HPI:
An otherwise healthy 39-year-old female presents to the emergency department complaining of right shoulder pain.

She had a fall the night previous where she fell directly onto the point of her right shoulder. She had dull, moderate pain but went to sleep after the fall as it was late and she had been drinking. She woke up on the morning of presentation with excruciating shoulder pain, inability to move her arm secondary to pain and a visible of the right shoulder deformity. No other traumatic injuries, no other complaints. She is not able to move her shoulder but can move her elbow and hand okay. No paresthesias, no weakness in the right arm.

On physical exam,
Her right shoulder is held against body, flexed at elbow. There is exquisite point tenderness over the AC joint. Appears deformed on visualization, with down-sloping of the anterior shoulder. Skin is intact. Palpation of the long bones and hands does not elicit tenderness or crepitus. The clavicle is neither tender nor deformed.  Active/passive elbow and wrist range of motion is full and painless. Passive ROM of the right shoulder is not tolerated well secondary to pain. Patient can give a thumbs up, make an okay sign, and cross his index and long fingers without issue. Sensation to light touch is intact in the radial, median, and ulnar nerve distributions in the hand. Radial pulse is palpable.

Right shoulder XRs were performed and are shown below. 

What is the diagnosis? Should you prepare the patient for shoulder reduction?

Answer:
AC Separation

AC separation of the shoulder usually results from direct trauma to the AC joint, when the arm is in an adducted position. Support of the AC joint is through the acromioclavicular and coracoclavicular ligaments. Tenderness and deformity at the AC joint is diagnostic of this clinically.  XRs are performed to confirm the diagnosis and also rule out underlying fracture.

There are six types of AC separation.
Involvement of the AC and CC ligaments determine the severity of acromio-clavicular injury. The types increasingly worsening in severity.

Radiographs:
Must have True AP, Axillary and Scapular Y views to diagnose (to rule out associated dislocation or fracture).

Management:
Treatment of type I and II injuries consists of rest, ice, analgesics, and immobilization (sling), followed by early range-of-motion exercises (7 to 14 days).

​Orthopedic consultation for Types III through VI.

Operative management is ORIF or ligament reconstruction: Type III in elite athletes, Types IV-VI.



​By: Dr. Michael Mollo M.D.

References:
1. Rudzinski J Pittman L Uehara D: Injuries to Bones and Joints, in Tintinalli J., et al (eds): Tintinallis Emergency Medicine: A Comprehensive Study Guide, ed 7., (Sec) 22 (Ch) 268:p 1832-1834.
2. Orthobullets
3. Northwestern Orthopedics

DIAGNOSIS AND TREATMENT
Based on the physical exam and the above radiograph, the patient was diagnosed with an anterior cruciate ligament (ACL) tear and a Segond fracture.

Patient was treated with a knee immobilizer and crutches for the immediate post-injury period. He was given outpatient referral for possible later surgical intervention.

DISCUSSION
This fracture was first described by Dr. Paul Segond in 1879 after experiments on cadavers.

A Segond fracture is a small bone avulsion from the lateral aspect of the tibia. This fracture is significant because it has a strong association with ACL injuries. Approximately 75% of patients with this fracture pattern with have an ACL injury. The associated exists because the stresses needed to produce this fracture also frequently produce ACL injuries. The exact mechanism of this fracture is unclear. It has been thought to be the result of an avulsion of the middle third of the lateral capsular ligament, however other theories exist. The iliotibial band or anterior oblique band may instead be involved.
​
A Segond fracture is a clue to the clinician to perform a thorough ligamentous exam of the knee to search for other injuries. A medial meniscus injury is also commonly seen.


A “reverse” Segond fracture also exists and is a small medial avulsion fracture of the tibia. This mirror fracture is rare, but is associated with injuries to the medial collateral ligament and the posterior cruciate ligament (PCL).

KEY POINTS
Segond fracture = small bone avulsion from lateral aspect of tibia.
ACL injury seen in 75% of these patients.
Perform a thorough ligamentous exam if this fracture pattern is seen.

​A 15 yr old female right hand dominant with no significant past medical history presents with left shoulder pain after sustaining injury while playing basketball. States she can not clearly recall the events but remembers extending her arm for the ball and having sudden onset of pain. Describes generalized constant aching pain to the left shoulder only. She has been unable to range her left shoulder since the event stating “it hurts too much”. She denies any numbness or tingling. No other complaints. Last PO intake approximately 6 hours ago.

​General: adolescent female sitting upright in bed with left arm flexed and adducted, moderate distress
LUE: left arm held flexed and adducted against her body. Square-like appearance to the shoulder compared to the right which appears rounded. No erythema, abrasions, lacerations, or ecchymosis. Unable to flex, extend, or abduct left shoulder due to pain. Full flexion and extension of elbow and wrist. She can make thumbs up, okay sign, cross fingers, touch thumb to pinky, and keep fingers spread against resistance. Sensation intact in the median, ulnar and radial nerve distributions. Sensation intact in the axillary nerve distribution.  2+ radial pulse

​Anterior left shoulder dislocation. She was given intranasal fentanyl, intraarticular lidocaine and nitrous oxide. Left shoulder was then reduced by external rotation with elbow at patient’s side. No complications. Post reduction films obtained show successful reduction with no fractures

​Anterior shoulder dislocations are the most common shoulder dislocation, accounting for approximately 95%. Majority of these occur in patients younger than 30 years old. Posterior dislocations account for about 5%, and inferior dislocations (luxation erecta) are extremely rare.
Anterior shoulder dislocations occur secondary to a “hyper” external rotation. The glenoid dislocates to the position of either subcoracoid (90%), subclavicular, or sublenoid. Usually the patient holds arms by their side. In a thin patient, the acromion appears prominent giving the classic “squared off” appearance the shoulder. In larger patients, the effected shoulder may appear more round instead of its normal square shape.
Intra-articular lidocaine can be used for pain relief prior to reduction as shown below.

​Nitrous oxide is also a common and effective means for pain relief. A full neurovascular exam is crucial, approximately 13.5% will have neurologic injury. Axillary nerve is the most commonly effected. This nerve is tested by assessing pinprick sensation over the lateral aspect of the arm. You can also test by motor abduction of the deltoid.
Films must be obtained prior to reduction if: first time dislocation, age over 40, presence of humeral ecchymosis, or traumatic mechanism. The scapular Y view will demonstrate anterior dislocation of the humeral head from the glenoid. Associated injuries to look for include Hill sachs defect, bankart lesions, fractures of the greater tuberosity, soft tissue injuries, and rotator cuff tears.
While we will not discuss in depth associated injuries, it is important to be aware particularly of hill sachs and rotator cuff tears. Hill sachs defect presents in up to 40% of anterior dislocations; this defined by a radiographic defect in the posterior lateral portion of the humeral head. Rotator cuff tears, also common, present more commonly in older patients. It is estimated between 35-86% of anterior dislocations in patients over 40 years old have a rotator cuff tear.
​
Shown below includes image of anterior shoulder dislocation with hill-sachs deformity on the left; and anterior shoulder dislocation with bankart lesion on the right. 
 

​There are several techniques for reduction, none of which have proven more efficient or effective over the other. A common technique, used in this patient, is the external rotation method. Patient sits up, straight back. Examiner holds the elbow at the patients side and with forearm in 90 degree angle, slowly externally rotates the arm. After successfully reduction, the arm is immobilized with splint and post reduction films obtained. Immobilization should be for 3 weeks if younger than 30 yrs old, and for 7-10 days if over 30 yrs old.

​This is a 13 yr old Caucasian male with no significant past medical history who is presenting with 2 week history of right hip pain. He describes a vague pain localized around the right hip worsened with movement mostly flexion and extension of the hip. No known alleviating factors. No history of trauma, fever, chills, nausea or vomiting, recent weight loss or night sweats. No other joints involved. No family history of rheumatologic or bone disorders. 

​General: Obese male, laying flat on bed in no distress.
RLE: Right lower extremity is slightly externally rotated compared to left. No thigh or calf atrophy. No erythema, swelling, or warmth to touch. No abrasions, lacerations or ecchymosis. 2+ dorsalis pedis pulse. Sensation intact in all dermatomes. Full active range of motion of right hip. Passive range of motion however is significant for slight external rotation with flexion of the hip. No patellar or fibular head tenderness. Full active and passive range of motion of knee. Noted to have slight external rotation of right lower extremity with gait.
GU: Normal male genitalia. No erythema, swelling, or tenderness of penis or scrotum. No urethral discharge.  
LLE: No erythema, swelling, or warmth to touch. No abrasions, lacerations or ecchymosis. 2+ dorsalis pedis pulse. Sensation intact in all dermatomes. Full active and passive range of motion of hip. No patellar or fibular head tenderness. Full active and passive range of motion of knee.

​Isolated right slipped capital femoral epiphysis. No involvement of the left side. Patient was taken to the operating room the following day and underwent percutaneous in situ fixation with two cannulated screws. TSH and free T4 obtained, normal. Counseling on weight loss provided.

​Slipped capital femoral epiphysis (SCFE) is a disorder where the femoral epiphysis displaces from the femoral neck through the physeal plate. It is a common hip disorder in adolescents affecting approximately 10 per 100,000. Note however, about 15% will present with no description of hip pain but rather knee or thigh discomfort. Thus it is important to maintain a high degree of suspicion to diagnose and treat early.
SCFE is more commonly seen in obese children; obesity is the single greatest risk factor. It more commonly affects males, African Americans, and Pacific islanders. Often it occurs during periods of rapid growth (the average age for boys 13 yrs old, females 12 yrs old). It can be associated with endocrine disorders including hypothyroidism, osteodystrophy of chronic renal failure and growth hormone treatment. If SCFE is diagnosed in a child who is <10 yrs old or whose weight is <50th percentile, an endocrine workup is warranted.
The displacement of the epiphysis occurs secondary to mechanical forces. Through the hypertrophic zone of the physis, slippage can occur. Cartilage within the perichondral ring acts as a weak point and with mechanical forces causes displacement.  With displacement, the epiphysis remains within the acetabulum. The neck slips anteriorly and rotates externally.
The most common presenting complains are pain and altered gait. Classically, an obese child presents with dull pain either in the hip, groin, thigh or knee without any history of trauma. Symptoms can be present anywhere from week to several months. Often an abnormal coxalgic gait is noted. The child may have decreased hip motion with obligatory external rotation during passive flexion of the hip. There may also be abnormal leg alignment with the foot slightly externally rotated and thigh atrophy.
Diagnosis is made by radiographs. It is recommended that both an AP and frog-leg lateral of the right and left hip is obtained. 17-50% of SCFE are bilateral. On the AP pelvis, Klein’s line can be drawn to help diagnose. This line is drawn along the superior border of the femoral neck. In a normal hip, the line will intersect the femoral head. In SCFE, Klein’s line does not intersect the femoral head.
 

P​If the child is able to ambulate, it is termed stable. Unstable SCFE occur in children unable to ambulate or if the epiphysis is displaced from the metaphysis. Each is treated by making the child non-weightbearing until orthopedic consultation and treatment. The importance in the difference is children with unstable SCFE may have further displacement with any manipulation; thus it is extremely important to immediately place child on stretch and instruct to not ambulate.
Children with SCFE should be referred to orthopedics promptly. Non-weightbearing is required until treatment. Treatment is surgical by either percutaneous in situ fixation or open reduction with the capital realignment. 

1. SCFE is where the femoral epiphysis displaces from the femoral neck
2. More common in obesity, males, African American, and Pacific islanders
3. Can be associated with endocrine disorders
4. Order AP and frog-leg views bilaterally to diagnose, assess Klein's line
5. Urgent orthopedic consultation for surgical treatment

​45 year old male right hand dominant with no significant past medical history presents by EMS after low mechanism motor vehicle crash complaining of left thumb pain.  States his left hand “jammed into the steering wheel” during the crash causing deformity to the left thumb. He denies any numbness or tingling but is unable to fully range due to pain. No prior left hand injuries. Non-smoker. 

​Swelling and deformity to the left thumb metacarpophalangeal joint. No abrasions, laceration or ecchymosis. 2+ radial pulse. Significantly limited flexion and extension of the left thumb at the MCP. Intact flexion and extension at the PIP. 2-point sensation intact. Good capillary refill.  

​Dorsal dislocation of the left thumb metacarpophalangeal joint

​Simple metacarpophalangeal joint dislocation of the left thumb.
​Patient was given pain medication through an IV and a radial and median nerve block was done for anesthesia. The joint was then reduced successfully at bedside with initial attempt. Post-op exam essentially unchanged except significant improvement in flexion and extension at MCP. There did not seem to be any significant instability. Regardless patient was placed in a thumb spica splint and follow-up with hand clinic in 1 week.

​Dislocation of digits are common. Dorsal MCP dislocations follow hyperextension of the affected joint with rupture of the volar plate. They are classified by direction as dorsal, volar, or lateral. 
Dorsal: distal digit displaced toward back of hand
Volar: distal digit displaced toward palm of hand
Lateral: distal digit displaced ulnar or radial direction
The most frequent direction of dislocation is a dorsal displacement.
Metacarpophalangeal dislocations are further classified by volar plate involvement.  For MCP dislocations other than the thumb this is simple (volar plate not interposed in the joint) or complex (volar plate entrapped in the joint).  For MCP dislocations of the thumb, classify as incomplete (volar plate ruptured, collateral ligament intact), simple (volar plate and collateral ligament ruptured), or complex (dislocated phalanx entrapped in intrinsic hand muscles and volar plate entrapped). Simple thumb MCP joint dislocation are in extension and reducible whereas complex dislocations are in bayonet apposition and not easily reducible. It is extremely important to obtain radiographs prior to attempting reduction to clarify whether the reduction should be attempted or referral to hand surgeon.
Emergency medicine physician should reduce the dislocation once confirmed a simple dislocation without associated open joint, fracture or entrapped volar plate. 

Tenosynovitis is an inflammation of a tendon and it is synovial sheath.  It most frequently occurs in the hands and wrists however can occur in any joint.  Tendon sheaths have 2 surfaces, a visceral layer (inner) and a parietal layer (outer).  When fluid and inflammatory markers accumulate between these two layers and their potential space, this is referred to as tenosynovitis.

There are 3 mechanisms that accounts for most episodes of tenosynovitis:
1.  Trauma (puncture wound, laceration)
2.  Contiguous spread from adjacent infected soft tissue
3.  Hematogenous

Organisms:
The most common pathogens are skin flora including Staphylococcus aureus and Streptococci. However, any organism can cause tenosynovitis.

Tenosynovitis is a clinical diagnosis.  There are four classic clinical findings as described by Kanavel: Tenderness over the entire flexor tendon sheath, symmetric finger swelling over the length of tendon sheath described as "sausage-digit", intense pain with passive extension, resting flexed posture of digit to minimize pain.  Often radiographs are obtained to rule out fracture or bony involvement.  Often these are normal.  No lab tests are sensitive or specific to tenosynovitis.

​

HPI:
 
The patient is a 41-year-old female with past medical history of diabetes who presents with right knee pain.  Patient states that approximately 2 days ago, she noticed that her knee was red, swollen, and has gotten sore to the point that she cannot walk.  Patient denies ever having symptoms like this before.  Patient denies any prior surgeries or trauma to the joint.
 
Physical exam:
 
Swelling and erythema over the right knee.  The patient is unwilling to walk in the exam room stating that she cannot secondary to pain.  The knee is warm to the touch with no overlying induration.  The patient has limited active and passive range of motion secondary to pain.  Patient has 2+ distal pulses with intact sensation to light touch in all dermatomes.
 
Radiographs:
 
Normal knee
 
Laboratory data:
 
CBC:  WBC 24K, Platelets 224
Serum glucose:  197
ESR:  39
CRP: 7.2
Joint aspiration: cloudy fluid, WBC 62K, gram stain negative, glucose 94
 
Diagnosis and Plan:
 
Septic arthritis.  Patient was started on vancomycin and orthopedics was consulted.  She was admitted to the hospital and taken to the OR later that night for washout.
 
Discussion:
 
Location:
 
The most commonly affected joints in descending order are the knee (>50%), hip, shoulder, elbow, ankle, sternoclavicular joint.
 
Risk Factors:
 
Greater than 80 years of age, presence of prosthetic joint, overlying skin infection, diabetes, rheumatoid arthritis, cirrhosis, HIV, history of gout or pseudogout, endocarditis, recent bacteremia, IV drug user, recent joint surgery.
 
Organisms:
 
Most common in all patients is Staphylococcus aureus which accounts for greater that 50% of infections. 
 
There are some specific patients that have high rates of other organisms that we should be aware:
 

• Healthy, sexually active adolescents and young adults:  Neisseria gonorrhea
• Neonates: gram negative bacilli
• Infants and elderly: group B strep
• Sickle cell disease: Salmonella
• IV drug users: Pseudomonas aeruginosa
• Immunocompromised host: Candida/fungal

 
ER Work-up:
 

• Plain radiographs
• CBC, ESR, CRP
• Joint aspirate with cell count and differential, gram stain, glucose
• Blood cultures (50% positive, even without fever)

 
Differential:
 
An emergency physician is only as good as the differential that they consider, therefore, we should maintain the following on their differential: gout, pseudogout, reactive arthritis, rheumatoid arthritis, Lyme disease, gonococcal arthritis, traumatic arthritis, cellulitis, bursitis.
 
Treatment:
 
There are no good randomized controlled trials for antibiotic treatment of septic arthritis.  Current recommendations are based on the most likely organism.  If you lucky enough to have a positive Gram stain, then you should treat gram-positive smear with vancomycin and gram negative smear with a third generation cephalosporin such as ceftriaxone.  Other specialized considerations are:
 

• Pseudomonas aeruginosa – ceftazidime and aminoglycoside
• Negative gram stain and immunocompetent – vancomycin
• Negative gram stain and immunocompromised, traumatic, or IV drug users - vancomycin and third-generation cephalosporin

 
Finally, once confirmed, orthopedic service should be consulted as these joints will need washout in the operating room.
 
Pearls:
 

• The likelihood of septic arthritis decreases significantly if the patient is able to bear weight and has no pain on passive range of motion
• Serum WBC count has low sensitivity
• Only approximately 60% of patients will have fever
• Sensitivity of CRP and ESR are 92% and 98% respectively
• IV antibiotics and orthopedic consultation are standard of care

HPI: 
Otherwise healthy 27-year-old male who presents with right knee pain.  The patient is a construction worker and while on a construction site today, a wooden wall fell onto him and other workers.  The patient received an isolated injury to his right knee and presents with pain and deformity.  Patient denies any other injuries, his vital signs are within normal limits.

​Exam:
Patient lying in a supine position.  Right knee has no significant effusion, erythema, or overlying abrasions/lacerations.  Palpation of the right knee reveals a large step off between the patella and anterior surface of the femur.  Patient is neurovascularly intact distally.  Representative x-ray is shown below.

http://radsource.us/
 
Discussion:
There are 5 different types of knee dislocations based on the direction of displacement from the tibia.

1. Anterior is the most common.  This is due to hyperextension injury and is often associated with a tear of the posterior cruciate ligament.  Arterial injury is usually secondary to intimal tear.
2. Posterior is the second most common type.  This is usually due to an axial load to a flexed knee, such as in a MVC with dashboard injury.  This has the highest rate of associated popliteal artery injuries.
3. Lateral dislocation is usually due to varus or valgus force.  These typically involve tears of the anterior cruciate ligament and posterior cruciate ligament.  These are associated with peroneal nerve injury.
4. Medial dislocation is usually due to varus or valgus force.  This is usually associated with posterior cruciate ligament injury.
5. Rotational dislocation is commonly associated with sports injuries.  Posterio-lateral is the most common rotation direction.

​Physical exam often times result with no obvious deformity.  It has been estimated that as many as 50% spontaneously reduce prior to arrival to the ED.  In the emergency department, vascular examination is of utmost importance.  With obvious deformity and absent pulses, reduction must take place immediately, before radiographs are obtained.  After reduction, dorsalis pedis and posterior tibial pulses should be palpated, but the palpation of pulses does not rule out arterial injury.  The next step should be measuring ankle-brachial index of the affected side.  If the ABI is normal (> 0.9), then you can monitor the patient with repeat examinations as this has a 100% negative predictive value for arterial injury.  If the ABI is abnormal (<0.9), then a CT angiography should be performed along with vascular surgery consultation.  If pulses are still not palpable after successful reduction, immediate surgical exploration should be performed.

There is one situation where reduction of the knee should not take place.  The “dimple sign” represents buttonholing of the medial femoral condyle through the anterior medial joint capsule.  The sign indicates an irreducible dislocation and closed reduction is contraindicated for the risk of skin necrosis.

http://jbjs.org/content/87/7/1571

Initial imaging consists of plain radiographs.  Remember, many of these reduce prior to arrival and the radiograph may appear normal.  Despite this, you should look closely for avulsion fractures and osteochondral defects.  CT angiography should be obtained as discussed above if necessary.
After reduction and verification of ABI, the patient should be placed in a splint with 20-30° of flexion.  Post reduction films should be taken after the splint or brace is applied to confirm placement.  If emergent surgical intervention is not warranted, many of these require delayed ligamentous repair.
Long-term complications consist of arthritic symptoms, instability of the joint, peroneal nerve injury, and chronic vascular compromise.

Management Pearls:

• Deformity with no pulses = immediate reduction
• Return of pulses after reduction does not rule out arterial injury
• After reduction, obtain ABI.  Normal ABI has 100% negative predictive value of arterial injury
• If abnormal ABI, proceed with CT angiography and vascular consult
• Knee should be splinted in 20-30° of flexion
• Patient will likely require surgical repair of ligamental injury

​References:
1.  Patel, Anay.  "Knee Dislocation."  Orthobullets 08/11/15.  Retrieved 10/15/15 from http://www.orthobullets.com/trauma/1043/knee-dislocation.
2.  Peskun, C.J. et al.  "Diagnosis and Management of Knee Dislocations."  The Physician and Sportsmedicine.  Dec, 2010.  4:38, pages  101-111.

By Dr. Phillip Lunsford

​HPI:
Otherwise healthy middle-aged male presents to ED with L hand pain.  He is a painter, and while cleaning a high-pressure pneumatic pain gun it accidentally discharged into the palm of his L hand.  He reports only moderate pain at the site.  Denies any other injuries, all vital signs within normal limits.  Event occurred 2 hours prior to ED arrival.

Exam:
Pin-hole size puncture wound on palmar surface of hand w/ moderate tenderness to palpation and minimal surrounding erythema.  Full passive/active ROM of all digits, neuromuscular function completely intact.  Cap refill <2 seconds in all 5 digits.  X-ray is unremarkable.

​Discussion:
High-Pressure Injection Injuries occur when a high-pressure injection device (pneumatic paint gun, grease gun, diesel injector, etc) injects into the operator.  Most common in male laborers in painting and automotive industries, and injury often occurs during cleaning of the device or while attempting to clear the nozzle.  Non-dominant hand involved ~75% of the time, with index finger injury most common, followed by middle finger and palm.

Despite benign outward appearance, there is almost always significant underlying damage, and should be considered a SURGICAL EMERGENCY.  Our job as ED providers is to recognize the seriousness of the injury and involve a hand surgeon as fast as possible!

Pathophysiology involves direct trauma resulting in local tissue damage, acute and chronic inflammation, and foreign body granuloma formation.  Tissue ischemia/necrosis from vascular compression, chemical inflammation, and secondary infection can lead to devastating functional outcomes, including amputation.

Key historical details that impact prognosis:

• Time from injury to treatment
• Force of injection (PSI)
• Volume of substance injected
• Composition of injected material (grease, latex, industrial solvent, oil/water-based paint, etc)

Time from injury to treatment is the most important prognostic factor.  Delay of >10 hours significantly increases risk of amputation.  Higher PSI and larger volume of injected material portend greater direct tissue damage.  Hydrocarbon-based substances (fuel, organic solvents, oil-based paint, paint thinners) cause more severe inflammatory reaction and tissue necrosis, with amputation rates >50%.  Grease, latex, and water-based paints re typically less destructive.

Obtain plain films in the ED to rule out coexistent fracture/dislocation.  Some injected materials may appear radiopaque on x-ray and could aide in pre-operative planning.  Administer broad-spectrum parenteral antibiotics in the ED, and update tetanus status.  Control pain as needed, and arrange for emergent orthopedic/hand surgery evaluation.  Transfer to Trauma Center if necessary.  Patient will need emergent operative irrigation and debridement.

Patient in HPI above had excellent functional outcome due to early presentation.  Below is a time-course representation of patient with a delayed presentation, outlining potential damage that can occur.

​Management Pearls:

• Despite benign appearance, underlying injury can be devastating
• Ask key historical details
• Plain films, antibiotics, tetanus, pain control in the ED
• Emergent orthopedic/hand surgeon consultation, DO NOT DISCHARGE HOME!

By Dr. Blake Johnson


References:
1. Aiyer, A. "High-Pressure Injection Injuries." OrthoBullets, 15 Mar 2014. Web. Retrieved 25 Sept 2015, from http://www.orthobullets.com/hand/12104/high-pressure-injection-injuries.
2. Sanford, S. "High-Pressure Hand Injury." eMedicine/Medscape, 12 Nov 2013. Web. Retrieved 25 Sept 2015, from http://emedicine.medscape.com/article/826620-overview.  (multiple images)
3. http://lifeinthefastlane.com/high-pressure-injection-injury/  (image)

HPI:  
Otherwise healthy middle-aged male presents to ED with L wrist pain following moderate speed motorcycle collision.  There was immediate pain/swelling to L wrist, and he is reluctant to range the joint.  He was helmeted and wearing full protective clothing.  Denies other injuries, all vital signs within normal limits.

Exam:
Prominent L wrist swelling.  Dorsal aspect of radial head firmly palpated beneath the skin with slight volar displacement of hand relative to forearm.  Skin intact, compartments are soft.  Radial and ulnar pulses palpable, distal cap refill <2 seconds.  Distal motor function intact, slightly diminished sensation in median nerve distribution of L hand.  (X-ray shown below)

Radiologist Interpretation:
Perilunate dislocation.  Concomitant scaphoid waist fracture (central third) w/ distal anterior displacement.  Minimally displaced ulnar styloid fracture.

Discussion:
Lunate dislocation (perilunate dissociation) is a high-energy injury with poor functional outcomes that almost universally requires operative intervention.  Unfortunately they are commonly missed on initial presentation (~25%) due to subtleties on radiographic imaging.

First, a review of normal carpal anatomy, characterized by 3 smooth lines called Gilula’s arcs:

Mechanism of lunate dislocation typically involves high-energy axial load to the wrist, trapping the hand in hyperextension with ulnar deviation.  Results in relative intercarpal supination causing varying degrees of carpal ligamentous rupture and articular dissociation.  Injury pattern occurs in a step-wise sequence of events corresponding to Mayfield Classification System:

·  Stage I      ->  Scapho-lunate dissociation (SL widening)
·  Stage II    ->  Above w/ luno-capitate disruption (capitate overrides lunate)
·  Stage III  ->  Above w/ luno-triquetral disruption (true “perilunate dissociation”)
·  Stage IV  ->  Lunate completely dislocated from lunate fossa (usually volar, i.e. “spilled tea cup sign”)

In addition to pain, stage IV dislocation and/or surrounding wrist fracture-dislocation can present with carpal tunnel compression and median nerve symptoms (~25% of patients).

Emergent orthopedic consultation recommended.  Closed reduction is performed in the ED using fingertraps to apply traction and to distract carpal bones while applying a sugar tong splint (may be all that is necessary).  For complete lunate dislocations (stage IV), lunate must be relocated back into lunate fossa:

1) Apply gentle traction w/ wrist slightly extended
2) Manual pressure to palmar projection of lunate while flexing wrist until “snap” occurs (indicates relocation as proximal pole of capitate overcomes dorsal lip of the lunate)

All acute lunate/perilunate dislocations require operative treatment with ORIF, ligament repair, and possible carpal tunnel release.  There is universally poor functional outcomes with non-operative treatment, and recurrent dislocation is the rule, not the exception.

Management Pearls:
·  Know radiographic pathoanatomy, EASY TO MISS!
·  Assess for median nerve pathology and vascular injury
·  Emergent orthopedic consultation
·  Closed reduction with finger traps, apply sugar tong splint
·  Likely does not require admission, but operative treatment ASAP
·  High energy mechanism, don’t miss coexistent fracture or other injuries


By Dr. Blake Johnson

 
References:
1. Karadsheh, M. “Lunate Dislocation (Perilunate Dissociation).” OrthoBullets, 24 Dec 2014. Web. Retrieved 16 Sept 2015, from http://www.orthobullets.com/hand/6045/lunate-dislocation-perilunate-dissociation.  (multiple images)
2. Murray, P. “Perilunate Fracture Dislocations.” eMedicine/Medscape, 22 Sept 2014. Web. Retrieved 16 Sept 2015, from http://emedicine.medscape.com/article/1240108-overview#a10.
3. http://radiologymasterclass.co.uk/tutorials/musculoskeletal/x-ray_trauma_upper_limb/wrist_trauma_x-ray.html  (multiple images)
4. http://sfghed.ucsf.edu/Education/ClinicImages/Clin%20L%20finger%20trap%20w%20wts.1.jpg  (image)
5. http://www.clicktocurecancer.info/kienbock-disease/ryan-j-grabow-mda-louis-catalano-iii-mdb.html  (image)
6. Original case in HPI referred by Dr. Vivek Tayal