ANTERIOR CRUCIATE LIGAMENT (ACL) RUPTURE
- 2 days ago
- 6 min read
Anterior cruciate ligament (ACL) injuries most often occur during sudden changes in direction, trunk rotation on a fixed foot, or incorrect landing mechanics . A significant number of patients describe a "tearing" or "popping" sensation inside the knee at the moment of rupture. The rapidly developing swelling that follows is usually due to intra-articular bleeding (hemarthrosis).
However, clinically, the primary determining factor is not pain, but instability. While pain and swelling are prominent in the early stages, patients later report a feeling of the knee "giving way," a lack of confidence, and loss of control, especially during rotational movements. This demonstrates that the cruciate ligament is not merely a passive ligament, but a central component of the knee's dynamic stability system.
The ACL is the primary structure that limits the anterior translation of the tibia over the femur, meaning it prevents the tibia from sliding forward relative to the upper leg. However, its function is not limited to preventing anterior sliding; it plays a crucial role in the rotational stability of the knee. Therefore, the problem after a rupture is a loss of three-dimensional control.
Image reference: https://orthoinfo.aaos.org/en/diseases--conditions/anterior-cruciate-ligament-acl-injuries/
LONG-TERM CONSEQUENCES OF CRUCIATE LIGAMENT INSUFFICIENCY
The literature reports an increased risk of meniscus injury in patients with ruptured cruciate ligaments . Meniscus tears are particularly common when treatment is delayed.
These findings demonstrate that ACL injury is not merely a ligament injury, but a process that affects joint biology and long-term joint health.
LACHMAN TEST: PHYSICAL DIAGNOSIS OF ANTERIOR CRUCIATE LIGAMENT RUPTURE
The Lachman test is one of the most reliable physical examination methods for evaluating anterior cruciate ligament tears . It is performed with the knee bent (flexion) at approximately 20–30 degrees. In this position, the physician stabilizes the femur (upper leg) and assesses the forward displacement of the tibia (lower leg).
Image reference: https://coreem.net/core/acl-injuries/
An intact ACL restricts anterior movement of the tibia and provides a clear sense of limitation. If the ligament is torn, the tibia moves further forward, and this sense of limitation is lost. The biggest advantage of the test is that it can be performed even immediately after the injury and is less affected by muscle spasm compared to other tests.
Therefore, the Lachman test is considered one of the cornerstones of clinical evaluation in cruciate ligament injuries.
