ACL Tear

ACL Tear Overview

The anterior cruciate ligament (ACL) runs through the knee from the front of the tibia (shinbone) to the back of the femur (thighbone) and is considered the main stabilizing ligament. The ACL is responsible for providing proper knee movement and preventing knee instability while performing athletic, work and everyday activities. An anterior cruciate ligament injury is common in the active population. An injury to the ACL can range from a mild sprain to a complete ACL tear. Dr. Jervis Yau, orthopedic knee specialist, specializes in diagnosing and treating ACL injuries in order to return Santa Barbara, Goleta, Santa Maria and Ventura, California patients to the activities they enjoy.

The ACL plays an important role within the knee joint by maintaining knee stability and providing protection to the two menisci of the knee. ACL injuries are commonly seen in sports such as skiing, football, basketball, soccer, tennis and gymnastics. ACL tears are typically a result of abnormal knee pivoting or twisting with the foot planted, but sometimes can occur from a direct blow. If not completely torn, the ACL can be stretched beyond its normal range, resulting in laxity of the ligament and persistent instability.

ACL Tear Symptoms

The symptoms of acute anterior cruciate ligament injury are pain, swelling, and stiffness of the knee joint. After the initial injury calms down, the most common complaint is that the knee buckles or shifts with certain movements (instability).  Symptoms vary based on injury severity. A mild sprain may cause pain with limited swelling, while a severe ACL tear may cause a “popping” sound or sensation followed by significant swelling, pain and the inability to bear weight.

ACL Tear Diagnosis

Dr. Yau will perform a complete medical review and physical examination to assess the injury severity and determine the level of knee instability. X-rays are commonly performed to rule out fractures, osteoarthritis and other potential knee injuries. Dr. Yau commonly recommends a MRI scan to confirm the diagnosis and evaluate for concomitant injuries.

Have you sustained an ACL injury?

Schedule an office consultation with Dr. Yau today.


ACL Tear Treatment

Not all patients who experience an anterior cruciate ligament injury require surgical intervention. The severity and symptoms of the ACL tear will determine the proper treatment plan. ACL injuries are typically graded from a scale of 1 to 3 based on progressive severity.

  • Grade 1: 3-5mm translation representing mild sprain
  • Grade 2: 5-10mm translation representing partial or complete ACL tear
  • Grade 3: >10mm translation representing complete ACL tear and/or other ligamentous injury


If an injury to the ACL does not involve significant knee instability, Dr. Yau will recommend  rest, ice, elevation and anti-inflammatory medications followed by physical therapy to restore function.


A complete ACL tear will typically require surgical intervention to restore normal knee function. Dr. Yau performs arthroscopic assisted ACL reconstruction by removing the damaged ligament and replacing it with a new tissue, called the graft. Dr. Yau will strive to use the patient’s own tendons for the graft, which is known as an autograft. This is because the patient’s own tissue heals faster and reduces the risks associated with a cadaver tendon graft (allograft). However, allografts may be good options in certain patients and those who had previous knee injuries or surgeries that do not have adequate tendons to take for grafting.

For additional resources on an anterior cruciate ligament injury, or to determine if you require surgery for your ACL tear, please contact Dr. Jervis Yau, orthopedic knee specialist in the Santa Barbara, Goleta, Santa Maria and Ventura, California area.