Diagnostic Value of Stress Radiography and Arthrometer Measurement for Anterior Instability in Anterior Cruciate Ligament Injured Knees at Different Knee Flexion Position.
PURPOSETo evaluate diagnostic value of stress radiography and arthrometer measurements for anterior instability at different knee flexion angle positions.
METHODSForty-three patients with complete anterior cruciate ligament (ACL) rupture (group 1) and 37 normal subjects (group 2) were enrolled prospectively. Arthrometer (KT-1000) measurements and stress radiography by Telos were used to evaluate side-to-side differences. Results were recorded according to the knee position (30°, 45°, 60°, and 90°). Areas under the receiver operating characteristic curves (AUCs) were used to evaluate the diagnostic accuracy of each evaluation method. The calculated cutoff values at 30° position were used to evaluate the sensitivity and specificity of combined evaluation with stress radiography and arthrometer measurements.
RESULTSThe side-to-side differences on stress radiography and arthrometer measurements were significantly different between groups (P < .05), except for the values at the 90° position in arthrometer measurements (P = .844). The amount of anterior translation decreased in both arthrometer measurements and stress radiography between 30° and 45° positions (P < .000); however, no further decrease was observed beyond 45°. The AUC of stress radiography at the 30° position was significantly higher than other values (AUC = 0.955; P = .000). Moreover, the clinical cutoff value of 3 mm showed 86.0% sensitivity and 89.2% specificity in stress radiography at 30°, which were higher than those in arthrometer measurements. Combined use of stress radiography and arthrometer measurements at the 30° position showed 100% sensitivity and 59.5% specificity as a screening test.
CONCLUSIONSEvaluation at the 30° knee position was significantly superior to that at other positions for both stress radiography and arthrometer measurements, whereas the 90° knee flexion position was not meaningful for any measurements. Evaluation needs to be performed with a 3-mm cutoff value for stress radiography at the 30° knee position; however, combined use of stress radiography and arthrometer measurements at the 30° knee flexion can have a higher diagnostic value.
LEVEL OF EVIDENCELevel I, diagnostic study of established criteria.
Department of Orthopedic Surgery, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, South Korea.,
Department of Orthopedic Surgery, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, South Korea.
Department of Orthopedic Surgery, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, South Korea; Orthopedic Department, Centre Hospitalier de Versailles, Le Chesnay, France. Electronic address: email@example.com.
Pub Type(s)Journal Article