Orthopaedics: Facebook Septic arthritis Vs Transient synovitis

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#Orthopaedics

Q) A 4 year old kid comes to OPD with complaints of high grade fever, decreased appetite and pain in right hip. On examination he has dehydration/ tenderness in Scarpa's traingle/ swelling in right hip region, flexion, abduction and external rotation at hip/ absent movements in right hip region. On Xray there is mild increase in medial joint space. Diagnosis is

1) Septic arthritis
2) Transient synovitis
3) Tubercular arthritis
4) Dislocation of hip

Answer is 1) Septic arthritis

Let us dissect this Multiple choice question. Read the question one more time and let's follow up. Put your Sherlock holmes hat and let's see what we can deduce!

1) A 4 year old kid.
2) Toxic due to dehydration.
3) In his right hip we have - Flexion, abduction, and external rotation. This collectively is called as FABER! Big clue here.
4) Absent movements

Looking at the option given, we can definitely eliminate dislocation of hip. It has FADIR - Flexion, Adduction and internal rotation.
Coming to TB. Now if try to recollect the 5 stages of TB you will find that 1st stage is FABER and next two stages are FADIR! 5th stage is Fibrous ankylosia known as TB arthritis. 4th stage has Wandering Acetabulum (It is a misnomer because both acetabulum and femur head is destroyed so actually remaining part of femur wanders! - also known as - Pestle and Mortar type)

Now two options left - Transient synovitis and Septic arthritis. Well you know Septic arthritis is an emergency condition. Even if you don't know any thing about other option, you can still get it correct. Child is toxic and absent movements points out toward emergency condition.

Both Transient synovitis and septic arthritis causes FABER which leads to more space in the joint leading to more inflammation and swelling. Any swelling disease in Orthopedics is approached as
"XMAS"
X- Xray
M-MRI
A-Arthroscopy which is USG guided.
S-(for)Swelling diseases

Wait! What would be treatment modalitis for both of them?
Ofcourse surgery followed by 6 weeks of Antibiotics for Septic arthritis
Whereas Transient synovitis as name suggest is less severe so we do conservative treatment.

Remember:
Septic arthritis - Absent movements
Transient synovitis - Decrease movements