Guide to Knee Surgery

What happens when the ACL is torn?

What happens when the ACL is torn Most people who rupture their ACL can recall the exact moment at which they felt it pop. This usually happens when changing direction quickly in pivoting or cutting sports like soccer, landing from a jump in sports such as basketball, or falling while skiing. The four "classic" symptoms that people may feel when they tear their ACL are:

• They hear a "pop" from inside the knee
• They feel the knee give away at the time of injury
• They develop a swollen knee immediately, or within a few hours
• The pain is bad enough that they can not continue play that day.

When the ACL ligament is stretched too far and ruptures, the blood vessels inside the ligament rupture as well, and this blood fills the knee joint, causing the knee to swell. While the ACL injury itself is usually not terribly painful, the swelling that results from blood inside the knee prevents most people from returning to the game or the athletic activity they were involved in at the time of injury. Examining an athlete immediately after they have had a knee injury can sometimes be difficult and it is often not possible to tell what structures, if any, have been injured. This is because the quadriceps and hamstring muscles "guard" the knee, preventing the examiner from testing the ligaments accurately. A better examination can usually be obtained after the swelling has gone down and the pain from the injury has subsided. Although accurate diagnosis of the exact injury can be difficult, it is relatively certain that an athlete who develops a swollen knee immediately after an injury should not return to play and should seek medical evaluation.

What to expect if you need to undergo knee surgery?

ACL surgery begins with an arthroscopic examination of the inside of your knee. In many ways, arthroscopic surgery has revolutionized the process of ACL reconstruction (and orthopedic sports medicine in general). This surgical technique uses three very small incisions that are about 1/4 of an inch in length to create "portals" into the knee. A fiber-optic light source illuminates the inside of the knee and a video camera feeds an image to a monitor so that the surgeon can see inside the knee. A sterile saline solution is continuously pumped through the knee via a cannula so that the operative field is always clear.

The term "arthroscopic" comes from two Greek words that mean "to look inside a joint." During arthrocsopic knee surgery, the surgeons maneuver and use their tools by watching the image (provided by the arthroscope) displayed on a video monitor.

After the surgeon inspects the knee for damage to the cartilage or the menisci, the remnants of the torn ACL are removed with a high-speed shaver. This tool is a very specialized device that is used to remove torn ligaments or torn pieces of cartilage from the knee. The surface of the intercondylar notch where the ACL normally attaches to the femur is then prepared with a high-speed burr so that the proper location for the tunnel for femoral fixation can be seen clearly.

Tunnels are then drilled through the bone in the femur and the tibia so that the graft can be placed in the center of the knee in the same position as the original ACL. A separate incision that is about 2 to 3 inches long also has to be made in order to harvest the graft from either the patellar tendon or the hamstring tendons. After the graft has been harvested, it is then prepared by placing several very strong surgical sutures through the graft that are used to fix it in place. Some surgeons will also braid the graft before passing it through the tunnels.

After the graft is passed through the tunnels, it is then tensioned and fixed in place. A variety of fixation techniques have been developed to anchor the graft to the bone. Different techniques are used for different types of grafts, and today, fixation failures, though possible, are very rare.

Once the graft has been fixed in place and any additional damage has been addressed, the incisions are closed and a sterile dressing is used to cover the knee. This dressing will usually stay on for several days while the wound begins to heal.