Orthopaedic Journal of Sports Medicine
The Effect of Anesthesia on Objective Anterior Cruciate Ligament Stability Testing: A Paired Analysis of Instrumented Laxity and Physical Examination
By E.S. Mameri, M.V. Credidio, T.S.P. Bueno and 3 others.
Abstract
Objective
To evaluate the effect of anesthesia on instrumented and manual knee stability testing in patients with anterior cruciate ligament (ACL) deficiency, and to determine whether demographic or injury-related factors predict anesthesia-related increases in instability.
Methods
This prospective cohort study included 100 adult patients with symptomatic ACL tears undergoing surgical treatment. Standardized knee examinations were performed immediately before and after anesthesia (sedation combined with spinal anesthesia). Instrumented anterior tibial translation was measured using a handheld Lachmeter, with side-to-side difference (SSD) analyzed as a continuous variable and using ≥3 mm and ≥4 mm diagnostic thresholds. Manual clinical examinations included the Lachman, anterior drawer, and pivot-shift tests. Pre- and post-anesthesia comparisons were performed using paired statistical tests. Logistic regression and bias-reduced (Firth) models were used to identify predictors of anesthesia-related increases in instability, including age, sex, body mass index, and meniscal pathology.