Sport Injuries and Rehabilitation

Soccer is being played by millions of people around the world, making it the most commonly played sport. As a result, the injury rate rises too. In the United States, more than 100,000 soccer-related injuries were reported annually. A two-fold increase in annual injuries reported was identified in one study lasting 25 years. Some of the common injuries include ankle sprains, bone fractures, ligaments and meniscus tear, adductor and hamstring strain. Anterior cruciate ligament (ACL) injuries accounts for majority of it. In one study, it was reported that an average of more than 200 ACL sprain happened daily.

The ACL is one of the ligaments that attach the thighbone (femur) to the shinbone (tibia). It measures between 2 to 4 centimeters in length and between 0.5 to 1 centimeters wide. It is made up of the anteromedial and posterolateral bundles and responsible for stabilizing the knee in response to anterior tibia load. While soccer players are likelier to get ACL sprains, compared to other sports, due to its physical demands, women particularly, make the knees five times more vulnerable to injury due to their physical aspects, hormonal changes and neuromuscular control.

This paper explores how ACL injury can affect athletes physically and physiologically, preventive measure to avoid ACL injuries and the rehabilitation process after ACL reconstruction (ACLR).

Knee Joint – A Complex Joint

The knee is a complex joint designed to act like a fulcrum which allows many different movements such as extension and flexion in walking, running and jumping and a small degree of sideways movement such as twisting or lateral skips. The main parts of the knee are the bones, tendons, cartilages, synovial membrane and the ligaments.

Bones are a combination of collagen and calcium making it a growing tissue that can withstand a considerable amount of pressure while still being flexible.

Tendons are a band of tough fibrous collagen connecting muscles to bones while stabilizing the bones during inactivity. During activity, some tendons act as springs that transmit force due to its elastic nature.

Cartilages are fluid-like connective tissue that can take up the shapes of forces applied on them. When a cartilage is damaged, surgeons and scientists adopt a repair procedure to delay the need for any joint replacements.

A viscous synovial fluid lubricates the joints of the knee to prevent friction. This fluid is excreted out by a membrane called the synovial membrane. This membrane lines the joint protecting it from rubbing against each other during motion. Synovial membrane suffers damages during osteoarthritis, Ross River virus or rheumatoid arthritis which may cause excessive or thinning of the synovial fluid in the knee.

The ligaments around the knee connect the femur, tibia, fibula and patella together. While many ligaments are found outside the knee joint, two are found within. These ligaments are known as cruciate ligaments: posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL). These two ligaments intersect each other to form an ‘X’.

ACL

Muscles around the knee joint work towards stabilizing the knee if it experiences extreme movements. The main muscles keeping the knee stable are the quadriceps and the hamstrings. These muscles help flex and extend the knees. The major stabilizing ligament, ACL, is situated in the center of the knee, and it runs diagonally from the base of the femur to the tibia (Forsythe et al., 2010). While it prevents the tibia from moving too far in front of the patella and femur (, it is used extensively in human daily activities including, sitting, standing, walking, running and involvement in any sports. Majority of knee-injury complaints are a result of an injured ACL. An injured ligament is also known as a sprain. The most common ACL injury is the ACL sprain and it is categorized into three scales; Grade I (mildest), Grade II and Grade III (most severe) ("Anterior Cruciate Ligament (ACL) Injuries - OrthoInfo - AAOS", 2018). The sprain will occur once the threads of the ligaments are stretched, partially or completely ruptured.

Complex and multi-ligament knee injuries can also lead up to ACL injuries.

Soccer and ACL

ACL injuries are prevalent in physical sports including soccer, volleyball and basketball because players tend to have rigorous movements involving sprinting, jumping, twisting, landing and turning. Over two-third ACL injuries occur in non-contact conditions (Y. Griffin et al., 2000). When an individual run straight, the ACL is usually not integral to the movement, but with soccer, ACL is paramount. Firmer and harder pitches do not help. The game speed increases with players moving fast in the field. Putting all these factors together increases the probability of players injuring the ACL.

ACL and Central Nervous System (CNS)

Athletes suffering from ACL sprains complain of knee instability. In recent studies, loss of stimulation due to ACL-deficient knees directly impacts the stable functions or position sense of the knee. Studies also revealed that proprioceptive loss persist after ACLR. Knee receptors, called mechanoreceptors, provide information to the brain. Specialized mechanoreceptors such as Ruffini receptors; sensitive to stretching, the Golgi-like tension receptors, the Vater-Pacini receptors; sensitive to rapid movement, and the free-nerve endings which function as the nociceptors play an important role in signaling the knee. These receptors acquire information from the muscle spindles or stretch receptors that has been transmitted by the central nervous system through the afferent nerve fibers. When transmitted information is lost due to damaged receptors, the muscles governing the knee responses accordingly and becomes wobbly and unstable.

Somatosensory evoked potential (SEP) is a dependable and non-invasive way of studying somatosensory route and in one study, data collected confirmed that proprioception sensation to this ligament triggers the mechanoreceptors which translates to the capability of the knee.

Since information from the same receptors determines the coordination and stabilization of the knee, it can be said that the condition of the ACL determines the outcome of knee function.

Prevention of ACL injury

Being one of the most commonly occurring injuries in sports, avoiding or reducing the number of ACL injuries has become an increasing need for sports activities.

Noncontact situations such as landing and pivoting maneuvers contribute to most ACL injury. While statistics only show that women are at a greater risk for ACL injury, many other factors can assist us to prevent ACL injury. In one study where an effective training program was presented, the number of athletes at risk of injury was greatly reduced. It was discovered that training programs reduce the risk of ACL injuries up to 52 percent in women and 85 percent in men. Specific training such as body consciousness, balancing, agility drills, muscle strengthening, stretching, jumping and landing techniques done at least two to three times a week help with the prevention of ACL injury.

Rehabilitation after ACLR

The primary goal of any rehabilitation process is to reduce the extent at which an injury has occurred by either reducing or reversing the loss of functionality. It also aims at controlling swelling and restores the full mobility of the knee and to maintain strength in the hamstrings and quadriceps. The rehabilitation process then progresses to ensure that the knees can be fully extended, legs straightened when standing, and minimal occurrence of inflammation and swelling.

The other purpose of rehabilitation is to correct impairment, prevent or possibly eliminate the occurrence of disability. Physiotherapy exercises, both at home and in the rehabilitation center, ensure that the knee regains its full capabilities from one stage to the next. The most common side-effect of ACLR is the permanent alteration of the knee mechanics. This is due to the ACL graft that is attached at a steeper angle, may result in both rotational instability and the disruption of the standard positioning of the knee. Additionally, chances of knee osteoarthritis (OA) occurring are increased similarly to the risk of re-injury.

Therefore, both programs must include a pain-management treatment section, strength and endurance program, a proprioception and coordination activity program and functional rehabilitation center.

For it to be a successful program, elements such as effective communication, ability to set reasonable game goals, and a firm belief regarding the efficacy of actions are important.

Lastly, a functional program keeps an account of an athlete optimum performance.