A 23-year-old man is admitted to the emergency department after injuring his knee while playing football. During physical examination there is pain and swelling of the knee, in addition to locking of the knee. Radiographic examination reveals a bucket-handle meniscal tear. Which of the following ligaments is most likely injured?
A 23-year-old man is admitted to the emergency department after injuring his knee while playing football. During physical examination there is pain and swelling of the knee, in addition to locking of the knee. Radiographic examination reveals a bucket-handle meniscal tear. Which of the following ligaments is most likely injured?
💡 Explanation
## **Core Concept**
A bucket-handle meniscal tear is a type of meniscal injury commonly associated with knee trauma. The menisci are stabilized by their attachments to the tibia and surrounding ligaments. The locking of the knee, as described, often results from a meniscal fragment becoming interposed between the femoral condyles and tibial plateau.
## **Why the Correct Answer is Right**
The medial meniscus is more commonly associated with bucket-handle tears due to its firm attachment to the deep layer of the medial collateral ligament (MCL) and the joint capsule. This firm fixation makes it more susceptible to tears, especially with twisting injuries. The anterior cruciate ligament (ACL) is frequently injured in conjunction with meniscal tears because both are commonly damaged during non-contact twisting injuries of the knee. The association between ACL tears and meniscal injuries, particularly medial meniscus tears, is well established.
## **Why Each Wrong Option is Incorrect**
- **Option A:** The lateral collateral ligament (LCL) is less commonly injured in the context of meniscal tears and knee locking. It provides lateral stability to the knee but is not directly related to meniscal tears.
- **Option B:** The posterior cruciate ligament (PCL) is more often injured in direct blows to the front of the tibia with the knee flexed, such as in a dashboard injury during a car accident, rather than in twisting injuries leading to meniscal tears.
- **Option D:** The medial collateral ligament (MCL) can be injured in knee trauma but is not as directly associated with the mechanism leading to bucket-handle meniscal tears and subsequent knee locking as the ACL.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that the combination of a meniscal tear (especially a bucket-handle tear) and knee locking significantly increases the likelihood of an associated ACL injury. This is because both injuries often result from similar mechanisms, such as non-contact twisting of the knee. Therefore, when evaluating a patient with a meniscal tear and knee locking, it is crucial to assess for ACL integrity.