The Stress and Injury Model and Cognitive Appraisal Model: Implications for Patients After Anterior Cruciate Ligament Reconstruction

Abstract

Injury-related fear has been cited as the primary barrier for return to sport after anterior cruciate ligament reconstruction (ACLR). Furthermore, injury-related fear has been predictive of secondary ACL injury within 24 months of return to sport. The Stress and Injury Model and the Cognitive Appraisal Model can be used to explain the negative consequences of injury-related fear after ACLR. This review discusses the application of both models to the post-ACLR population. Theory-based clinical practice and research recommendations will be provided to potentially improve sports participation and decrease injury risk after ACLR. [Athletic Training & Sports Health Care. 2020;12(4):181–187.]

Health-related quality of life (HRQL) includes physical, emotional, and social well-being.1 Although the literature has reported increased physical HRQL in athletes compared to their peers, sports participation has recently been associated with poor emotional and social HRQL.2,3 Increased life pressures, such as separation from family or worries of public perception in the media, have contributed to these detriments.2 Unfortunately, increased life stressors can negatively affect athletes' ability to successfully and safely perform their respective sport, and may lead to musculoskeletal injury.4 Athletic injuries can affect all aspects of HRQL, including emotional and social well-being.3 However, the emphasis of musculoskeletal rehabilitation is to improve the physical impairments, often neglecting the influence of the injury on other dimensions of HRQL. Addressing all aspects of HRQL during musculoskeletal rehabilitation is necessary for athletic trainers to successfully implement patient-centered care. Patient-centered care is care that is responsive to the patient's preferences, needs, and values, in contrast to just identifying and addressing physical impairments.5

Patients who have undergone anterior cruciate ligament reconstruction (ACLR) often exhibit deficits in emotional and social HRQL.6 These deficits have been cited as the primary reason for reduction or cessation of sports participation in this population.7 Therefore, treatment algorithms that include the assessment and treatment of emotional and social detriments are warranted. After ACLR, 1 of 3 patients fail to return to competitive levels of sports, and psychological readiness has been cited as the primary barrier.8 It has been demonstrated that patients who exhibit increased levels of injury-related fear after ACLR are 13 times more likely to sustain a secondary injury to the ACL limb within 24 months of reconstruction.9 Thus, rehabilitation that addresses not only the physical impairments often identified after ACLR, but also HRQL detriments could help to mitigate these negative responses. This in turn should enhance the provision of patient-centered care delivered and improve overall health outcomes.

Psychosocial factors also affect neurocognitive functioning in healthy athletes. Specifically, psychosocial factors have been associated with delayed reaction times.4 Consequently, deficits in reaction time can increase susceptibility to injury in the highly active population.10,11 Previous literature has shown that individuals who sustain non-contact ACL injuries have deficits in reaction time prior to sustaining their ACL injury when compared to healthy controls.12 Thus, it is imperative to address other factors that influence reaction time deficits in patients after ACL injury, including psychosocial factors. Addressing psychosocial factors could decrease risk for subsequent reinjury in a population already vulnerable to 30% reinjury rates.13

In addition to neurocognitive deficits, Grooms et al14 demonstrated that patients exhibit changes in brain activation after ACLR when compared to healthy matched controls. Interestingly, not only were changes in the sensorimotor system observed, but patients after ACLR also activated an area of the brain associated with pain processing.14 However, none of the patients self-reported pain while undergoing the functional magnetic resonance imaging scan.14 This suggests that the observed changes in brain activation may not only be influenced by physical impairments, but may also be a result of other factors, such as psychosocial factors. Therefore, an understanding of theory-based models that explain the negative ramifications of psychosocial factors after injury may assist clinicians with addressing not only subjective outcomes after ACLR, but also objective neurological impairments that may be related to these psychosocial factors.

The Stress and Injury Model was designed to explain the effects of pre-injury psychological factors on athletic injury.15 A second model, the Integrated Model of Psychological Response to Sports Injury, commonly known as the Cognitive Appraisal Model, was developed to explain post-injury psychological responses to athletic injury.16 Knowledge and application of these two models will allow clinicians to implement appropriate theory-based psychological intervention strategies to (1) decrease injury risk in healthy athletes and (2) enhance rehabilitation strategies and improve outcomes after injury. Specifically, we believe these two models are directly applicable to the sequelae of impairments, HRQL detriments, neurological changes, and reinjury risks commonly documented after patients undergo ACLR. Therefore, the purpose of this study was to discuss the Stress and Injury Model and the Cognitive Appraisal Model. We also evaluated the current literature that examines psychosocial factors in individuals with a history of ACLR and how these factors can influence recovery outcomes and risk for reinjury. This study is not an extensive review of the literature, but provides compelling information to support the use of the Stress and Injury Model and the Cognitive Appraisal Model in athletic training clinical practice. In addition to theoretical discussion, recommendations for clinical practice are provided.

Literature

Stress and Injury Model

The Stress and Injury Model15 is a theoretical framework that describes the relationship between stress response and injury rates in high functioning, physically active individuals. The Stress and Injury Model is used as a theoretical framework to predict and prevent stress-related athletic injuries (Figure 1). The model describes the process of an athlete encountering a stressful athletic situation and the factors that potentially contribute to the athlete sustaining an athletic injury as a result of the stress response. This model suggests that four different factors can influence the stress response of the athlete: the athlete's personality, history of stressors, coping resources, and interventions. First, the personality of the athlete, such as locus of control and trait anxiety, can influence cognitive appraisal and changes in physiological/attentional demands associated with a stressful athletic situation. Athletes who feel more in control of the situation may respond differently than athletes who feel lack of control. Second, history of stressors can affect an athlete's ability to maintain attention and appropriately appraise stressful situations. Previous musculoskeletal injury is a stressor that could potentially negatively affect the stress response. Third, coping resources, such as mental skills training, can alter how an athlete perceives and responds to a stressful athletic situation. If an athlete has the mental skills to mitigate increased levels of performance anxiety, then that athlete may have a decreased stress response during a stressful athletic situation compared to an athlete without those coping resources. Finally, Williams and Andersen15 proposed that interventions, such as cognitive restructuring and relaxation skills, can positively influence the stress response.

Stress and Injury Model and Reinjury After ACLR

The Stress and Injury Model can be used to explain reinjury outcomes in patients after ACLR. Paterno et al9 examined the relationship between injury-related fear, objective measures of function, and rates of secondary injury after ACLR and return to sport. All participants completed rehabilitation for a primary ACLR. In addition, functional outcomes and the Tampa Scale of Kinesiophobia (TSK-11), a patient-reported outcome measure that examines fear of movement and/or reinjury,17 were captured when participants were cleared to return to sport. Participants were then tracked for 24 months after clearance for return to sport to identify secondary ACL injury. Results demonstrated that individuals with higher scores on the TSK-11, or increased levels of injury-related fear, were four times more likely to report lower activity levels, seven times more likely to have hop test scores less than 95%, and six times more likely to have quadriceps strength symmetry of less than 90%.9 Most interesting, however, was that participants with elevated levels of injury-related fear were 13 times more likely to suffer a secondary ACL injury. Thus, individuals with self-reported injury-related fear were less active, had lower functional performance, and were at an increased risk of sustaining a secondary ACL injury.9

Similar results have been reported by other research teams.18–20 All 329 patients completed the Anterior Cruciate Ligament Return to Sport after Injury scale (ACL-RSI),19 a patient-reported outcome measure that assesses psychological readiness preoperatively and 12 months postoperatively. No differences in preoperative ACL-RSI scores were observed; however, those patients who sustained a secondary ACL injury exhibited lower psychological readiness at the 12-month time point when compared to those who did not sustain a secondary injury.18 These results suggest that failure to address the psychological factors that may arise during the rehabilitation process prior to return to sport may increase the risk of reinjury in patients after ACLR. McPherson et al20 also used the ACL-RSI to identify changes in psychological readiness that were associated with ACL injury. In this cohort of 115 patients who returned to sport, 21 sustained a secondary ACL injury. Results demonstrated that those individuals who were more nervous about playing sport, less confident in their knee, more frustrated with having to consider their knee during their sport, and exhibited increased injury-related fear on patient-reported outcome measures, were more likely to sustain a secondary ACL injury.20 Thus, the stress response during sports participation may be negatively influenced by each of these psychological factors during sports participation.

If an individual after ACLR exhibits lower psychological readiness and decreased coping resources, then a negative stress response may occur. Unfortunately, none of the aforementioned studies9,18,20 assessed the coping ability of the patients enrolled. This is an aspect of the Stress and Injury Model15 that we believe could positively affect the rehabilitation of these patients. Assessment of patients' ability to cope with their knee injury could provide further insight into why some patients developed negative psychological responses during their rehabilitation and why some patients were able to successfully return to sport. As suggested by the model, history of stressors can negatively affect the stress response and lead to injury.15 Individuals with a history of ACLR who return to sport with negative psychological responses and are unable to overcome their stress response could possibly experience a shift in physiological/attentional demands, and ultimately sustain a reinjury. The current literature on return to sport after ACLR highlights the importance of addressing all HRQL domains, including emotional, to improve return to sport rates and mitigate reinjury risks in patients after ACLR. Interventions to modify negative psychological factors that influence HRQL can help to prevent this shift in physiological/attentional demands during sports participation.

Cognitive Appraisal Model

The Integrated Model of Psychological Response to Sports Injury, also known as the Cognitive Appraisal Model, was developed by Wiese-bjornstal et al16 to provide an avenue for clinicians to understand how cognitive changes can affect rehabilitation and recovery outcomes after sustaining an athletic injury (Figure 2). Cognitive appraisal is the process by which athletes judge their injury and how this judgment or appraisal affects their emotional response and recovery outcomes. Negative cognitive appraisal of an injury and rehabilitation can affect short-term and long-term health outcomes. This model suggests that four different factors can influence the cognitive appraisal of an athlete who has sustained an injury: personal factors, situational factors, emotional responses, and behavioral responses.16

Personal factors are psychological, demographic, and physical factors that can influence the cognitive appraisal of an injured athlete. If an athlete has poor coping skills, then this could negatively influence their cognitive appraisal of their injury and rehabilitation. Situational factors, such as the environment, can influence the cognitive appraisal processes. For instance, if athletes do not feel social support from their athletic trainer or feel that the environment itself is not conducive for their success, then a negative appraisal of their injury and subsequent poor outcome may occur.21 Emotional responses, including injury-related fear, can influence an athlete's cognitive appraisal. Development of injury-related fear may not only affect ability to return to sport after injury, but can negatively affect long-term engagement in physical activity in previously high functioning, physically active individuals.6 Finally, behavioral responses, such as adherence to rehabilitation and use of psychological strategies, can alter the cognitive appraisal of an injured athlete and long-term recovery outcomes. If athletes do not report to rehabilitation or begin to engage in avoidance behaviors, then their health outcomes may be negatively altered.16

Cognitive Appraisal Model and Return to Sport After ACLR

Although athletes may initially choose to undergo ACLR to return to sport,22 the ultimate return to sport decision may be influenced by a multitude of factors, including personal and situation factors.6,21,23 The Cognitive Appraisal Model may help to explain the poor physical and psychosocial recovery outcomes observed in patients after ACLR. As discussed, the primary barrier for return to sport after ACLR is injury-related fear.8 When applying the Cognitive Appraisal Model, injury-related fear is an emotional response after musculoskeletal injury that can affect recovery outcomes. Thus, those individuals with increased levels of injury-related fear after ACLR may experience a shift in their cognitive appraisal associated with their ability to participate in sports. This change in cognitive appraisal may negatively influence behavioral responses, such as adherence to rehabilitation, effort, or intensity. In cohesion, these factors could contribute to an athlete failing to return to sport.

Previous literature supports this hypothesis. More specifically, in a qualitative analysis of factors that affect HRQL and physical activity engagement in individuals 5 to 20 years after ACLR, injury-related fear emerged as a prominent theme.6 Throughout the entire post-ACLR experience, all participants described experiencing injury-related fear, which started from the time of their index ACL injury until their participation in the study. Participants engaged in one of three behavioral responses: fear suppression, fear accommodation, or fear avoidance. Those individuals interviewed who reported suppression of injury-related fear also demonstrated the ability to cope with their fears, and subsequently were able to maintain their previous level of sports participation. These individuals stated that they used their injury-related fear as motivation to return to sport. Participants who reported fear accommodation did not return to previous levels of sport, but were satisfied with their activity level and quality of life. Finally, participants who engaged in fear avoidance behaviors reported cessation of all physical activity and deficits in their quality of life.6

The results of Filbay et al6 represent how athletes' cognitive appraisal of their ACLR and the factors associated with their injury can influence behavioral responses. Emotional responses, specifically injury-related fear in this population, severely affected the athletes' ability to engage in physical activity and their HRQL. It is also important to appreciate that emotional responses work in unison with other factors, such as personal and situational factors, to influence the cognitive appraisal process of athletes after ACLR. Those individuals who used their injury-related fear as motivation were able to overcome their emotional responses to have a successful recovery. Those who did not, or did not possess the necessary coping skills to overcome their injury-related fear, engaged in avoidance behaviors that led to poorer recovery outcomes.6

In addition, Sadeqi et al24 quantitatively supported the association between an individual's cognitive appraisal and successful return to sport. In a prospective study with 2-year outcomes, it was demonstrated that those patients after ACLR who successfully returned to sport exhibited significantly higher psychological readiness, as measured by the ACL-RSI, when compared to those patients who did not return to sport.24 Echoing results demonstrated by Filbay et al6 and Sadeqi et al,24 Burland et al21 completed a qualitative analysis to determine which psychosocial factors influenced return to sport decisions after ACLR. Psychosocial factors, such as hesitancy, lack of confidence, and injury-related fear, influenced the decision to return or not to return to sport after ACLR. However, intrinsic characteristics, including a strong sense of athletic identity, in combination with competitive rehabilitation environments facilitated return to sport after ACLR. Additionally, the researchers discovered that having a strong support system within and outside of rehabilitation led to increased confidence for patients after ACLR.21

Findings

Although the literature presented in this review is not exhaustive, numerous studies have demonstrated the effects of negative psychological responses on rehabilitation outcomes after ACLR.25–31 Application of the Cognitive Appraisal Model can be used to explain the observed results of these studies. For instance, personal factors, specifically the strong sense of athletic identity, positively affected the cognitive appraisal of athletes and led to return to sport.21 Although this personal factor may be difficult to modify throughout rehabilitation, other modifiable situational factors observed including competitive rehabilitation environments and increased social support positively influenced cognitive appraisals and facilitated return to sport.21 Thus, rehabilitation environments and methods for providing social support to patients after ACLR that could help to improve health outcomes should be modified. Emotional factors may also be modified, which may improve outcomes in individuals after ACLR. As reported, patients with increased levels of negative emotional responses led to failure to return to sport, whereas increased levels of positive emotional responses led to return to sport.21 Ultimately, each of these factors worked in combination to influence the athlete's cognitive appraisal of return to sport.

Limitations of the Models

These models are not without limitations. The Stress and Injury Model was designed to describe psychosocial factors that lead to initial injury rather than psychosocial factors after the injury has been sustained. However, we believe the model can be adapted to explain reinjuries after ACLR. Currently, most of the ACLR literature examines emotional responses throughout the rehabilitation process prior to return to sport participation. The Stress and Injury Model can be modified to characterize these observed recovery outcomes after ACLR and can provide theoretical support for the implementation of psychoeducation in this population. As demonstrated in the Stress and Injury Model, implementation of appropriate psychosocial interventions can alter the stress response and help to mitigate risk of sustaining an athletic injury during stressful athletic situations.16 It is important that athletes possess the interventions and appropriate coping resources needed to overcome the stress response during an athletic situation and potentially decrease the risk of reinjury. This could prevent a history of previous injury impeding the athlete's ability to perform. Future research should examine the modification of the Stress and Injury Model to further characterize the observed outcomes after ACLR.

A limitation of the Cognitive Appraisal Model is that the model was designed to understand the recovery process and not to predict injury. Therefore, the Cognitive Appraisal Model should not be used to explain the relationship between psychosocial factors and sustaining an athletic injury. Rather, this model characterizes the relationship between psychosocial factors and rehabilitation outcomes after ACLR, which can help to explain outcomes observed in the ACLR literature. However, we believe the combination of the Stress and Injury Model and the Cognitive Appraisal Model provides a better picture of the overall effect of psychosocial impairments in the ACLR population.

Implications for Clinical Practice

After a patient undergoes ACLR, athletic trainers should consider factors other than physical impairments that can negatively affect recovery and HRQL. Psychosocial factors, including injury-related fear, should be addressed throughout the rehabilitation process. Poor recovery outcomes after ACLR linked to psychosocial impairments demonstrates the need for interprofessional collaboration to reduce psychosocial impairments throughout musculoskeletal rehabilitation. Athletic trainers and sports psychology professionals should work together to develop a rehabilitation plan that would allow for a holistic approach to rehabilitation after ACLR. Instead of focusing on physical health or psychological health in isolation, interprofessional collaboration would allow for a cohesive rehabilitation plan that provides effective patient-centered care. Moreover, implementation of psychological interventions throughout rehabilitation can provide the athlete with interventions to use independently to decrease the stress response during competition after return to sport has occurred. If a sports psychology professional is not available, it is important that athletic trainers use their competencies in psychosocial strategies to address psychological responses to injury. Goal setting, relaxation techniques, and positive self-talk are just a few psychoeducation techniques within the scope of athletic training clinical practice that can enhance health outcomes in patients after ACLR.

Additionally, it is important to objectively evaluate psychosocial impairments throughout the ACLR rehabilitation and recovery process. Throughout the rehabilitation process after ACLR, previous literature has demonstrated fluctuations of injury-related fear.32 Thus, use of patient-reported outcome measures can provide clinicians with objective measures to evaluate psychosocial impairments. Patient-reported outcome measures can be used to determine treatment effectiveness of psychosocial interventions. An array of valid and reliable patient-reported outcome measures can be used in this population to address psychosocial impairments, including the ACL-RSI,19 TSK-11,33 Knee Self-Efficacy Scale,34 Athlete Fear Avoidance Questionnaire,35 and Fear-Avoidance Beliefs Questionnaire.36

Conclusions

The Stress and Injury Model and the Cognitive Appraisal Model can be used to understand the effects of psychosocial factors on injury recovery and reinjury after ACLR. Clinicians should use these models to provide patient-centered, holistic health care by developing intervention strategies to address the psychosocial factors that may impede recovery or lead to secondary injury. Interprofessional collaboration between athletic trainers and sports psychology professionals should be considered to optimize recovery after ACLR and improve all dimensions of HRQL in this population.

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