic hand muscle. Sensory: ulnar side ring finger and 5th finger. Test: abduction of the fingers, particularly index finger with resistance, little finger sensation.

Xrays

Several lines to look at for subtle/occult fractures.

Anterior humeral line: On lateral view, anterior line of humuer should go through middle 1/3 of capitellum. If displaced, consider supracondylar fracture.

Radiocapitellar line: On lateral view, line through center of radius should transect radial head and capitellum. If displaced, consider radial head fracture or dislocation.

Other xrays: Greenspan view looks at radial head/capitellum view.

Anterior fat pad: should be thin line anterior to distal humerus. Sail sign: large anterior fat pad likely related to fracture: intra-articular involvement.

Posterior fat pad: should not be present. Any fat pad posteriorly likely represents intra-articular involvement.

Pediatric ossification centers: in chronologic order, use mneumonic CRITOE: capitellum, radial head, internal epicondyle, trochea, olecrannon, external epicondyle. Also dirty phrase: Come Rub My Tree Of Love. Radiopedia Video.

Injuries

Biceps rupture: nearly all proximal, caused by resisted overuse/contraction. Usually snap/pop sensation, pain to anterior shoulder with midarm ball. Flexion of elbow in aduction/external rotation will elicit pain. Not necessarily weak due to other accessory muscles. Distal biceps rupture rare, felt in antecubital fossa, does have strength loss. Treatment: sling, ice, ortho referral. Usually surgical repair.

Triceps rupture: rare, unable to extend elbow. Treatment: sling, ice, ortho referral. Complete tear requires surgery.

Lateral epicondylitis: ‘tennis elbow.’ Overuse injury. Tenderness over lateral epicondyle. Pain with forced extension and supination of forearm against resistance. Treatment: rest, ice, NSAIDs, counterforce brace.

Medial epicondylitis: ‘golfer’s elbow.’ Basically opposite of tennis elbow. Medial epicondyle. Pain with forced flexion, pronation of forearm, also sometimes have ulnar neuropathy. Treatment: rest ice, NSAIDs, counterforce brace.

Elbow Dislocation: 90% are posterolateral. Usually present with elbow in 45 degrees of flexion. Check neurovascular complications (usually ulnar). Associated fractures: coronoid process and radial head (all 3 make up ‘terrible triad’). Reduction:longitudinal traction with downward pressure on forearm. Have countertraction as well. Distal traction is continued and elbow is flexed. Alternative: put hands on posterior humerus with elbow flexed at 90 degrees. Put both thumbs on olecrannon and rotate it back into place. Consider putting elbow flexed on backing of chair. Splint in long arm posterior mold with elbow flexed at 90 degrees. Simple reductions can have early ROM after 1 week (with ortho referral and clearance).

Supracondylar Fractures: most common fracture of elbow in children. FOOSH with 95% extension type injuries. Displaced fractures must be reduced and require emergent ortho consult. Look for anterior humeral line on xray for subtle fractures. Always for median nerve (anterior interosseous branch) and radial artery involvement: distal radial pulse as well as OK sign with thumb/index finger. Complication: Volkmann is a compartment syndrome due to post-ischemic swelling.

Nursemaid’s Elbow: radial head subluxation, seen in the very young (1-4 years old). Radial head displaced out of annular ligament. Treatment: squeeze proximal forearm, extend elbow, supinate forearm, then flex. If still having pain, get xray. If still considered nursemaid’s, do same thing, but hyperpronate instead.

Nightstick Fracture: isolate midshaft ulnar fracture from direct blow. Treatment: splint in short arm splint. Fractures >50% displaced, 10% angulation, or involving proximal 1/3 are unstable for likely ORIF.

Radial Head Fractures: most common fractures of the elbow. FOOSH. Usually associated with other injuries. Can affect DRUJ (distal radius ulna junction) called Essex-Lopresti lesion. Look for fat pad abnormalities and Greenspan xray view. Also radiocapitellar line. Treatment: nondisplaced with sling. Displaced usually need surgical repair and referral in 24 hours.

Monteggia Fracture: Proximal third ulna with radial head dislocation. Typically in diaphyseal with anterior dislocation. Apex of ulna fracture points in direction of radial dislocation. Treatment: ORIF.

Galeazzi Fracture: Distal third radial fracture with dislocation of distal radioulnar joint. FOOSH. “Reverse Monteggia” fracture. GRUM mneumonic (GR for Galeazzi/Radius and UM for Ulna/Monteggia). Treatment: ORIF.

Other Fractures (Intercondylar, epicondyle, Trochea, Capitellum, Coronoid): Treat with long arm splint (splint from axilla to proximal to MCP with 3/4 arm encircled and elbow flexed to 90 degrees) with ortho referral.


 

Board Questions

Q1. What nerve is most commonly injured with a supracondylar fracture?

A1. Anterior Interosseous nerve. Wrong answers: Radial, ulna, musculocutaneous.

Q2. What is the most common elbow fracture in adults?

A2. Radial head fracture. Wrong answers: supracondylar, trochea, coronoid, etc.

Q3. What nerve is being tested for motor deficits with the “OK sign” with thumb/index fingers?

A3. Anterior interosseous nerve. Wrong answers: Radial, ulnar, posterior interosseous, recurrent branch of median nerve.

Q4. Which ossification center ossifies last in adolescents?

A4. Lateral epicondyle. Wrong answers: Medial epicondyle, olecrannon, trochea, etc.

Q5. Which type of fracture is this?

 

A5. Monteggia Fracture. Wrong answers: Galeazzi fracture, Nightstick fracture, Radial Head fracture, Supracondylar Fracture.


Clinical Cases

None yet


References/Resources

Tintinalli, Seventh Edition, Chapter 267: Injuries to the Elbow and Forearm.

CrashingPatient, Scott Weingart, Humerus and Elbow, Reviewed 11/19/15.

Radiopedia, Elbow ossification (mneumonic) Video.

Academic Life in EM, Tricks of the Trade: Nursemaid elbow reduction, Fred Wu, Reviewed 11/19/15.

267. Injuries to the Elbow and Forearm

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