Finger Tips – tendons and ligaments

Cite this article as:
Sinead Fox + Kate Jackson. Finger Tips – tendons and ligaments, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.25422

Little fingers get everywhere, and injuries are common. The mechanism of injury tends to be age-dependent with the under-fives magnetically drawn to door hinges and the over-fives more likely to do some damage during higher impact sport. Below are a few common injuries of the tendons and collateral ligaments of the fingers that you might come across in PED.

  • Ensure adequate analgesia prior to assessment, occasionally the administration of a local anaesthetic is required… don’t forget bubbles too!
  • As tendon/ligament injuries may not occur in isolation, an assessment must include inspection, palpation, (look, feel, move!), assessment of vascular structures, and testing of motor and sensory functions.
  • Children typically tend to display hand dominance between the ages of 2-4 years old; if the child is old enough make sure to record hand dominance in the medical or nursing notes.
  • In older children/adolescents document details of sport participation/ hobbies/professional goals as these may be taken into account by hand surgeons when considering treatment options.

Part 1: Flexor tendon injuries

Anatomy

There are two flexor tendons for each finger and one for the thumb.

The flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) are the flexor tendons of the fingers, and the flexor pollicis longus (FPL) is the only thumb flexor.

The flexor tendons travel distally from the forearm through the carpal tunnel and are named based on the forearm muscles from which they arise.

The flexor digitorum profundus (think profound i.e. deep) arise from the deeper layer of the flexor muscles. The flexor pollicis longus tendon of the thumb also arises from the deeper muscle layer. The flexor digitorum superficialis (think superficial) is the continuation of the more superficial layer.

  • FDP inserts at the base of the distal phalanx and flexes the DIP joint (tip: FDP is at the point of the finger).
  • The FDS tendon divides into two slips that wrap around the FDP to insert into the sides of the middle phalanx. FDS flexes the PIP joint.

The Pulley System

The flexor tendons are enclosed in a synovial sheath that lubricates them and minimizes friction.

It is organized into segments of transverse fibres forming annular pulleys (annular means ring-like; think of the ring-like lesions of annular eczema) and oblique fibres comprising cruciate pulleys (cruciate means crossed, like the cruciate ligaments of the knees).

There are three cruciate pulleys (C1-3) and five annular pulleys (A1-5) pulleys. These pulleys keep the flexor tendons close to the bone and prevent bowstringing of the tendon.

The pulley system

Evaluation

Closed flexor tendon injuries are usually caused by forced extension of the finger in active flexion. The child may present with reduced flexion of the finger or pain when bending the finger and there may be localized swelling or open wounds.

The FDS and FDP tendons should be tested individually; it is not enough just to observe the child make a fist as tendon injuries can be easily overlooked or missed.

  • To check FDS function, hold all adjacent fingers in extension and then release the finger you want to assess. Ask the child to flex the free digit at the PIP joint.
  • To examine the FDP, hold the middle phalanx in extension and ask the child to flex the DIP joint.
Testing FDP
Testing FDS

Examination Pearls

Tendon function can be difficult to assess in a very young or uncooperative child. In these circumstances observation of digital cascade and wrist tenodesis can be useful physical examination tools to assess tendon integrity of hand and fingers.

  1. Digital Cascade

When the child’s hand is in a resting position, the fingers should have a natural cascade of progressively increasing flexion from the index finger through to the little finger.

The digital cascade
  1. Wrist Tenodesis

Squeezing the forearm muscles while observing the fingers can also be used to assess flexor tendon continuity. If flexor tendons are intact, the child’s fingers should flex when the forearm muscles are squeezed.

Wrist tenodesis

A: Extending the wrist flexes the fingers. With intact flexor tendons and a relaxed or distracted patient, passive wrist extension results in finger flexion. If flexor tendons are damaged then the injured finger(s) will rest in an extended position when the wrist is extended.

B: Flexing the wrist extends the fingers. Similarly, with intact extensor tendons, passive wrist flexion results in finger extension. If the extensor tendons are damaged, the injured finger(s) will rest in a flexed position when the wrist is flexed.

Wound Exploration

It is important to remember that tendons move; looking into a wound and seeing an intact tendon does not exclude a tendon injury. If the wound is sustained while the finger is flexed and the finger is examined while it is extended, the level of the tendon injury will not correspond to the level of the skin laceration. Therefore it is important to ask the parent or older child/adolescent about finger position at the time of the injury and put the injured digit through a passive range of movement while examining the wound.  If you are in doubt or cannot rule out a tendon injury refer the patient to the local hand surgery team.

Classification

The sites of the flexor tendon injuries are divided into five zones.

*The term ‘No Man’s Land’ was coined by hand surgeon Mr. Sterling Bunnell in 1918 because at that time it was felt no man (or woman) should attempt repair within this zone due to the complexities of the anatomy and risk of adverse outcomes. While this belief is no longer a common practice, it highlights the intricacies of surgical repair within this zone.

Jersey finger (Zone 1 injury)

Juno is a fifteen-year-old girl who is attending ED with an injury to her left ring finger. She was playing rugby earlier today and her hand got caught in another player’s jersey during a tackle. On examination, you note swelling, bruising, and tenderness to the volar base (on the palmar side) of her distal phalanx on her left ring finger. When you lie her left hand flat on a table with the palm facing upwards and hold the middle phalanx of her ring finger in extension she is unable to flex her distal phalanx at the DIP joint. She also can’t bend the DIP joint when trying to make a fist. You correctly identify that she has an injury to her FDP tendon and make the diagnosis of Jersey Finger. You send Juno to X-ray to assess for a fracture.

Mechanism

Disruption of the FDP tendon is known as Jersey finger. This injury is caused by the forced extension of the DIP joint during active flexion. It commonly occurs when an athlete’s finger catches in another player’s jersey, usually while playing a tackling sport such as rugby or American football. For those that prefer more solo pursuits, it can also be caused by an overly tight crimp grip in climbers.

 

Presentation

A patient with Jersey finger may present with pain and swelling to the volar (the palmar) aspect of the DIP joint and the finger will be extended at rest. The ring finger is commonly affected. The integrity of the FDP should be evaluated as outlined above. An injured FDP will produce very restricted or no movement. An x-ray should be performed to rule out an avulsion fracture at the volar base of the distal phalanx.

X-ray demonstrating an avulsion fracture at the base of the distal phalanx of the little finger in Jersey Finger. Case courtesy of Dr Ian Bickle, Radiopaedia.org. From the case rID: 26251
The clinical appearance of Jersey Finger. Case courtesy of Dr Salem Bauones, Radiopaedia.org. From the case rID: 26251
Jersey finger – disruption of insertion of FDP

Treatment

Early referral to a hand surgeon for assessment and appropriate treatment is paramount.

Operative: The majority of these cases require surgical intervention to reattach the tendon to prevent tendon retraction and optimize function. The prognosis for patients with jersey finger worsens if treatment is delayed and severe tendon retraction is present.

Non- Operative: A partial tear may be managed conservatively (splinting, NSAIDS, physiotherapy). However, from a PED perspective, these injuries should be considered surgical cases until deemed otherwise by a hand specialist.

You do not identify a fracture on Juno’s X-ray and you refer her to the Plastic Surgery team for prompt review as it is possible she may require surgery to repair her FDP tendon.

…A quick overview of Trigger thumb

Trigger thumb, although uncommon, maybe a reason for presentation to the PED, typically when a child is 2 years old. Paediatric Trigger thumb results from a mismatch in the size of the Flexor Pollicis Longus (FPL) and the first annular pulley (A1) disrupting normal tendon gliding. Children find it difficult to extend the IP joint of the thumb, with clicking or snapping felt or heard. Some patients even have a fixed flexion deformity at the IP joint. Characteristically, a palpable mass is felt at the level of the MCP joint crease on the volar (palmar) surface of the thumb representing a nodule in the FPL as well as thickening of the flexor tendon sheath. This is commonly referred to as ‘Notta’s Node’.

Its aetiology is poorly understood. Historically, trigger thumb was thought to be congenital, however, this is controversial and an argument exists that trigger thumb is an acquired condition. Diagnosis is usually based on clinical exam. X-rays or alternate imaging is rarely indicated, although parents will occasionally try attribute symptoms to a recent history of trauma. This is usually a red herring!

Paediatric trigger thumb can be managed surgically or conservatively with splinting and a physiotherapy regime – sometimes it can spontaneously resolve, although the spontaneous resolution of paediatric trigger thumb can be less likely after 2 years old. Surgical release of the first annular pulley may be offered as a treatment option to restore thumb IP joint movement if there is a fixed flexion deformity beyond the age of 12 months or if conservative management fails.

 

Part 2: Extensor Tendon Injuries

Anatomy

Distal to the MCP joint, the common extensor tendon divides into three slips: one central and two lateral bands. The central slip inserts at the base of the middle phalanx and the two lateral bands extend along the radial and ulnar margins of the middle phalanx to converge at the distal third of the middle phalanx to form the terminal extensor tendon, which inserts at the base of the distal phalanx. The central slip extends the middle phalanx at the PIP joint level and the terminal extensor tendon extends the DIP joint. The Extensor Pollicis Longus (EPL) extends the thumb at the IP joint.

Extensor tendon anatomy

Evaluation

The extensor tendons are assessed by applying pressure to the dorsum (back) of the finger while the patient is attempting active extension.

Testing extensor tendons

To test the Extensor Pollicis Longus (EPL), ask the patient to place their hand flat on a table and lift up their thumb against resistance.

Testing EPL

Classification

The extensor mechanism can be divided into 9 anatomical zones. Odd-numbered zones are located over joints, and even-numbered zones are located over bones. Tendon injuries can be categorized according to these anatomical zones.

Extensor tendon zones

A little nugget: an easy way to recall the extensor zones is to remember the odd numbers (I, III, and V) are at the joints (DIPJ, PIPJ, and MCPJ).

Injuries in zone 1 (the DIP joint) and zone III (the PIP joint) cause some unique injury patterns which we’ll explore below.

The thumb has a unique classification system as it has one fewer phalanx.

Mallet Finger: zone I injury (Baseball Finger)

Isabelle is an 8-year-old girl who was playing with her twin sister, Sophie, in their bedroom while their Mummy and Daddy were busy working from home in another room. Sophie accidentally closed the bedroom door catching Isabelle’s finger in the hinge side of the door. In ED you see that Isabelle’s right, dominant index finger is bruised and swollen at the DIP joint and there is a superficial abrasion to the dorsum of the DIP joint. Isabelle’s point of maximal tenderness is to the DIP joint. You try your best to assess finger function but Isabelle is crying and says she is too sore to move her fingers. But you note that the index finger appears flexed at the DIP joint and you suspect a Mallet injury. You give Isabelle analgesia and refer her for an x-ray.

Mechanism

Mallet finger is a partial or complete avulsion of the terminal extensor tendon from its insertion on the distal phalanx, commonly resulting from sudden flexion of an extended DIP joint. It can also occur secondary to a crushing mechanism.

Presentation

Mallet finger can be an open or closed injury with or without a fracture. Patients present with a flexion deformity at the distal phalanx and an inability to extend finger at DIP joint. The DIP joint can be swollen and ecchymosed.

Mallet finger

In children, this injury typically occurs due to an avulsion fracture of the distal phalangeal epiphysis, the insertion point of the terminal extensor tendon.

Case courtesy of Dr Hani Salam, Radiopaedia.org. From the case rID: 12227

Classification

Mallet fingers can be described using a classification scheme (I through IV) developed by Doyle (1993).

Classification of Mallet finger

Treatment

Early referral to a hand surgeon for assessment and advice regarding appropriate treatment is essential.

Non-operative: Closed acute injuries with or without fractures can be managed with 6-8 weeks of extension splinting at DIP joint, followed by gentle active flexion ROM.

A 2004 Cochrane review found insufficient evidence to support the use of any particular splint when treating mallet injuries; all achieve similar outcomes. However, patient compliance is vital to a successful outcome.

Operative:

Open injuries are treated by surgical repair.

Closed injuries may be considered for surgical management if there is joint subluxation or an avulsion fracture of more than 30-50% of the articular surface.

Complications: Swan-neck deformity

Correct management of an acute mallet injury is critical as a poorly managed or untreated chronic terminal extensor tendon injury can lead to swan-neck deformity.

Swan-neck deformity is caused by prolonged DIP flexion with dorsal subluxation of lateral bands and PIP joint hyperextension.

It takes a while before Isabelle and her Mum return to the ED from X-ray. Fortunately, the analgesia seems to have had some effect and Isabelle is more relaxed. You review the X-ray and do not identify a fracture. On examination, you confirm there is a flexion deformity at the DIP joint and note that Isabelle is unable to actively extend at the DIP joint. Suspecting a mallet injury, you apply an extension splint and refer Isabelle to plastics. They opt to treat the injury conservatively with an extension splint at the DIP joint for 6 weeks. They give Mum and Isabelle careful advice about compliance with splinting and give her an appointment for follow up in out-patients.

Central Slip Injuries: zone III injury

Michael is a 15-year-old talented basketball player. He was playing in a school league basketball final three days ago, when he felt a sudden sharp pain in his left middle finger after a failed attempt at catching the ball. He played until the end of the game but attended a minor injuries unit the following day as his finger was swollen and painful at the PIP joint. After a normal X-ray, he was diagnosed as having a soft tissue injury and discharged home with his fingers buddy-strapped. However, his pain has not improved and he’s still unable to fully extend his finger at the PIP joint, so his dad brings him to your ED. He has a digital copy of the X-Ray for you to review.

Mechanism

Central slip injuries are extensor tendon injuries at the middle phalanx most often resulting from forced flexion of an extended PIP joint, a mechanism commonly seen in basketball players. Other injuries that can accompany central slip disruption include volar (palmar) dislocations of the PIP joint, dorsal avulsion fractures of the base of the middle phalanx, and lacerations to the dorsal surface of PIP joint.

Presentation

The PIP joint may be swollen and bruised. The area of maximal tenderness is generally over the dorsal aspect of the PIP joint.

Closed central slip injuries can be easily missed or misdiagnosed as a sprain or soft tissue injury as there is no wound and sometimes no abnormality seen on X-ray.

The physical examination can be challenging- some patients have no loss of active extension at the PIP joint as extension is still provided by the lateral bands of the extensor tendon despite the disruption of the central slip. Even when there is a loss of extension, this can be overlooked or attributed to pain. (Don’t forget to provide adequate analgesia prior to assessment!)

These pitfalls can be avoided by maintaining a high index of suspicion for a central slip injury and undertaking a careful examination including Elson’s test to establish the integrity of the central slip, especially in the patient who presents with a painful, swollen PIP joint without gross deformity. Occasionally, ring blocks are required to allow a proper assessment of ROM.

Elson’s Test

  • Ask the patient to bend the affected PIP joint 90° over the edge of a table and ask them to extend the middle phalanx against resistance.
  • If the central slip is intact (negative test), extension is strong and the DIP remains floppy because the extension force is now placed entirely on maintaining extension of the PIP and the lateral bands cannot act distally in this position.
  • When a rupture of the central slip is present (positive test) there will be weak PIP extension, and the DIP will extend abnormally and become rigid.

There is also a modified version of Elson’s test that can be used. Here’s how the Modified Elson’s Test is done:

  • Ask the patient to place their injured and uninjured contralateral fingers knuckle to knuckle in 90 degree PIP flexion, with the middle phalanges pressed against each other. The patient is then asked to extend both DIP joints.
  • Negative test (normal)- DIP joints symmetrically flexed.
  • A positive test (central slip injury)- Injured DIP joint extends more (See diagram below).
The modified Elson’s test. A) Uninjured fingers show a symmetric inability to straighten the DIP joint when the middle IP joints are flush against each other. B) In a central slip injury, the DIP joint is pathologically straightened, which is seen in the left hand in this example. From AliEM.com (Illustration by David Ting)

This video from Brian Lin demonstrates both tests beautifully.

These tests can be limited by pain and the patient’s ability to co-operate, if a closed central slip injury is suspected then the PIP joint should be splinted in an extension and follow up in a hand clinic arranged.

Treatment

Early referral to a hand surgeon for assessment and advice regarding appropriate treatment is essential.

Non Operative:

  • Closed injuries
  • Extension splinting of the PIP joint for up to 6 weeks to allow central slip restoration

Operative: Surgical treatment reserved for

  • Open injuries
  • Displaced avulsion fractures of the middle phalanx
  • PIP instability
  • Failed non-surgical treatment

Complications: Boutonnière deformity

Failure to recognize and treat a central slip injury in the ED may result in a problematic Boutonnière deformity later on.

Boutonnière deformity is characterized by flexion of the PIP joint and hyperextension of the DIP joint. It develops secondary to loss of extension force on the PIP joint, with volar subluxation of the lateral bands and subsequent DIP joint hyperextension.

Extensor mechanism over the finger. A) Intact central slip and lateral band mechanism. B) Disrupted central slip leading to a Boutonnière’s deformity. after ALiEM.com

On examination, you note swelling and bruising to the PIP joint. Michael tells you that he is maximally tender on palpation to the dorsal surface of his PIP joint. He is able to partially extend his finger at the PIP joint but using Elson’s test you note weak PIP extension, and an abnormally extended and rigid DIP joint. You diagnose a central slip injury and explain the diagnosis to Michael and his dad before referring Michael to the plastic surgery team for assessment. Plastics treat Michael in an extension splint for 6 weeks to allow central slip restoration.

Part 3: Collateral Ligament Injuries

Anatomy

The collateral ligaments stabilize the phalanges laterally at the DIP, PIP and MCP joints.

Mechanism

Forced ulnar or radial deviation of any of the IP joints can cause partial or complete collateral ligament tears.

Presentation

Collateral ligament injuries of the fingers present as tenderness on palpation overlying affected ligament, swelling and sometimes bruising.

Evaluation

The integrity of a collateral ligament is assessed by applying valgus and varus stress to the involved joint with the joint in full extension and with the joint in 30 degrees of flexion. Compare the laxity of the injured finger with an unaffected finger. Increased laxity or lack of an endpoint signify an injury.

An x-ray should be performed to out-rule an avulsion fracture at the insertion site of the ligament.

Treatment

If the joint is stable and no large fracture fragments are identified, the injury can be treated with buddy strapping.

Treatment Pearl: Buddy strapping

If the ring finger is involved, it should be secured to the little finger as the little finger is naturally extended and easily injured if exposed.

Ulnar Collateral Ligament Injury of the Thumb (Skier’s Thumb / Gamekeeper’s Thumb)

Tess was very excited as she stepped out onto the fresh crunchy snow all kitted up and raring to go. However, she didn’t count on it being so slippery and fell more or less right away whilst holding her ski poles. She had a lot of pain in her thumb and it looked a bit swollen.

It sounds like Tess has Skier’s Thumb, which is an injury to the ulnar collateral ligament of the MCP joint of the thumb.

Ulnar collateral injury

Mechanism

This injury is usually caused by forced abduction or extension at the MCP joint, typically falling onto an outstretched hand with something in the palm, falling onto an abducted thumb or as a result of a ball or object striking the ulnar aspect of the thumb during sports. This force stretches or tears the ulna collateral ligament, resulting in complete or partial rupture of the and can be associated with an avulsion fracture.

Presentation

Pain, swelling, and bruising are usually noted over the ulnar aspect (the index finger side) of the MCP joint of the thumb. The patient will also be tender on palpation to this area. Occasionally, a mass or a lump can be felt at the site of tenderness, which may suggest a Stener Lesion*. In severe ulnar collateral ligament injuries, the proximal phalanx may become subluxed with radial deviation on the metacarpal head.

*Stener Lesion

  • Normally, the ulnar collateral ligament lies deep to the adductor pollicis tendon.
  • A Sterner Lesion can form when a torn UCL becomes displaced superficially to adductor pollicis longus.
  • The presence of a Stener Lesion is an indication for surgical repair of this injury.

Evaluation

Evaluation of an ulnar collateral ligament injury involves valgus stress (radial deviation) testing of the joint at neutral and 30 degrees of flexion at MCP joint of the thumb. Compare the patient’s injured with their uninjured thumb to find out what is normal for that child. Hold the base of the thumb then apply sideways (lateral) pressure to the tip of the thumb. Increased laxity or lack of an endpoint signify an injury. It may be kindest to put in a ring block to prevent guarding due to pain, to increase the accuracy of the exam.

Functionally it’s important to test the (in)ability to grasp between thumb and finger. A stable pinch mechanism depends on the integrity of the radial collateral ligament of the index finger and the UCL of the thumb.

An X-ray should be performed to out-rule an avulsion fracture.  If an avulsion fracture is present, this will be seen at the ulnar corner of the base of the proximal phalanx. Ultrasound or MRI may be used to identify a tear to the UCL or diagnose the presence of a Stener Lesion.

Avulsion fracture to ulnar corner of proximal phalanx of thumb. Courtesy of Orthobullets.com

Treatment

Non- operative: A partial UCL rupture may be treated conservatively. Conservative management involves immobilization of the MCP joint in a thumb spica cast or thermoplastic thumb splint.

Operative: Complete UCL rupture or the presence of Stener Lesion are indications for surgical repair. Early immobilization with a thumb spica will also prevent further damage and make it more comfortable for the child while awaiting surgical review.

Tess’ thumb is very bruised and extremely tender. You pop in a ring block and with valgus stress you can tell there is increased laxity compared to the other side. There’s no fracture on x-ray. You refer Tess to your colleagues in plastics, who, after an ultrasound, diagnose a partial rupture of her ulnar collateral ligament. Her thumb’s immobilised in a thumb spica. 6 months later she’s back on the slopes!

Selected References

Allan, C. H. (2005). Flexor tendons: anatomy and surgical approaches. Hand clinics21(2), 151-157.

Armstrong, M. B., & Adeogun, O. (2009). Tendon injuries in the pediatric hand. Journal of Craniofacial Surgery20(4), 1005-1010.

Avery, D. M., Inkellis, E. R., & Carlson, M. G. (2017). Thumb collateral ligament injuries in the athlete. Current reviews in musculoskeletal medicine10(1), 28-37.

Dorani, B. (2020). Soft Tissue Injuries of the Hand. Retrieved from https://www.rcemlearning.co.uk/reference/soft-tissue-injuries-of-the-hand/#1583314733632-1b04992c-edab

Elson, R. A. (1986). Rupture of the central slip of the extensor hood of the finger. A test for early diagnosis. The Journal of bone and joint surgery. British volume68(2), 229-231.

Forward, K. E., Yazdani, A., & Lim, R. (2017). Mallet Finger in a Toddler: A Rare But Easily Missed Injury. Pediatric emergency care33(10), e103-e104.

Guly, H.R. (1991). Missed tendon injuries. Archives of Emergency Medicine, (8), 87-91.

Handoll, H. H., & Vaghela, M. V. (2004). Interventions for treating mallet finger injuries. Cochrane Database of Systematic Reviews, (3).

Hatch, D. (2019). Extensor Tendon Injuries. Retrieved from https://www.orthobullets.com/hand/6028/extensor-tendon-injuries

Kalainov, D. M., Hoepfner, P. E., Hartigan, B. J., Carroll IV, C., & Genuario, J. (2005). Nonsurgical treatment of closed mallet finger fractures. The Journal of hand surgery30(3), 580-586.

Leggit, J., & Meko, C. J. (2006). Acute finger injuries: part I. Tendons and ligaments. American family physician73(5), 810-816.

Lo, I. & Richards, R.S. (1995). Combined Central Slip and Volar Plate Injuries at the PIP Joint. Journal of Hand Surgery, 20B (3), 390-391.

Matzon, J. L., & Bozentka, D. J. (2010). Extensor tendon injuries. The Journal of hand surgery35(5), 854-861.

Nugent, N., & O’Shaughnessy, M. (2011). Closed central slip injuries–a missed diagnosis?, Irish Medical Journal, 104 (8):248-250.

Perron, A. D., Brady, W. J., Keats, T. E., & Hersh, R. E. (2001). Orthopedic pitfalls in the emergency department: closed tendon injuries of the hand. The American journal of emergency medicine19(1), 76-80.

Ritting, A. W., Baldwin, P. C., & Rodner, C. M. (2010). Ulnar collateral ligament injury of the thumb metacarpophalangeal joint. Clinical Journal of Sport Medicine20(2), 106-112.

Shah, A. S., & Bae, D. S. (2012). Management of pediatric trigger thumb and trigger finger. JAAOS-Journal of the American Academy of Orthopaedic Surgeons20(4), 206-213.

Sheth, U. (2019). Mallet Finger. Retrieved from https://www.orthobullets.com/hand/6014/mallet-finger

Sullivan, M. A., Cogan, C. J., & Adkinson, J. M. (2016). Pediatric hand injuries. Plastic Surgical Nursing36(3), 114-120.

Thurston, M. and Dawes, L. et. al. Gamekeeper Thumb. Retrieved from https://radiopaedia.org/articles/gamekeeper-thumb

Wahba, G., & Cheung, K. (2018). Pediatric hand injuries: Practical approach for primary care physicians. Canadian Family Physician64(11), 803-810.

Yoon, A. P., & Chung, K. C. (2019). Management of acute extensor tendon injuries. Clinics in plastic surgery46(3), 383-391.

Elbow dislocations

Cite this article as:
Becky Platt. Elbow dislocations, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.28344

You are called to assess 14-year old Oliver who has presented to your ED by ambulance with an elbow injury.  He dived to make a save while playing football and landed on his outstretched hand.  He reports feeling a click in his elbow, followed by excruciating pain.  He was given methyoxyflurane in the ambulance which has helped. 

Assessment of any child and examination of their elbow should be approached in an age-appropriate and systematic way.  In addition to examining for bony tenderness, vascular and neurological status should be tested.

Oliver’s elbow looks significantly swollen, deformed and bruised.  You feel for a radial pulse – it’s there – and  undertake a neurovascular assessment, which is intact.  You prescribe him some intranasal fentanyl and order AP and lateral x-Rays of his elbow.

The elbow is an incredibly stable joint due to the way the humerus and ulna articulate (giving anterior-posterior and varus-valgus stability), strengthened by the medial and lateral collateral ligaments and the joint capsule.  Muscles and tendons further strengthen this ring.  A significant amount of force is needed to dislocate the elbow. 

Traumatic dislocation of the elbow is rare in the paediatric population comprising only 3-6% of all childhood elbow injuries, but the most common large joint dislocation (Lieber et al., 2012).  It is usually the result of a fall onto an outstretched hand, often with a large amount of force involved.  

Clinically, it is obvious that there is significant injury around the elbow; this is not something you will miss or be tempted not to x-ray.  Displaced supracondylar fractures can sometimes be confused with elbow dislocation as both present with a grossly swollen elbow and significant pain.  A quick and easy way to distinguish the two clinically is to palpate for the equilateral triangle formed by the olecranon and the two epicondyles: this is lost in elbow dislocation as the humerus creates a fullness in the antecubital fossa. There is no need to check movements in a deformed elbow but be sure to undertake a neurovascular assessment as a priority.  

The easiest way to classify simple elbow dislocations is by describing the direction of ulna dislocation in relation to the distal humerus.

Classification of elbow dislocations

90% of paediatric elbow dislocations are postero-lateral with the radiographic appearance as below:

But beware: elbow dislocations rarely present in isolation.  They often coexist with other elbow injuries. Associated fractures are likely to occur prior to closure of the epiphyses; when they are closed, collateral ligaments are likely to be ruptured (Lieber et al., 2012). The most common associated fracture is a medial epicondyle avulsion which can become incarcerated in the joint – scrutinize the elbow x-rays for associated fractures. This illustrates the importance of knowing CRITOE.

Elbow dislocation with medial epicondyl avulsion from Orthobullets.com. The white arrow points to the avulsed medial epicondyl while the red arrow shows where it has been avulsed from.

Oliver returns from x-ray and you review his films. You note the posterior dislocation but cannot see any associated fractures on Oliver’s films. You contact your orthopaedic team for further assistance.

Management

Many elbow dislocations reductions can be carried out in the emergency department with adequate muscular relaxation and appropriate analgesia.  A reasonable amount of force is often required to achieve reduction using traction on the forearm with counter-traction around the elbow.  This should be carried out or supervised by a clinician experienced in the procedure. 

Common pitfalls in elbow reduction

Be very careful to conduct a thorough neurovascular assessment before attempting reduction. The brachial artery and median nerve may become stretched over the displaced proximal ulna and ulnar nerve can become damaged when medial epicondyle avulsions complicate elbow dislocations. If a deficit is found after reduction you need to know whether it was present before you attempted relocation…

And if you can’t reduce the dislocation go back and have another look at the x-ray – it could be due to an avulsed medial epicondyle in the joint. Any elbow dislocation with an incarcerated piece of avulsed bone in the joint must be reduced in theatre and not in the ED.

Complications

Possible complications following elbow dislocation include residual limitation of the range of movement, recurrent instability, neurovascular injury, avascular necrosis of the epiphyses and degenerative arthritis. Early diagnosis and stable reduction, with fixation of concomitant fractures if necessary, are generally associated with better outcomes.  For the Emergency department clinician, it is therefore critical that children with this injury are assessed and managed with the minimum possible delay, ensuring that associated fractures are recognised and managed appropriately.

After sedation with ketamine, Oliver’s elbow is reduced in the department with a satisfying clunk signifying reduction.  His elbow is put through a full range of movement to test joint stability and an above elbow backslab applied.  You order repeat x-Rays to evaluate the position and to check for the joint spacing and any fracture fragments within the joint as this would require surgical intervention.  The post-reduction films are good and Oliver’s neurovascular assessment remains normal and he leaves your ED with a follow-up appointment in fracture clinic in a week’s time.

References

Cadogan, M. (2019) Elbow Dislocation https://lifeinthefastlane.com/elbow-dislocation/

Edgington, J. (2018) Elbow Dislocation – Pediatric.  

https://www.orthobullets.com/pediatrics/4013/elbow-dislocation–pediatric

Lieber, J., Zundel, S., Luithle, T., Fuchs, J., & Kirschner, H-J. (2012) Acute traumatic posterior elbow dislocation in children.  Journal of Pediatric Orthopaedics B. 21(5) 474-481

Rasool, M. N. (2004). Dislocations of the elbow in children. The Journal of Bone and Joint Surgery, 86, 1050–1058. 

Sibenlist, S. & Biberthaler, P. (2019) Simple Elbow Dislocations in Biberthaler, P., Sibenlist, S. & Waddell, J.P. Acute Elbow Trauma.  Fractures and dislocation injuries (eBook).  Springer

Sofu, H., Gursu, S., Camurcu, Y., Yildirim, T., & Sahin, V. (2016). Pure elbow dislocation in the paediatric age group. International Orthopaedics, 40(3), 541–545

Does Every Child With Fever Have Sepsis? Damian Roland at DFTB19

Cite this article as:
Team DFTB. Does Every Child With Fever Have Sepsis? Damian Roland at DFTB19, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.20382

Damian Roland is a Paediatric Emergency Medicine and Honorary Associate Professor, who is also the chair PERUKI (Paediatric Emergency Research United Kingdom and Ireland). Damian delivered this thought-provoking talk on guidelines, gestalt and real-world practice on behalf of Rachel Rowlands, who was unable to attend. You can follow him in Twitter at @Damian_Roland 

#doodlemed on this talk by @char_durand below

This talk was recorded live at DFTB19 in London, England. With the theme of  “The Journey” we wanted to consider the journeys our patients and their families go on, both metaphorical and literal. DFTB21 will be held in Brisbane, Australia.

If you want our podcasts delivered straight to your listening device then subscribe to our iTunes feed or check out the RSS feed. If you are more a fan of the visual medium then subscribe to our YouTube channel. Please embrace the spirit of FOAMed and spread the word.

Radial head and neck fractures

Cite this article as:
Becky Platt. Radial head and neck fractures, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.21165

Aisha is 10 years old. She loves gymnastics but today, during a cartwheel, she injured her right elbow.  Aisha is cradling her right arm in her left hand and is reluctant to move it, despite having had ibuprofen at home.  

 

Assessment of any child and examination of their elbow should be approached in an age-appropriate and systematic way.  In addition to examining for bony tenderness, vascular and neurological status should be tested.

 

On examination, you note swelling around the elbow, especially on the lateral aspect.  Aisha has tenderness particularly over the radial head and complains of pain on any movement especially supination and pronation.  She has normal sensory and motor function of radial, ulnar and median nerves and normal pulses, colour and capillary refill time to her hand. You prescribe further analgesia, apply a broad arm sling for comfort and order lateral and AP x-rays of her elbow.

Radial head and neck fractures comprise around 5% of all elbow injuries in children, with a peak at 9-10 years of age. They normally result from a FOOSH (‘fall onto an outstretched hand’).  Fractures through the radial head are rare in children: more commonly the physis (the growth plate: the disc of cartilage between the epiphysis and metaphysis), or radial neck will be involved.

 

Radial Neck fractures

Radial neck fractures can generally be diagnosed on lateral and AP elbow x-ray.  It’s useful to remind yourself of the elbow anatomy prior to looking at the x-ray so that you know what you’re looking for.  It’s really important to appreciate that part of the radial neck sits outside of the capsule. Most radial neck fractures occur at the level of the annular ligament, which forms a collar around the radial neck to anchor it to the ulna.

Elbow ligaments. From RCEM Learning

This means that not all radial neck fractures have a joint effusion. Don’t be fooled by a lateral elbow x-ray without a fat pad sign – this just means there’s no joint effusion; it doesn’t mean there isn’t a radial neck fracture.

The appearance can be quite subtle, so it’s useful to remind yourself what the radial neck looks like on a normal X-ray:

Normal radial neck. Case courtesy of Dr Henry Knipe, Radiopaedia.org. From the case rID: 24158

In particular, notice how the contours of the radial neck form smooth curves, as above. These smooth curves are lost in radial neck fracture:

Radial neck fracture. Case courtesy of Dr Jeremy Jones, Radiopaedia.org. From the case rID: 42688

 

Mildly angulated radial neck fracture (black arrow) and posterior fat pad (white arrow). Reproduced with permission from Emery et al. Ped Rad. 2016; 46:61-6

How are radial neck fractures classified?

Radial neck fractures were classified by O’Brien (1965)  as follows:

Type I: <30 degrees displacement

Type II: 30-60 degrees displacement

Type III: >60 degrees displacement

O’Brien’s classification of radial neck fractures. From Orthobullets

 

Other radial neck classifications have been described so, to avoid confusion, it’s probably safest to describe the degree of displacement rather than the classification type, especially as displacement of radial neck fractures in children is uncommon.

 

How should radial neck fractures be managed?  

Most paediatric radial neck fractures are type I: undisplaced or minimally displaced.  These do really well with conservative management with immobilization in a collar and cuff.  Those with displacement of >30 degrees tend to have a worse outcome and should be referred to orthopaedics as reduction, and possible internal fixation will be required.

 

Which children need to be discussed with the orthopaedic team before they go home?

  • Any displaced radial neck fractures
  • Any radial neck fractures with a second elbow injury

 

Radial neck fractures – do not miss…

30-50% of children with a proximal radial fracture have another fracture – examine the child and their x-rays very carefully.  Having a second injury is associated with a poorer outcome. The most common associated injuries are:

  • elbow dislocations
  • medial epicondyle fractures
  • olecranon fractures

 

Radial neck fractures can also be associated with compartment syndrome of the forearm, although thankfully this is rare.   Compartment syndrome is a limb-threatening condition caused by increased pressure within the closed space of a muscular compartment which causes compression of the nerves, muscles, and vessels within the compartment.  Untreated, this can lead to ischaemic injury within 4-8 hours.

 

Assessing for compartment syndrome – the 5 Ps

  • Pain – the most important indicator.  Often diffuse and progressive, not resolved by analgesia, worsened by passive flexion of the injury.
  • Pallor – assess distal to the injury.  Dusky or cool skin (compared to the other side) or delayed capillary return.
  • Pulse – weak or absent pulse indicates poor perfusion,
  • Paralysis – assess active movement of the wrist and fingers.  This may cause pain but the purpose is to assess ability to move.
  • Paraesthesia – ask about pins and needles or a feeling of the hand “falling asleep”.  Assess sensation with light touch or using an object such as a pen lid.

Any concerns about potential compartment syndrome must be escalated to an ED or orthopaedic senior without delay as this is a time-critical situation.

 

Radial Head fractures

Like radial neck fractures, radial head fractures are also most often due to a FOOSH.  Unlike radial neck fractures, radial head fractures typically occur after the proximal radial physis has closed so are more common in older children. They are usually clearly visible on x-ray and the majority are undisplaced and respond well to conservative management in a collar and cuff or sling.  Displaced fractures of the radial head are rare and will need an urgent orthopaedic referral.

Radial head fracture. Case courtesy of Dr Henry Knipe, Radiopaedia.org. From the case rID: 24158

 

 

Aisha returns from X-Ray and you spot an undisplaced fracture of the radial neck, visible on the AP and lateral views.  You remember that associated fractures are common and so have a careful look for other injuries and check the epiphyses using the CRITOE rule.  Aisha has an isolated, non-displaced radial neck fracture with no other injuries: you pop her in a collar and cuff and organize virtual fracture clinic follow up.  You make sure to give her and her family advice about analgesia and signs of any neurovascular compromise before they leave.

 

References

Barclay, T. (2019) Elbow Joint. Innerbody https://www.innerbody.com/image/skel14.html

Davies, F., Bruce, C. E., & Taylor-Robinson, K. J. (2011). Emergency Care of Minor Trauma in Children. London: Hodder & Stoughton.

De Mattos, C. B., Ramski, D. E., Kushare, I. V., Angsanuntsukh, C., & Flynn, J. M. (2015). Radial Neck Fractures in Children and Adolescents. Journal of Pediatric Orthopaedics, 36(1), 6-12.

Edgington, J. & Andras, L. (2018) Radial head and neck fractures – pediatric https://www.orthobullets.com/pediatrics/4011/radial-head-and-neck-fractures–pediatric

Emery, K. H., Zingula, S. N., Anton, C. G., Salisbury, S. R., & Tamai, J. (2016). Pediatric elbow fractures: a new angle on an old topic. Pediatric Radiology, 46(1), 61–66.

Gaillard, F. https://radiopaedia.org/articles/radial-head-fractures?lang=us Accessed 23/06/2019

Gomes, C. & Lowsby, R. (2018) Elbow Injuries.  RCEM Learning https://www.rcemlearning.co.uk/reference/elbow-injuries/

Hill, C. E., & Cooke, S. (2017). Common Paediatric Elbow Injuries. The Open Orthopaedics Journal, 11, 1380–1393.

Kraus, R. (2014). The pediatric vs. the adolescent elbow. Some insight into age-specific treatment. European Journal of Trauma and Emergency Surgery, 40(1), 15–22.

Lampert, L. (2016). Compartment Syndrome – The 5 Ps. Ausmed. Retrieved from https://www.ausmed.com/cpd/articles/compartment-syndrome

Nicholson, L. T., & Skaggs, D. L. (2019). Proximal Radius Fractures in Children. The Journal of the American Academy of Orthopaedic Surgeons, 00(00), 1–11.

Nickson, C. (2018) Compartment Syndrome. Life in the Fast Lane https://lifeinthefastlane.com/compartment-syndrome/

O’Brien, P.I. (1965) Injuries involving the proximal radial epiphysis.  Clinical Orthopaedic related Research, 41, 51-58.

Shabtai, L., & Arkader, A. (2016). Percutaneous reduction of displaced radial neck fractures achieves better results compared with fractures treated by open reduction. Journal of Pediatric Orthopaedics, 36(4), S63–S66.

Tan, B. H., & Mahadev, A. (2011). Radial neck fractures in children. Journal of Orthopaedic Surgery (Hong Kong), 19(2), 209–212.

Olecranon fractures

Cite this article as:
Becky Platt. Olecranon fractures, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.21080

14-year old Noah was rocking on his chair while daydreaming his way through a maths lesson this morning… and fell off.  He reports that he landed directly on his left elbow and that it has been painful throughout the day.  He attends your ED this afternoon with his unamused mother.

Assessment of any child and examination of their elbow should be approached in an age-appropriate and systematic way.  In addition to examining for bony tenderness, vascular and neurological status should be tested.

You ensure Noah has been given analgesia before examining him.  His pain score is 5 and he seems comfortable after paracetamol and ibuprofen when his arm is resting.  His elbow is notably bruised and swollen. He is particularly tender over the olecranon and any movement is painful.  His neurovascular status is normal with good radial and ulnar pulses, normal sensation in the radial, ulnar and median nerve distributions and as he’s able to make the rock, paper, scissors and ok hand signs, you’re happy he has full motor function.  You order AP and lateral films of his elbow and pop him in a broad arm sling for comfort before sending him round for his x-rays.

Epidemiology and mechanism of injury

Olecranon fractures in children are rare, comprising around 5% of elbow fractures. Compare this with supracondylar fractures which comprise over half of all elbow fractures in the paediatric population. Olecranon fractures may result from a fall onto an outstretched hand (FOOSH), direct trauma or, occasionally, a stress fracture from repetitive throwing motion in athletes.

They can be classified according to the Mayo classification.

Examination findings

In addition to pain, there will almost certainly be generalised swelling around the elbow, usually with visible evidence of trauma, such as bruising or abrasion, over the olecranon process.  Point tenderness over the olecranon is often a feature, but the degree of swelling can sometimes make this difficult to appreciate.  Inability to fully extend the elbow is common, and pain on extension, supination and pronation is expected.  In those with comminuted or significantly displaced fractures it may be possible to feel crepitus over the olecranon.

Radiology

Interpreting children’s elbow x-rays can be mind boggling. Epiphyses ossify at different rates and so it can be easy to confuse a normal olecranon epiphysis with a fracture.  The olecranon epiphysis normally appears around 9 years and fuses at 15-17 years.   Be sure to refer to the CRITOE rules and if you’re not sure whether you’re seeing a normal epiphysis or a fracture, seek senior advice.  The olecranon can be best assessed on the lateral film.

This x-ray shows a normal olecranon epiphysis:

Case courtesy of Dr Jeremy Jones, Radiopaedia.org. From the case rID: 26814

Some olecranon fractures are obvious…

…but some can be incredibly subtle as illustrated in this series from Radiology Assistant:

Some olecranon fractures may only be visible on one view.  This may be the AP or the lateral.  The below elbow x-rays show a transverse olecranon fracture visible on the AP view only (arrow).  Note the raised anterior and posterior fat pads on the lateral view.  And an extra bonus point to those who spotted the subtle radial neck fracture.

Management

The majority of olecranon fractures (around 80%) are either undisplaced or minimally displaced (less than 2mm); these can be managed conservatively with an above elbow back-slab with good functional outcome.

Minimally displaced (<2mm) fracture in a 7 year old, requiring conservative management only. Case courtesy of Dr Jeremy Jones, Radiopaedia.org. From the case rID: 23650

Complications

In children with a displaced olecranon fracture, there is risk of complications including delayed or non-union, ongoing elbow stiffness and impaired function.  Refer any child who has an olecranon fracture with these features as they’re likely to require surgical intervention:

  • >2-4mm displacement
  • angulation of >30°
  • intra-articular involvement
  • extensor mechanism disruption
  • instability on extension
  • comminution

Olecranon fracture with >30 degrees of displacement, requiring surgical fixation. From Orthobullets.com.

The practitioner seeing injured children in the ED must be aware of the potential for these.  Displaced olecranon fractures can cause growth disturbances resulting in fixed flexion deformity of the elbow joint and associated morbidity into adulthood.

The ulnar nerve is particularly at risk of injury with olecranon fracture. Ensure you carry out a thorough neurovascular assessment, in particular checking sensation over the little finger and that the small muscles of the hand are functioning normally (the “scissors” sign).

A significant proportion of olecranon fractures are associated with concomitant injury, including radial neck fracture and /or supracondylar fracture and any co-existing injury is prognostic for poorer outcome.  When interpreting the x-ray, it is important therefore to have a systematic approach.

Bullets of wisdom 

  • Don’t confuse an unfused olecranon epiphysis with a fracture
  • But don’t forget that olecranon fractures can be subtle – maintain a high index of suspicion in children with direct trauma and inability to extend their elbow
  • Olecranon fractures are sometimes only visible on one view and this can be the lateral or the AP
  • Displaced fractures can have devastating consequences and must be referred to orthopaedics as they may need surgical intervention
  • Document neurovascular status and be sure to check ulnar nerve function
  • And look for a concomitant radial neck or supracondylar fracture

Noah returns from X-Ray and you review his films. He has a posterior fat pad sign and on closer scrutiny you spot an intra-articular fracture of the olecranon. You recognise that this type of fracture can be associated with complications and refer him to the orthopaedic team.  You ensure that his pain score and neurovascular status are being assessed regularly.

 

References

Cabanela M.E. & Morrey B.F. (1993) The Elbow and Its Disorders. 2nd ed. Philadelphia, PA, USA: WB Saunders cited in Sullivan, C. W., & Desai, K. (2019). Classifications in Brief: Mayo Classification of Olecranon Fractures. Clinical Orthopaedics and Related Research, 477(4), 908–910.

Caterini, R., Farsetti, P., DʼArrigo, C., & Ippolito, E. (2002). Fractures of the Olecranon in Children. Long-Term Follow-Up of 39 Cases. Journal of Pediatric Orthopaedics B, 11(4), 320–328.

Corradin, M., Marengo, L., Andreacchio, A., Paonessa, M., Giacometti, V., Samba, A., … Canavese, F. (2016). Outcome of isolated olecranon fractures in skeletally immature patients: comparison of open reduction and tension band wiring fixation versus closed reduction and percutaneous screw fixation. European Journal of Orthopaedic Surgery and Traumatology, 26(5), 469–476.

Degnan, A. J., Ho-Fung, V. M., Nguyen, J. C., Barrera, C. A., Lawrence, J. T. R., & Kaplan, S. L. (2019). Proximal radius fractures in children: evaluation of associated elbow fractures. Pediatric Radiology, 1–8.

Edgington, J. & Andras, L. (2019) Olecranon fractures – pediatric https://www.orthobullets.com/pediatrics/4010/olecranon-fractures–pediatric?expandLeftMenu=true

Hill, C. E., & Cooke, S. (2017). Common Paediatric Elbow Injuries. Open Orthopaedics Journal, 11, 1380–1393.

Kraus, R. (2014). The pediatric vs. the adolescent elbow. Some insight into age-specific treatment. European Journal of Trauma and Emergency Surgery, 40(1), 15–22.

Nicholson, L. T., & Skaggs, D. L. (2019). Proximal Radius Fractures in Children. The Journal of the American Academy of Orthopaedic Surgeons, 00(00), 1–11.

Pace, A., Gibson, A., Al-Mousawi, A., & Matthews, S. J. (2005). Distal humerus lateral condyle mass fracture and olecranon fracture in a 4-year-old female – Review of literature. Injury Extra, 36(9), 368–372.

Perkins, C. A., Busch, M. T., Christino, M. A., Axelrod, J., Devito, D. P., Fabregas, J. A., … Willimon, S. . (2018). Olecranon fractures in children and adolescents: outcomes based on fracture fixation. Journal of Children’s Orthopaedics, 12, 497–501.

Rath, N. K., Carpenter, E. C., Ortho, F., & Thomas, D. P. (2011). Traumatic Pediatric Olecranon Injury. A Report of Suture Fixation and Review of the Literature. Pediatric Emergency Care, 27(12), 1167–1169.

Medial epicondylar fractures of the humerus

Cite this article as:
Lisa Dunlop. Medial epicondylar fractures of the humerus, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.21036

In this section we will mainly discuss medial epicondylar fractures. Medial condylar fractures are a rare pattern of fracture and managed in a similar manner to lateral condylar fractures. It is important to differentiate between medial condylar and epicondylar fractures as condylar fractures are intra-articular and require urgent open reduction and internal fixation.