Comparison of 5 Different Methods for Measuring Stress Radiographs to Improve Reproducibility During the Evaluation of Knee Instability

Abstract

Background: Although stress radiography is frequently used to assess abnormal knee instability, the reliability and reproducibility for an evaluation of anterior-posterior instability of the knee may be affected by a variety of factors.

Stress Radiography for the Diagnosis of Knee Ligament Injuries: A Systematic Review

“…Only two studies in this review reported results for comparison of measurement techniques using different landmarks and reference points on stress radiographs [28,30]. Although we recognize that the choice of landmarks may influence the accuracy and reliability of measurements in stress radiography, this was beyond the scope of the present review.…”

“…No diagnostic accuracy data were reported for diagnosis of isolated varus knee injuries on stress radiography. Overall, excellent intrarater and interrater ICCs were reported for the diagnosis of ACL [28,30], PCL [28,42], varus [12,26], and valgus [25] injuries on stress radiography. However, only six studies included analysis of intrarater and interrater reliability [12,25,26,28,30,42].…”

“…Fifteen studies (39%) focused solely on the diagnosis of anterior cruciate ligament (ACL) instability, nine (24%) on the posterior cruciate ligament (PCL), two (5%) on varus, two (5%) on valgus, and 10 (26%) on multiligament assessment. Of the multiligament studies, four studies described anterior, posterior, varus, and valgus stress radiography [13,17,19,32]; one described anterior, posterior, and varus stress [18]; four described anterior and posterior stress only [28,[46][47][48]; and one described posterior and varus stress only [43]. A total of 23 studies were purely descriptive studies of a stress radiography technique, whereas 15 studies were comparative either among stress radiograph techniques or between stress radiography and other diagnostic techniques.…”

“…Its applications include diagnosing acute and chronic injuries [1,21,30,32], comparing instability preoperatively and postoperatively [20,24,39,55], and monitoring stability in nonoperatively treated patients [17]. A variety of stress techniques have been described that assess ligament stability using an anteriorly, posteriorly, varus-, or valgus-directed force to the knee [10,14,17,28,29,37,40,41,43,45]. Side-to-side differences in the amount of displacement (anterior or posterior) or gapping (varus or valgus) increase suspicion of a functional deficit in knee ligament stability.…”

Anterior cruciate ligament assessment using arthrometry and stress imaging

“…Ideally, landmarks should be easily and unequivocally identifiable, and should not be highly dependent on subtle changes in knee rotation or flexion. Theoretically, posterior landmarks are the least dependent on knee flexion, since the center of knee flexion lies posterior to the midshaft axis [6][7][8]. Central landmarks are the least dependent on axial knee rotation, since they again are nearest to the center of rotational motion.…”