Comparison of the ceiling effect in the Lysholm score and the IKDC subjective score for assessing functional outcome after ACL reconstruction

BackgroundTo compare the ceiling effect of the Lysholm and IKDC subjective scores for assessing functional outcome after ACL reconstruction and evaluated the correlation with the one-leg hop test.MethodsA total of 134 patients who underwent ACL reconstruction between 2007 and 2011 were enrolled in this study. All patients fulfilled the postoperative 6- and 12-month evaluations. The ceiling effect of the Lysholm and IKDC subjective scores was assessed, and the correlations between two scales and one-leg hop test were analysed.ResultsFor the entire sample, the ceiling effect for the Lysholm score was 14.9% and 30.6% at 6 and 12 months postoperatively. The values for the IKDC subjective score were 5.2% and 17.2%, respectively. In all subjects, the correlation coefficients [95% confidence intervals] between the IKDC subjective score and one-leg hop test at 6 and 12 months (r = 0.492, [0.34 to 0.62]; r = 0.296, [0.12 to 0.46]) were higher than those for the Lysholm score (r = 0.355, [0.18 to 0.51]; r = 0.241, [0.06 to 0.41]), respectively.(p < 0.05).ConclusionWith regard to evaluating ACL reconstruction outcomes in patients, no significant difference between the IKDC subjective and the Lysholm scores exists in terms of the amount of ceiling effect and the correlation with the LSI. However, the concern that the ceiling effect of the Lysholm score was greater than the IKDC subjective score, should be addressed in assessing the patient's functional status postoperatively.Level of evidence: III, retrospective comparative study.