Alexander E Weber, MD
Orthopaedic surgeon & sports Medicine specialist

ACL Reconstruction (Patellar, Quadriceps, & Hamstring tendon)

Orthopaedic Surgeon & Sports Medicine Specialist in Beverly Hills, El Segundo, Glendale, & Los Angeles, CA

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ACL Reconstruction (Patellar, Quadriceps, & Hamstring tendon) services offered in Beverly Hills, El Segundo, Glenale & Los Angeles, CA

ACL injuries commonly occur during sports activities that involve twisting or overextending the knee. Symptoms of an ACL injury include a loud "pop" sound, knee swelling, and instability or giving way of the knee. A physical examination, X-rays, MRI scans, and arthroscopy are diagnostic tests used to determine an ACL injury. ACL reconstruction aims to tighten the knee and restore its stability, but there are risks and complications associated with the procedure, including nerve and blood vessel damage, decreased range of motion, and repeat injury to the graft. Post-operative care involves immediate rehabilitation to restore knee movement and strength. ACL reconstruction is a common and successful procedure indicated for patients wishing to return to an active lifestyle, especially those wishing to play sports involving running and twisting.

Patellar tendon:

ACL reconstruction using the patellar tendon involves replacing the damaged ACL, which is a major knee ligament connecting the femur to the tibia, with a section of the patellar tendon. This ligament provides stability to the knee joint and prevents excessive forward and rotational movements of the tibia in relation to the femur. When the ACL is torn, it can lead to instability and a feeling of weakness in the knee. Reconstruction surgery is performed to replace the damaged ligament with a tissue graft.

Causes & symptoms:

An injury to the anterior cruciate ligament (ACL) frequently occurs during sports activities that involve twisting or overextending the knee. There are several ways that the ACL can be injured, including a sudden change in direction, slowing down while running, landing improperly from a jump, or sustaining a direct blow to the side of the knee, such as during a football tackle.

The symptoms of an ACL injury may include a loud popping sound and a sensation of the knee giving way or buckling. Swelling of the knee may occur within a few hours after the injury due to bleeding from the vessels within the torn ligament. You may also experience instability in the knee, especially when trying to change direction.


A thorough physical examination of the knee along with diagnostic tests such as X-rays, MRI scans, and arthroscopy can be used to diagnose an ACL injury. X-rays may be required to exclude any fractures.

Moreover, a doctor may conduct the Lachman's test to determine the integrity of the ACL. In a Lachman test, a knee with a torn ACL may display an increased anterior displacement of the tibia and a soft or indistinct endpoint when compared to a healthy knee.

The pivot shift test is another way to assess an ACL tear. In this test, if the ACL is ruptured, the tibia will shift anteriorly when the knee is completely extended, and as the knee bends beyond 30°, the tibia will return to its original position in relation to the femur.


The primary objective of ACL reconstruction surgery is to restore the stability of the knee by tightening it. This surgical procedure involves the replacement of the damaged ACL with a section of the patellar tendon obtained from the patient's leg. The patellar tendon, which runs from the kneecap to the shinbone, is harvested to extract the new ACL. The surgery is carried out under general anesthesia, and two small incisions of around ¼ inch are made around the knee. An arthroscope, which is a tube with a small camera at the end, is inserted through one of the incisions to visualize the inside of the knee joint. A sterile solution is then pumped into the knee to expand it, providing the surgeon with a clear view of the joint's interior. The damaged ACL is removed, and the pathway for the new ACL is prepared. Next, the middle third of the patellar tendon, along with small bone plugs at each end where it attaches, is removed through an incision over the tendon. The remaining portions of the tendon on either side of the graft are sutured back in place. The arthroscope is reintroduced into the knee joint through one of the incisions. Small holes are drilled into the tibia and femur bones at the point where they meet in the knee joint, forming tunnels in the bone to accept the new graft. The graft is then threaded through the predrilled holes in the tibia and femur. Finally, screws are used to secure the new tendon into the bone to keep it in place while it heals into the bone. The incisions are then sutured closed, and a dressing is applied.

Risks, complications, and post-operative care:

The patellar tendon method of ACL reconstruction surgery may be associated with various risks and complications, including numbness, infection, deep vein thrombosis, nerve and blood vessel damage, graft failure or loosening, decreased range of motion, crepitus, pain, and repeat injury to the graft.

Following the surgery, rehabilitation starts immediately, and a physical therapist will instruct you on exercises to strengthen your leg and restore knee movement. It is recommended to avoid competitive sports for around 5 to 6 months to allow the new graft to fully integrate into the knee joint.

Overall, ACL reconstruction is a commonly performed and successful procedure that is usually recommended for individuals who wish to return to an active lifestyle, particularly those who engage in sports involving running and twisting. ACL injury is a frequent type of knee ligament injury, and surgery may be necessary to regain full knee function.