Ball and socket ankle joint in connection with bilateral tarsal synostosis in a boy with congenital absence of the portal vain: a novel malformation complex

BACKGROUND Contracted valgus flat foot in the adolescent is frequently caused by tarsal synostosis or synchondrosis. These synostoses are prevalently symptomatic during adolescence, when by ossifying they block the subtalar joint in valgus. Careful and detailed examinations might reveal additional abnormalities. CASE PRESENTATION A 16-year-old boy of Austrian origin presented with contracted valgus foot associated with tarsal hypomobility and pain. Talonavicular synostosis with ball and socket ankle joint was detected via lateral radiographs and 3 DCT scan. Preoperative laboratory investigations revealed leucocytopenia, and thrombopenia. Computerised abdominal tomography showed portal vein atresia and portopulmonary hypertension. CONCLUSION Clinical research is the corner stone to elucidate the aetiological understandings in patients with malformation complex. The latter is a critical task for the development of scientific bases for preventive strategies. Careful examination for these abnormalities should lead the clinician to earlier referral of patients for additional examination by a specialised medical team. This often enables more focused care for the individual and better characterisation/documentation of the malformation complex. The association of tarsal synostosis and the previously unreported associated occurrences of congenital absence of the portal vein, portopulmonary hypertension, cardiomegaly and splenomegaly have been encountered. We stress that our present patient illustrates and supports the pathophysiological hypotheses that have previously proposed for the concurrent existence of absent portal vein, hepatic nodular hyperplasia and portopulmonary hypertension. Nevertheless, no previous single report signifies the existence of tarsal synostosis in connection with the above-mentioned abnormalities.