MSK: Trauma and Overuse, Elbow and Forearm Flashcards
What is the most common cause of an elbow joint effusion?
Adults: Radial head fracture
Pediatrics: Supracondylar fracture
Elbow joint effusion, suspicious for occult fracture
Note: The posterior fat pad is visible (“sail sign”).
Posterior elbow dislocations are often associated with…
Capitellum fracture
Which fat pad is more specific for an elbow effusion?
The posterior fat pad
Note: You can see the anterior fat pad sometimes in normal elbows.
What can cause a falsely elevated posterior fat pad on a lateral elbow radiograph?
If the radiograph is not a true 90 degree flexed lateral image
Next step
If you see a radial head fracture/dislocation, recommend wrist radiographs to look for another fracture/dislocation in the forearm “ring.”
Next step
If you see a distal ulna fracture/dislocation, recommend elbow radiographs to look for another fracture/dislocation in the forearm”ring.”
What are the major eponymous forearm fractures?
- Monteggia (proximal fracture dislocation)
- Galeazzi (distal fracture dislocation)
- Essex-Lopresti (proximal fracture and distal dislocation)
Monteggia fracture (Fracture of the proximal ulna with dislocation of the radial head)
Note:
Proximal forearm fracture/dislocation (monteggiA = proximal alphabet).
“MUgr” (Monteggia = ulnar fracture).
Galeazzi fracture (Fracture of the radial shaft with anterior dislocation of the distal ulna)
Note:
Distal forearm fracture/dislocation (galeaZZi = distal alphabet).
“muGR” (Galeazzi = radial fracture).
Which eponymous forearm fracture is common in children, but rare in adults?
Monteggia fracture/dislocation
What are the components of a Monteggia fracture?
- Fracture of the proximal ulna
- Dislocation of the radial head
Note:
Proximal forearm fracture/dislocation (monteggiA = proximal alphabet).
“MUgr” (Monteggia = ulnar fracture).
What are the components of a Galeazzi fracture?
- Fracture of the radial shaft
- Dislocation of the distal ulna
Note:
Distal forearm fracture/dislocation (galeaZZi = distal alphabet).
“muGR” (Galeazzi = radial fracture).
What are the components of an Essex-Lopresti fracture?
- Fracture of the radial head
- Dislocation of the distal ulna
Is an Essex-Lopresti fracture unstable?
It is unstable if there is rupture of the interosseous membrane
Essex-Lopresti fracture (fracture of the radial head with dislocation of the distal ulna)
Note: Unlike Monteggia and Galeazzi fractures, Essex-Lopresti involved both the elbow and wrist.
What is a classic cause of cubital tunnel syndrome?
An accessory anconeus muscle
Note: In real life, the most common cause of cubital tunnel syndrome is repetitive valgus stress.
Arrow
Accessory anconeus muscle (AKA anconeus epitrochlearis)
Note: This can cause cubital tunnel syndrome. The normal anconeus muscle is on the lateral side of the elbow.
Where is the cubital tunnel?
Between the olecranon and the medial epicondyle (deep to the cubital tunnel retinaculum, AKA Osborne’s ligament)
What travels in the cubital tunnel?
Ulnar nerve
Clinical manifestations of cubital tunnel syndrome
Ulnar nerve paresthesias (affecting the pinky and ulnar aspect of the 4th digit)
Cubital tunnel syndrome
Note: Edema and enlargement of the ulnar nerve in the region of the cubital tunnel (olecranon/medial epicondyle).
What are the 2 types of epicondylitis? Which is more common?
Lateral epicondylitis (i.e. tennis elbow due to repetitive extension) is more common
Medial epicondylitis (i.e. golfers elbow due to repetitive flexion) is less common
What is injured in lateral epicondylitis?
- Extensor tendon (classically the extensor carpi radialis brevis)
- Radial collateral ligament complex
What is injured in medial epicondylitis?
- Common flexor tendon
- Ulnar nerve (possible if long term)
Lateral epicondylitis (AKA tennis elbow)
Note: The lateral epicondyle is on the radial side.
Medial epicondylitis (AKA golfer’s elbow)
Note: The medial epicondyle is on the ulnar side.
Partial medial ulnar collateral ligament tear
Note: This is the “T sign” and is common in pitchers.
Where does the ulnar collateral ligament attach?
The sublime tubercle on the medial coronoid
This injury is most common in what pt population?
Pitchers (due to repeated valgus overload)
The ulnar collateral ligament has 3 bundles. Which is the most important?
Anterior bundle
Little leaguer elbow (medial epicondyle chronic injury)
Note: This is any repetitive, chronic injury to the medial epicondyle (stress fracture, avulsion, or delayed closure of the medial epicondylar apophysis).
Little leaguer elbow
Any repetitive, chronic injury to the medial epicondyle (stress fracture, avulsion, or delayed closure of the medial epicondylar apophysis)
Note: This is often associated with an ulnar collateral ligament injury.
Valgus overload syndrome
A chronic elbow injury seen in some pitchers, resulting in:
- Ulnar collateral ligament injury
- Arthritis at the posterior humerus/ulna
- Osteochondral defect at the capitellum
Medial epitrochlear ultrasound
If you see medial trochlear lymphadenopathy, think cat-scratch disease (i.e. Bartonella infection)
Olecranon bursitis is commonly seen in…
Pts on dialysis (AKA dialysis elbow), due to constant pressure from positioning during dialysis
Common cause of biceps tear
Weight lifting (bad deadlift form)
What is the most common location for a complete biceps tear?
In the shoulder (with the tendon avulsing off the labrum or at the level of the bicipital groove)
Partial biceps tears are often associated with…
Bicipitoradial bursitis
Note: Median nerve injury can also occur.
Bicipitoradial bursitis
Note: This is often seen with partial biceps tendon tears.
Avulsion of the triceps tendon
Note: This is often associated with a Type 2 Salter Harris fracture of the olecranon in children.
Olecranon bursitis
Olecranon bursitis
Olecranon bursitis
What is the second most commonly dislocated large joint in the adult?
Elbow
Note: Shoulder dislocations are the most common.
What fractures are commonly associated with elbow dislocations?
- Radial head fracture (most common)
- Coronoid process fracture
Posterior elbow dislocation
Medial elbow dislocation
Posterolateral rotary instability of the elbow
The pattern followed during posterior elbow dislocation that starts in the posterolateral corner due to a lateral ulnar collateral ligament rupture and then leads to dislocation
