Association Between Self-Reported Kinesiophobia and Single-Leg Hop for Distance in Patients With ACL Reconstruction: A Systematic Review

Abstract

Context:

Psychological readiness is a significant factor in determining successful return to sport (RTS) and physical activities after anterior cruciate ligament (ACL) reconstruction. Knowing the influence of kinesiophobia on physical tests that are used to guide RTS, such as the single-leg hop for distance (SLHD), would contribute to advancing clinical practice.

Objective:

To investigate the association between kinesiophobia and SLHD performance in patients after ACL reconstruction.

Data Sources:

A comprehensive search strategy entailed surveying 6 databases for relevant articles published from January 2009 to March 2021.

Study Selection:

Articles published in English that were a minimum of level 3 evidence describing kinesiophobia, as measured by the Tampa Scale for Kinesiophobia, and related to SLHD performance in patients after ACL reconstruction.

Study Design:

Systematic review.

Level of Evidence:

Level 3.

Data Extraction:

Study characteristics, sample population demographics, instrument(s), or approach(s) used to assess kinesiophobia and SLHD performance, and corresponding results.

Results:

A total of 152 potential studies were identified, 106 studies underwent screening, 40 were reviewed in full, and 7 studies were included. Meta-analysis could not be performed because of differences in experimental design among studies and instances of missing outcome data. Currently, moderate evidence indicates patients with ACL reconstruction that exhibit less kinesiophobia perform better on the SLHD test.

Conclusion:

The outcomes of this review propose that sports health practitioners consider the influence of kinesiophobia on SLHD performance as a criterion for RTS and physical activities in patients after ACL reconstruction. Higher quality studies are necessary to establish the extent of association between these variables.

Anterior cruciate ligament (ACL) injuries result in functional capacity deficits that can significantly limit daily living and sports activities. ³ Approximately 45% to 60% of patients with ACL reconstruction are not able to return at their previous level of activity, despite being cleared to do so as gauged by performance on physical tests.^2,4,5 Consequently, psychological readiness has been increasingly recognized as a significant factor influencing return to sport (RTS) ²³ and may account for the limitations of physical measurements to categorically predict it.^{4,10,12,17,28,47,54} Various tools exist to evaluate kinesiophobia and return to physical activities after musculoskeletal injury.^23,50,59,61 However, it is rarely measured in current standard clinical practice. ¹⁹ Instead, conventional physical performance tests, predominantly the single-leg hop for distance (SLHD), are more often implemented as criteria to guide RTS. ⁴⁹ This may reflect common barriers to evidence-based practice ⁵² and signals a call to expand knowledge and advocacy on the influence of kinesiophobia on outcomes in patients who suffer ACL injury and undergo treatment. ⁶³ Therefore, the purpose of this systematic review is to examine the association between kinesiophobia and SLHD performance to determine if a routine test used to gauge physical performance capacity may dually serve as an indicator for fear of movement. The information from this review may be used to help overcome barriers to implementing evidence-based practice and promote the progression of relevant clinician-friendly assessments. ⁴⁹

Methods

Study Team

Our interprofessional team encompassed academicians and clinicians with expertise in research methodology, orthopaedic sports medicine, and rehabilitation science.

Search Strategy and Data Sources

The systematic search complied with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and the study protocol was registered in PROSPERO (no. CRD42020181550). The MEDLINE/PubMed (Medical Subject Headings terms), Cochrane Library, CINAHL, SPORTDiscus, PEDro, and AMED databases were used to survey literature published between January 2009 and March 2021. A subsequent manual search entailed the reference lists of identified studies and Google Scholar to capture all relevant articles. Keywords are provided in Table 1.

Table 1.

Search strategy (from January 2009 to March 2021)

ACL reconstruction AND Kinesiophobia: 144 articles

Anterior cruciate ligament reconstruction AND Kinesiophobia:162 articles

ACL reconstruction AND Tampa Scale of Kinesiophobia: 88 articles

Anterior cruciate ligament reconstruction AND Tampa Scale of Kinesiophobia: 105 articles

Inclusion and Exclusion Criteria

Articles were eligible for inclusion if they represented randomized controlled trials, cohort, or cross-sectional studies. Physically active patients enrolled in the research studies must have suffered an ACL injury and undergone joint reconstruction. Experiments must have used the Tampa Scale of Kinesiophobia (TSK) to measure fear of movement. The TSK represents one of the first related instruments determined to be valid and reliable with applications to RTS after ACL reconstruction.^40,64 Furthermore, reports must have included performance on the reliable^34,51,53 SLHD, which is currently recognized as the strongest somatic predictor for RTS in this patient population.^13,25,40 Articles published in languages other than English or prior to 2009 were excluded. Research studies utilizing measures other than the TSK or SLHD were also omitted. Investigations involving other musculoskeletal trauma were eliminated.

Study Selection and Eligibility Criteria

After accounting for duplication, relevant titles and corresponding abstracts were imported into Sysrev (https://sysrev.com/). Initially, identified studies were independently screened for eligibility based on the title and abstract by 2 authors; discrepancies in opinion were arbitrated by a third author. Afterward, the full texts of eligible studies were screened according to inclusion and exclusion criteria. Any disagreements at this stage were independently arbitrated by the third and fourth authors. Cohen kappa (κ) coefficient was used to assess agreement between the first and second authors. ²²

Data Extraction, Methodological Quality Assessment, and Summary of Evidence

The following were extracted from each study by 1 author: year, design, location, and aims; sample population demographics; instrument(s) or approach(s) used to assess psychological and functional capacity; and study results. Two authors assessed article quality using the modified Downs and Black checklist (Appendix 1, available in the online version of this article), ¹⁸ which is a valid instrument for rating methodological aspects of randomized and nonrandomized controlled trials ³¹ and has been identified as a high-ranking quality assessment tool for systematic reviews. ¹⁶ In the modified version, the scoring of item 27 was changed to “1” instead of “5”; therefore, the highest possible score was 28. When consensus could not be reached on scoring an item, a third author made the final decision. Tallied scores were assigned a corresponding qualitative descriptor. ³³ Using the same methods, the study team applied the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system to summarize evidence for translation of knowledge to clinicians. ²⁷

Results

Identification of Studies

A PRISMA flowchart is presented in Figure 1. Of the 152 potential records, 106 studies underwent preliminary screening, 40 were reviewed in full, and 7 studies were ultimately included for appraisal. Interrater agreement was excellent with κ = 0.82. ²⁰

Figure 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart.

Data Extraction, Methodological Quality Assessment, and Summary of Evidence

The search resulted in 4 cross-sectional, 2 randomized controlled trial, and 1 prospective cohort studies. Article characteristics are summarized in Appendix 2 (available online). Studies represented data from 385 participants (male = 162; female = 117) with a mean age ranging from 16 to 42 years, including 3 countries: the United States, Australia, and Iran. Across studies, patients represented a variety of sports or physical activity levels. Ratings from the modified Downs and Black checklist are summarized in Appendix 1 (available online). Four of the 7 studies^29,30,46,48 included in this systematic review were classified as poor to moderate quality, 1 was rated as fair, ⁵⁸ and 2 studies^8,21 were rated as high. Based on the outcomes from these studies, while accounting for some inconsistency of results and risk of bias, we propose a moderate level of evidence exists to support the association between kinesiophobia and the SLHD, indicating patients with less kinesiophobia perform better on the SLHD. ²⁷

Discussion

A goal of ACL reconstruction is to return patients to their prior level of sports or physical activity. Historically, this outcome was speculated to depend on the surgeon’s skills. ⁴² However, research has demonstrated that numerous other variables, which include but are not limited to patient demographics, coexisting medical conditions, timing of interventions, psychological factors, and postoperative rehabilitation are also influential. ³ Psychological factors are the least studied of these variables, ⁹ even though their importance in patients who are unable to successfully RTS or engage in prior level of physical activity, despite satisfying criteria from physical performance tests, is known.^32,36

Kinesiophobia is defined as an excessive, irrational, and debilitating fear of physical movement and activity resulting from a feeling of vulnerability to painful injury or reinjury. ³⁷ This mental state mediates the development of chronic pain through neuroplastic changes in brain regions responsible for behavior and processing of sensory information. ¹⁵

Kinesiophobia and its negative impact on physical performance capacity is prevalent in various clinical populations, including patients suffering from chronic fatigue syndrome and fibromyalgia ⁴⁵ as well as those having undergone renal transplantation. ⁶⁴ Similar trends exist with total knee arthroplasties, patellofemoral pain, and chronic low back pain.^11,14,26 Its effect is related to various characteristics of a disease or dysfunction that includes symptom severity, such as pain, self-reported quality of life, ⁴⁵ and physical self-efficacy level. ⁶⁴ With systemic conditions, identifying and targeting kinesiophobia is critical to treatment success. Although current clinical practice guidelines advocate for evaluating psychological factors with RTS decision making after ACL reconstruction, application is not as widespread as the use of physical performance tests. ⁴⁹ Implementation of this practice may be the result of research, changing, and lack of time barriers. ⁵² To help surmount these, practitioners seek clinical measures that can be efficiently executed, analyzed, and interpreted. ⁵⁵

High levels of kinesiophobia captured from the TSK are associated with insufficient and asymmetric hamstring strength, inferior SLHD performance, unfavorable landing mechanics, and poor patient-reported function after ACL reconstruction.^39,46,48,57 Of these, the SLHD is a strong predictor for self-reported and objective measures of knee joint function as well as RTS after ACL reconstruction. It is also an inexpensive test easily conducted in clinical and field settings with precision and accuracy by a range of sports health and performance practitioners. ⁶⁰ Therefore, the SLHD has potential to serve as a clinician-friendly test with versatility in providing indications of somatic and psychological readiness for RTS and physical activity after ACL reconstruction.

From the studies we appraised, only Norte et al ⁴⁶ and Hart et al^29,30 conducted correlation and/or regression analyses. Norte et al reported a low-to-moderate inverse relation between kinesiophobia and SLHD. Moreover, regression indicated that a single-leg crossover hop for distance accounted for 35% to 39% of the variance predicting kinesiophobia. While Hart et al ²⁹ did not directly evaluate the association between kinesiophobia and SLHD, they did note a significant relation between kinesiophobia and self-reported knee function, although the correlation coefficient was not reported. Observation of mean data provided by Hart et al ²⁹ demonstrate those with less kinesiophobia consistently displayed greater performance on the SLHD and single-leg side-to-side hop for time across patients without or varying degrees of concomitant knee osteoarthritis. Similarly, mean data reported by Chmielewski et al ⁸ suggested those with less kinesiophobia consistently displayed greater performance on the SLHD. Furthermore, Paterno et al ⁴⁸ noted that patients with high fear were 7 times more likely to exhibit an SLHD limb symmetry index less than 95%. Contrastingly, Hart et al ³⁰ found no statistically significant correlation between kinesiophobia and any hop test, including the SLHD in patients.

Although moderate evidence elucidates potential association between kinesiophobia and SLHD, it is insufficient at this time to recommend employing the SLHD as a surrogate for the TSK in gauging kinesiophobia. Instead, SLHD performance may yield an artifact for potential fear of movement inhibiting successful RTS or physical activities that signal the need for clinicians to evaluate kinesiophobia’s probable influence as a mitigating factor using current self-reported means. Coincidently, variation in patient demographics, experimental design, and methodological quality among the studies appraised to produce these assertions warrants consideration and calls attention to the need for follow-up with high-quality studies to confirm, refine, or refute them.

In light of the outcomes from this systematic review, work by Baez et al ⁷ suggests that even when SLHD and time since ACL reconstruction are controlled for, kinesiophobia has the greatest influence on RTS. Additionally, knee self-efficacy and knee-related quality of life influenced step counts in patients after ACL reconstruction the most. These findings submit that psychological factors, explicitly injury-related fear and self-efficacy, are more highly correlated with RTS and physical activity levels than functional outcomes. ⁷ Hence, physical performance tests alone may not be suitable to gauge kinesiophobia. Additional discovery is necessary to determine the interplay between kinesiophobia and physical performance tests for shaping future clinical recommendations on this topic.

Commonality among the articles cited in this review affirms the integration of kinesiophobia measures and treatment into standard practice,^6,35,38 including managing generalized musculoskeletal pain.^24,41 To date, effectively managing postoperative pain and carefully timing surgery have been suggested as factors to consider in blunting kinesiophobia in patients with ACL reconstruction. ⁵⁶ Another approach to consider may be cognitive-behavioral therapy in conjunction with functional exercise, which represents a positive strategy for treating kinesiophobia and avoidance behavior toward physical activity in various patient cases (Figure 2).^1,44,45 This type of multimodal intervention may serve as a mechanism to advance the treatment of patients with ACL reconstruction as has been documented with other various musculoskeletal disorders. ⁶² In spite of these endorsements, the findings of Meierbachtol et al ⁴³ suggests different tasks induce fear of reinjury and RTS training programs may not always fully allay those fears. Thus, while evaluating kinesiophobia may serve to identify and treat it, persistence in certain patient populations currently remains unknown. ⁴³

Figure 2.

Adapted biopsychosocial model of return to sport after injury. ¹

Study Limitation

The GRADE framework is highly subjective; therefore, practitioners should use caution in extrapolating our findings to clinical applications at this time. The generalizability of our results is also constrained considering our review was limited to 1 instrument assessing kinesiophobia and 1 type of hop test. Other limitations consist of our English-language restriction and not having searched other databases, such as PsycINFO, and Psychology and Behavioral Sciences Collection, which may have omitted relevant works in this review.

Conclusion

The outcomes of this review propose that sports health practitioners consider the influence of kinesiophobia on SLHD performance a criterion for RTS and physical activities in patients after ACL reconstruction. Higher quality studies are necessary to establish the extent of association between these variables.