Confidence to Return to Play After Anterior Cruciate Ligament Reconstruction Is Influenced by Quadriceps Strength Symmetry and Injury Mechanism

Abstract

Background: Although the restoration of quadriceps strength symmetry is a primary rehabilitation goal after anterior cruciate ligament reconstruction (ACLR), little is known about the potential relationship between quadriceps strength symmetry and psychological readiness to return to play (RTP). Hypothesis: Quadriceps strength symmetry will be associated with psychological readiness to RTP after ACLR. Secondarily, injury mechanism will influence the association between quadriceps strength and psychological readiness to RTP. Study Design: Retrospective cohort. Level of Evidence: Level 3 (cohort study). Methods: A total of 78 female patients completed strength testing and the Injury–Psychological Readiness to Return to Sport (I-PRRS) scale at an outpatient clinical facility as part of return to sport testing after ACLR. Linear regression analysis was used to assess the relationship between the I-PRRS and the independent variables of interest (quadriceps strength symmetry and injury mechanism). Results: For all patients combined, a significant symmetry × mechanism interaction was found. When split by injury mechanism, a significant linear relationship was found between quadriceps strength symmetry and the I-PRRS score in patients who experienced a noncontact injury (n = 55; P = 0.01; R2 = 0.24). No such relationship was found for those who experienced a contact injury (n = 23; P = 0.97; R2 = 0.01). Conclusion: Greater quadriceps strength symmetry was associated with greater psychological readiness to RTP in female athletes after ACLR. This relationship, however, was present only in those who experienced a noncontact injury. Clinical Relevance: Clinicians should consider both the physical and the psychological factors in assessing a patient’s readiness to RTP. This may be particularly important for those who have experienced an ACL tear through a noncontact mechanism.

Predicting Anterior Cruciate Ligament Reinjury From Return-to-Activity Assessments at 6 Months Postsurgery: A Prospective Cohort Study

“…37,38 Greater quadriceps strength has also been related to greater psychological readiness to return to sport which may enhance the rehabilitation progression prior to returning to activity. 39 In the patients with Delayed RTA, 6-month quadriceps strength and symmetry measures did not predict reinjury.…”

Confidence to Return to Play After ACL Reconstruction: An Evaluation of Quadriceps Strength Symmetry and Injury Mechanism in Male Athletes

“…A prospective sample size calculation was performed in G*Power (Version 3.1.9.5) to determine the number of patients needed to assess the relationship between quadriceps strength symmetry and psychological readiness to RTP. Using a 5% significance level, 90% power, R 2 value of 0.24, 9 and 4 predictors (interaction term, time post-ACLR, injury mechanism, quadriceps strength symmetry), a minimum of 54 patients was deemed necessary.…”

“…Patients underwent quadriceps strength testing and psychological readiness to RTP assessment as part of normal clinical care as previously described. 9 Rehabilitation was not standardized as patients were treated at various clinical facilities. Graft type and the timing of the testing post-ACLR also differed among patients (Table 1).…”

“…A motor-driven dynamometer (BTE Primus, BTE) was used to assess isometric quadriceps strength. 9 Patients were seated on a chair and straps were used to secure the thigh of the testing limb. The rotational axis of the unit was aligned with the lateral femoral condyle, and the resistance pad of the lever arm was positioned above the malleoli.…”

“…In a previous publication, increased psychological readiness to RTP after ACLR was associated with increased quadriceps strength symmetry in female athletes. 9 However, this relationship only was observed in those who had experienced a noncontact injury. Since critical life events that are not clearly understood may alter one’s LOC (eg, I just planted my foot and my ACL tore), 15 female athletes who experienced a noncontact injury may have experienced a shift in their belief system that was more dependent on internal factors such as quadriceps strength.…”