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From PEKN 1P93 Winter 2014: Group 20: Treatment Rehab, Knee injuries
What is the anterior cruciate ligament (ACL)?
The anterior cruciate ligament (ACL) is a band of connective tissues located in the knee joint. More specifically, its origin is on the medial anterior aspect of the tibial plateau, and it is locked to its insertion on the lateral femoral condyle. The anatomical role of this ligament is to limit the tibia from excessive medial and lateral rotation. The ACL alone accounts for approximately 85%-90% of total knee stability and knee joint kinematics. 0:00 - 1:50 of Dr. Nabil A. Ebraheim`s video from the University of Toledo Medical Center is a visual representation of the anatomical and physiological components of the knee joint. 
What are the mechanisms of an ACL injury?
According to the American Academy of Orthopaedic Surgeons (2014), injuries to the anterior cruciate ligament are considered sprains and are graded on a severity scale.
- Grade 1 Sprains ACL injuries considered to be a GRADE 1 SPRAIN involve mild damage to the anterior cruciate ligament. This may include the ligament being slightly stretched, but still functional and intact to help with stability of the knee joint
- Grade 2 Sprains When the anterior cruciate ligament is stretched to the point where it becomes loose, this may be referred to as a partial tear of the ligament. This level of severity of injury is referred to as a GRADE 2 SPRAIN.
- Grade 3 Sprains A GRADE 3 SPRAIN is most commonly referred to as a complete tear of the anterior cruciate ligament in which the ligament has been completely separated into two pieces and in result, the knee joint becomes unstable and at risk for further injury. 
The ACL is susceptible to being sprained, partially torn and completely torn. All of these terms represent a progressive increase in the percentage of ruptured connective fibres from the ligament itself. The majority of ACL injuries are caused in a non-contact fashion (70% of all ACL injuries), very common in sports like soccer, basketball, rugby, skiing where the athletes perform very rigorous changes in direction, pivotal maneuvers and abrupt hyper extensions. In the case of ACL injuries due to contact, football is a common physical activity where impact on the knee from another player through tackling is prominent. The unfortunate reality of ACL injuries, caused through physical contact, also results in injury of the medial collateral ligament (MCL) and the medial meniscus. This notorious triple combination is collectively known as the "unhappy triad". Individuals who experience a complete tear of their ACL often report a popping sensation, which is in fact the ligament being ripped from its insertion on the femur. The ligament disconnects from the insertion because it is the weaker point of attachment then the origin. ACL injury incidences are not equal amongst males and females. Females are 2-8 times more likely to injure their ACL, although there have been more male cases of ACL injuries reported. There are a combination of factors that contribute to the high occurrence of female ACL injuries. To list a few; neuromuscular imbalance as a result of imbalanced contribution from the muscles of the upper leg and females have a tendency to rely more on there quadriceps then their hamstrings. The female pelvis is wider and shorter then the male pelvis. This anatomical difference in females causes an increase in the Q angle, which in turn leads to compensation of the lower body, in this case, the knee joint. Such an increase in the Q angle can lead to femoral anteversion, tibial external torsion, and subtalar pronation. The ACL is surrounded by interstitial fluid inside the knee. The majority of sprains and partial tears can heal themselves in this environment with proper rest and care. However, when the ACL has undergone a complete tear, it shrivels up and cannot heal at this point because there are no remaining connective fibers attached to both locations allowing the ruptured fibers to grow up along like vines growing up along a wall. 
Why is information pertaining to the ACL important?
Just like the best way to quit smoking is to never start, the best way to recover from an ACL injury is to never injure the ACL in the first place. The United-States has an approximately 200 000 reported ACL injuries, in which half, 100 000, decide to undergo a knee reconstruction surgery. Before any injury the risk of ACL injury is 1 in 3 000, after an individual has experienced an ACL injury, the risk of subsequent injury to the graft or other knee is 1 in 50. It is also important to be aware of information about ACL injuries because 70% of people who have had an ACL injury and do not undergo reconstructive surgery develop osteoarthritis. Osteoarthritis, or bone arthritis, is a painful condition caused by the scarceness or absence of cartilage found at the surface of the femur to allow a smooth knee flexion and extension. There are many more examples listed below in the section Did You Know? that effectively put into perspective the results of an uneducated approach to the ACL injury. The most important thing that can be accomplished from educating individuals about ACL injuries and prevention is to have them apply the knowledge in ways that would lower their risk of an ACL injury. The most beneficial methodology to prevent ACL injuries caused through contact and non-contact physical activity. In the present day, many individuals susceptible to ACL injuries do not follow a physical activity program with the objective to prevent further ACL injuries, but instead the program is oriented around improving running speed, jumping height, cardiovascular health, etc. Information pertaining to the ACL is important because it can make it so that experiencing an ACL injury or even a "unhappy triad" will not be a set back in an individual's mobility, health and quality of life. 
Basic Anatomy of the Knee and Associated Injuries 
Did You Know? 
- On average, annually in the US there is estimated to be 200 000 ACL injuries, in which around 100 000 are reconstructed
- Around 70% of these ACL injuries occur in a ‘non-contact’ way, frequently seen in agility sports like soccer, basketball, skiing
- The age group that is found to have the highest rate of experiencing an ACL injury are people who participate in sports and live an active lifestyle, that is the age group 15-45
- NCAA statistics: women are 2-8 times more likely to injure the ACL, although there are more male cases of ACL injury reported each year. Factors influencing the high occurrence of females to injury are; lower extremity alignment (wider pelvis, knee valgus, and foot pronation), joint laxity, hamstring flexibility, muscle development, hormonal differences, and ACL size.
- The most common multi-ligament knee injury (result of impact, i.e. a tackle in football) includes the ACL, MCL and the medial meniscus.
- Lachman Test (98% accuracy in predicting an ACL injury) other types of ACL tests: Anterior Drawer Test, Pivot Shift Test, T-2000 Arthrometer Test
- Meniscus Tests: McMurray`s Exam
- Graft harvest sites: patellar tendon, hamstring tendon, and quadriceps tendon. Also graft can be allografts (cadaver) or autograft (patient’s tissue)
- Post surgery, there is an average of 2.6% of ruptures at a mean of 2.5 years post-surgery.
- Before any ACL injury, the risk of injury is 1 in 3 000. Risk of subsequent injury to graft or other knee increases to 1 in 50.
- 70% of people who have injured the ACL (a complete tear, grade 3 sprain) and do not undergo reconstruction surgery develop osteoarthritis.
- People who have a knee injury and follow a physical activity program prior to surgery, achieve better post surgery results than those who do not complete a physical activity program before surgery
- It has been determined that the longer you wait to begin physical therapy following surgery, the more difficult and painful it is to restore full range of motion and strength. Studies also show that the optimal time to start doing physical activity after surgery is 2 days.
- The most effective methods used by therapists to treat knee injuries are manual therapy techniques such as joint mobilization, soft tissue mobilization, and PNF (Proprioceptive Neuromuscular Facilitation) techniques, as well as modalities such as ultrasound, ice, and electrical stimulation
- Patients recovering from surgery return to physical activity in an average of 6-12 months. Factors that influence the recovery time include: the patients individual progress, the type/severity of injury and the type of physical activity the patient is returning to.
Before the 19th Century
The history of rehabilitation and treatment of injuries started in 1813 by the founding father of the Royal Central Institute of Gymnastics, Pehr Henrik Ling. Starting as a young arts teacher, Ling noticed the benefits that daily exercise and stretching had on his ability to stay healthy. When the institute opened in Stockholm, Sweden, it was mainly concerned with teaching individuals proper stretching and daily exercise routines that they could then teach to others to help improve their physical activity levels and health. Although Ling never truly helped individuals post-injury, he paved the way for the start of post-injury therapy. In 1887, 48 years after his death, Sweden was the first country to officially recognize Physical Therapy as a medical profession.
The Effects of World War One on Physical Therapy
Over the course of the next 20 years, neighbouring countries also adopted their own forms of Physical Therapy and created an official medical profession and, in result, this position within the medical field had slowly started to make great strides in their ability to help injured individuals. Then during 1914, the First World war started, which acted as a catapult and allowed Physical Therapy an opportunity to show how useful it could truly be. At the end of the war, many soldiers came home with disabling injuries, causing physical activity levels to drop. Nurses, who were referred to as "reconstruction aides", started to accept patients in hospitals and for the first time, started to offer physical therapy to the masses. Although physical therapy was offered to the masses, it was still only available in hospitals, limiting the availability of the "reconstruction aides". 
The Effects of World War Two on Physical Therapy
However, at the end of the Second World War, the countries involved, once again had a scare due to the levels of physical activity that their injured soldiers had experienced after returning from the deadliest war in human history. The Physical Therapy Association decided in 1950 that Physical Therapy clinics would be moved out of the hospital setting and into universities, private and public medical centres. They created specific rehabilitation centres to accommodate the need. This was done to counteract the abundance of individuals in need of physical therapy and to increase the level of physical activity throughout the country. Over the course of the next 50 years, physical therapy has taken tremendous leaps forward with the ability to help treat and rehabilitate injured individuals, and in 1990, the Field of Sports Medicine was created. 
Modern Day Physical Therapy
Now, in the 21st century, where culture in North America is dominated by professional and amateur sports that has ledd the field of Sports Medicine to grow extremely fast. New electronic devices, prevention techniques, education, knowledge and innovative techniques are available to be used to help decrease the time it takes to return to a pre-injury activity level. Physical and Sports Therapy has been crucial to all societies over the past 100 years in making significant leaps in individuals' personal health and quality of life, creating a better world for today and tomorrow.  
 Target Audience
The intended participants for this information on the treatment and rehabilitation of knee injuries, with a focus on ACL injuries, would be geared towards adolescents and adults (ages 15 to 45) who are involved in mild to vigorous physical activity and sport, which currently have experienced a knee injury. The information provided is also immensely helpful for athletes or individuals who want to try and prevent future knee injuries and pain. Knee injuries are becoming very common and due to the higher levels of physical activity in adolescences and adults, the occurrences of knee injuries are becoming an increasing risk to society’s physical health and well-being. Sustaining a healthy adolescent and adult population that is free from injury is also crucial to the health of today's society. It is also important to keep in mind the gender differences in the risk of ACL injury. That being said, females when compared to males are more likely to experience an ACL injury due to a combination of intrinsic (age, hormonal differences, body size and limb girth, limb dominance, flexibility, muscle strength and imbalance, reaction time and postural stability, anatomic alignment and foot morphology) and extrinsic (level of competition, skill level, shoes and orthotic equipment) factors. 
With the increase in the occurence of knee injuries, more research is being done to learn how to properly prevent and treat these. Many studies have focused on knee injury prevention to help this growing problem decrease. A key area that has been focused on recently is pre-activity stretching and warming up for athletic activity.
Recent studies have shown that proper warm up and stretching techniques are directly related to the enhancement of physical performance, and the prevention of major sport injuries. These techniques can be specifically used to prevent ACL injury in sport. There are three major categories of warm up techniques and three major categories of stretching techniques, which are used today to enhance physical performance and decrease sport injuries. (Shellock, 1985). Categories for warm-up techniques include; a) passive warm-up, b) general warm-up, and c) specific warm-up, while categories for stretching techniques include; a) ballistic, b) static, and c) proprioceptive neuromuscular facilitation (Shellock, 1985). These warm-up and stretching techniques have been proven to increase flexibility and performance in athletes, and more importantly reduce the risk of major injuries i.e. knee ligament tears (Shellock, 1985).  
Researchers have also investigated the external factors that might influence the occurrence of knee injuries. With the surge of knee injuries in athletic activity and sports, researchers want to discover if these new 'innovations' help the safety and health of current athletes.
Alentorn-Geli (2014) reviewed different risk factors associated with males injuring their ACL as a result of physical activity. Alentorn-Geli (2014) believed that the high incidence of ACL injuries as well as the devastating effects it has on patient's health has led to research for the prevention of such injuries. Alentorn-Geli's (2014) study investigated internal and external reasons for why ACL injuries have become more prevalent. Alentorn-Geli (2014) found that external factors played a more crucial role in knee injuries than internal factors. One of the most prevalent external factors was weather conditions. An example: if the field was either to wet or too dry, the likelihood of ACL ruptureis increased. Alentorn-Geli (2014) also found that the playing surface had an impact on ACL injuries, where the 3rd generation turf field with rubber fill had an increased likelihood of injury than the 1st and 2nd generation solid turf fields. Grass also has the same likelihood of ACL injury as the 1st and 2nd generation turf fields. Alentorn-Geli (2014) also found that cleat shape on footwear made a significant difference. Alentorn-Geli (2014) investigated edge, flat, screw in, and pivot disk style cleats. Alentorn-Geli (2014) found that edge designs creat more torsion on the knee joint than other cleats. Only one significant internal risk factor was noted. Alentorn-Geli (2014) found that males with a higher posterior tibial slope of the lateral tibial plateau may increase their susceptibility of ACL injury. Alentorn-Geli (2014) noted that further investigation must be made into this to protect the physical well being of our current day athletes. This research will help future decisions to be made in regards to the players' and athletes' equipment, playing fields and overall safety which will prevent future ACL injuries, and help sustain a healthy, physically active population. 
Differences Among Genders
Dugan (2005) studied sports-related knee injuries in female athletes compared to male athletes. This research focuses on non contact ACL injuries that occur in female athletes in comparison to male athletes at a similar level of competition. Dugan's (2005) article also discusses the importance of rehabilitation and the type of physical activities, which can help strengthen the muscles and tendons around the injury site. This will help to prevent further injury and decrease pain in female athletes (Dugan, 2005). Dugan (2005) also discusses the role of sex hormones and dynamic neuromuscular imbalances in female athletes compared to male athletes and whether or not these characteristics play a role in the increased number of ACL injuries in female athletes. Dugan (2005) stresses that understanding gender differences in knee injuries will lead to a more effective prevention strategies for female athletes in hopes of decreasing the rate of ACL tears in female athletes annually.
Phisitkul (2006) reviewed many studies regarding MCL (medial collateral ligament) injuries. Phisitkul (2006) concluded that the majority of MCL injuries occur in young adults that participate in sports such as skiing, hockey and football. Phisitkul (2006) also found that these injuries are one of the most common knee injuries that occur annually. Phisitkul (2006) stated that minor to severe tears in the medial collateral ligament rarely require surgical reconstruction. Only tears that have been accompanied by ACL or PCL tears require surgical reconstruction by augmentation on an acute basis. Phisitkul (2006) explained that the most common area of the MCL to rupture is by the femoral insertion with a fully extended knee. Without proper rehabilitation of the MCL and continued displacement of the knee, it is very likely that the ACL will also rupture (Phisitkul, 2006). It was concluded that the MCL will heal properly if an individual follows a prescribed rehabilitation program. Phisitkul (2006) states that the rehabilitation program that was most commonly used was one with protected range of motion exercises and progressive strength training exercises that focused on the injured knee. Individuals with injury that had undergone this rehabilitation program had high success rates when returning back to their sport or physical activity. 
Fear of Returning?
Many athletes that have knee injuries often are unable to return to the pre-injury level due to a fear of being injured again. Due to their inability to gain the stability and strength in their knee, they are not able to continue physical activity. Flanigan (2013) investigated both the physical and psychological well being of individuals that have sustained an ACL injury. Flanigan (2013) conducted a study on individuals who went through ACL reconstruction from two different doctors between 2007 and 2008 and looked at their ability to return to pre-injury activity levels. Flanigan (2013) noticed that out of the the 135 patients who completed the self assessment, only 46% of individuals who had ACLR surgery returned to their previous level of activity before the injury. Flanigan (2013) found that 50 of these non-returners did not return due to persistent knee symptoms (such as swelling, pain, and stiffness) and kinesiophobia (the fear of re-injury). The other 23 non returners, did not return due to personal conditions, unrelated to the knee problem. However 69% of individuals that had reported significant knee symptoms were still persistent. Flanigan (2013) fears that due to this low return rate to pre-injury activity, the ACLR surgery is not as effective as the patients preoperative expectations and can result in a lower overall quality of life for the patient. Flanigan (2013) also found that since ACLR has little effect on post-traumatic arthritis in the knee, more aggressive, short and midterm, rehabilitation programs must be made in order to increase the overall physical activity level of patients and justify the cost and time ACLR requires. Without the additions of improvements to these rehabilitation programs, patients will continue to have a fear of kinesiophobia and persistent knee symptoms that will prevent them to have an adequate healthy and active lifestyle. 
Need for Continued Research on Knee Injuries and ACL Tears
A number of studies have investigated the rehabilitation methods that are most efficient for restoring knee mobility and stability to the fullest capabilities. According to Hewett et al.(2013) physically active patients with an anterior cruciate ligament (ACL) rupture often undergo ligament reconstruction surgery. ACL reconstruction surgery is one of the leading standards of care for patients who have sustained this injury (Hewett, Di Stasi & Myer, 2013). Hewett et al.(2013) claim that less than half of individuals who have undergone reconstruction surgery return to physical activity or exercise within the first year post surgery. Although ACL reconstruction surgery usually successfully restores the mechanical stability and capability of the injured knee, post operative outcomes may vary, thus, creating the need for individual rehabilitation programs to improve stability, strength, and range of motion training and techniques to improve the rate of return of individuals to pre-injury physical activity programs and levels (Hewett, Di Stasi & Myer, 2013). 
 Existing Physical Activity Programs
- Accelerated ACL Reconstruction Rehabilitation Program 
This program aims to provide a fast recovery for patients who have undergone an ACL reconstruction surgery. This program is broken down into four phases including both preoperative and postoperative exercises. At the end of these four phases, approximately 4 weeks post surgery, the patient will be tested with an isokinetic strength test, an isometric leg press test and a KT-1000 ligamentous stability test in order to determine relative progress of the patient and therefore be able to guide the patient in the right direction.
- Knee Conditioning Program – American Academy of Orthopedic Surgeons 
This program is an exercise-conditioning program that is designed to help rehabilitate patients who have undergone knee surgery or are recovering from a knee injury so that they may return to daily activities. This is a general exercise program that involves a wide range of exercises to improve strength, flexibility, and range of motion.
- CDC (Centers for Disease Control and Prevention) 
This program investigates a secondary symptom as a result of primary knee injury, arthritis. This program is designed for individuals who have arthritis as a result of a previous injury and want to overcome the symptoms and return to a healthy and active lifestyle. This programs main focus relies on promoting physical activity and in doing so, preventing injuries. This program uses sport, recreational activities, and moderate exercises to help rehabilitate patients of all capabilities.
- Chester Knee Clinic - Knee Cartilage Damage Caused By Overuse 
This program is designed to be an extensive rehabilitation program for individuals who have had a Carticel (Autologous cultured chondrocytes) Implantation. Carticel is a cell solution implanted in your knee that, over time, develops and matures into cartilage. This program is a long term program meant to help prevent the symptoms of cartilage degeneration and stregnthen the knee to return it to its pre-injury activity level. This is a three phase program wherein the first stage, week one to approximately week twelve, the patient must protect the knee from weight bearing while keeping it in motion. During the transition phase, month 3-10, it is necessary to start to stregthen the knee with light weights and basic weight bearing movements. During the final stage, months 10-18, the knee regains most of its functional use, and more aggressive and functional exercises are permitted.
- Rehabilitation After Injury to the Medial Collateral Ligament of the Knee - Sport Medicine, Massachusetts General Hospital, Orthopaedics
 This program is a strength rehabilitation program for all grades of MCL tears which uses many different strength building exercises, stretching exercises, a stationary bike and light resistance training. The aim of this program is to allow the athlete or individual to return to daily physical activity or sport.
 Best Practice Activity Suggestions
The role of physical activity in the prevention, rehabilitation and treatment of anterior cruciate ligament injuries is vital to the success of recovery. Physical activity has been proven to be beneficial for patients who have sustained an ACL injury or have undergone ACL reconstruction surgery. Patients are often assessed by a medical professional and than referred to a registered physical therapist to be prescribed a rehabilitation exercise program to restore functionality to the injured knee. It is crucial that the patient experience a rehabilitation exercise program, tailored to their individual needs, within days of sustaining injury or post operative surgery. These programs are designed to improve strength, stability, range of motion, neuromuscular performance and overall functionality. The programs listed below outline prevention programs and post operative or post injury programs to rehabilitate the muscles around the ACL to improve functionality of the knee joint.
ACL Prevention Activity Suggestions
Noyes, Barber-Westin, Tutalo-Smith and Campbell (2013) describe a sports specific anterior cruciate ligament injury prevention training program to improve neuromuscular and athletic performance among female high school soccer athletes.
A similar prevention training program offered through the Ontario Soccer Association in partnership with Sports Centre - Injury Rehabilitation Inc. describes specific neuromuscular exercises to improve an individual's strength, stability, flexibility and range of motion. This program has been designed to prevent non contact ACL injuries. The program highlights strength training and stretching activities to improve the muscle strength around the anterior cruciate ligament to prevent injury during physical activity. This program has been effective to prevent ACL injury in both male and female athletes. This program should be completed three to four times a week to ensure effectiveness and overall success. The following video is a supplementary resource from the Ontario Soccer Association that outlines simple exercises that help strengthen the muscles around the ACL and improve flexibility and stability of the knee joint. 
ACL Prevention Program - Courtesy of the Ontario Soccer Association
ACL Post Operative Activity Suggestions
The following physical activities are examples of practices that are included (to a certain degree) in most, if not all, of the best rehabilitation programs to rehabilitate the knee after an ACL injury or reconstruction surgery has occurred (or even people suffering from osteoarthritis localized in the knee). These activities have been proven to be beneficial in the rehabilitation process through a combination of efforts to rehabilitate strength, stability, range of motion, capability, and overall functionality of the knee. 
- Weight bearing
- Proper stretching techniques
- Electronic muscle stimulation
- Manual therapy techniques (performed by therapists) such as joint mobilization, soft tissue mobilization, and PNF (Proprioceptive Neuromuscular Facilitation) techniques, as well as modalities such as ultrasound, ice, and electrical stimulation (goal is getting full range of motion back)
- Cycling/stationary bike
- Physical activity programs which include exercises developing core balance, proprioceptive balance and coordination, acute and chronic muscular strength
- Yoga and Tai Chi
- Sport specific agility activities
Please be advised that there is risk of injury associated with participating in any level of physical activity and exercise. These activities are to be attempted at an individual pace and level of exercise. Modifications may be made to accommodate different individual body types, gender, and age. Patients should be aware that the goal of these activities is to successfully rehabilitate the injured region, allow the individual to participate in physical activity or exercise, and avoid causing further injury. Patients should consult a medical professional or a registered physical therapist before beginning any form of physical activity or exercise.
 Future Directions
Injury Prevention Screenings
According to Sugimoto, Myer, McKeon and Hewett (2012), anterior cruciate ligament (ACL) injuries are prevelant among individuals involved in high risk physical activity and sport. ACL injuries are often the result of non contact activities such as strong impact from landing from a jump, pivotal twist of the knee, or sudden stopping motion (Sugimoto et al., 2012). ACL injuries can also be the result of contact activities such as taking a blow to the knee from a tackle during a football game (Sugimoto et al., 2012). However, Sugimoto et al. (2012) claim that females have a higher risk of injury to the ACL than do males. Sugimoto et al. (2012) suggests the development and implementation of a screening system to identify at-risk athletes in order to improve the efficiency of ACL injury prevention strategies so that females can become less likely to suffer from an ACL injury. These prevention strategies would include neuromuscular training to reduce anterior cruciate ligament injury in female athletes. Sugimoto et al. (2012) believe that by improving these prevention strategies through neuromuscular training that females will be less likely to sustain an ACL injury. 
The rate of knee injuries is something that is not slowing down. There is a direct relationship between playing sports on a turf field with cleats (increase in traction to ground) and an increase in knee injuries, specifically ACL tears because they occur, for the most part, through non-contact activity (accounting for approximately 70% of all ACL injuries). Most athletes who experience a knee injury will go for surgery to reconstruct or repair the damage. There are multiple approaches to perform this surgery, each with its own pros and cons. A new surgical procedure method that is on the uprise amongst surgeons is the Ligament Advanced Reinforcement System (LARS). This type of surgery enables the native ligament to regrow to its pre-injury function, as well as offering immediate graft stability, reduced rehabilitation time and a highly biocompatible polyethylene terephthalate (PET) artificial ligament measure to have 5 times the tensile strength of a normal ligament. With these things in mind the future direction of knee rehabilitation should aim towards reducing the frequency of knee injuries by studying the factors that increase the probability of knee injury (turf fields) and improving them. The end goal of any surgical procedure is to repair and improve the functionality and quality of life for the patient as well as creating the least amount of obstacles down the road such as during the rehabilitation process. To obtain more information about the LARS treatment please visit : 
In today's society, the rate of knee injuries has drastically increased, especially ligament, meniscus, and cartilage related injuries. There has been more effort being put into finding new therapies that will help decrease time of recovery for patients. Han Dave (2012) researched a highly controversial, yet potentially incredible new therapy called Mesenchymal Stem Cell Therapy, which has the opportunity to greatly decrease patients recovery times and their ability to return to their pre-injury activity level. Stem cells have the ability to form self renewal and regeneration, which would help the injured area return to its pre-injury state more quickly. Although most people believe stem cells come from human embryos, Han Dave (2012) talks of using MSC's (Mesenchymal Stem Cells) that are harvested from adult bone marrow, and have the ability to change into mainly bone, cartilage, ligament, tendon and fat. Although MSC's are not as adaptable to change as embryonic stem cells, they provide an effective and also a more humane and ethical way of using stem cells to help individuals during the rehabilitation process (Han Dave, 2012). Han Dave (2012) believes that MSC therapy has a strong potential to be an effective therapy, however MSC therapy is currently performed with animal species. The downside is that very few MSC animal therapy studies have been translated into human clinical trials. Although Han Dave (2012) believes MSC Therapy might be the way of the future for decreasing recovery time for patients post operative due to knee injury, its clinical trials will continue to increase. In future years MSC therapy may form a new and effective form of treatment for knee injury patients.
Today there is a greater concern for suffering an anterior cruciate ligament (ACL) injury because the long-term affects for sustaining this injury are extremely serious. Approximately 10 to 20 years after the diagnosis, on average, 50% of those with a diagnosed anterior cruciate ligament or meniscus tear will produce osteoarthritis with associated pain and functional impairment: "the young patient with an old knee" (Lohmander, 2007). This often occurs in athletes, who have sustained the injury through sport, however, it can occur to the average male or female who is not in competitive sport. The American Orthopaedic Society for Sports Medicine suggests that a better understanding of variables such as age, sex, genetics, obesity, muscle strength, activity, and reinjury can improve future prevention and treatment strategies (Lohmander, 2007). Lohmander stresses that if more clinical trials and tests are done to patients who have sustained an ACL injury, and all these variables are considered at the same time, it will lead to more positive results for ACL injuries, and decrease cases of osteoarthritis. Thus, decreasing the severity of the long-term negative affects (Lohmander, 2007). 
New Anatomical Research
As of recent, in November of 2013, a new ligament within the human knee has be successfully discovered after years of speculation. The ligament was first proposed to exist in 1879 by French surgeon Paul Segond, but it was never surgically classified. The newly discovered ligament of the knee is the anterolateral ligament or ALL (Claes & Bellemans, 2013). Claes and Bellemans (2013) believe that this ligament plays a protective roll of the ACL as we twist and turn. Claes and Bellemans think that the ALL is the reason why some patients say their knees give out when twisting and turning during physical activity and sport after surgery and rehabilitation of an ACL injury. With knowledge of this ligament, there has been a huge breakthrough in the medical and kinesiology field. With discovery of this ligament, technology and techniques will aide in future research and surgical techniques for surgeons during surgery of an ACL tear. This will also help to increase the stability of the knee of a patient who tore their ACL, due to the fact that the ALL is most commonly ruptured when a person tears their ACL.
 External Links
- Ontario Physiotherapy Association http://www.opa.on.ca/pdfs/KNEEInjuryInfo.pdf
- International Journal of Behavioural Nutrition and Physical Activity http://www.ijbnpa.org/content/7/1/9/
- American Aceademy of Orthopedic Surgeons http://orthoinfo.aaos.org/menus/leg.cfm
- National Institute of Arthritis and Musculoskeletal and Skin Diseases http://www.niams.nih.gov/Health_Info/Knee_Problems/knee_problems_ff.asp#l
- LARS Distributed by Corin http://www.coringroup.com/lars_ligaments/mediapr/faqs/
- Sports Medicine, Arthroscopy, Rehabilitation, Therapy and Technology http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3016369/
- Prevalence and Incidence of ACL Injuries in Various Sports (football, basketball, soccer, rugby, skiing) http://biomed.brown.edu/Courses/BI108/BI108_2004_Groups/Group06/Group6project/Sports/SACLinjury.htm
- Sports Institute: Physical Therapy http://www.sportsphysicaltherapy.com/research/articles/acl-faq's.aspx
- New Ligament Discovered in Knee http://www.bbc.com/news/health-24826323
- Rehabilitation after Injury to the Medial Collateral Ligament of the Knee http://www.massgeneral.org/ortho/services/sports/rehab/Medial%20collateral%20Ligament%20Injury%20(MCL)%20Rehabilitation.pdf
- Centers for Disease Control and Prevention http://www.cdc.gov/arthritis/pa_overview.htm
 Notes and References
- ↑ Larry J. P., Jeniffer B., Alison G. (2012) School of Health Professionals, Virtual Health Care Team - Anterior Cruciate Ligament http://shp.missouri.edu/vhct/case3505/index.htm .
- ↑ Kim, J., & Smith, J. (2009). Sports Medicine: Knee: Anterior Cruciate Ligament Injury (ACL).
- ↑ CBC Health Group - Physiotherapy Centers. A History of Physiotherapy. 2012. Canada.
- ↑ Shellock, F & Prentice, W. (1985). Warming-Up and Stretching for Improved Physical Performance and Prevention of Sports-Related Injuries. "Sports medicine volume 2, issue 4".
- ↑ Alentorn-Geli, E., Mendiguchía, J., Samuelsson, K., Musahl, V., Karlsson, J., Cugat, R., & Myer, G. (2014). Prevention of anterior cruciate ligament injuries in sports-Part I: Systematic review of risk factors in male athletes. Knee Surgery, Sports Traumatology, Arthroscopy, 22(1), 3-15.
- ↑ Dugan, S. (2005). Sports-related knee injuries in female athletes - what gives? American Journal of Physical Medicine & Rehabilitation, 84(2), 122-130.
- ↑ Phisitkul, P., James, S.L., Wolf, B.R., & Amendola, A. (2006). MCL Injuries of the Knee: Current Concept Review. "The Iowa Orthopaedic Journal, 26, 77-90".
- ↑ Flanigan, D., Everhart, J., Pedroza, A., Smith, T., & Kaeding, C. (n.d). Fear of Reinjury (Kinesiophobia) and Persistent Knee Symptoms Are Common Factors for Lack of Return to Sport After Anterior Cruciate Ligament Reconstruction. Arthroscopy-The Journal Of Arthroscopic And Related Surgery, 29(8), 1322-1329.
- ↑ Hewett, T. E., Di Stasi, S. L., & Myer, G. D. (2013). Current Concepts for Injury Prevention in Athletes After Anterior Cruciate Ligament Reconstruction. American Journal Of Sports Medicine, 41(1), 216-224.
- ↑ Noyes, F. R., Barber-Westin, S. D., Tutalo Smith, S. T., & Campbell, T. (2013). A TRAINING PROGRAM TO IMPROVE NEUROMUSCULAR AND PERFORMANCE INDICES IN FEMALE HIGH SCHOOL SOCCER PLAYERS. Journal Of Strength & Conditioning Research (Lippincott Williams & Wilkins), 27(2), 340-351.
- ↑ Sugimoto, D., Myer, G. D., McKeon, J. M., & Hewett, T. E. (2012). Evaluation of the effectiveness of neuromuscular training to reduce anterior cruciate ligament injury in female athletes: a critical review of relative risk reduction and numbers-needed-to-treat analyses. British Journal Of Sports Medicine, 46(14), 979-988
- ↑ Dave, L., Nyland, J., McKee, P. B., & Caborn, D. M. (2012). Mesenchymal Stem Cell Therapy in the Sports Knee: Where Are We in 2011?. Sports Health: A Multidisciplinary Approach, 4(3), 252-257.
- ↑ Lohmander, L. S., Englung, M., Dahl, L. L., & Roos, E. (2007). The Long-term Consequence of Anterior Cruciate Ligament and Meniscus Injuries Osteoarthritis. " The American Orthopaedic Society for Sports Medicine".
- ↑ Mundasad, S. (2013, November 7). New Ligament Discovered in Knee, Belgian Surgeons Say. BBC new.