Does the Lachman testing method affect the reliability of the International Knee Documentation Committee (IKDC) Form?

The aim of this study was to evaluate the effect of manual and instrumented means of Lachman testing on the reliability of the IKDC form. A single observer assessed 102 patients with ACL deficiency (direct comparison group). Another observer assessed 35 of these patients (inter-observer group) and the initial observer re-assessed 47 patients (test-retest group). The Lachman test was performed by both manual and instrumented means and the IKDC form was completed. Direct comparison of the manual and instrumented Lachman test revealed satisfactory levels for use. Further comparison revealed satisfactory test re-test and unsatisfactory inter-observer reliability for both means. On application into the IKDC form, direct comparison of both means of testing revealed satisfactory agreement for the overall score, but not the ligament group or Lachman item scores. Test-retest and inter-observer reliability testing revealed unsatisfactory agreement for the overall, ligament group and Lachman item scores for both means of testing. When using the IKDC form we recommend that a single observer perform the Lachman test by manual means on each occasion. If the original IKDC form is used only the overall score should be presented. Where the new IKDC form is used we recommend caution in the presentation of the examination section. We call into question the usefulness of the original IKDC form and the examination section of the new IKDC form in clinical research.