Self-Reported Fear Predicts Functional Performance and Second ACL Injury After ACL Reconstruction and Return to Sport: A Pilot Study

M. V. Paterno, K. Flynn, S. Thomas, L. C. Schmitt, Self-Reported Fear Predicts Functional Performance and Second ACL Injury After ACL Reconstruction and Return to Sport: A Pilot Study, 2018, Sports Health. 2018 May/Jun;10(3):228-233.

Current rehabilitation protocols and RTS clearance criteria after ACLR are primarily based on time from surgical reconstruction and measures of physical function.

Most RTS discharge criteria include some combination of time since surgery, subjective reports of function, lower extremity strength measurements, functional tests (eg, hop testing), and/or quality of lower extremity movements. Ardern et al cited psychological readiness as the factor most strongly associated with successful RTS. Furthermore, several studies have suggested fear of reinjury as a contributing, if not primary, factor for patients not returning to sport.


The purpose of this study was to determine whether self-reported fear at time of RTS was related to activity level at time of RTS, objective clinical measures of function at time of RTS, and incidence of second ACL injury within the first 24 months after RTS. Additionally, the authors hypothesized that patient-reported fear at the time of RTS would predict patients at greater risk of a second ACL injury after ACLR and RTS.

Test measure

Patient-Reported Fear

  • At the time of RTS, each participant completed the shortened version of the Tampa Scale of Kinesiophobia (TSK-11). Scores on the TSK-11 range from 11 to 44, with higher scores indicating greater fear of movement/reinjury.

Marx Activity Rating Scale (Marx)

  • Marx was used to determine the participants’ activity level at time of RTS. The Marx is a 4-item questionnaire that assesses how frequently the patient participates in running, cutting, and pivoting activities. A score of 16 indicates the patient participated in running, cutting, pivoting, and decelerating activities at least 4 days per week, comparable to the level of activity of an athlete participating on a high school or collegiate athletic team.

Hop test

  • single-leg hop for distance, triple hop for distance, triple-crossover hop for distance, and 6-m timed hop

Isokinetic biodex test

  • The peak torques to body weight (kg).


At time of RTS, all patients (N = 40) completed the TSK-11 and the Marx activity scale; 38 patients were able to complete the single-leg hop for distance, and 39 patients were able to complete the isometric quadriceps strength assessment. At the time of RTS, patients were dichotomized into those who reported greater fear (n = 19; TSK-11 score ≥17) and those who reported lesser fear (n = 21; TSK-11 <17) on the TSK-11.

Patients who reported greater fear on the TSK-11 were 4 times (OR, 3.73; 95% CI, 0.98-14.23) more likely to report lower levels of activity (≤15) on the Marx activity scale.

With regard to functional performance, patients with greater fear were 7 times (OR, 7.1; 95% CI, 1.5-33.0) more likely to have a single-leg hop LSI less than 95%

Patients with greater levels of fear were 6 times more likely to have an isometric quadriceps strength limb symmetry index less than 90% (OR, 6.0; 95% CI, 1.3-27.8).

Fifteen (37.5%) patients suffered a second, noncontact ACL injury within 24 months of RTS after ACLR, leaving 25 patients in the reference group. Eight patients (20%) suffered an ipsilateral graft retear, and 7 patients (17.5%) suffered a contralateral ACL injury.

Chi-square analysis revealed patients with a TSK-11 score of 19 or greater at the time of RTS were 13 times (relative risk [RR], 13.0; 95% CI, 2.1-81.0) more likely to suffer an ipsilateral second ACL tear within the first 24 months after RTS


Consistent with the tested hypothesis, patients with greater levels of fear at the time of RTS presented with an increased likelihood of reduced levels of activity, asymmetry on single-leg hop for distance assessment, and asymmetry on an isometric QF strength performance test at time of RTS. Furthermore, patients who returned to pivoting and cutting sports with greater selfreported fear demonstrated an increased risk of suffering a second ACL injury in the 24 months after RTS

Other references

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