OBJECTIVE: The objective of this study is to compare the validity of the Drop Leg Lachman's test (DLLT) with Lachman's test (LT) in appreciating abnormal knee AP laxity using KT-1000, specifically comparing LT and DLLT in terms of sensitivity and specificity.

METHODS: A prospective randomized cross-sectional study was used on 36 patients complaining of unilateral knee symptoms from April 2009 to November 2009, 18 to 50 years of age consulting at the UP-PGH Department of Orthopedics Sports Clinic. Descriptive statistics were used to obtain the frequency, percentage, mean, standard deviation and range. Data was analyzed and calculated using the KT-1000 and STATA software.

RESULTS: The subjects included 31 (86%) males and 5 (14%) females. Thirty-six percent were students and the rest were employed. The average age of the subjects was 28 years old with a range from 17 to 50 years. Their average weight was 72 kilograms with a range of 50 to 92 kilograms. Their average height was 170 centimeters with a range of 157-187 centimeters. Twenty eight (78%) complained of knee pain, 7 (17%) of knee instability and 1 (2%) of knee tightness. All of the subjects attribute the current complaint to a previous trauma, 72% were basketball-related. The average duration of onset of symptoms to testing was 22 months. Our study showed identical results of 95.45% sensitivity and 50.0% specificity when DLLT and LT were compared to KT-1000.

CONCLUSIONS: The Drop Leg Lachman's test shows no statistical difference with that of Lachman's Test in diagnosing knee instability using the KT-1000 as gold standard. It has an identical transitivity of 95.45 % and specificity of 50%.