Between 100,000 and 200,000 anterior cruciate ligament (ACL) tears occur among athletes each year.1 The ACL attaches the anteromedial tibial plateau to the posteromedial lateral femoral condyle of the knee. The ligament is comprised of 2 bundled strands and is supplied by the middle genicular and inferior genicular arteries. The main function of the ACL is to prevent the tibia from moving anteriorly and the femur from moving posteriorly. The ligament also aids in preventing hyperextension of the knee, proprioception, and tibial rotation.2

Girls and women are at greater risk for ACL injury than are boys and men, especially when playing contact and fixed-object high-impact sports.3 High-contact sports have the highest rates of ACL tears followed by  sports that involve high impact rotational landing on a fixed leg such as in gymnastics and obstacle course racing.1,3 Noncontact injuries are usually associated with some combination of an almost fully extended and internally rotated hip, almost fully extended knee with internal tibial rotation, planted foot, as well as quick deceleration and cutting movements.1,4

In addition to the physical limitations resulting from an ACL injury, several severe psychological effects may occur that must be recognized by the health care team to yield higher success rates and return to sport for athletes. 

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Physical Findings of Anterior Cruciate Ligament Tear

Multiple physical findings have been associated with ACL tears. Continuous swelling, popping sound, or popping sensation during injury and feeling like the knee is giving out are all common findings.4 The Lachman test, anterior drawer test, pivot shift test, and lever sign test can all be performed to evaluate whether the ACL is intact or torn.5 If torn, laxity of the knee joint will be felt or seen, indicating a positive test.

Further imaging is used to assist in formal diagnosis of the torn ligament. Plain radiographs are often used in ACL injuries to rule out potential fractures or dislocations of the knee. A Segond fracture is an avulsion from the tibial plateau and is highly indicative of an ACL tear when present.4 A depression greater than 1.0 mm in the lateral femoral condyle, known as a lateral femoral notch sign (LFNS), is also indicative of an ACL tear.6

However, the ACL is not seen on plain radiographs and imaging is typically normal, indicating the need for further workup. Magnetic resonance imaging (MRI) is the preoperative gold standard for ACL tears and is highly sensitive and specific. The accuracy of diagnosing smaller tears is further improved by incorporating oblique coronal and sagittal views.4 With MRI, an ACL tear is seen as torn ligament fibers, soft tissue mass, or high signal seen in the intercondylar notch.2

Psychological Effects of ACL Recovery

The psychological impact of ACL injury is one of the main factors contributing to an athlete’s return to sport. Athletes often struggle with a fear of reinjury, mood changes, and neurologic changes and may show more guarded and calculated movement.7-9 Ohji et al discovered that an athlete’s mentality affects their return to sport following an ACL injury with those having a higher athletic identity and sports commitment showing a higher rate of return to sport.10 It is also important to note injured athletes experience a sudden reduction in the uplifting endogenous opiates they previously generated during exercise.11


Fear of reinjury, or kinesiophobia, is a large determinant in returning to preinjury athletic level.7 Kinesiophobia may decline over the first several years post-ACL reconstruction, and as it declines the athlete is more likely to participate in activities with a higher risk for knee injury.12 However, patients’ level of fear after ACL injury can lead to differences in recovery.

Paterno et al observed a relationship between athletes’ level of fear measured on the Tampa Scale of Kinesiophobia-11 and strength at 6 months and 1-year recovery.13 Athletes with higher fear levels at 6-months and 1-year postsurgery were less likely to have returned to sport at 1-year postreconstruction. Athletes who had not returned to sport at 1 year due to higher fear and less confidence also reported weaker quadriceps strength on the affected leg. Furthermore, a potential association between fear of reinjury and a second ACL injury within 24 months of their first injury was found. However, many other factors play a role in the risk for a second ACL injury such as younger age, higher activity level, and allograft reconstruction.13 Lowe et al recommended that functional bracing be implemented post-ACL reconstruction for 6 to 12 months during return to sport to reduce fear of reinjury and increase the athlete’s confidence.14

Several studies have examined the neurological changes of the brain that occur after ACL injuries. In one study, researchers followed a football player during ACL reconstruction recovery and found increased premotor, lingual gyrus, and secondary somatosensory activation during movements of the injured knee.9 These findings may correspond to a more focused and attentive plan when completing movements on a knee post-ACL reconstruction.9 Anterior crucial ligament injuries also negatively affect joint proprioception. Joint position sensation is more affected than detection of joint movement but the functional value of these proprioceptive findings is not evident.15

Mood Changes

Anterior cruciate ligament injury can also have an impact on overall mood and mental health. Some athletes have struggled with posttraumatic stress disorder (PTSD) following injuries.7 In one study, 42% of patients with ACL reconstruction were found to meet the criteria for major depressive disorder.8 Isolation from others and lack of self-worth may also lead to lower life satisfaction scores, anger, depression, and mood disturbances.8 A study observing depression in collegiate athletes after musculoskeletal and concussive injuries found a peak in symptoms early in the injury and a slow decrease in symptoms until return to sport is accomplished. It was theorized that a decrease in endogenous opiates may contribute to sudden depressive symptoms.

Endogenous opiates typically produce happiness, comfort, and safety, and are released during exercise. As an athlete’s training reduces after injury, endogenous opiates can decrease simultaneously. Another theory is that athletes’ identity is linked to their sport and, without being able to participate, they feel a lack of self-worth. Finally, the athlete may feel the need to ignore their mental suffering for the sake of preserving an image of mental strength.11 Counseling, imagery therapy, relaxation, self-motivation techniques, and simply asking the athlete how they are feeling throughout the recovery are helpful to the athlete’s mental health.7


Optimism also plays a role in recovery from ACL injury. When athletes have a higher self-efficacy by believing in their ability to recover and take an optimistic approach towards problems, they are more likely to adhere to treatment and follow through with recovery. Eighty-one athletes undergoing ACL recovery were examined using multiple appraisals, scales, and questionnaires. Data was collected on rehabilitation beliefs, appraisals, rehabilitation adherence, coping strategies, optimism, and perceived knee function. Study results showed greater optimism among athletes yielded higher coping strategies, efficacy beliefs, and adherence to rehabilitation programs. Measuring how optimistic an athlete is before rehabilitation may provide information to guide a more structured and individualized recovery program for each athlete based on their psychosocial needs.16

Clinical Approach to ACL Injury Psychological Recovery

There is an overwhelming need for the entire ACL recovery health care team to learn how to support an athlete’s psychological recovery. To create an individualized recovery process focusing on providing this psychological support, the feelings and mental impairments of athletes must be recognized and understood. Focus groups with physical therapists show that they spend a lot of time with athletes during recovery and use multiple approaches to support patients on a mental level.

Some physical therapists admitted to feeling as though they lack knowledge on the psychological impact of ACL injury and have learned to support their athletes through trial and error and by asking colleagues for advice. The therapist reported that psychological effects of ACL injury are often more significant to patients than physical effects as patients experience isolation from their sports and teammates, fear of pain, and loss of motivation.

Additionally, psychological impairments are often more difficult for physical therapists to treat than physical injury. Physical therapists found it helpful to educate their patients on what to realistically expect during recovery including the importance of adhering to the complete recovery program and adversities that may arise during recovery. Finally, goal setting, both big and small, was noted to provide patients motivation and a sense of accomplishment throughout the lengthy recovery process.17

Patient-Centered Health Care Team  

A patient-centered health care team should assess each patient’s psychological state after injury and adapt the recovery plan to better suit the individual. Different focuses may include motivation, optimism, self-efficacy, or self-esteem.18 Taking time to actively become involved in all areas of health with patients and create an environment where they feel important and heard is significant because athletes have a long recovery period ahead.

Another important tool is connecting athletes who are going through the same experience with support groups or joint physical therapy sessions. Encouragement and understanding from another athlete can decrease loneliness and isolation during recovery when typical interactions with teammates are decreased.

Prognosis and Conclusion

Many factors affect return to sport in athletes following ACL injuries. Evidence suggests that knee effusion, pain, kinesiophobia, quadriceps strength, motivation, self-efficacy, and athlete confidence all may contribute to return to sport. Fear of reinjury is a common reason athletes do not reach the same level of competition that they were at preinjury.19 In one study, researchers concluded that an athlete with a previous ACL tear is 15 times more likely to experience a contralateral ACL tear or ipsilateral tear (graft rupture) than those without previous ACL injury.20 Conflicting evidence was found on whether those who returned to sport had an athletic performance that was better, worse, or unchanged compared with their preinjury performance.21

Long-term consequences of an ACL tear may emerge later in life. Osteoarthritis symptoms of the patellofemoral joint include anterior knee swelling, pain, and limited activity. Osteoarthritis is diagnosed on plain radiographs via the presence of osteophytes and loss of articular cartilage.22 Findings from a randomized control trial showed the risk for osteoarthritis 14 years after an ACL repair was 3 times higher in the reconstructed knee versus the contralateral knee. This trial found no difference in osteoarthritis after patellar reconstruction vs hamstring reconstruction, but a big risk factor for osteoarthritis after reconstruction was a meniscus resection during the surgery. Duration of time between injury and repair was not found to be a significant risk factor.23

Educating patients on these long-term consequences as well as addressing the potential psychological adversities they may experience can better prepare them for a more complete recovery.

Makenzie Grilliot, PA-S, is a PA student at Augusta University in Georgia; Eudiah Ochieng, MPH, MPA, PA-C, is a certified physician assistant currently working in Pain Medicine in Roswell, Georgia.


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