The anterior cruciate ligament (ACL) is a support structure in the knee that prevents the forward and backward movement of the bones of the knee. It is often injured in athletic activities or during traumas such as motor vehicle accidents. The ACL is usually repaired in most individuals by surgical reconstruction of the ligament. Anesthesia has its own set of risks. The surgery itself has a wide variety of risks. In growing children, there is the added surgical risk of injury to the growth plate, leading to bone growth issues.
Infection
Infection at the surgical site and within the joint is not that common; however, it can occur if proper sterile technique isn't followed during the procedure. The "AAOS Comprehensive Orthopaedic Review" reports the infection rate at less than 1 percent. The reconstructed ligament can be taken from a cadaver and transplanted into the injured patient. This procedure carries a very small risk of HIV and Hepatitis C even with very careful screening and processing.
Injury to Vessels and Nerves
Surgical procedures involve a risk of damage to vessels, nerves, and other structures. ACL reconstruction surgery carries a small risk of injury to the neurovascular structures located in the back of the knee, or popliteal space.
Deep Venous Thrombosis (DVT)
A deep venous thrombosis (DVT) is a blood clot that forms in the deep veins of the leg or arm. Pieces of the clot can break off and travel to the lungs, leading to a deadly condition known as a pulmonary embolism. If the clot breaks off and travels to the brain, a patient can have a stroke. Precautions are taken during surgery and during the post-operative period to prevent DVTs from forming.
Instability
Stretching or rupture of the newly reconstructed ligament does occur during the post-operative period, requiring a revision surgery to re-reconstruct the ligament. This can happen at any time during the post-operative course.
Stiffness
Post-operative stiffness is reported in up to 25 percent of patients after ACL reconstruction, according to the American Academy of Orthopaedic Surgeons. Physical therapy can help improve the knee range of motion. Sometimes scar tissue known as a cyclops lesion can form in the knee and limit the knee's range of motion during the post-operative period.
Extensor Mechanism Injury
The extensor mechanism is the term that refers to the tendons connecting the thigh muscles to the patella and the patella to the tibia, or shinbone. Some ACL grafts are taken from part of the extensor mechanism--either the patella tendon or the quadriceps tendon. Removing a portion of the extensor mechanism to use as a graft can lead to rupture of the tendons, or fracture of the patella due to weakening from surgical manipulation.
Pain
Post-operative pain can occur after ACL reconstruction surgery. Pain can occur at the incision sites or from the site where the new ACL is taken. Some patients report kneecap pain, especially if part of the extensor mechanism was used for the newly reconstructed ACL.
References
- American Academy of Orthopaedic Surgeons: ACL Injury- Does it Require Surgery?
- "AAOS Comprehensive Orthopaedic Review"; Dr. Jay Lieberman (ed), 2008.
