Hey there, time traveller!
This article was published 3/7/2014 (2635 days ago), so information in it may no longer be current.
A strained or ruptured anterior cruciate ligament -- also known as an ACL -- is one of the most common knee injuries an athlete can suffer. It is also one of the most devastating, with injured athletes often requiring surgery and as much as six months of rehabilitation for a full recovery.
Last year, the Pan Am Clinic alone performed 350 ACL surgeries.
Most of the athletes suffering these injuries are in high-demand sports such as basketball, football, hockey and soccer. But you can also injure yourself by skateboarding, playing ultimate Frisbee or volleyball, or participating in any other sport that requires landing from a jump, sudden deceleration or planting and cutting manoeuvres.
Another important trend in ACL injuries concerns gender. The incidence of ACL rupture in female athletes is up to five times higher than males when comparing the same sport between the sexes.
What accounts for these injuries?
Let's begin with the knee. It is the largest and most complex joint. Three bones form the knee joint: the femur (thigh bone), the patella (kneecap) and the tibia (shin bone). Since the shape of these bones provides minimal stability, the soft structures of the knee joint are critical to stabilize the joint during dynamic movements.
Several major muscle groups cross the knee joint, including the quadriceps and hamstrings. Four major ligaments connect the bones of the knee joint: the medial collateral ligament (MCL), the lateral collateral ligament (LCL), the ACL and the posterior cruciate ligament (PCL).
ACL injuries can be grouped into two categories: non-contact and contact. Non-contact injuries can result from common skills and movements performed in sport, such as planting and cutting, landing on a straight knee, and one-step stop landing with the knee in hyperextension. Contact injuries involve a blow to the leg or knee by another player or object.
ACL ruptures can be treated non-operatively or operatively, depending on patient demands and symptoms. Individuals who partake in high-demand activities during sport or vocation are most likely to require surgery since the ACL will not heal without surgical intervention.
Since an ACL cannot be surgically repaired, the ligament needs to be reconstructed. Reconstruction of an ACL requires the use of a tendon graft, which can come from the patient's own body (autograft), or from a donor (allograft). Two of the most common autografts are semitendinosus/gracilis tendon (hamstring) grafts, and bone-patellar-tendon-bone (BPTB) grafts. In a survey study by members of the Pan Am Clinic Foundation research team, led by Dr. Peter MacDonald, hamstring grafts are the most common type of graft used in Canada, whereas BPTB grafts are used more often in the United States; however, the trend in the United States is shifting.
ACL reconstructive surgery techniques have improved dramatically over the years. Today, they are performed through an arthroscope, which is a camera that is inserted into the knee so surgeons can view inside the joint. Once bone tunnels are drilled into the tibia and femur, the graft is inserted into the tunnels and secured on each end with a button, screw and staple. The Pan Am Clinic is at the forefront of ACL reconstruction surgery and has completed two studies investigating the optimal placement of bone tunnels for ACL reconstruction. Return to full participation in sport or work can take six to 12 months.
Fortunately, there are programs to help reduce the risk of ACL injuries. The Sportsmetrics program is a case in point. It uses a combination of exercises -- dynamic warm-ups, jump training, high-intensity strength training and flexibility training -- to better protect the knees. Studies have shown it is effective in lowering the rate of ACL injuries.
Jeff Leiter is Albrechtsen Research Chair and executive director of the Pan Am Clinic Foundation.