4.4 of 72 Ratings
Technique guides are not considered high yield topics for orthopaedic standardized exams including ABOS, EBOT and RC.
Which of the following is true regarding matrix metaloproteinases (MMPs)?
They are activated by chelating agents
They mediate the destruction of cartilage in septic arthritis
Toll-like receptors inhibit the formation of MMPs
They have a anabolic effect on cartilage
Stromelysin is an indirect antagonist of many MMPs
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A 3-year-old presents with a 24-hour history of limping and progressive inability to bear weight. The parents recount no history of trauma, but note that he recently had an upper respiratory infection. A clinical photo is shown in Figure A. The patient’s vital signs are stable. Physical exam is limited because of pain. A hip ultrasound is shown in Figure B. Laboratory values are as follows: WBC-15.0 (97% PMN), ESR-120, CRP-5.0. What is the next best step for this patient?
Admit for observation
Repeat hip ultrasound
Obtain an MRI
Start the patient on IV antibiotics
Emergent hip arthrotomy with irrigation and debridement
A 2-year-old child is diagnosed with a septic hip. Initially, no organisms grew on the standard blood agar plate. However, after 1 week, the offending organism was recovered in an aerobic blood culture medium. Which of the following organisms was the most likely cause?
A 2-year-old boy is seen for evaluation of a limp. His history is significant for a left knee infection treated with IV antibiotics as a neonate and a family history of cancer. Laboratory testing demonstrates a normal ESR and CRP. The remainder of his workup is negative. An AP pelvis is seen in Figure A. What was the most likely etiology of his condition?
Untreated neonatal hip infection
Slipped capital femoral epiphysis
An 8-day-old infant is admitted to the hospital for septic arthritis of the hip. He went home on day two after an uneventful vaginal birth. Which of the following will most likely be the causative organism by culture?
Group B Streptococcus
A 7-year-old boy developed a limp with right leg pain five days ago, and today has trouble bearing weight. On exam, he is lethargic and has chills. His temperature is 38.4 degrees centigrade. He points to his right inguinal region as the source of the discomfort. He winces with compression of his pelvis. Lab studies reveal a white blood cell count of 11,400/ul, CRP of 0.9 mg/dL (normal < 1.0 mg/dL), and erythrocyte sedimentation rate of 55 mm/h. A pelvis radiograph is shown in Figure A. Ultrasound guided aspiration of the right hip joint yields 9,000 leukocytes per mL. What is the most appropriate next step in management?
Further imaging of the pelvis
Open drainage and irrigation of the right hip joint
Repeat aspiration of the hip joint
Percutaneous screw fixation of the proximal femoral physis
Nonsteroidal antiinflamatory medications and observation
An 18 month-old child has been brought to the emergency room by his mother. He had the sudden onset of hip pain 3 days ago and now won't put weight on the affected limb. The child is febrile and an ultrasound (longitudinal view of the proximal femur) shown in Figure A shows the unaffected hip on the left and affected hip on the right. The patient is taken to the operating room for hip aspiration which reveals 60,000 leukocytes with 95% polymorphonucleocytes. What is the most likely diagnosis?
Acute rheumatic fever
Juvenille rheumatoid arthritis (JRA)
An 8-month old infant is brought by his parents to your office for fever and malaise. Your inspection of the patient is detailed in Image A. An oral temperature of greater than 38.5 has been found to be the best predictor of this child's condition. What is the second best predictor?
Elevated neutrophil count
Elevated rheumatoid factor
Presence of bacteria on CSF gram stain
A 3-year-old boy presents with his caregiver with concerns regarding a long-standing gait disturbance. The birth history is unknown except for a prolonged ICU stay for sepsis. A pelvic radiograph is shown in Figure A. What is the most likely cause for this child's limp?
Developmental dysplasia of the hip
Residual effects of previous untreated septic hip arthritis
Acute femur fracture secondary to child abuse
A 6-week old boy refused to move his left hip. The patient was delivered by C-section 4 weeks premature, but otherwise is healthy. He has been afebrile. Examination reveals some mild, diffuse swelling about the left proximal thigh. Passive motion of the hip elicits discomfort. An AP pelvis radiograph is shown in Figure A. What is the most appropriate next step in management?
Which of the following Gram stain images most accurately represents the primary causative organism for pediatric osteomyelitis and septic arthritis?
In differentiating pediatric septic hip from transient synovitis, an elevated ESR (>40), history of fever, refusal to bear weight and what other finding has been identified as predictive of a septic hip?
Elevated absolute neutrophil count
Serum white blood cell count > 12,000 cells/cubic millimeter
Positive blood cultures
Pain with hip extension
Symptoms greater than 3 days
A 10-month-old infant is brought to the emergency department for fevers, irritability, and avoidance of motion in the right leg. On physical exam, passive motion of the right hip elicits crying. An AP pelvis and an ultrasound of the right hip are shown in Figures A and B respectively. A hip aspiration yields 82,000 WBC with >80% PMNs. Which of the following is the strongest predictor of a poor prognosis?
CRP > 5mg/L
Delay in treatment >4 days
Age > 6 months
Absence of associated osteomyelitis
ESR > 40mm/hr