Ultrasound-guided core needle joint biopsies in children: pathological findings, diagnostic performance, and clinical...

Synovial-joint abnormalities in children can be caused by different conditions, including autoimmune arthritis, infection, and neoplasm. An ultrasound-guided biopsy targeting the synovial membrane can aid in determining the etiology when the cause is unclear.

To determine the diagnostic performance, findings, and outcomes of ultrasound-guided joint biopsy in children.

This is a retrospective study on patients who underwent ultrasound-guided joint biopsy from May 2000 to December 2024. Patient demographics, clinical information, imaging, procedure details, pathology findings, adverse events, and clinical outcomes were collected and reviewed.

Thirty-one patients (25 females) with a mean age of 10.2 years underwent 34 biopsies. Presenting symptoms were pain (33/34), mobility issues (33/34), and swelling (20/34). Effusion (19/28), joint capsule thickening (24/28), and contrast enhancement (20/28) were the most common MRI findings, while joint capsule thickening (29/29) and effusion (19/29) were the most frequent ultrasound findings. The most common joints biopsied were the hip (16/34), knee (9/34), and ankle (4/34). Core needle biopsy was performed in all cases. The mean number of passes was 4.5 (SD 1.8), obtaining a mean of 4.1 cores (SD 1.9). Biopsy was diagnostic in 20/34 (59% [CI 41-76%]) joints, and only one patient required surgical biopsy. Synovitis was the most common diagnosis (14/34), followed by pigmented villonodular synovitis (2/34). No major adverse events were observed.

Ultrasound-guided joint biopsy in children has moderate diagnostic performance; however, it can be clinically impactful, even when non-diagnostic, helping in joint disease management, potentially preventing surgery, with low adverse event incidence.