Description
Background: In addition to commonly used patient-reported outcome measures (PROMs), recently there has been a growth in studies investigating psychological readiness and functional performance as useful predictors to successful return to sport at pre-injury level. Vertical jump tests have demonstrated to reliably detect functional asymmetries between limbs and assess knee biomechanics by measuring explosive strength power and reactivity.
Objectives: The purposes of this study were to (1) evaluate prospectively clinical and functional outcomes of athletes following ACL reconstruction up to 12 months after surgery, (2) to identify the correlations between functional and subjective tests, and (3) to determine which factors influence patients’ capability to resume sports at pre-injury level.
Design and Methods: 37 patients who underwent ACL reconstruction were prospectively assessed pre-operatively, 6, and 12 months after surgery using International Knee Documentation Committee (IKDC) Subjective Knee Form, Tegner activity level, and the ACL–Return to Sport after Injury (ACL-RSI) scale. Jumping ability was instrumentally assessed by an infrared optical acquisition system using a test battery including mono- and bipodalic vertical jumps, and a side-hop test.
Results: Thirty-three patients (89%) were available for clinical evaluation at follow-up. Average age at surgery was 34.0 years (SD 11.5). Mean overall IKDC, and ACL-RSI scores increased from preoperatively (P<0.001). Jump tests showed improvements at 12-month evaluation compared to 6-month follow up (p<0.01), but not compared to baseline (p=n.s.). No statistically significant correlation was reported for ACL-RSI and jump tests (p=n.s.). No differences were observed in terms of jumps between patients who returned to pre-injury activity level and those who did not (p=n.s.). Patients who returned to pre-injury activity level reported higher IKDC and ACL-RSI scores (p<0.05).
Conclusions: One year after ACL reconstruction, an improvement in jumping ability was observed, while a persistence of lower limbs asymmetries was noted 6 months after surgery. The ability to perform vertical jumps was not influenced by psychological outcomes 12 months following ACL surgery. Higher values of subjective knee score and psychological readiness predicted return to sport at preinjury level, while no correlation was reported concerning jumping performance.
