Friday February 13, 1998 4:45 pm
Saddleback College Sports Medicine
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Knee Injury: Anterior Cruciate Ligament
By Kat Pabico
So you finally go out and play football with your friends. First type of exercise in a year, and what happens? Your knee gives out just as you cut back to prevent from being blocked, tackled or demolished for that matter.
You can not move your knee. It is painful and it is starting to swell up. What happened? More than likely, you have injured the soft tissues that support the knee. In this case, you have torn the Anterior Cruciate Ligament (ACL)
The ACL prevents anterior translation of the tibia on the femur. It works in conjunction with the posterior cruciate ligament to control the gliding and rolling of the tibia on the femur during normal flexion and extension.
The twisted configuration of the fibers of the ACL and the shape of the femoral condyles allow for the screw home mechanism of the knee during the final 20 degrees of extension when the tibia externally rotates on the femur. The ACL has undergone some degree of tension in all positions of knee movement.
Ligamnets act as the scaffolding for the bones of the knee. The collateral Ligaments run up the inside and outside of the knee, while the ACL and the Posterior cruciate ligament cross within the joint. A sprain occurs when any of these ligaments are stretched excessively or torn.
The ACL is often torn during contact and non-contact sports such as football, basketball and baseball. An estimation of at least fifty thousand knee sprains occur each year in the U.S. among skiers alone. Fortunately, less than fifteen percent require surgery.
Symptoms
The following are some symptoms which defines three categories of ligamentous injury:
1. Grade 1 "mild" sprains are those with mild tenderness, minimal hemorrhage and swelling, no abnormal motion and minimal disability. There are minor tears of ligament fibers. There is minimal loss of strength, no lengthening, and no loss of function.
2. Grade 2 "moderate" sprains are those with moderate loss of function, more joint reaction, slight to moderate abnormal motion, and partial tearing of ligament tissues. There is stretching of some ligament fibers and tearing of some.
2. Grade 3 "severe" sprains are those with marked abnormal motion, indicating a complete tear of the liogament. This causes a total loss of strength and functional ability and may require surgery.
Treatments
Treatment for sprains depend on the severity of the injury. For mild sprains rest, ice, compression and elevation is required (R.I.C.E.). All that is needed is about two to three weeks of treatment including physical therapy exercises.
If it is a second-degree sprain, treatment will vary depending upon the individuals determination to healing quickly and the severity of the damage with the cartilage or muscles. The knee will often need protection for about six to eight weeks with a removeable splint and range of motion exercises that allows for limited movement along with physical therapy exercises.
If it is a grade three sprain, surgury is often considered with prolonged splint or brace protection. Some continued protection may even occur after eight weeks. Bracing was usually misinterpreted as a protection device for stability. Instead, it is to protect and prevent re-injury during the healing process of the ligament. Physical therapy will follow for rehabilitation.
The following are some physical therapy exercises to help rehabilitate the injured ACL:
A torn anterior cruciate ligament usually means living less aggressively on the knee. Any activity involving sudden stops and turns would be more difficult to take and much more hazardous. The cruciate ligaments prevent the bones from slipping backward or forward out of joint. Without an ACL for added support, going down hills or stepping in a hole can be a lot more treacherous because you wouldn't have the resiliency and protection you once had. This means you can still run after your child, but clearing over a toy would send you to the ground.