
Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric musculoskeletal evaluation. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.
Module Goals
- List the indications for performing pediatric musculoskeletal (MSK) point-of-care ultrasound (POCUS)
- Describe the technique for performing specific pediatric MSK POCUS applications
- List anatomical landmarks for specific MSK POCUS applications
- Interpret signs of fracture, effusion, dislocation, and osteomyelitis with POCUS
- Describe the limitations of MSK POCUS
Case Introduction: Adolescent with Left Knee Swelling
A 13-year-old female with no past medical history presents to the emergency department with pain and swelling to her left knee. The pain started 3 days ago, with the pain worsening and swelling noted on the day prior to arrival. She can bear weight but has a limp. She has had no other current or past joint pain or swelling, no known trauma, no fever or other infectious symptoms, no recent travel, and no known insect or tick bites. She spent the summer at camp in the northeast United States. Her vaccines are up to date.
On arrival, her vital signs are:
| Vital Sign | Finding |
|---|---|
| Temperature | 37.3 C |
| Heart rate | 109 bpm |
| Blood pressure | 117/74 |
| Respiratory rate | 20 |
| Oxygen saturation (room air) | 99% |
On physical examination, she is well appearing and in no acute distress. Her exam is significant for left knee swelling and tenderness to palpation anteriorly with decreased knee flexion due to pain. She has no redness, warmth, or numbness around her knee. She has an antalgic gait but can bear weight.
Given her pain and swelling of her left knee, blood tests and X-rays are ordered, and orthopedics is consulted. You decide to perform a musculoskeletal point-of-care ultrasound (MSK POCUS) examination.
Case Resolution
A musculoskeletal POCUS of the left knee with a linear, high-frequency probe demonstrated a joint effusion in the suprapatellar bursa with internal septations (Figures 45 and 46).

Figure 45. Left knee POCUS demonstrating a joint effusion in the suprapatellar bursa (L) and internal septations within the effusion (R).
Figure 46. Longitudinal scan of the left knee showing the joint effusion with internal septations.
Initial laboratory studies showed a white blood cell count of 10 × 109/L, ESR 69 mm/hr, and CRP 32 mg/L. Knee radiographs were negative for fracture. Orthopedics performed an arthrocentesis that yielded synovial fluid with 52,000 white blood cells/µL, raising concern for septic arthritis.
The patient was admitted, started on intravenous antibiotics, and taken to the operating room for incision, drainage, and washout. Joint fluid cultures returned negative, but Lyme serologies returned positive. She was transitioned to a 28-day course of doxycycline for Lyme arthritis.
References
- Grechenig W, Clement HG, Fellinger M, Seggl W. Scope and limitations of ultrasonography in the documentation of fractures—an experimental study. Arch Orthop Trauma Surg. 1998;117(6-7):368-371. doi:10.1007/s004020050268. PMID: 9709853
- Wilson C. Suprapatellar bursitis: causes, symptoms, treatment & recovery. Knee Pain Explained. Published June 2, 2024. Accessed May 23, 2026. https://www.knee-pain-explained.com/suprapatellar-bursitis.html
- Morello R, Mariani F, Snelling PJ, Buonsenso D. Point-of-care ultrasound for the diagnosis of distal forearm fractures in children and adolescents: a scoping review. Eur J Pediatr. 2024;184(1):19. doi:10.1007/s00431-024-05877-w. PMID: 39548004
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- Jones RM, Malia L, Snelling PJ, et al. Diagnostic accuracy of point-of-care ultrasound for hip effusion: a multicenter diagnostic study. Ann Emerg Med. 2025;86(6):566-575. doi:10.1016/j.annemergmed.2025.04.033. PMID: 40481828



































