Table 3.
Classification and regression tree analysis with four different follow-up times for players with ACLR (n = 112)
| Follow-up times, months | ||||
|---|---|---|---|---|
| 0–12 | 0–24 | 0–36 | 0–>36 | |
| Secondary ACL injury, n (%) | 17 (15) | 28 (25) | 35 (31) | 43 (38) |
| Sensitivity, % | 94 | 96 | 77 | 88 |
| Specificity, % | 81 | 70 | 80 | 78 |
| Overall correct classification, % | 83 | 77 | 80 | 82 |
| Accuracy, % | 93 | 86 | 86 | 87 |
| Entrance on CART, Levela | ||||
|---|---|---|---|---|
| 0–12 | 0–24 | 0–36 | 0–>36 | |
| 1. Time between injury and ACLR, months | 2 | 2 | ||
| 2. Level of play, n (%) | ||||
| 3. IKDC (0–100) | 4 | |||
| 4. ACL-RSI (0–10) | 1 | |||
| 5. ACL-QoL (0–10) | 3 | 3 and 5 | ||
| 6. SMPS—personal standards (1–5) | ||||
| 7. SSP—somatic anxiety (0–100) | 4 | |||
| 8. SSP—psychic anxiety (0–100) | 3 | |||
| 9. SSP—stress susceptibility (0–100) | 3 | 1 | ||
| 10. SSP—impulsiveness (0–100) | 2 | 3 and 4 | ||
| 11. SSP—adventure seeking (0–100) | ||||
| 12. Ankle dorsiflexion, side difference, degrees | ||||
| 13. Knee extension ACLR leg, degrees | 5 | 1 | 1 | |
| 14. LSI—single hop for distance, % | ||||
| 15. LSI—side hop, % | 5 | 4 | 3 | |
| 16. 5-jump test, cm | 2 | 2 and 5 | 2 | |
| 17. Tuck jump (0–10) | 3 | |||
| 18. Knee collapse ACLR leg in DVJ, cm | ||||
| 19. Knee collapse non-ACLR leg in DVJ, cm | ||||
| Significant risk profiles with increased likelihood of sustaining a secondary ACL injury | ||||
|---|---|---|---|---|
| Node number and variables included | Relative risk (95% confidence interval) | |||
| 0–12 | 0–24 | 0–36 | 0–>36 | |
| 7: ACL-RSI, SSP-impulsiveness, SSP-stress susceptibility, and IKDC | 4.62 (2.04–10.47) | |||
| 10: ACL-RSI, SSP-impulsiveness, SSP-stress susceptibility, and IKDC | 8.16 (3.97–16.78) | |||
| 13: SSP- stress susceptibility, time between injury and ACLR, SSP-impulsiveness, and knee extension ACLR leg | 7.67 (3.15–18.64) | |||
| 4: Knee extension ACLR leg and 5-jump test | 3.39 (2.28–5.05) | |||
| 14: Knee extension ACLR leg, 5-jump test, SSP-psychic anxiety, and LSI-side hop | 2.70 (1.62–4.50) | |||
| 12: Knee extension ACLR leg, time between injury and ACLR, LSI-side hop and SSP-somatic anxiety | 3.73 (2.25–6.19) | |||
| 14: Knee extension ACLR leg, time between injury and ACLR, LSI-side hop, SSP-somatic anxiety, and ACL-QoL | 2.11 (1.31–3.39) | |||
aNumbers 1–5 are for the level of entrance in the CART analysis for the selected variables by CART: 1, first level with the strongest association; 2, second level with the second strongest association, etc. Two numbers indicate that the variable is selected on two different levels (e.g. 3 and 4). Variables in bold type were selected by CART. ACL, anterior cruciate ligament; ACL-QoL, ACL-Quality of Life; ACLR, anterior cruciate ligament reconstruction; ACL-RSI, Anterior Cruciate Ligament-Return to Sport after Injury; DVJ, drop vertical jump; IKDC, International Knee Documentation Committee Subjective Knee Form; LSI, Limb Symmetry Index; SMPS, Sport Multidimensional Perfectionism Scale; SSP, the Swedish Universities Scales of Personality