Chronic pain in the hip, groin or thigh can be caused by a wide spectrum of diseases posing extended diagnostic problems. We describe the case of a 10-years old child with chronic pain in the groin with gait restriction for more than six months without successful classification and treatment. The girl suffered from heavy pain in the groin after a sporting contest which forced her to walk with walking sticks and to avoid climbing stairs. Within six months she was examined by pediatric, orthopedic, pediatric surgery, pediatric orthopedic, radiology, pediatric rheumatology specialists. Working diagnoses were transient synovitis (coxitis fugax), arthritis, streptococcal arthritis, Morbus Perthes, rheumatic fever, rheumatoid arthritis. She was treated with antibiotics and ibuprofen in high dosage. Repeated laboratory tests and imaging studies (ultrasound, x-rays, magnetic resonance imaging) of the hip and pelvis did not support any of these diagnoses. Six months after beginning of the complaints the girl was presented by her mother to our institution. The physical examination showed a sharp localized pain in the groin, just in the region of the inguinal ligament with otherwise free hip movement. There was no visible inguinal hernia. The family history for hernia was positive. After infiltration of the ilioinguinal nerve the girl had a complete long-lasting disappearance of pain and gait disturbance. This led to the diagnosis of inguinal hernia with nerve entrapment. After hernia repair and neurolysis/neurectomy there was a continuous state of disappearance of pain and gait disturbances.
Conclusion: To avoid such a diagnostic dilemma one should always discuss all possible causes. Non-visible inguinal hernia may be more common in females than previously thought. Nerve entrapment as a cause of groin pain has been well described. The relationship of the start of complaints with sporting activity, a positive family history for inguinal hernia, a lack of signs of inflammation and bone involvement in the laboratory and imaging studies together with a localized pain in the groin, almost immediate long-lasting disappearance of pain after infiltration of the ilioinguinal nerve allowing free motion leads to the diagnosis of inguinal hernia with nerve entrapment. Hernia repair and neurolysis are the adequate treatment avoiding unnecessary radiation.