Although it doesn’t get the spotlight much in emergency medicine, the ED diagnosis and management of elbow injuries is of significant clinical importance. There are several easy-to-miss injuries that can lead to functional impairment. Even minor errors in management can result in long term consequences for patients. In this EM Cases main episode podcast with Dr. Arun Sayal, the brains behind the CASTED Course and Dr. Dale Dantzer, upper extremity orthopedic surgeon at North York General Hospital, we discuss pitfalls in the diagnosis and management of elbow injuries and answer questions such as: What is an easy way to remember the surgical indications for radial head fractures? What is the significance of a coronoid process fracture and how does it change management when seen with a radial head fracture? What is the best way to assess for pronation and supination of the forearm? Why is it so important to assess for the extensor mechanism on physical exam for patients with olecranon fractures? What is a quick easy way to test the peripheral nerves of the upper extremities? Which often missed soft tissue injuries of the elbow require urgent operative management? and many more…

Podcast production, sound design & editing by Anton Helman

Written Summary and blog post by Shaun Mehta and Lorraine Lau, edited by Anton Helman March, 2019

Cite this podcast as: Helman, A. Sayal, A. Dantzer, D. Ten Pitfalls in the Diagnosis and Management of Elbow Injuries. Emergency Medicine Cases. March, 2019. https://emergencymedicinecases.com/elbow-injuries. Accessed [date]

Key concepts in elbow injuries diagnosis and management

  • At 3 weeks of immobilization, there is high risk for chronic elbow stiffness and possible long-term disability
  • While we don’t need to memorize orthopedic classification systems, we should glean key points from them
  • Keep your differential broad for elbow injuries just like you would with a patient presenting with chest pain
  • Learn how to recognize uncommon elbow injuries

Radial head fractures: Sometimes not so simple

The most common adult elbow fracture is a radial head fracture, often seen following a FOOSH—or fall on an outstretched hand—type of mechanism. Since force is transmitted along the entire extremity, ensure you fully examine from the sternoclavicular joint to the hand.

Radial head fracture mechanism of injury

Valgus stress = lateral force. The normal carrying angle of the elbow is slightly valgus. The vector of force with a FOOSH therefore goes through the lateral elbow where the radial head meets the elbow. This explains why the radial head and neck are often implicated, and why medial ligamentous structures are susceptible to injury as the medial side “opens up”.

Radial head fracture physical exam

To identify the radial head, make an equilateral triangle using the following landmarks:

  • Olecranon (laterally)
  • Lateral condyle (superior and anterior to the olecranon)
  • Radial head = third point of the triangle

diagnosis and management of elbow injuries

Pronating and supinating the forearm brings out the radial head.

The elbow is not just a hinge-joint

The elbow moves in supination and pronation, as well as flexion and extension. Ensure all ROMs are assessed on physical exam.

Testing pronation of the forearm. Ensure the elbows are held tight against the trunk. Normal pronation = 90 degrees with thumbs parallel to the floor.

Testing supination of the forearm. Ensure the elbows are held tight against the trunk. Normal supination = 90 degrees with thumbs parallel to the floor.

Pearl: Ask your patient to put their thumbs up while pronating and supinating to get a better sense of how close to their full range of motion they can get.

This video reviews the bony surface anatomy of the elbow including the radial head.

Make note of any mechanical blocks, with difficult pronation and supination being common in a radial head injury. Consider an Essex-Lopresti injury – this is a fracture-dislocation injury involving the radial head (fracture) and DRUJ – distal radioulnar joint (dislocation). Treatment for this specific injury is immobilization in supination.

Pitfall #1. Failure to test properly for pronation and supination range of motion. Testing for pronation and supination ROM with the elbows held tight against the trunk may reveal a subtle radial head or neck fracture or an Essex-Lopresti fracture-dislocation.

It is important to assess flexion/extension of the elbow with gravity eliminated because the weight of the forearm when gravity is not eliminated may be more painful for the patient and thus hinder full range of motion. One way to “eliminate gravity” is to have the patient point the tip of their elbow directly at you with their forearm parallel to the floor, and then asking them to flex and extend their elbow fully.

X-ray interpretation for radial head fractures

First, get a true lateral view x-ray for all elbow injuries

true lateral x-ray is crucial for all elbow injuries. On a 2-dimensional image of an x-ray without orthogonal views, you can easily miss subtle findings. Subtle misalignments can sometimes only be picked up on one view and not on another.

To identify a true lateral view, look for:

  • Superimposition of the trochlea and the capitellum
  • The “hourglass” or “figure of 8” appearance

true lateral elbow x-ray

Consider a radial head injury in any of the following:

  • Disruption of the usual smooth continuous concave shape of the radial head (may be very subtle or not visible on initial x-rays)
  • Anterior sail sign
  • Posterior fat pad sign
  • Disruption of the radiocapitellar line

Joint effusion showing anterior “sail sign” and posterior fat pad sign

Radiocapitellar line. A line drawn through the middle of the radius normally goes through the middle 1/3 of the capitellum.

Pitfall #2: Accepting an inadequate AP x-ray view of the elbow if the patient is unable to extend the elbow enough. Consider separate x-ray views of the humerus and forearm to better assess the integrity of the bones of the elbow.

ED management of radial head fractures: The 30-3-33 Rule

Most radial head and neck fractures are not surgical and can be treated conservatively with a simple sling for comfort. For patients with significant pain and swelling, consider placing a backslab splint. Do not immobilize the elbow for >3 weeks due to risk of chronic elbow stiffness.

Pitfall #3. Immobilizing the elbow for >3 weeks. Prolonged immobilization may lead to chronic elbow stiffness and long term functional impairment.

The Mason classification gives guidance on when radial head/neck fractures may require operative fixation. For a simpler approach, consider expeditious surgical consultation if the fracture satisfies the 30-3-33 rule:

emergency management of pediatric seizures

  • >30 degrees angulation
  • > 3 mm displacement of the fracture fragment
  • > 33% surface area of the radial head involved

Looking for the second injury: the coronoid process fracture and the “terrible triad”

In suspected radial head and neck injuries, make sure to examine the coronoid process, or the anterior proximal portion of the ulna. Coronoid fractures tend to cause elbow instability and may require ORIF, and may be a sign of elbow subluxation or dislocation. They occur with FOOSH and elbow hyperextension, and present with pain over the antecubital fossa. Ask the patient if they felt a pop and subsequent reduction of the elbow during the fall. Coronoid fractures can be subtle on x-ray. It is imperative to look carefully for coronoid fractures on x-ray for all elbow injured patients as these tiny fractures may indicate an unstable joint.

elbow injuries

Subtle coronoid process fracture.

Look out for the terrible triad of the elbow: a radial head fracture, coronoid fracture and elbow subluxation/dislocation. On x-ray, there may not be a sail sign because the hemarthrosis escapes the joint due to significant ligamentous injury.

A terrible triad injury is significant and requires a call to orthopedic surgery ASAP. Immobilize with a long arm posterior plaster splint, positioning the forearm in supination.

Pitfall #4. Failure to look for a second injury after diagnosing a radial head fracture. Specifically, look for a coronoid process fracture and subtle signs of subluxation by ensuring that the clear space around the trochlea is symmetrical and smooth.

Terrible triad: radial head fracture, coronoid process fracture and elbow subluxation

Posterior Elbow Dislocations

Posterior elbow dislocation mechanism of injury

The mechanism once again is a FOOSH but with elbow hyperextension usually a high force. Elbow dislocations (as opposed to shoulder dislocations) are associated with major ligamentous disruption. 90% of elbow dislocations are posterior. Posterior elbow dislocations are more common in teens.

Posterior elbow dislocation physical exam clues

On exam, the patient is often holding their elbow in 45 degrees of flexion. The posterior protuberance of the olecranon sitting posterior to the humerus is best seen from behind the patient. Palpate the medial condyle, lateral condyle and tip of the olecranon; normally they form a symmetrical isosceles triangle. If they don’t, consider a subluxation or dislocation of the elbow.

Pitfall #5. Assuming no dislocation if the joint appears in place in the ED. Some patients with elbow dislocation will have reduced spontaneously prior to your assessment. Usually the patient will recall the sensation that the joint “popped out” and then “popped back in” again. The x-ray may be unrevealing however, all elbow dislocations are associated with major ligament disruption and thus require rigid immobilization, even when the x-ray is normal.

As with any fracture or dislocation, perform a pre- and post-reduction neurovascular exam and look for signs of compartment syndrome.

upper extremity peripheral nerve testing

elbow injuries

 

Posterior elbow subluxation x-ray interpretation

Frank posterior elbow dislocations are obvious on x-ray. However subtle subluxations are often missed. For subtle subluxation look at the x-ray for a smooth, symmetric clear space around the trochlea, similar to assessing the clear space of the ankle mortise. Again, patients may have reduced their dislocation spontaneously before your assessment in the ED and the x-ray may be normal. If a fracture is identified and the story is consistent with a dislocation that was reduced spontaneously, this should be managed similarly to a dislocation found of x-ray that is reduced in the ED.

Elbow dislocation closed reduction: Traction-countertraction technique

Before the reduction attempt, place the forearm in supination. Muscle relaxation is crucial for any attempt to be successful.

  1. Assistant immobilizes humerus with elbow flexed at 30 degrees, applies countertraction at middle or distal humerus
  2. Apply traction to distal forearm with forearm supinated
  3. If unsuccessful, apply downward pressure at mid-forearm and the olecranon posteriorly while maintaining in-line traction

Pitfall #6. Failure to position the forearm in supination before posterior elbow dislocation reduction. It is important to place the forearm in supination to allow the trochlea of the humerus to more easily pass over the coronoid process of the olecranon during closed reduction.

Traction counter traction technique for closed reduction of elbow dislocation. Ensure that the forearm is supinated and that pressure is not applied over the antecubital fossa.

If the traction countertraction technique fails, standing at the posterior aspect of the humerus, hook the fingers of both your hands anterior to the condyles, trying to avoid compression in the antecubital fossa. Put both your thumbs on the olecranon at the junction with the triceps and use the leverage you can produce between your fingers and thumbs to push the olecranon up and over the trochlea.

diagnosis and management of elbow injuries

Immobilize the elbow at 90 degrees of flexion with a well padded backslab and counsel the patient to expect that they will be unable to extend beyond 30 degrees for 6 weeks, may not regain full extension for at least 2-3 months, and are unlikely to return to weight-bearing exercises before 4 months. Simple dislocations (no fracture) require closed reduction and a brief period (<3 weeks) of immobilization in a back slab while elbow dislocations associated with a fracture usually requires ORIF and should be seen by orthopedics within 72 hours.

Olecranon fractures: it’s all about extensor mechanism integrity

Mechanism of injury: Olecranon fractures typically occur after a direct blow to the olecranon in older patients.

Physical exam: In the case of a suspected olecranon fracture, the most important element to assess is the extensor mechanism and the integrity of the triceps. Similar to the importance of assessing the integrity of the extensor mechanism of the knee for patella and quadriceps tendon injuries with an active straight leg raise test to predict the likelihood of operative intervention, make sure to check extension against mild resistance – one way to do this is to have the patient point the tip of their elbow directly at you with their forearm parallel to the floor, and then asking them to extend their elbow against the resistance of your hand.

Perform a neurovascular exam, specifically checking for ulnar nerve sensation and power. Also look for the second injury, in particular a subluxed elbow. All olecranon fractures are intra-articular, so look for asymmetry in the intact olecranon-coronoid interface to suggest subluxation.

Management: well padded posterior splint and sling

  • Non-operative treatment: for < 2 mm displacement
  • For olecranon fractures with 2 mm-5 mm displacement, management depends on patient age, extensor mechanism function and surgeon preference
  • Operative treatment: for fractures with > 5 mm displacement and/or complete loss of extensor mechanism

Pitfall #7. Failure to assess the integrity of the extensor mechanism for patients with olecranon fractures. Patients with olecranon fractures who are unable to extend their elbow against resistance are likely to require operative intervention.

Monteggia fracture-dislocation

The forearm is a ring structure, and so force often results in injuries in two locations. If you see a fracture in one location, it is commonly associated with a dislocation in another location. A caveat to this rule is a “nightstick” fracture, which is an isolated forearm fracture from direct force to the forearm.

A Monteggia injury involves a fracture of the ulna and dislocation of the radial head. A Galeazzi injury involves a fracture of the radius and dislocation of the distal ulna or DRUJ. An easy way to remember which injuries are involved in a Monteggia fracture-dislocation is with the FUME mnemonic.

FUME mnemonic for Monteggia injury

Fracture of

Ulna is called

Monteggia when at the

Elbow, the other bone (radius) is dislocated

elbow injuries

Monteggia fracture-dislocation. Note the radial head dislocation.

It is imperative to carefully assess for radial head subluxation for all ulna fractures by assessing the radiocapitellar line.

Radiocapitellar line. A line drawn through the middle of the radius normally goes through the middle 1/3 of the capitellum.

Pitfall #8. Failure to assess the radiocapitellar line for patients with ulna fractures. Monteggia fracture-dislocation is un unstable injury and is managed operatively, while an isolated nondisplaced ulna fracture is managed nonoperatively. Scrutinize the x-ray for radial head subluxation for all patients with ulna fractures.

Operative soft tissue injuries of the elbow

Distal biceps tendon injury

Distal biceps tendon injuries present in younger patients after lifting (or attempting to lift) a heavy object, whereas a proximal injury is often seen in older patients due to degenerative changes. Distal biceps tendon rupture requires urgent surgery, because after 3 weeks the muscle shortens/retracts and the tendon is difficult or impossible to retrieve. Distal biceps tendon rupture can be easily missed because they may not present with the classic “popeye sign” the way proximal biceps tendon ruptures do.

On exam, perform the Hook test: use your index finger to hook the biceps approaching it from the lateral/radial side. If there is no tendon palpable (an empty space without being able to “hook” the biceps tendon with your finger), there is likely a distal biceps rupture. For more details, see EM Cases Episode 58.

elbow injuries

Pitfall #9. Assuming that urgent operative intervention is not required for all biceps tendon injuries. While proximal biceps tendon ruptures are usually managed nonoperatively, distal biceps tendon ruptures are usually managed operatively within 2-3 weeks of the injury.

Triceps tendon injury

Triceps tendon injuries often present in young, muscular male patients after forced extension from a FOOSH mechanism. They complain of pain in the posterior elbow region, and may have felt a pop during the injury.

Assess the extensor mechanism and feel for a divot on the posterior aspect of the elbow just proximal to the olecranon where the triceps tendon inserts. Place these patients in a sling and follow up with orthopedics. Operative management is usually required within 6 weeks of injury.

emergency management of pediatric seizuresPitfall #10: Routinely ordering ultrasound imaging for suspected biceps or triceps injuries. Ultrasound imaging is not required to diagnose biceps tendon rupture or triceps tendon rupture. Ultrasound reports may be misleading and are not recommended by our experts in this setting. These are clinical diagnoses.

References for ten pitfalls in the diagnosis and management of elbow injuries

  1. Tintinalli, Judith E., et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. Eighth edition. New York: McGraw-Hill Education, 2016.
  2. Marx, John A., and Peter Rosen. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier/Saunders, 2014.
  3. Pappas N, Bernstein J. Fractures in brief: radial head fractures. Clinical orthopaedics and related research. 468 (3): 914-6.
  4. Regan W, Morrey B. Fractures of the coronoid process of the ulna. J Bone Joint Surg Am. 1989;71 (9): 1348-54.
  5. Gottlieb M, Schiebout J. Elbow Dislocations in the Emergency Department: A Review of Reduction Techniques. J Emerg Med. 2018;54(6):849-854.
  6. Skelley NW, Chamberlain A. Anovel reduction technique for elbow dislocations. Orthopedics 2015;38:42–4.
  7. Wiegand L, Bernstein J, Ahn J. Fractures in brief: Olecranon fractures. Clin Orthop Relat Res. 2012;470(12):3637-41.

Drs. Helman, Sayal and Dantzer have no conflicts of interest to declare

Now Test Your Knowledge:

1. Which of the following statements is FALSE regarding elbow injuries?

A. Normal carrying angle of the elbow is slightly valgus

B. Force vector with a FOOSH goes through the medial/ulnar elbow

C. Radial head or neck are often injured from a FOOSH

D. Medial/ulnar ligamentous structures are often injured from a FOOSH

Answer: B

The normal carrying angle of the elbow is slightly valgus. The vector of force with a FOOSH, therefore, goes through the lateral elbow where the radial head meets the elbow. This explains why the radial head or neck are often implicated, and why medial/ulnar ligamentous structures are susceptible to injury as the medial/ulnar side “opens up”.

2. A 32-year-old female presents to your emergency department after slipping on ice and suffering a FOOSH injury. On exam, she is tender over the radial head and has pain in the mid-dorsal wrist with supination and pronation but no tenderness over the distal radius or snuffbox. X-ray shows a fracture of the radial head. What is the most likely diagnosis and ED management?

A. Essex-Lopresti injury – immobilization in supination

B. Essex-Lopresti injury – surgical consult

C. Monteggia injury – surgical consult

D. Galeazzi injury – surgical consult

Answer: A

Essex-Lopresti injury involves a fracture of the radial head with dislocation of the Distal Radial Ulnar Joint (DRUJ). It is treated by immobilization in supination

Monteggia injury involves a fracture of the ulna and dislocation of the radial head.

Galeazzi injury involves a fracture of the distal 1/3rd of the radius and dislocation of the distal ulna or DRUJ

3. Which of the following X-ray findings of the elbow does NOT suggest a radial head fracture?

A. Disruption of the usual smooth continuous concave shape of the radial head

B. Anterior sail sign

C. Posterior fat pad sign

D. Superimposition of the trochlea and the capitellum

Answer: D

Consider a radial head injury in any of the following:

– Disruption of the usual smooth continuous concave shape of the radial head

– Anterior sail sign

– Posterior fat pad sign

– Disruption of the radiocapitellar line

Superimposition of the trochlea and the capitellum is used to ensure that you are looking at a true lateral view X-ray of an elbow

4. Which of the following statements regarding the ED management of radial head fractures is TRUE?

A. Most radial head and neck fractures require surgical intervention

B. Radial head fractures often require immobilization for > 3 weeks

C. Mason classification gives guidance on when radial head/neck fractures may require operative fixation

D. Consider expeditious surgical consult if > 20% of the surface area of the radial head is involved

E. C and D

Answer: E

– Most radial head and neck fractures are not surgical and can be treated conservatively with a simple sling for comfort

– Do not immobilize the elbow for >3 weeks due to risk of chronic elbow stiffness

– The Mason classification gives guidance on when radial head/neck fractures may require operative fixation. For a simpler approach, our experts recommend the 30-3-33 rule:

>30 degrees angulation

> 3 mm displacement of the fracture fragment

> 33% surface area of the radial head involved

5. A 45-year-old man presents after falling backward on his elbow. He heard a pop and is now holding his elbow in 45 degrees of flexion. There is a posterior protuberance of the olecranon that makes you suspicious of a posterior elbow fracture. What motor functions should you test for in this patient?

A. Ulnar nerve – peace sign, radial nerve – hitchhiker’s thumb, medial nerve – making a fist

B. Ulnar nerve – hitchhiker’s thumb, radial nerve – peace sign, medial nerve – making a fist

C. Ulnar nerve – making a fist, radial nerve – hitchhiker’s thumb, medial nerve – peace sign

D. Ulnar nerve – peace sign, radial nerve – making a fist, medial nerve – hitchhiker’s thumb

Answer:  A

elbow injuries

6. A healthy 61-year-old female presents after a fall on her elbow. She has significant pain at the tip of her elbow and has some pain with elbow extension. X-ray shows an olecranon fracture with 6 mm of displacement. What is the generally accepted treatment of this injury?

A. Non-operative treatment with a sling

B. Non-operative treatment with a posterior splint and sling

C. Operative treatment

D. Management depends only on the patient’s extensor mechanism function and surgeon preference

Answer: C

Management of olecranon fractures depends on the degree of displacement, extensor mechanism function, and surgeon preference:

  • < 2 mm displacement: non-operative treatment with a well-padded posterior splint and sling
  • 2 – 5 mm displacement: management depends on patient age, extensor mechanism function, and surgeon preference
  • > 5 mm displacement and/or complete loss of extensor mechanism: operative treatment

7. An 80-year-old male presents with forearm pain after falling down 2 steps of stairs and landing on his outstretched hand. He has an obvious deformity over the forearm. His X-ray is shown below. What is the most likely diagnosis?

elbow injuries

A. Fracture of the ulna

B. Fracture of the radius

C. Monteggia injury

D. Galeazzi injury

Answer: C

Monteggia fracture dislocation is defined as proximal 1/3 ulnar fracture with associated radial head dislocation/instability. It is more common in children than in adults. Closed reduction is usually successful in children while most Monteggia fractures in adults are treated surgically.

8. Which of the following is TRUE regarding distal biceps tendon injury?

A. Distal injury is often seen in older patients due to degenerative changes

B. Proximal injury tend to present in younger patients after lifting a heavy object

C. Distal injury can be treated supportively

D. The hook test can be used to detect a distal biceps rupture

Answer: D

– Proximal injury is often seen in older patients due to degenerative changes

– Distal injury tend to present in younger patients after lifting a heavy object

– Distal injury may require urgent surgery because after 3 weeks the muscle shortens/retracts and the tendon is difficult or impossible to retrieve

– Distal biceps tendon rupture can be easily missed because unlike proximal biceps tendon rupture, they may not present with the classic “popeye sign”. Apply the Hook test instead.

Hook test: use your index finger to hook the biceps approaching it from the lateral/radial side. If there is no tendon palpable (an empty space without being able to “hook” the biceps tendon with your finger), there is likely a distal biceps rupture.

elbow injuries

9. Which of the following is FALSE regarding triceps tendon injury?

A. Often present in young, muscular male patients

B. From forced extension during a FOOSH mechanism, may have felt a pop during the injury

C. On exam, a divot may be appreciated on the posterior aspect of the elbow

D. Immobilize these patients with a posterior slab and follow up with orthopedics

Answer: D

Triceps tendon injuries often present in young, muscular male patients after forced extension from a FOOSH mechanism. They complain of pain in the posterior elbow region and may have felt a pop during the injury.

Assess the extensor mechanism and feel for a divot on the posterior aspect of the elbow just proximal to the olecranon where the triceps tendon inserts. Place these patients in a sling and follow up with orthopedics. Operative management is usually required within 6 weeks of injury.

10. A 25 y/o gymnast presents to the ED after missing a high bar and falling on her outstretched left hand. She complains of pain and swelling at the elbow. On exam, she has no tenderness at the snuffbox or distal radius with normal active ROM of the wrist but is tender on both the medial and lateral elbow with obvious swelling around the elbow and limited active ROM. Neurovascular exam reveals decreased sensation to the tip of the 5th digit. X-ray reveals a joint effusion without a fracture or dislocation. What is the most likely diagnosis?

A. Essex Lopresti injury

B. Ulnar collateral ligament tear

C. Isolated occult radial head fracture

D. Occult posterior elbow dislocation

Answer: D

A common pitfall is assuming no elbow dislocation if the joint appears in place in the ED. Some patients with elbow dislocation will have reduced spontaneously prior to your assessment. Usually, the patient will recall the sensation that the joint “popped out” and then “popped back in” again. The x-ray may be unrevealing. However, all elbow dislocations are associated with major ligament disruption, sometimes of both the medial and lateral ligaments, and thus require rigid immobilization, even when the x-ray is normal.

Decreased sensation to the tip of the finger is a sign of ulnar nerve injury which may occur in posterior elbow dislocations.

While occult radial head fracture may reveal a joint effusion without fracture on x-ray, on physical exam there is tenderness at the radial head without medial elbow tenderness or swelling.

11. A 40 y/o man presents to the ED after falling down a set of stairs complaining of elbow pain. He is unsure of how he landed. He is tender both at the radial head and in the antecubital fossa with limited flexion/extension as well as forearm supination and pronation. His x-ray is shown. What is the most likely diagnosis?

A. Radial head fracture

B. “Terrible triad” (radial head fracture, coronoid fracture, elbow subluxation or dislocation)

C. Coronoid process fracture

D. Lateral condyle fracture

Answer B

This x-ray reveals a “terrible triad” (radial head fracture, coronoid fracture and elbow subluxation). In suspected radial head and neck injuries, make sure to examine the coronoid process or the anterior proximal portion of the ulna. Coronoid fractures tend to cause elbow instability and may require ORIF, and maybe a sign of elbow subluxation or dislocation. They occur with FOOSH and elbow hyperextension and present with pain over the antecubital fossa. Ask the patient if they felt a pop and subsequent reduction of the elbow during the fall. Coronoid fractures can be subtle on x-ray. It is imperative to look carefully for coronoid fractures on x-ray for all elbow injured patients as these tiny fractures may indicate an unstable joint.

This x-ray also reveals an elbow subluxation: normally the trochlea of the distal humerus sits symmetrically in the “cup” of the olecranon. If there is not a symmetrical smooth space around the trochlea in the “cup”, an elbow subluxation should be suspected.