2025 – PAGE 418 – ORTHOPEDICS AND SPORTS MEDICINE
TOXIC SYNOVITIS (AKA TRANSIENT SYNOVITIS OF THE HIP)
In toxic synovitis (AKA transient synovitis of the hip), patients have pain with active range of motion (much less or absent with passive ROM). There may be a history of a low-grade fever or a recent infection. A Gram stain of fluid from the joint will be negative.
PEARLS: This is a diagnosis of exclusion. Even if the story fits, you must order joint aspiration to exclude a septic arthritis!
SEPTIC ARTHRITIS
Septic arthritis will present with a patient that has a high fever, elevated inflammatory markers, possible erythema at the joint, and pain with active and passive manipulation of the joint. Diagnose by joint aspiration. If the results are inconclusive, treat with an anti-Staphylococcus antibiotic.
PEARLS: If no imaging is given and you are asked for the next best step in a patient with any signs of a possible infection, ASPIRATE the joint. Do not order imaging! The most common etiology in children is STAPHYLOCOCCUS AUREUS. If you are presented with a teen, consider Neisseria gonorrhea coverage as well
PEARLS: A septic arthritis is much more acute than Juvenile Rheumatoid Arthritis. If you’re confused on the exam, GIVE antibiotics. The differential also includes SERUM SICKNESS, in which case there should also be a history of urticaria and arthraLGIA (pain, but no signs of inflammation).
OSTEOMYELITIS
Osteomyelitis is a bone infection. Look for pain at the metaphysis and other signs of infection (fever, leukocytosis, etc.). Use a bone scan OR aspiration to diagnose because it is the most specific test to rule in osteomyelitis. MRI is the most sensitive (helps rule out). Treat with IV antibiotics to cover Staphylococcus aureus, but remember that Salmonella osteomyelitis is more common than Staphylococcal osteomyelitis in children with sickle cell anemia (www.pbrlinks.com/SICKLEOSTEO). Treatment is usually long, 4–6 weeks.
PEARL: Once an organism has been identified and sensitivities are available, you may do a trial of inpatient oral antibiotics and then discharge if s/he does well.
STRAINS
Strains refer to a tear in part of a MUSCLE. This is much more benign and common than sprains.
MNEMONIC: Rename it sTrUSCLE—kind of like a toaster STRUdel.