In the active straight leg raise test, an inability or pain suggests a tear of which structure?

In the active straight leg raise test, an inability or pain suggests a tear of which structure?

• A. Patellar/Quadriceps tendon tear
• B. ACL tear
• C. MCL tear
• D. Meniscal tear

Answer: (A)

The test is probing the knee’s extensor mechanism. To perform an active straight leg raise, the quadriceps must contract through the quadriceps tendon to straighten the knee, transmitting force via the patellar tendon. If either of these tendons is torn, the extensor mechanism can’t generate the necessary force, so the leg cannot be lifted or is painful during the motion. That makes a tear of the patellar or quadriceps tendon the best explanation for an inability or pain with this test. Injuries to the ACL, MCL, or meniscus affect ligaments or cartilage and stability rather than disrupting the active extension pathway, so they don’t explain the specific inability to perform the straight leg raise.

The test is probing the knee’s extensor mechanism. To perform an active straight leg raise, the quadriceps must contract through the quadriceps tendon to straighten the knee, transmitting force via the patellar tendon. If either of these tendons is torn, the extensor mechanism can’t generate the necessary force, so the leg cannot be lifted or is painful during the motion. That makes a tear of the patellar or quadriceps tendon the best explanation for an inability or pain with this test. Injuries to the ACL, MCL, or meniscus affect ligaments or cartilage and stability rather than disrupting the active extension pathway, so they don’t explain the specific inability to perform the straight leg raise.