Psychological Readiness Is Weakly Related to Physical Function Tests at Return to Sport for Men and Not at All for Women Following Anterior Cruciate Ligament Reconstruction and Rehabilitation

Purpose: To assess the relationships between physical function tests of the operative limb and psychological readiness to return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction (return to sport after injury [ACL-RSI]) by sex. The secondary purpose was to quantify sex-specific differences in physical function test outcomes.

Methods: Patient records were retrospectively identified as cases who performed RTS physical function testing (strength, horizontal hops, vertical jumps, single-leg leg press, and drop landing knee excursion, etc.), and completed a 6-question ACL-RSI survey at the time point they were cleared to RTS. Independent t-tests compared all variables between sex at P ≤ .05. Correlations and regression models were produced per sex to identify factors related to operative limb physical function tests and ACL-RSI scores.

Results: With a total of 127 patients (63 men; 64 women), there was no difference in ACL-RSI scores and leg press repetitions between sex (P = .32 and P = .12, respectively). There were sex differences for all other physical performance outcomes (P < .001 for all). To estimate readiness using physical function test scores, the men's regression model identified knee excursion (β = 0.345; P = .033) as the only contributor to ACL-RSI (R² = 0.089), whereas there was no relationship between physical performance outcomes and ACL-RSI in women (R² = 0.00, P = 1.00).

Conclusions: Men and women reported similar ACL-RSI scales, indicating high readiness to return to sport. Likely due to sex-related physiological differences, men performed better at most physical function tests. Further, male ACL-RSI could be predicted using only one physical function outcome and 91% variability of the ACL-RSI coming from other contributors not evaluated, as indicated by R². No physical function variables predict ACL-RSI in women. The evaluated variables are considered the primary indicators relevant for patients to be permitted to RTS yet cannot adequately predict psychological readiness in these patients.

Level of evidence: Level III, retrospective comparative study.