Author Credentials

Franklin D. Shuler MD PhD Grant Buchanan MD Cody Stover MD Brock Johnson MD Milad Modarresi MD John Jasko MD




Septic arthritis is an orthopaedic emergency which requires timely management to prevent joint destruction and poor outcome. Differentiating septic arthritis from transient synovitis in pediatric patients is aided by the use of Kocher criteria which have excellent sensitivity but lack specificity. In addition to these two disorders, primary pyomyositis is bacterial infection of skeletal muscle that most commonly affects children. Patients present with pain, swelling, fever, and elevated inflammatory markers which mimics septic arthritis. If left untreated, pyomyositis can lead to abscess formation and sepsis.

Due to potential for nearly identical presentations of septic arthritis and pyomyositis, differentiation of these two disorders can be aided with the use of MRI which has a high sensitivity for detecting muscle edema and abscess formation. In this case series, we discuss the use of MRI to assist with the diagnosis of pyomyositis versus septic arthritis. The authors advocate the use of MRI in questionable or complicated cases of septic arthritis or where synovial fluid aspiration is unable to be obtained promptly.

Conflict(s) of Interest


References with DOI

1. Kocher MS, Zurakowski D, Kasser JR. Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. The Journal of Bone and Joint Surgery American volume. 1999;81(12):1662-70. https://doi.org/10.2106/00004623-199912000-00002

2. Singhal R, Perry DC, Khan FN, Cohen D, Stevenson HL, James LA, et al. The use of CRP within a clinical prediction algorithm for the differentiation of septic arthritis and transient synovitis in children. The Journal of Bone and Joint Surgery British volume. 2011;93(11):1556-61. https://doi.org/10.1302/0301-620x.93b11.26857

3. Bickels J, Ben-Sira L, Kessler A, Wientroub S. Primary pyomyositis. The Journal of Bone and Joint Surgery American volume. 2002;84-a(12):2277-86. https://doi.org/10.2106/00004623-200212000-00024

4. Gubbay AJ, Isaacs D. Pyomyositis in children. The Pediatric Infectious Disease Journal. 2000;19(10):1009-12; quiz 13. https://doi.org/10.1097/00006454-200010000-00015

5. Chiedozi LC. Pyomyositis. Review of 205 cases in 112 patients. American Journal of Surgery. 1979;137(2):255-9.

6. Mignemi ME, Menge TJ, Cole HA, Mencio GA, Martus JE, Lovejoy S, et al. Epidemiology, diagnosis, and treatment of pericapsular pyomyositis of the hip in children. Journal of Pediatric Orthopedics. 2014;34(3):316-25. https://doi.org/10.1097/bpo.0000000000000106

7. Rosenfeld S, Bernstein DT, Daram S, Dawson J, Zhang W. Predicting the presence of adjacent infections in septic arthritis in children. Journal of Pediatric Orthopedics. 2016;36(1):70-4. https://doi.org/10.1097/bpo.0000000000000389

Included in

Orthopedics Commons