Abstract
Introduction
The anterior cruciate ligament (ACL) provides stability to the knee joint, with its primary function to prevent anterior translation of the tibia on the fixed femur [1]. The ACL is the most commonly injured ligament of the knee, with a reported prevalence of 30 per 100,000 [2]. This ligament is most frequently injured during sporting activity [3] and accounted for 23% of all injuries sustained in American football over the years 2004–2009 [4]. In Ireland, ACL ruptures account for 13% of all knee injuries sustained in Gaelic football, with an overall prevalence among Gaelic football players of 1.3% [5]. This high prevalence rate in the Irish context is unsurprising given the high levels of sport participation (47.2%) and the rise in female participants [6], who are 2–5 times more at risk of ACL rupture versus their male couterparts [7]. The associated costs of ACL rupture are high [5] due to absence from sports participation, surgical treatment and lengthy rehabilitation required after ACL rupture. The average time between surgery and return to sports training is seven months, with return to sporting competition averaging nine months [8].
Surgical reconstruction is the most common treatment approach after ACL rupture [9] and is usually indicated in those wishing to return to sports participation [10]. Outcomes are generally positive with Ardern et al. [11] reporting high recovery rates for knee strength, laxity and function after anterior cruciate ligament reconstruction (ACLR). Additionally, clinical outcomes do not appear to differ significantly according to the type of ACL graft chosen [12]. However, even with these apparent positive outcomes after surgery, full return to sports participation is not always achieved. Figures for people who do not return to their pre-injury level of sporting ability vary from 22 to 47% [13, 14], with appoximately 17% not returning to sports participation at all after surgery [15]. Given the apparent disparity between knee functional ability and return to sport rates in this population, recent literature has shifted its focus towards identifying potential biopsychosocial factors influencing recovery after ACLR. The foremost of these being fear of movement (kinesophobia) [15].
The term kinesiophobia was first introduced in 1990 and describes a situation where “a patient has an excessive, irrational and debilitating fear of physical movement and activity resulting from a feeling of vulnerability to painful injury or reinjury”[16]. Kinesiophobia may be a barrier inhibiting people from reaching their full activity potential after surgery. Czuppon et al. [15] highlighted fear as the most commonly cited reason preventing people from returning to sport. Although studies have demonstrated that fear levels are highest prior to surgery [17] and decline gradually through the rehabilitation phase post surgery [18]; fear levels continue to be described as “high” in approximately 20–24% of patients at the end of rehabilitation [13, 19]. Cognitive behavioural models, such as the fear-avoidance model [20, 21], propose that painful experiences have the potential to elicit kinesiophobia in individuals. Injury may be catastrophically interpreted by patients and lead to safety seeking behaviours such as activity avoidance [22]. This potentially may lead to disuse, deconditioning and increased disability [22]. These potentially negative consequences could have a devastating impact on a patient’s recovery after ACLR. The negative consequences of kinesiophobia warrants further exploration as it has been shown to be associated with increased pain, disability, stress, and depression [23].
Currently in Ireland, ACLR rehabilitation comprises of progressive strengthening and flexibility exercises with no mention of fear management [2]. The implications of this may be that a component of ACLR rehabilitation may be currently overlooked in the Irish health context and therefore required investigation. Thus considering the prevalence and potentially significant negative consequences that kinesiophobia may have on recovery after ACLR, an investigation of its prevalence and impact is warrented in a population of people who have undergone an ACLR in the Irish Health Service Executive (HSE).
Consequently a cohort study, in a population of participants who underwent ACLR was completed. The aim of this study was identify if those who undergo ACLR report elevated levels of kinesiophobia after surgery. Establish if a population of people following ACLR report elevated levels of fear of movement using the Tampa Scale of Kinesiophobia (TSK). Establish the return to pre-injury sport participation and performance rate in this population group.
Methodology
Ethical considerations
Ethical approval for this research study was granted by the HSE Mid-Western Regional Hospital Research Ethics Committee. A waiver of consent were granted to review the hospital’s records.
Sample recruitment and eligibility
The university hospital’s records were reviewed to identify patients who would meet the eligibility criteria. Potentially eligible participants were invited to participate in the study. Table 1 outlines the eligibility criteria.
Eligibility criteria for this cohort study
Eligibility criteria for this cohort study
The Tampa Scale of Kinesiophobia (TSK)
The TSK was the primary outcome measure used in this study (Fig. 1). The TSK is a 17-item questionnaire used to assess and quantify kinesiophobia levels. This questionnaire takes the form of a Likert scale, with each question allowing a range of 4 possible answers. The possible total scores range from 17–68 with those scoring >37 identified as demonstrating high levels of kinesiophobia [24]. This outcome measure was deemed appropriate for this cohort study because: The psychometric properties of this questionnaire are sound [25]. Published reported on kinesiophobia levels in the ACLR population have used the TSK as a key outcome measure. Thereby its inclusion enables a comparison to be drawn with the current body of research in this area [26, 27]. The TSK is a short and easy to use questionnaire and it was envisaged that these properties may facilitate responses from invited participants [28]. Tampa Scale for Kinesiophobia.
A short demographic questionnaire was designed to obtain information about age, gender, surgery specific information (e.g. year of surgery), and sports participation pre- and post-surgical intervention. The questionnaire was drafted and revised by two members of the research team. The questionnaire was then piloted for readability before being submitted for ethical approval. Benefits of this questionnaire included the ability to compare sport participation levels before and after ACLR, along with enabling factors such as age, gender and post-op sports performance levels to be compared to TSK scores.
All potential participants were given 6 weeks to return the TSK and demographic questionnaires.
Data analysis
All data was analysed using Microsoft Excel (2013) and SPSS (Version 22.0). All ordinal or categorical data was analysed using frequency analysis, while content analysis was performed on all word data obtained from the demographic questionnaire. The Johnston and Carroll [29] model of psychological response to injury was used to inform the content analysis and give a better understanding of which answers suggest kinesiophobia. This model reports that hesitation, not giving full effort, being wary of potential injury provoking situations and fear of re-injury all represent kinesiophobia.
TSK, while being a Likert scale, was analysed as a continuous variable for the purpose of this study in keeping with other studies which use the TSK as an outcome measure [27] and reported to be statistically sound option [30]. The TSK was analysed parametrically as the sample size exceeded 30 [31]. Mann-Whitney U test was used to provide a comparison between TSK score post-op activity levels (Those who did/did not return to sport).
Results
A total population of 179 potential participants were identified and sent a hardcopy of the information leaflet, demographic questionnaire and the TSK. Participants that consented to participate completed the questionnaires and returned them in a stamped addressed envelope for returning the attached questionnaires. Of the 179 potential participants suitable for inclusion in this study, a total of 57 responses were returned (32%). Of these responses, 45 were eligible for analysis in this study. All 45 participants completed the demographic questionnaire, while 37 participants completed the TSK. Demographic data for the total population of participants (N = 45) analysed is included in Table 2.
Demographic data of the participants included in the study
Demographic data of the participants included in the study
Age values in mean, +/–represents standard deviation. Gender, Year of ACL Surgery and Post-op Physiotherapy Sessions attended values written in number of participant responses (% of sample). N = number of participants.
Of the 45 participants who completed the demographic questionnaire, seven (15.6%) indicated that they had not participated in sport prior to their ACL rupture and thus did not complete the additional components of the questionnaire referring to sports participation. This study found that prior to ACLR the majority (86.8%) engaged in sporting activity at minimum twice per week, with a small proportion (15.8%) engaging in sporting activity 6-7 times per week. Many (78.9%) reported that they competed at club level or above. Of those who participated in sport prior to surgery, many (73.7%) reported that they returned to some form of sport activity after their ACLR. However, the percentage of participants who reported returning to pre-injury level of sports performance and competition after ACLR was 42.1% and 47.4%, respectively. Findings can be seen in Table 3.
Responses to the demographic questionnaire
Responses to the demographic questionnaire
Values written in number of participant responses (% of total responses). N = number of participants.
Thirty seven participants completed the TSK questionnaire. Total scores for this measure were normally distributed (Shapiro-Wilk = 0.436). The mean total score for the participants was 41.24±7.19 (95% CI 43.64-38.85), with a large proportion (78.4%) of the cohort (N = 29) scoring 37 or above, which represents high levels of kinesiophobia in the respondents.
Return to pre-injury level of sports competition
Three themes were identified from responses to an open question asking participants why they did not return to their pre-injury level of sports competition. These themes were: Fear of Movement, Persistent Symptoms and Life Events. Of these, Fear of Movement was the most prevalent with 75% (N = 15) stated that this was a limiting factor. Fear secondary to the risk of re-injury was explicitly stated by 35% (N = 7), with examples including “fear of re-injury” and “not wanting to risk another injury”. A proportion 40% (N = 8) implied kinesiophobia without specifying “fear” in their answers, examples include “afraid of putting same weight on the leg” and “I did not feel my knee was up to the same level of physical activity”. The remaining 25% (N = 5) who did not return to pre-injury competition were categorised as either persistent symptoms or life events categories (N = 2, N = 3 respectively). Life circumstances included fear of the risk of not being unable to work with a repeat ACL rupture was reported by 10% (N = 2).
Return to pre-injury level of sports performance
Of the participants surveyed, 55.3% (N = 21) reported that they did not return to pre-injury level of sports performance after ACLR; with 1 participant not elaborating on what prevented them from doing so. The content of the answers from the remaining 20 participants were analysed. Kinesophobia was the most prevalent barrier reported (N = 14) “fear of my cruciate going again.” and “cautious of going again (playing sport).” Persistent symptoms of swelling, weakness and pain also commonly reported (N = 7) “to this day it still swells, aches and hurts.” Life events was also reported with a number identifying risk of missing work (N = 3) or “unable to break back into high standard team in order to regain full potential”.
Discussion
This study aimed to explore kinesophobia levels in an Irish population of people who underwent ACLR. A response rate of 32% was achieved which is in keeping with general response rates to questionnaire surveys [32]. This lower response rate of 32% could limit the study by introducing bias into the survey results. This study also achieved a good distribution between male and female respondents, which is similar to the distribution of another survey on this topic [15]. A high proportion of people who responded to this study were found to have high levels of kinesiophobia. The mean TSK score of 41 and proportion reporting high levels of kinesophobia are higher than previously reported [17, 33]. However, the studies may not be comparable as due to differences in study design and participants. Time since surgery may influence results as significant reductions in kinesphobia have been found between 12 weeks and 1 year after surgery [17, 33]. However, Ardern et al. [14] identified no significant differences between those less than and greater than 4 years post-op. The majority of the respondents in this study reported that they returned to some form of sports activity after surgery, which is similar to the results of Czuppon et al. [15] who reported that 83% returned to sport and less than 50% returned to pre-injury level of sports performance.
The findings of this study suggest that kinesphobia may be a significant factor limiting return to sport after ACLR. The open ended questions enabled participants to report specific limiting factors inhibiting their full return to sport. Kinesiophobia was reported as the primary barrier limiting return to previous competition and participation levels. This fear appeared to be due to both a lack of confidence in physical capacity and the potential risks associated with return to sport, such as re-injury and risk of missing work due the long rehabilitation process associated with ACL rupture.
Impact of fear of movement
The wider impact of kinesphobia, outside return to sport rates, is relatively unexplored in people following ACLR. Chmielewski et al. [18] reported an inverse relationship between subjective reports of knee function and fear, with higher kinesphobia associated with poorer knee function. This result was substantiated in a more recent study by Lentz et al. [34] which reported that those who did not return to sport due to fear displayed higher TSK scores and reduced self-reported levels of knee function. Currently, the cause and effect link between these variables is unclear. Fear avoidance models conceptualize the role of avoidance behaviour and propose a link between expectancies, beliefs and perception of pain with the likelihood of activity avoidance, disuse and the development of chronic pain [35]. Activity avoidance, secondary to kinesphobia, often prevents patients from realising that activity may not actually lead to pain and potential re-injury. Thus patients are never afforded the opportunity to change any maladaptive beliefs [35]. The clinical implication of this has been outlined in other musculoskeletal conditions, as Kinesiophobia has been associated with increased pain and disability in patients with patellofemoral pain syndrome (PFPS). Similarly kinesphobia has been demonstrated to be the strongest predictor of functional outcome in PFPS, surpassing even biomechanical and structural variables [36].
Clinical significance
ACLR rehabilitation protocols in place in Ireland do not currently address the role fear plays in achieving a full recovery [2]. The divide between patient needs and current practice could potentially impact negatively on recovery and return to sport. Ardern et al. [26] concluded that positive psychological responses expressed pre- and early post-operatively were associated with a return to pre-injury level of sport and thus recommend clinical screening early after ACLR to identify patients at risk of not returning to sport [26]. Kinesphobia is a potentially modifiable variable, which has been identified as impacting negatively on outcomes after ACLR. Therefore, treatments targeting negative psychological beliefs should be included in the rehabilitation process. Benz and Flynn [37] suggest improving therapist-patient communication, patient expectations and clinical atmosphere, in order to stimulate the added benefits associated with the placebo effect [37]. Biopsychosocial interventions such as education, graded exposure and cognitive behavioural therapy have all demonstrated improved clinical outcomes for fear beliefs and avoidance behaviours in people with low back pain [38–41]. In people with patellofemoral knee pain, a link has been identified between reduced kinesiophobia and improved clinical outcomes. Thus the use of interventions aimed at reducing maladaptive beliefs is advocated to improve outcomes [42].
While the benefits of biopsychosocial intervention and clinical screening following an ACLR are as yet unclear and under-explored. The addition of these interventions to the structured ACLR rehabilitation protocol could potentially be accompanied by clinically significant improvements in terms of outcomes such as return to sport and reduction in fear avoidance behaviours.
The may have a positive impact on both kinesiophobia [15] and adherence to rehabilitation after ACLR [43].
Although the response rate of this study was in keeping with other questionnaire based surveys, the sample size remained small which may have impacted negatively on the results. Thus high level of kinesophobia may be due the smaller population size in this study [44]. The inclusion of an information leaflet and a stamped addressed envelope has been shown to increase response rate [28, 45]. Studies have shown that, although e-mail results in quicker responses, postal questionnaires often report greater response rates [46]. Hence the relevant information was posted to individuals to maximise the response rate. Sample bias is an unavoidable limitation to questionnaire based studies with participants who respond, potentially, not being entirely representative of the target population. Desirable responding [47] and differences in satisfaction following ACLR may have influenced responses in this study [48].
Although the demographic questionnaire used in this study was basic and created simply to ascertain demographic variables, return to sports rates and barriers limiting return to sport; it remains yet an unvalidated questionnaire. The questions may have been ambiguous or vague and could have been interpreted differently by participants, thereby potentially creating bias in results [49]. However the questionnaire underwent a number of iterations and was piloted prior to being sent to participants to minimise this risk.
Research is needed to evaluate potential improvements in clinical outcomes with the addition of kinesophobia screening and/or biopsychosocial interventions within the rehabilitation process. Greater outcomes, such as increased return to sport rates and improved self-reported knee function after ACLR could greater substantiate the theory that addressing psychological variables such as fear may influence recovery post-op.
Conflict of interest
None to report.