UMEM Educational Pearls - Orthopedics

Knee Dislocation:

• It is not uncommon for a patient to have dislocated their knee and it to spontanously reduce prior to presenting to the ED. 
• Consider the possibility of a spontaneously reduced knee dislocation in any patient with bicruciate (ACL and PCL) ligament instability.  
• Normal pulses and capillary refill does not exclude occult vascular injury to the popiteal artery.
• At a minimum the patient should have Ankle Brachial Indexs performed and if <0.9 serial exams and Doppler ultrasound studies should be obtained.
• Angiography is not absolutely required, and several studies have shown that a selective approach to angiography is acceptable.  As the studies below showed, most patients with findings requiring operative repair on angiography had abnormal physical exams.

Show References

Pelligrini-Stieda Lesion:

A Pelligrini-Stieda lesion is shown in the radiograph below.  This lesion was originally described in 1905, and is associated with a tear of the Medial Collateral Ligament.  Heterotrophic calcification forms causing chronic pain, which typically needs to be surgically excised.

So for the students out there, it is possible to diagnosis an MCL tear on plain radiographs.  Just not very often.

The Segond Fracture:

An benign appearing avulsion fracture of the lateral tibeal plateau that is marker for more significant injuries such as:

1. Anterior Cruciate Ligament (ACL) tear associated with this fracture 75-100% of the time
2. Injury to the Medial Meniscus occurs with a Segond fracture 66-75% of the time.

If this avulsion fracture is seen consider immobilzing the patients knee until they can follow up with Orthopedics and/or get an MRI to determine if additional injuries are present.

A recent study by Smith et al showed that the general abdomen/pelvic CT scan in trauma patients obtained with 5mm slices is a better screening test for spine fractures than plain films. They also showed that when compared to dedicated reconstructed thoracolumbar CT scan (2mm slices focused on the spine) it did not miss any clinically significant fractures.

The statistic for plain radiographs and the nonreconstructive CT scan are shown below.

The take home point is that dedicated Spine CT scans are probably not needed unless they are going to be used to guide surgical or non-surgical management, and plain films should probably be abandoned in patients that are undergoing CT scans of the chest/abdomen/pelvis.

Show References

Impingement Syndrome and the Diagnostic Accuracy of 5 Common Tests

It is also reported that subacromial impingement syndrome (SAIS) is the more frequent cause of shoulder pain.

The authors of this study attempted to determine the diagnostic accuracy of the following 5 tests for SAIS:

• Hawkins-Kennedy
• Neer
• Empty Can
• Painful Arc
• External Resistance

The study demonstrated that any 3 positive tests out of the 5 has a sensitivity of 0.75 (0.54-0.96) , specificity of 0.74 (0.61-0.88), positive likelihood ratio of 2.93 (1.60-5.36) and negative likelihood ratio of 0.34 (0.14-0.80).  See the table below for the individual test characteristics.  No single test was deemed accurate enough to make the diagnosis by itself.

So in the end you should be familiar with most of these tests in order to use a combination of them to make the diagnosis of impingement syndrome.  Future pearls will review how to perform these tests.

Show References

Scaphoid Fractures:

For suspected scaphoid fractures with negative radiographs it is common practice to put a person in a short arm thumb spica splint until followup up radiographs can be obtained in 10-14 days.

However, there is evidence that a short arm thumb spica splint is not enough for people that have a true scaphoid fracture.  Gellman et al demonstrated that long arm thumb-spica cast immobilization for six weeks followed by short arm thumb-spica cast immobilization decreased time to union by 25% when compared to short arm thumb-spica casting alone.

The theory is that the short arm splint still allows for forearm rotation that can cause shearing motion of the volar radiocarpal ligaments.  A long arm splint prevents this shearing action.  The disadvantage of a long arm splint though is potential elbow joint stiffness and muscle atrophy that can occur during the prolonged period of immobilization.

So for your next patient with a scaphoid fracture seen on radiographs place them in a long arm thumb spica splint.

Show References

Acute paronychia

• Usually result from minor trauma of the skin around the fingernail such as biting, manicures, picking a hangnail or finger sucking.
• Staphylococcus aureus is the most common infecting organism. However other mouth flora such as Streptococcus and Pseudomonas species, gram-negative bacteria, and anaerobic bacteria can also be a cause.
• Recommended treatement consists of incision and drainage and placing the patient on  amoxicillin /  clavulanic acid or clindamycin to cover all the organisms noted above.

Scaphoid Fractures in Children:

1. Rare before the age of 11.
2. Make up less than 0.34% of all pediatric fractures
3. Scaphoid fractures may be missed 12.5% - 37% on the initial presentation.
4. 30% of patients will have an radiographically apparant fracture on repeat films done 2 weeks later.
5. These physical exam findings are more specific for fracture:
   1. Volar tenderness over the scaphoid
   2. Pain with radial deviation
   3. Pain with active wrist range of motion.  
6. Though snuff box tenderness was seen in 100% of patients eventually proven to have a fracture, it was also seen in 92% of the patients that did not have a fracture at follow-up making it non-specific but sensitive.
    

Because of the high (30%) fracture rate seen on followup films it is recommended that all children be placed into a thumb spica splint until followed up.

Show References

Slipped Capital Femoral Epiphysis (SCFE)

SCFE can present as hip, thigh or knee pain in the young adolescent. Risk factors include hypogonadism, hypothyroidism, hypopituiratism, and obesity. One way to make the diagnosis is to obtain a AP view of the pelvis and draw a line(Klein's line) along the superior border of the neck of the femur.  This line should intersect the femoral epiphysis. If it does not the diagnosis of SCFE can be made.

However, this is only about 40% sensitivity. Green et al recently published a study that demonstrated that if you measure the distance from Klein's line and the lateral edge of the femoral epiphysis on both sides, and the difference between the two is more than 2mm you can make the diagnosis of SCFE more accurately and sooner.

FIGURE 1. Measurement methods on an anterior-posterior radiograph of a right slipped capital femoral epiphysis. White lines indicate Klein’s line for each hip. A and B, indicate maximum epiphyseal width lateral to Klein’s line. As A is 2mm narrower than B, the right (A) hip qualifies as a slip using our modification but not Klein’s original definition.

Show References

Wound Irrigation

A recent article by Thomas et al showed that any concentration of betadiene and hydrogen peroxide used to irrigate a wound was  more toxic to fibroblasts (required for wound healing) then it was to bacteria.  Low concentrations of chlorhexidine remained bactericidial while having minimal affects on fibroblasts. 

WIth the addition of this study the routine practice of soaking a wound in betadiene or hydrogen peroxide should be abandoned.  Good irrigation with normal saline or even tap water is all that is really needed to decontaminiate a wound.  If a bactericidal agent is needed then low concentrations of chlorhexidine should be used.

Show References

Winged scapula is caused by muscular injury or damage to corresponding muscular innervation. Mechanism can be due to blunt or penetating thoracic trauma.

• Trapezius muscle
  • Long thoracic nerve
• Serratus Anterior muscle
  • Spinal Accessory Nerve

Clinical findings include

• Protruding medial edge of the scapula
• Exacerbation by pushing against resistance
• Difficulty lifting arm over head

Treatments

• Initial splinting and orthopedic referral
• Depending on mechanism - trial of physical therapy
• Surgical treatments include fascial grafts or adjacent muscle attachment

Show References

Snuff Box Tenderness:

It has become the standard of care that individuals with snuff box tenderness, or pain with axial loading of the thumb, be placed in a thumb spica splint for 1-2 weeks until follow up x-rays can be done.  This is done to rule out an occult scaphoid fracture.  However, this practice can be hugely inconvenient to the patient and result in some atrophy of their forearm.

An alternative approach is to obtain a CT scan through the wrist to look specifically at the scaphoid bone.  If the CT scan is negative you can send them home with some pain control, RICE (Rest, Ice, Compression, Elevation) treatment and let them use thier thumb.  No splint is needed.  If it is positive then you can splint them and have them follow up with orthopedics or hand surgery.

AC Joint Dislocations

The acromioclavicular (AC) Joint is commonly injured when a person falls onto their shoulder.

The AC Joint consists of three ligaments:

• acromioclavicular ligament (AC)
• coracoacromial ligament (CA)
• coracoclavicular ligament (CC)

Injuries to this joint are classified as Type I – Type VI and involve sprain or tears of the AC or CC ligaments

• Type I – Is a sprain of the joint without complete tear of either the AC or CC ligament
• Type II – Does not show significant elevation of the lateral end of the clavicle but is due to a tear of the AC ligament.
• Type III – Results from tears in the AC and CC ligament. Noted by > 5 mm elevation of the AC joint.
• Types IV – VI : are associated with complications of a Type III injury.

Monteggia's Fracture

• Fracture of the proximal 1/3 of the ulna with an associated radial head dislocation.
• Mechanisms of injury include direct blow, hyperpronation and hyperextension.
• Radial head is dislocated anteriorly in 60% of the cases.
• can be associated with Posterior Interosseous Nerve (PIN) palsy. 
• PIN is the deep motor branch of the radial nerve and supplies the wrist extensors except for Extensor Carpi radialis Longus.  The palsy can be delayed so be sure to document wrist extenson strength.
• Most patients will require operative repair of the ulna fracture.
• Splint the  forearm in neutral rotation with slight supination, keeping the elbow flexed at 90 degrees.

Show References

Jones fracture

• Fracture of proximal metaphyseal 5th metatarsal
  • located w/in 1.5 cm distal to tuberosity of 5th metatarsal
• Prone to malunion
  • Watershed area (poor blood supply)
  • Under tension from multiple tendons
• Treatment
  • Immobilize with posterior-mold splint
  • Non-weight bearing - crutches
  • Prompt orthopedic evaluation
    • Some cases are managed with non-weight bearing casts
    • Others are repaired operatively.
    • Delayed jones fractures with malunion will require operative repair.
• Distinguish from pseudo-jones fracture (dancers fracture)
  • metatarsal styloid avulsion fracture, generally does not require operative repair
  • much more common than true Jones fracture.

Presented with persistant foot pain from
Jones fracture malunion.

Show References

Blast Injuries:

In honor of the 4th of July holiday, here is a quick pearl about blast injuries.

• Blast injuries due to fireworks most often affect the hands. 
• Other than the obvious superficial wounds that are seen on exam, the EP should be aware of significant cavitation and destruction of muscles that can occur in the forearm, thenar and hypothenar muscle groups which may be distal from the gross wound seen. 
• The energy from the blast is often transmitted through the carpal tunnel leading to an acute carpal tunnel syndrome from contusion of the median nerve.
• Patients should also be monitored for compartment syndrome.
• These patients can have significant injruies that are not immediately apparent. Consider observing these patients for awhile, or have them seen by hand surgery in case complications develop later on.

Show References

Metacarpal Fractures and Growth Plates:

The growth plates on metacarpals are on the distal end of the bone, except for the 1st metacarpal which is on the proximal end near the carpal bones.

Don't mistake this for a fracture line, however, make sure you get comparison views if they are tender over the area, as this can help you diagnosis a Salter Harris Type 1 fracture.

High Pressure Injection Injuries:

• These injuries initially often have a pretty benign appearance which may result in the injuried person seeking medical treatment late, or the initial medical provider not recognizing the seriousness of the injury.
• Even when treated promptly and aggressively most patients will end up with an amputation of thier finger or have permanent loss of funciton, strength, sensation, or chronic pain.
• In a couple of hours, these injuries tend to result in significant swelling that can lead to compartment syndrome. The swelling can be due to the actual disruption of cells from the high pressure, or due to toxic effects of the injected agent.
• Initial Management should consist of:
  • X-rays: Help to evaluate the extent of the injection.  Radio-opaque solvents will be seen on x-ray, but even radio-lucent solvents may be seen as lucency or air on the x-ray
  • Broad Spectrum antibiotics to prevent infection
  • Corticosteroids to decrease the inflammatory response brought on by the injected agent
  • Tetanus Prophylaxis if needed
  • Emergent hand surgery referral
• Most if not all patients will require emergent debridement of the affected area.

Show References

Shoulder Dislocations -- Treatment

• Shoulder dislocations once reduced have typically been treated by placing the arm in a sling and swathe which holds the shoulder in adduction and internal rotation. 
• However, several studies have now shown that placing the arm in a splint with the shoulder adducted and in 10 degrees external rotation helps to prevent recurrent shoulder dislocation. 
• Patients should remain in the brace/split for 3 weeks.
• External rotation is not recommended if there is an associated fracture.
• Some commerical splints are now available to hold the shoulder in external rotation, however, you can make a small strut with plaster or fiberglass to achieve the same result.

Show References

Nursemaid Elbow:

It is typically taught that the way to reduce a nursemaid's elbow is to hold the elbow at 90 degrees, then firmly supinate and flex the elbow. Place your thumb over the radial head and apply pressure as you supinate.(Taken from Sean Fox's Pearl on 7/20/2007)

However, there is a growing body of evidence that is showing that hyperpronating the forearm actually has a higher success rate on first attempt, is easier to perform, and is associated with less pain then supinating the forearm.  The overall reducation rates where similar for both methods.

The hyperpronation method consists of hyperpronating the forearm and then flexing the elbow.  Since the child tends to already hold their arm in partial pronation, the hyperpronation technique tends to need less force and has been associated with less pain.

Show References