ACL Tear

ACL Anatomy Overview

Anatomy

The knee joint is the junction between the femur (thigh) bone and the tibia (shin bone). The end of the femur is referred to as the distal femur and the top of the tibia is referred to as the proximal tibia or tibial plateau.  The kneecap is referred to as the patella. The knee is said to have three compartments – medial (inside), lateral (outside), and patellofemoral (directly behind the patella).  Articular cartilage covers the end of the femur, top of the tibia, and behind the patella and allow the bone to glide easily with one another. A ligament is a tight band of tissue that connects bone to bone and helps to increase stability. The knee has a ligament on the inside (medial) and outside (lateral) of the knee called collateral ligaments (MCL and LCL). In the center part of the knee there are two ligaments that cross each other known as cruciate ligaments. One is the anterior cruciate ligament (ACL) and the other is the posterior cruciate ligament (PCL).

What is an ACL Tear?

The role of the ACL is to prevent the tibia from moving forward with respect to the femur. If stretched too far, the ACL will tear and instability of the knee will result. Often times, this comes with high-risk sports like soccer, football, basketball, lacrosse, rugby, and skiing. The majority of ACL injuries come from non-contact injuries with a sharp twisting of the knee, pivoting, sudden stopping when running, jumping, deceleration while cutting, or sidestepping movements.

Symptoms of Hip Arthritis

  • Sudden “pop” at the time of injury.

  • Immediate swelling and pain in the knee.

  • Instability or buckling of the knee.

  • Difficulty walking.

  • Stiffness of the knee.

Diagnosing an ACL Tear

A thorough patient history and physical exam can help to identify patients with a suspected ACL tear. X-ray images and MRI are useful diagnostic tools to help rule out other injuries and to confirm the diagnosis. 

Treatment for ACL Tears

Nonsurgical options:

  • Activity modifications and brace.
  • Anti-inflammatory medications.
  • Physical therapy.

Surgery:

  • For patients wishing to return to high-risk sports or active lifestyle, ACL reconstruction is recommended.