Ultrasound in hip pain - What else to look for

Abstract

When investigating hip pain it is important to have a symptomatic approach. Infants are generally not able to be specific about where their pain is originating from and they are unreliable historians. Signs of hip pathology include not weight bearing, walking with a limp and reduced joint movement. The most common cause of hip pain is transient synovitis which may occur following viral infection, allergic reaction or trauma, but is usually of unknown aetiology. Other pathologies to consider are haemarthrosis, septic arthritis, Perthes disease, slipped capital femoral epiphysis and juvenile rheumatoid arthritis. Ultrasound scanning of the hip is best achieved from the anterior approach to assess the synovial capsule. Comparison views are very useful. In the event that the hip joint is normal it is important to remember that there are many other causes of hip symptoms and that any pathological process that involves one of the muscles that control the hip joint may present with signs and /or symptoms suggestive of hip joint disease. Possible pathologies include myositis, bleed, abscess tumour and avulsion. In the absence of primary hip or surrounding muscle pathology the examination should be extended to look for other disease processes which may explain the signs because of their secondary effects on muscles. Such pathologies include appendicitis, pelvic pathology, pyelonephritis, discitis, osteomyelitis, lymphadenopathy or tumour. In the toddler age group two additional diagnoses should be considered, a lower limb fracture and neuroblastoma with secondary involvement of the hip joint. In summary, remember that not all hip pain or hip symptoms relate to the joint itself. All of these can be diagnosed at the time of a hip ultrasound if a symptomatic approach is used, thereby expediting diagnosis and appropriate treatment.