Pre-tibial synovial cyst after reconstruction of the anterior cruciate ligament: case report☆☆☆

Arthroscopic reconstruction of the anterior cruciate ligament has been modernized through new surgical techniques and new materials. When tibial fixation is performed using an absorbable screw, complications may occur, such as formation of a pre-tibial cyst. The case described here is about a patient who presented an anteromedial synovial cyst in his right knee, three years after having undergone ACL reconstruction. The patient did not present any pain nor any complaints other than a mass that progressively increased in size, worsened after physical activities. Imaging examinations were requested: simple radiography of the knee and magnetic resonance. Anteromedial imaging of the knee showed a mass with well-delimited borders and internal fluid content, suggestive of a synovial cyst, with communication with the joint cavity through the tibial tunnel, without presenting enlargement or absorption of the bone tunnel. The cyst was surgically resected and the tibial tunnel occlusion was performed using a bone plug. The diagnosis of a synovial cyst was subsequently confirmed through the results from the anatomopathological examination. The patient presented good clinical evolution, with disappearance of the symptoms and a return to physical activities.