injuries poisoning
Knee Extensor Mechanism Injuries
Diagnosis of Knee Extensor Mechanism Injuries
Clinical evaluation X-rays MRI Examination of the knee can suggest which structure is injured: Quadriceps tendon tear: The patella is palpably displaced inferiorly (patella baja). Patella tendon tear: The patella is displaced superiorly (patella alta). Transverse patellar fracture: There is often a palpable gap between the two bone fragments. However, swelling in the area can be significant and mask these findings so that the injury may be misinterpreted as a ligamentous knee joint injury with hemarthrosis. If patients have knee swelling and pain after an injury, clinicians ask patients to sit and try to extend their injured leg to test active knee extension or to lie on their back and raise the injured leg, keeping the leg straight. Always test active knee extension if patients have knee swelling and pain after an injury. Routine knee x-rays are taken. Patella alta and patella baja can be seen on knee x-rays. X-rays often show displacement or fracture of the patella but may appear normal. MRI confirms the diagnosis. 