The pelvic x-ray shows
a right sided hip effusion in this skeletally immature patient. There is bulging of the right gluteal fat pad indicative of presence of a hip effusion, where as the left gluteal fat pad is normal.
This subtle sign on plain hip x-ray is very useful finding in a case with suspected hip effusion due to any cause when an ultrasound is not immediately available. Word of caution – absence of this sign on plain imaging does not mean there is no hip effusion.
Case closure – the patient had signs of sepsis with high inflammatory markers and was diagnosed with staphylococcal right hip septic arthritis on further investigations.