Figure 5

Radiographs of both knee joints. Anteroposterior radiographs of the affected (a) and contralateral (b) knee joint. The "dromedar-sign" with only one tibial spine is visible (a - arrow) as opposed to the normal radiological finding with two spines (b - arrows). If a "dromedar-sign" is visible on plain radiographs the arthroscopic surgeon should be alert of an aplasia of the cruciate ligaments.