LIGAMENTOUS INSTABILITY OF THE KNEE IN CHILDREN SUSTAINING FRACTURES OF THE FEMUR - A PROSPECTIVE-STUDY WITH KNEE EXAMINATION UNDER ANESTHESIA

Fifty-five children with 55 fractures of the femur were prospectively studied for the presence of ligamentous instability of the knee within 3 weeks from the time of injury. Two patients (4%) demonstrated insta bility on examination under anesthesia. A g-year, 4-month-old boy sust ained a second-degree injury to the lateral collateral ligament that h ealed after hip spica cast treatment. The other patient, a 12-year, 8- month-old boy, sustained an avulsion fracture of the posterior cruciat e ligament from the tibial insertion with >1 cm posterior displacement of the tibia on the posterior drawer test. After placement of an intr amedullary rod, the avulsion fracture was treated with open reduction and internal fixation. Although the incidence of ligamentous instabili ty of the knee in this study is less than that reported for adults wit h femur fractures, children should nevertheless have a thorough knee e xamination for ligamentous stability as well as radiographic evaluatio n of the knee.