The Dreaded, But Very Common ACL Injury
The anterior cruciate ligament (ACL) is a band of dense connective tissue which courses from the femur (larger upper bone of the leg) to the tibia (lower bone of the leg). The ACL is a key structure in the knee joint, as it resists anterior tibial translation and rotational loads. Meaning it helps prevent the knee from overly twisting (usually inwards) or the lower bone shift aggressively forward, it actually provides approximately 85% of the total restraining force of anterior translation or this forward movement.
Most of these injuries occur during sporting activities (but not always !). The most common reason it occurs is when the person's foot is planted on the ground and the knee is twisted inward but the upper body and femur is twisted in the opposite direction usually when trying to suddenly change direction. It can also occur if there is extreme hyperextension or hyperflexion of the knee or there is direct contact (usually to the outside) of the knee.
Several studies have shown female athletes have a higher incidence of ACL injuries than males because of differences in pelvic and lower leg alignment and the effects estrogen has on ligament properties. For these reasons, when it comes to rehabbing a female patient special emphasis must be placed on ensuring certain muscles around the pelvis are really strong to prevent it reoccurring. Here at TC Physiotherapy, we place a huge emphasis on hamstring strength in both male and female cohorts, Unfortunately, this is regularly overlooked when it comes to rehabbing the injury.
The Hamstrings are very important because they need to be able to extend the hip, flex the knee and rotate the femur and tibia but most importantly they stop excessive translation or too much shifting of the tibia on the femur. (see below)
If you hamstrings are long and weak (which most peoples are !) this will affect your ability to be able to fully straighten the knee, if you can’t do this you will be placing your knee under severe stress and it is likely that the injury will re-occur and/or lead to other knee injuries when you are back playing sport.
Strength training in general for the knee is also very important as it increases stability and helps to compress the joint. Without that stability, you have a loose, sloppy joint, that’s really going to be subject to increased wear and tear. The most important factor is you get the right rehab program for you and not to do a generic one. As the name suggests ‘cruciate’ is a ‘crucial’ ligament in the knee and yes it a serious injury but it doesn’t mean the end of your sporting career once you have gone through a proper rehab program tailored to your specific needs.