One of the most common knee injuries is an ACL injury. An ACL injury is a tear or sprain of the anterior cruciate ligament (ACL) — one of the strong bands of tissue that help connect your thigh bone (femur) to your shinbone (tibia).
ACL injuries most commonly occur in athletes who participate in high demand sports that involve sudden stops or changes in direction, jumping and landing — such as soccer, badminton, basketball, football and downhill skiing.
Many people hear a pop or feel a “popping” sensation in the knee when an ACL injury occurs. Your knee may swell, feel unstable and become too painful to bear weight.
Depending on the severity of your ACL injury, treatment may include rest and rehabilitation exercises to help you regain strength and stability, or surgery to replace the torn ligament followed by rehabilitation. A proper training program may help reduce the risk of an ACL injury. Once torn, an ACL cannot regrow or heal on its own.
Who requires ACL Reconstruction?
- You’re an athlete and want to continue in your sport, especially if the sport involves jumping, cutting or pivoting
- More than one ligament is injured
- You have a torn meniscus that requires repair
- The injury is causing your knee to buckle during everyday activities
- You’re young (though other factors, such as activity level and knee instability, are more important than age)
Why not suture it?
Most ACL tears cannot be sutured (stitched) back together. To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. Your doctor will replace your torn ligament with a tissue graft. This graft acts as a scaffolding for a new ligament to grow on.
What are the types of graft available?
Grafts can be obtained from several sources.
- Often, they are taken from the patellar tendon, which runs between the kneecap and the shinbone.
- Hamstring tendons at the back of the thigh are a common source of grafts.
- Sometimes a quadriceps tendon, which runs from the kneecap into the thigh, is used.
- Finally, cadaver graft (allograft) can be used.
There are advantages and disadvantages to all graft sources. You should discuss graft choices with your own orthopedic surgeon to help determine which is best for you.
Procedure
Surgery to rebuild an anterior cruciate ligament is done with an arthroscope using small incisions. Arthroscopic surgery is less invasive. The benefits of less invasive techniques include less pain from surgery, less time spent in the hospital, and quicker recovery times.
- How you prepare?
Before your surgery, you’ll likely undergo several weeks of physical therapy. The goal before surgery is to reduce pain and swelling, restore your knee’s full range of motion, and strengthen muscles. People who go into surgery with a stiff, swollen knee may not regain full range of motion after surgery. It usually takes three or more weeks from the time of injury to achieve full range of motion. It is also recommended that some ligament injuries be braced and allowed to heal prior to ACL surgery.
ACL reconstruction is generally an outpatient procedure or there can be one day stay. Arrange for someone to be with you and drive you home.
- Food and medications
Tell your surgeon about any medications or dietary supplements you take. If you regularly take blood-thinning medications, your doctor may ask you to stop taking these types of drugs for at least a week before surgery to reduce your risk of bleeding.
Follow your doctor’s instructions about when to stop eating, drinking and taking any other medication the night before your surgery.
- What you can expect?
General anesthesia or regional anesthesia may be used during ACL reconstruction. The patient, the surgeon, and the anesthesiologist select the anesthesia used for surgery. Patients may benefit from an anesthetic block of the nerves of the leg to decrease postoperative pain. ACL reconstruction is usually done through small incisions — one to hold a thin, tube-like video camera and others to allow surgical instruments access to the joint space.
- During the procedure
The surgery usually begins with an examination of the patient’s knee while the patient is relaxed due the effects of anesthesia. This final examination is used to verify that the ACL is torn and also to check for looseness of other knee ligaments that may need to be repaired during surgery or addressed postoperatively.
If the physical exam strongly suggests the ACL is torn, the selected tendon is harvested (for an autograft) or thawed (for an allograft) and the graft is prepared to the correct size for the patient.
After the graft has been prepared, the surgeon places an arthroscope into the joint. Small (one-centimeter) incisions called portals are made in the front of the knee to insert the arthroscope and instruments and the surgeon examines the condition of the knee. Meniscus and cartilage injuries are trimmed or repaired and the torn ACL stump is then removed.
In the most common ACL reconstruction technique, bone tunnels are drilled into the tibia and the femur to place the ACL graft in almost the same position as the torn ACL. A long needle is then passed through the tunnel of the tibia, up through the femoral tunnel, and then out through the skin of the thigh. The sutures of the graft are placed through the eye of the needle and the graft is pulled into position up through the tibial tunnel and then up into the femoral tunnel. The graft is held under tension as it is fixed in place using interference screws, spiked washers, posts, or staples. The devices used to hold the graft in place are generally not removed. The graft will serve as scaffolding on which new ligament tissue can grow.
Before the surgery is complete, the surgeon will probe the graft to make sure it has good tension, verify that the knee has full range of motion and perform tests such as the Lachman’s test to assess graft stability. The skin is closed and dressings (and perhaps a postoperative brace and cold therapy device, depending on surgeon preference) are applied.
- After the procedure
Once you recover from the anesthesia, you can go home the same or the next day. Before you go home, you’ll practice walking with crutches, and your surgeon may ask you to wear a knee brace or splint to help protect the graft.
Your doctor will give you specific instructions on how to control swelling and pain after surgery. In general, it’s important to keep your leg elevated, apply a cold wrap or ice to your knee, and rest as much as possible.
Medications to help with pain relief include over-the-counter drugs. Your doctor might prescribe stronger medications. If opioids are prescribed, they should be taken only for breakthrough pain as they have many side effects and a significant risk of addiction.
Follow your surgeon’s advice on when to ice your knee, how long to use crutches and when it’s safe to bear weight on your knee. You’ll also be told when you can shower or bathe, when you should change dressings on the wound, and how to manage post-surgery care.
- Physical therapy
Progressive physical therapy after ACL surgery helps to strengthen the muscles around your knee and improve flexibility. A physical therapist will teach you how to do exercises that you will perform either with continued supervision or at home. Following the rehabilitation plan is important for proper healing and achieving the best possible outcomes.
- Risks
ACL reconstruction is a surgical procedure. And, as with any surgery, bleeding and infection at the surgical site are potential risks. Other risks associated with ACL reconstruction include:
- Knee pain or stiffness
- Poor healing of the graft
- Graft failure after returning to sport