Orthopedics

Consultant Teachings No. 3: Evaluation of Tendinous Hand Injuries for the Emergency Provider

Clinical Case:  You are working in a community emergency department one evening when a woman presents with a laceration across the fingerpad of her right thumb that she sustained after falling onto a piece of glass.  The laceration itself is pretty small - about a centimeter across - and has minimal bleeding.   The X-ray ordered by the triage nurse is negative for retained foreign body.  Before you just sew this up and send the patient on her way, you appropriately decide to do a thorough hand exam, including for tendonous injury.  The patient keeps saying that its hard to bend her finger because it hurts...
 
Consultant Teaching: Tendon Injuries to the hand are often complex entities that are subject to ongoing research regarding optimal procedures for management and rehabilitation. The flexor and extensor tendon anatomy is quite complex. Both are divided into numerous “zones” created to help clarify the optimal treatment, which can vary markedly depending on injury location. Missed tendon injuries increase morbidity by complicating later management and are therefore a leading cause of malpractice claims in the world of Emergency Medicine. The most important and fundamental aspect of evaluation in these patients is a detailed hand exam. Outlined below is a guide for the evaluation and management of any patient presenting to the ED with a suspected hand injury.

Flexor Tendon Injuries
The first step is to obtain a detailed history of the mechanism of injury. Was the injury caused by a rusty farm knife or a sharp chard of glass? What was the position of the patient’s hand when the injury occurred? This is a frequently missed point to mention. You can imagine that, if the patient was lacerated with flexed fingers while gripping a knife, the location of the tendon injury itself may be in a very different location than the skin laceration when evaluating the hand in a more extended posture. Just because you can no longer see the damaged tendon in the wound doesn’t mean it’s not there.

Step 1: Observation 
Evaluate the location and depth of the laceration. Look at the resting posture of the hand and the
patient’s digital cascade. When in doubt, you can usually find clues by looking at the resting finger position of the uninjured hand. Your clinical suspicion should be raised if a particular finger rests in a more extended position relative to the others.

Step 2: Passive Range of motion
These hand injuries can be really painful. A good place to start is assessment of passive motion with a maneuver that elicits the tenodesis effect. Try it on yourself - With a relaxed hand, when you passive flex your wrist, your MCP/PIP/DIP joints will extend. Similarly, wrist extension will cause passive flexion of those digits. If you passively extend the patient’s wrist and there is persistent extension of the DIP or PIP joints, you may have a flexor tendon injury in that digit. 

Step 3: A detailed (ie purposeful) neurovascular exam 
Flexor tendon injuries are frequently associated with neurovascular injury because of the palmar
location of these structures. The best way to assess nerve function is with a two-point discrimination exam. This can easily be performed with a paper clip. Remember that each finger has proper digital nerves on its palmar aspect on both the radial and ulnar sides: test them both. *Tip 1* If you get abnormal results that don’t make sense given the injury, test the other hand! Your patient who forgot to mention his terrible neuropathy will appreciate this. *Tip 2* Under NO circumstances should a digital block be performed if you are planning to consult the hand service on call. If analgesia is an issue, let the hand service know and proceed with necessary oral/IV medications until your consulting service is able to evaluate the patient’s neurovascular status. This is not only important for our documentation, but is critical for possible surgical planning.

Sensory territories of the hand (Source: wikipedia)
There are multiple ways to assess the vascular status. Assessment of cap refill, a digital Allen’s test (same concept as the wrist, but with compression of the radial and ulnar palmar arteries of each finger) and pulse oximetry can all help establish whether or not a concomitant vascular injury is present.



Step 4: Flexor Tendon Exam
A quick anatomy review is necessary here because, in the hand, form truly follows function. The flexor digitorum profundus (FDP) and superficialis (FDS) tendons are both extrinsic hand muscles that power finger flexion. The FDP lies deep to FDS and then attaches distally to the distal phalanx of the 2nd-5th digits. The FDS attaches at the base of the intermediate phalanx of these digits. Why is that important to know for your physical exam? Since these muscles share a common belly and are intimately associated with one another, you must carefully isolate the desired tendon on each digit. Asking a patient to “wiggle their fingers” is an easy way to improperly assess hand function and miss isolated tendon injuries. To test the FDS: all adjacent digits must be held with all joints in extension while the patient flexes the finger at the PIP joint. To test the FDP: hold the middle phalanx in extension while asking the patient to flex just their distal phalanx. Another reason not to digital block these patients is that pain with these movements may clue the examiner into a possible partial tear or laceration.

For completeness, it is also important to document motor testing for all muscles with separate nerve innervations, regardless of its proximity to the wound in question.

Extensor Tendon Injuries 
Like the flexor tendons, these also can be diagnostic challenges due to the complex anatomy of the extensor mechanism. This region is comprised of extrinsic muscles that power digit extension, like the extensor digitorum communis (EDC) and an extensor aponeurosis with multiple connecting bands and ligaments. Again, a detailed history will provide valuable insight and context for your exam. Is it a result of a fight-bite injury? A crushing mechanism?

The general principles of the physical exam addressed above regarding observation, passive range of motion and a detailed neurovascular exam still apply. As diagrammed in the image above, for the dorsal hand, it is especially important to assess both the radial and ulnar nerves.

With regard to hand posture, take note if there is a resting flexed position of the digit, a mallet finger, or boutonniere deformity. This should heighten your suspicion for a tendon injury.

Assessment of the Extensor Tendon 
A few important considerations are noteworthy here. First, do not be fooled by the action of the lumbricals! Remember, these muscles provide extension of the PIP and DIP joints via the lateral bands. Have the patient lay their hand flat on a table (extends the MCP joint and helps remove the influence of lumbricals) and extend at the MCP joint against resistance. Extension along an affected digit may still be possible even after complete laceration, due to the multiple contributions to the extensor mechanism. Look closely for a lack of hyperextension or differential extension in the affected finger that may be a sign an extensor tendon injury has occurred. The junctura tendinae are intertendinous fascial connections located around the MCP joint that attach tendons of the EDC and help coordinate their movements. This anatomic structure is important to keep in mind because the junctura may allow for some extension of an injured digit if the tendon injury is proximal to them.

Lastly, if you are concerned about an injury to the “central slip” (eg. a lac or crush injury to the middle phalanx), then an Elson test can be performed. To do this test, flex the PIP 90 degrees over a table and have them extend against resistance. If the central slip is intact, the DIP joint will be supple. If it is ruptured, there will be weak extension of the PIP and a rigid DIP due to the action of the lateral bands.

So, I did my hand exam… What next? Management of these injuries is often multifactorial and depends on the location of the injury, the structures involved, patient and other factors that are beyond the scope of this post. Doing a correct and detailed physical exam is the first, and most important, step in making sure a patient doesn’t walk out of the ED with an undiagnosed tendon or neurovascular injury.  When practicing in the community, if you suspect that there is an associated tendonous injury based on your clinical exam, clean and repair the laceration as you otherwise would but subsequently place the patent in a dorsal blocking splint, with 15-20 wrist flexion with the hand in intrinsic plus position (MCPs at 70-90 degrees and DIP/PIP straight) and make sure they have follow-up with a hand surgeon.  
 
At the end of the day, it’s important to keep a high level of suspicion - a referral to a hand surgeon for a suspected tendon injury is just as valid as a referral for a definite tendon injury. 

Check out these videos:
Tenodesis effect: https://www.youtube.com/watch?v=j0RBU_phUKw 
Elson test: https://www.youtube.com/watch?v=wudDvOiSUlw
Generic hand exam: https://www.youtube.com/watch?v=imPQve7ZL3o

Submitted by Chris Cosgrove, MD. Ortho PGY2
Reviewed by: Daniel Osei, MD. Hand Attending

EverydayEBM Editor: Maia Dorsett (@maiadorsett)

Consultant Teachings No. 2: Thoracolumbar Spinal Fractures - A Spine Consult Isn't Always Necessary

Clinical Scenario:  You are working one evening in the emergency department when an intoxicated young female is brought in by EMS after being involved in a reportedly high speed MVC.  She is clinically intoxicated, uncooperative and tachycardic.  She gets a pan-scan CT which identifies some facial fractures and isolated transverse process fractures of the thoracic spine.  As you decide on the next steps to take care of the patient, you debate whether to discuss the patient with a Spine specialist.

Clinical Question: Which spinal fractures should you discuss with a Spine specialist?  Are there some that do not require any intervention at all?

Literature Review:  With the increased availability and increased utilization of CT scanners in the ED, it has become common practice to “pan-scan” patients who present after a trauma, especially those patients who are obtunded/intoxicated or present following a high risk mechanism.  The use of the CT scan to identify thoracic or intrabdominal injuries has concomitantly lead to an increase in diagnosis of fractures of the thoracic and lumbar spine.  As an example, in one retrospective study conducted in the UK of 303 blunt trauma patients who had a Chest/Abdomen/Pelvis CT performed, only six scans (2%) identified thoracic injury and four (1.3%) demonstrated intrabdominal injury while 51 scans (17%) demonstrated an injury to the thoracolumbar spine [1].

With respect to screening for thoracolumbar spinal injuries specifically, the Eastern Association for the Surgery of Trauma practice guideline now recommends CT scan as the primary imaging modality [2]. This is based on a body of evidence that strongly supports that CT scan is more sensitive than X-ray for detection of thoracolumbar spinal injuries.  For example, in one small German study of 107 minor trauma patients, radiographs had a sensitivity of only 49.2% and specificity of 54.7% for thoracolumbar spinal injury compared with CT scan which served as "gold standard" [3].

While CT scan is more sensitive, not all the spinal fractures that are found are clinically significant (i.e. requiring spine precautions or bracing/surgical intervention) [4].  For example, in the small German study cited above X-ray alone missed 16/28 fractures of the the mid thoracic spine, but none of these were considered  unstable [3].  Of the 94 fractures identified in 51 patients by Chest/Abdomen/Pelvis CT in the UK study, 43 (46%) were considered not clinically significant [1].  Thus, the increased sensitivity of our diagnostic evaluation of trauma not only increases our detection of clinically important fractures, but otherwise stable spinal trauma.

Spine consultation for certain types of stable spinal injuries often comes at the expense of increased patient wait times, prolonged spinal precautions,  increased institutional cost, decreased patient satisfaction, and possibly even poorer outcomes if such consultation delays a patient’s transfer to the floor or ICU [4].   Below is a guide to approaching and managing two types of commonly seen fractures in the Emergency Department.

Transverse Process Fractures  

Source: www. waybuilder.net

Transverse Processes (TPs) of the vertebrae primarily function as sites of paraspinal muscle and ligament attachments. They are part of the posterior column in the classic Denis “three column” classification, which divides the spinal column into anterior, middle and posterior structural elements. The vertebral body consists of the anterior and middle columns and is the main axial load bearing part of the spinal unit. The posterior column consists of the elements behind the vertebral body, with the most important components being the pedicles, facet joints and ligamentous complex. Stability for the spinal column is maintained through a series of attachments between the various spinal elements (anterior, middle and posterior). An isolated TP fracture is a stable fracture and does not compromise spinal stability. Additionally, isolated TP fractures are not associated with neurologic deficits. The spinal cord and nerve roots are not in proximity to the TPs, nor are they at high risk of displacing in a manner that would put the nerve root or cord at risk.

A small 2008 retrospective study from the University of Missouri looked at a cohort of 84 patients with TP fractures; 47 were isolated and 37 were associated with other spine fractures [5]. In this study, no patients with isolated TP fractures required surgery or bracing for spinal stability. Furthermore, none of these patients had any neurologic deficits. The authors concluded that conservative management of isolated TP fractures was appropriate, without the need for orthopaedic or neurosurgical consultation. However, if the TP fracture is associated with another spinal fracture such as a vertebral body fracture, a specialist consultation is warranted for treatment recommendations regarding the associated injury, but not necessarily the TP fracture itself. Of course, a cervical TP fracture that extends into the transverse foramen also necessitates additonal imaging and likely spinal consultation, as it may warrant a CT angiogram for evaluation of vertebral artery damage.

Compression Fractures

Vertebral compression fractures are the most common fragility fracture, affecting approximately 25% of people over the age of 70. Compression fractures are a result of axial force on the anterior column that results in a wedge deformity of the vertebral body. The vast majority of compression fractures do not require surgical intervention. Moreover, these fractures are often stable due to their impacted nature. No study has proven that bracing vertebral compression fractures prevents further vertebral collapse, decreases pain, or improves patient satisfaction. Treatment of most vertebral body compression fractures can focus on reducing associated pain with appropriate pain medications. A thorough approach to a patient presenting with an acute compression fracture should include the following:

1: Patient factors: What was the mechanism of injury (simple fall or high-energy injury)? Is the patient ambulatory, bed or wheelchair bound? Are there significant medical comorbidities (ie morbid obesity, extensive pulmonary disease) that would make bracing an ineffective or even dangerous treatment option? Is the patient’s pain controlled enough to obtain an accurate neurologic exam? Is the patient tender over the spinal segment in question?

2: Fracture factors: Is the fracture stable or unstable? The best way to evaluate is to use the patient’s own physiologic forces to see if there is further displacement of the fracture. Barring any neurologic deficits, plain supine AND upright radiographs of the affected area should be obtained. The goal is to see if there is any significant height loss or increased kyphosis between the series. If not, it’s a safe bet that the fracture is stable.

Given a stable fracture, the next step is determined primarily by patient comfort level. If the patient is able to tolerate sustained physiologic loads (ie sitting or standing), it is reasonable to send them home with observation only, no bracing required. Follow up could be provided by their primary care provider or PM&R. If they are in too much pain to stand or sit despite appropriate analgesia, an extension orthosis (like an off-shelf TLSO) is sometimes beneficial and can be provided by the spine consultant on call. If the compression deformity is acute and deemed to be unstable, if there are any neurologic deficits or other associated spinal pathologies, certainly a spine consultation is necessary and appropriate at that time.

Take Home Points:  The increased use of CT imaging, especially in trauma, may lead to the identification of injuries that do not necessarily warrant intervention other than pain control.  For neurologically intact patients, it is useful for the emergency physician to be aware of which fractures warrant either bracing or surgical intervention as unnecessary  consultation can lead to prolonged length of stay and increased cost without significant benefit to the patient.

Submitted by Chris Cosgrove, Orthopedic Surgery PGY-2
Faculty Reviewed by : Lukas Zebala, MD, Assistant Professor, Orthopaedic Surgery

Everyday EBM Editor Maia Dorsett (@maiadorsett)

References:
1. Venkatesan, M., Fong, A., & Sell, P. J. (2012). CT scanning reduces the risk of missing a fracture of the thoracolumbar spine. Journal of Bone & Joint Surgery, British Volume, 94(8), 1097-1100.
2. Sixta, S., Moore, F. O., Ditillo, M. F., Fox, A. D., Garcia, A. J., Holena, D., ... & Cotton, B. (2012). Screening for thoracolumbar spinal injuries in blunt trauma: An Eastern Association for the Surgery of Trauma practice management guideline. Journal of Trauma and Acute Care Surgery, 73(5), S326-S332.
3. Karul, M., Bannas, P., Schoennagel, B. P., Hoffmann, A., Wedegaertner, U., Adam, G., & Yamamura, J. (2013). Fractures of the thoracic spine in patients with minor trauma: Comparison of diagnostic accuracy and dose of biplane radiography and MDCT. European journal of radiology, 82(8), 1273-1277.
4. Homnick, A., Lavery, R., Nicastro, O., Livingston, D. H., & Hauser, C. J. (2007). Isolated thoracolumbar transverse process fractures: call physical therapy, not spine. Journal of Trauma and Acute Care Surgery, 63(6), 1292-1295.
5. Bradley, L et al. Isolated transverse process fractures: spine service management not needed. J Trauma 2008 Oct; 65(4):832-6.