Knee dislocations

Mechanism:

High-energy:

- Usually from MVC (dashboard injury resulting in axial load to flexed knee) or fall from height

Low- energy:

- Often from athletic injury (with a rotational component)

Associated injuries:

- Vascular injury 

- Nerve injury: usually common peroneal nerve injury

Types:

Anterior: Most common (30-50%)

-        due to hyperextension injury

-        usually involves tear of PCL

Posterior: 2^nd most common  (25%)

-        due to axial load to flexed knee (dashboard injury)

-       Highest rate of vascular injury (25%) – with complete tear of the popliteal artery

Lateral (13%)

-        due to varus or valgus force

-        usually involves tears of both ACL and PCL

-        highest rate of peroneal nerve injury

- An anteromedial skin furrow, or “dimple sign” at the medial joint line, is suggestive of a posterolateral dislocation, which are irreducible!

Physical exam:

-        no obvious deformity- 50% spontaneously reduce prior to ED arrival!

-        obvious deformity:

o   reduce immediately, especially if absent pulses

Management:

- considered an orthopedic emergency

1. palpate the dorsalis pedis and posterior tibial pulses. Palpable pulses DON’T rule out a vascular injury
2. reduce the knee

- apply longitudinal traction to the extremity (This is usually all that is required to reduce a knee)

- Anterior knee dislocations may require additional lifting of the distal femur

- Posterior dislocations may require lifting of proximal tibia to complete reduction.

- After reduction, the knee should be immobilized in a long leg posterior splint with the knee in 15-        20 degrees of flexion.

https://www.youtube.com/watch?v=aN7zDxtyHy8

3. measure Ankle-Brachial Index (ABI):

            - ABI > 0.9

                        - monitor with serial vascular exams

            - ABI < 0.9

- perform a CT angio

- if arterial injury confirmed then consult vascular surgery

4. Immediate surgical exploration is indicated if pulses are still absent following reduction. Ischemia time >8 hourshas amputation rates as high as 86%!
5. The patient should be taken to the OR for external fixation if:

  - vascular repair (takes precedence)

- open fx and open dislocation

- irreducible dislocation

- Compartment syndrome

- obese

- multi trauma patient

Sources: Ortho bullets, emdocs

Flexor tenosynovitis

- Definition: o   Infection of the synovial sheath that surrounds the flexor tendon.

o   It’s a surgical emergency!!

-       Epidemiology

o   Incidence 2-9% of all hand infections

-       Risk factors

o   diabetes

o   IV drug use

o   immunocompromised patients

-       Mechanism

o   Penetrating trauma

o   direct spread from:

• Felon
• Septic joint
• Deep space infection

-       Microbiology

o   Staph Aureus (40-75%)

o   MRSA (29%)

o   Strep

-       Presentation:

o   pain and swelling

• typically presents in a delayed fashion (over last 24-48 hours)
• usually localized to palmar aspect of one digit

o   Physical exam:

• Kanavel signs:

1. digit held in flexion
2. tenderness to palpation over the tendon sheath
3. pain with passive extension of the digit
4. fusiform swelling of the digit

-       Imaging:

o   X-ray:

• radiographs are not required, but may be useful to rule out a foreign object

o   MRI

• cannot distinguish infectious flexor tenosynovitis from inflammatory but may help determine the extent of the ongoing process

-       Management:

o   Vancomycin + Cefepime

o   Call ortho! low threshold to take the patient to the OR for I&D once suspected (orthopedic emergency)

o   Nonoperative (rare)

• Hospital admission, IV Abx, and hand immobilization
• Indications:

o   early presentation

o   if signs of improvement within 24 hours, no surgery is required

Check out this 5 minute video from our amazing Dr. Anna Pickens!

https://emin5.com/2014/04/20/flexor-tenosynovitis/

Sources: Ortho bullets, EMin5, UpToDate

Holiday heart syndrome

Holiday heart syndrome: -        is an irregular heartbeat pattern seen in patients who are otherwise healthy

-        It is associated with binge drinking, which is common during the holiday season.

-        Atrial fibrillation (AFib) is the most common arrhythmia seen in holiday heart syndrome.

Causes of AFib:

-        Catecholamine excess or increased sensitivity:

o   Exogenous (eg. adrenaline infusion)

o   Endogenous

• Subarachnoid haemorrhage
• Phaeochromocytoma
• Thyrotoxicosis

-        Atrial distension:

o   Pulmonary hypertension

• Primary
• secondary, such as OSA, PE, pulmonary fibrosis

-        Abnormality of conducting system

o   Congenital cardiac disease, eg. septal defect

o   Infiltrative cardiac disease, eg. amyloidosis, sarcoidosis

o   Ischemic heart disease

o   Haemochromatosis/iron overload

o   Hypothermia

-        Increased atrial automaticity / irritation:

o   Alcohol (“holiday heart”)

o   Caffeine

o   Electrolyte derangement (hypokalaemia, hypomagnesaemia)

o   Myocarditis

Complications of AFib:

• Loss of atrial systole (aka “atrial kick”) (normally responsible for about 20% of ventricular filling)
• Decreased diastolic filling time due to tachycardia
• Rate-related cardiomyopathy (can occur over weeks)
• Atrial thrombus formation

Management of AFib:

• determine if the patient is stable or unstable
• Unstable features:

• chest pain
• dyspnea
• heart failure
• hypotension
  • Electrical cardioversion
    • 120 to 200 J (biphasic) and 200 J for monophasic devices
    • provide procedural sedation

-        Management of stable patients:

o   Seek and treat underlying cause first!

• replace electrolytes (e.g. K > 4 mmol/L, Mg > 0.9 mmol/L)
• treat cause (e.g. ischemia, sepsis, thyroid function)

o   rate control vs rhythm control

• Rhythm control:
• essential in unstable patients
•      If less than 48 hours of AFib onset
• Rate control:
• Diltiazem (0.25 mg/kg IV (max 20 mg) administered over 2 mins followed by 0.35 mg/kg IV (max 25 mg) administered over 5 mins if no resolution
• Metoprolol 5 mg IV q15 min
• Avoid calcium channel blockers in decompensated heart failure (digoxin is preferred)

o   Anticoagulation (based on the CHA2DS2-VASc score)

Sources: Life in the Fastlane, EMDOCS