ACL Series: Part 1

An ACLR (Anterior Cruciate Ligament Reconstruction) is not only one of the most common sports injuries for level 1 sports (football, soccer, basketball, etc), but is also one of the longest recoveries from a surgical standpoint due a multitude of factors. 

That attracts a TON of attention and research over the past few decades. We know more and more about the ACL and how it functions, but injuries continue to go up, to nearly 200,000 injuries per year! 

​What is the ACL?

The anterior cruciate ligament is a band of connective tissue that connects the shin bone (tibia) to the thigh bone (femur) and prevents forward movement / shifting and rotational forces of the tibia against the femur. This is critical in overall stability of the knee joint especially when it comes to athletic movements (sprinting, jumping, cutting, pivoting, etc). 

Types of ACL injuries: 

• Direct Contact: about 30% of the cases (Brophy 2021)
• Non-Contact: 70% of the cases: moving in a certain way.​

Mechanism of Non-Contact Injuries: This clearly makes up most of the ACL injuries and usually occurs with a leg firmly planted with a body rotation, landing with a hyperextended or valgus knee during a land from a jump, or during a quick pivot or change of direction. 

Other Risk Factors
Risk factors for ACL injuries include external factors (shoe choice and friction of playing surface, weather) and internal factors (bony morphology, hormonal, neuromuscular risk factors ). 

Gender Differences
Women are 3x more likely to tear their ACL … the reasons are unclear but there are some theories and some factors backed by some research.

• Different dynamic positioning : females usually demonstrate more knee valgus (knock kneed) which could put more stress on the ACL when rotation is added to the mix
• Different and smaller shape of their intercondylar notch and plateau (the space where the ACL lies). This is thought to predispose females to ACL injuries. 
• Wider pelvis and greater Q angle: A wider pelvis requires the femur to have a greater angle towards the knee, lesser muscle strength provides less knee support, and hormonal variations may alter the laxity of ligaments. 
• Greater ligament laxity: Young athletes with non-modifiable risk factors like ligament laxity are at a particularly increased risk of recurrent injury following ACL reconstruction (ACLR).
• Muscle Strength Ratios: Women tend to be more quad dominant, increasing the anterior translation stresses, and possibly leading to more ACL injuries.

​
​Grades of Injury: An ACL injury is classified as a grade I, II, or III sprain

1. Grade 1: ACL is stretched, not torn. There is tenderness and a little swelling. There is minimal to no instability or laxity. 
2. Grade 2: Partial tear with more tenderness and moderate swelling. This may show some instability and loss of function. 
3. Grade 3: Complete tear (rupture). Varying levels of swelling and pain, but more unstable and loss of function. There may have been an audible pop.

Associated Injuries: in over 50% of ACL injuries, the meniscus is injured as well. The unhappy triad involves the ACL, meniscus, and medial collateral ligament. There is also a possibility of cartilage lesions as well as bone bruising due to the impact of the tibia against the femur. 

ACL Reconstruction Rehab is a MARATHON. Especially for an athlete, the return to sport timelines are along the lines of 8-12 months depending on the sport and athlete presentation. Rehab consists of attaining prior range of motion, strength, power, agility and working on specific return to sport requirements and skills so that the athlete feels confident with athletic movement and has the objective data to back it up. 

Although returning back to sport is always the goal, research shows that just 65% of athletes return to their prior level of function and play! This is an extremely low lumber in our opinion and we feel that number should be much higher. 

This is where the importance of having a therapist that specializes in ACL reconstruction surgical rehab is very helpful due to the specialty of services and specific progressions necessary for a successful return to sport.

---