The absence of the cruciate ligament is a rare pathology which is described as a congenital entity often being bilateral and in combination with other malformations. Patients mostly deny symptoms of instability but demonstrate signs of laxity. There is not a standardized treatment yet.We report a case of congenital cruciate ligament aplasia which was treated with an ACL reconstruction.In the described case, the patient had a bad clinical result after ACL reconstruction with a fixed posterior subluxation of the tibia. Resection of the ACL reconstruction and physical therapy led to a better clinical result.While some authors report favourable results with cruciate ligament reconstruction, others report good results with a conservative regime of symptomatic treatment. When patients do not complain of instability conservative treatment might be one option, since the knee joint is adjusted to this abnormality. Surgical treatment should be considered when conservative therapy is frustrane. If however reconstructive surgery is done in cruciate ligament aplasia both cruciate ligaments need to be reconstructed. After isolated ACL reconstruction the tibia might be fixed posteriorly, leading to extension problems and severe patellofemoral pain as seen in our case.