Anterior Cruciate Ligament - Rehab and Prevention

Blog Series - Anterior Cruciate Ligament (ACL) Part 2

Rehabilitation and Prevention

Incidence

As already mentioned in our first blog about injuries to the cruciate ligaments and the knee, injuries to this joint and its structures are very common, especially to the anterior cruciate ligament. We also see this in our practice at BodyLab Osteopathy and Physiotherapy in Zurich, where we frequently treat patients with knee injuries. According to Switzerland's accident statistics, there were approximately 50,000 occupational and non-occupational accidents involving knee dislocations, sprains, or strains annually between 2012 and 2016. The costs for these knee injuries averaged more than 500 million Swiss Francs during the same period [1]. Majewski, Habelt, and Steinbrück categorized all sports injuries of the knee recorded by them over a ten-year study into various categories [2]. During this period, 7,769 knee injuries were recorded, of which 3,482 involved either the cruciate ligaments, collateral ligaments, or the menisci; all classified as internal knee injuries. Almost half of all internal knee injuries solely affected the anterior cruciate ligament (ACL) [2].

Costs and Consequences of an Anterior Cruciate Ligament Tear

These injuries cost the healthcare system millions of francs annually, and acute knee injuries can also lead to degenerative diseases such as chondropenia or osteoarthritis due to their biochemical joint processes. These secondary issues can lead to increased functional limitations in daily life and sports as one ages, as well as incur higher costs beyond just the injury itself [3]. Myklebust and Bahr even showed that 50-100% of women who suffered an ACL tear will show radiological signs of knee osteoarthritis in the following 10-20 years [4]. The German Knee Society's (DKG) expert group also describes that 7-24% of patients with an operated ACL will suffer another ligament tear in the non-affected knee [5]. In young patients (<26) engaging in high-risk sports (e.g., football, volleyball, handball), almost

every fourth athlete sustains a second ACL injury upon returning to their high-risk sport, often during the early return-to-play (RTP) phase after rehabilitation [6]. Compared to uninjured, healthy youths, the risk of ACL injury is 30 to 40 times higher in patients with reconstruction [6].

Women after puberty participating in the same sports as men are exposed to a 2- to 10-times higher ACL injury risk due to various factors like hormonal balance or neuromuscular control [7].

You can learn more about the anatomy and function of the cruciate ligaments here in our first blog.

Risk Factors

Literature describes various risk factors that can contribute to ACL tears. These risk factors are divided into two categories: extrinsic factors like weather conditions, clothing, materials, or playing surface, and intrinsic factors like anatomical, physiological, neuromuscular, genetic, or biomechanical aspects [12].

Anatomical risk factors primarily refer to the length, width, and volume of the cruciate ligaments. Differences in the angle of the cruciate ligaments also impact the risk of an ACL injury.

According to Quatman et al., a combination of anterior tibial translation and internal tibia rotation, as well as abduction and anterior tibial translation led to a 3.9- and 4.6-fold increase in ACL load compared to normal landing conditions [18].

Landing in a knee valgus position increases ACL load further because ground reaction force is elevated in this position, posing a higher risk for ACL tears, especially in women. The body's center of gravity is often behind the affected knee in