Hydatid cyst in the hip joint of a young patient: a case report

BACKGROUND: Hydatid disease, or cystic echinococcosis, is a zoonotic infection caused by the larval stage of Echinococcus granulosus, predominantly affecting the liver and lungs. Musculoskeletal involvement is rare, comprising only 0.5-4% of cases, with even fewer reports of cysts in joints. CASE PRESENTATION: A 12-year-old Yemeni female of Arab ethnicity was referred to a military hospital in Sanaa after presenting with septic right hip pain for over 6 months. Imaging studies revealed narrowing of the right joint space, irregularities of the femoral head and acetabulum, and slight thinning of the right femoral head articular chondral surface. Open diagnostic surgery was performed, revealing fluid-filled sacs (hydatid cysts). After 4 months of follow-up, the patient's gait improved, and the Trendelenburg test was negative. Laboratory investigations were normal, and the X-ray showed improvements in the irregularities of the femoral head and acetabulum. CONCLUSION: Although uncommon, hydatid disease affecting the hip joint should be considered when diagnosing hip-related conditions, such as tuberculosis. Surgical removal and cleaning of the hip joints yield favorable functional outcomes.