Comparison of score evaluations and instrumented measurement after anterior cruciate ligament reconstruction

Forty-four patients who had undergone unilateral anterior cruciate ligament reconstructions were evaluated retrospectively with seven different scoring systems (International Knee Documentation Committee, Orthopadische Arbeitsgruppe Knie, Lysholm, Feagin and Blake, Zarins and Rowe, Cincinnati, and Marshall scores). The results varied between systems and therefore lacked reliability. Of the 44 patients, 32 were rated as excellent according to the Cincinnati score while only 3 patients were rated as normal according to the International Knee Documentation Committee form. Good and excellent results were found twice as frequently with the Cincinnati and Lysholm scores compared with the scores of Zarins and Rowe or the International Knee Documentation Committee form. Statistical analysis confirmed this observation and revealed significant differences between the scoring systems. Side-to-side differences using the manual maximum displacement test with the KT-1000 arthrometer revealed good correlation with the International Knee Documentation Committee and the Orthopadische Arbeitsgruppe Knie questionnaires. None of the other scoring systems, which do not measure anterior laxity, produced reasonable correlation with instrumented measurements. We found that certain population-specific factors as well as the distribution of single findings can distort the results of scoring systems. To avoid these interference factors, the patient sample should be homogeneous and selected prospectively and there should be agreement about the value of single findings.