Development of computer tablet software for clinical quantification of lateral knee compartment translation during the pivot shift test

Abstract

The pivot shift test is a commonly used clinical examination by orthopedic surgeons to evaluate knee function following injury. However, the test can only be graded subjectively by the examiner. Therefore, the purpose of this study is to develop software for a computer tablet to quantify anterior translation of the lateral knee compartment during the pivot shift test. Based on the simple image analysis method, software for a computer tablet was developed with the following primary design constraint - the software should be easy to use in a clinical setting and it should not slow down an outpatient visit. Translation of the lateral compartment of the intact knee was 2.0 ± 0.2 mm and for the anterior cruciate ligament-deficient knee was 8.9 ± 0.9 mm (p < 0.001). Intra-tester (ICC range = 0.913 to 0.999) and inter-tester (ICC = 0.949) reliability were excellent for the repeatability assessments. Overall, the average percent error of measuring simulated translation of the lateral knee compartment with the tablet parallel to the monitor increased from 2.8% at 50 cm distance to 7.7% at 200 cm. Deviation from the parallel position of the tablet did not have a significant effect until a tablet angle of 45°. Average percent error during anterior translation of the lateral knee compartment of 6mm was 2.2% compared to 6.2% for 2 mm of translation. The software provides reliable, objective, and quantitative data on translation of the lateral knee compartment during the pivot shift test and meets the design constraints posed by the clinical setting.

Anterolateral knee biomechanics

“…A range of values for the movements of the medial and lateral condyles have been published [32]. This observation has led to a method to grade the pivot-shift which visualises the movements of the lateral aspect of the knee [36]. The overall effect is that the anterolateral aspect of the proximal tibia moves anteriorly as the internal rotation adds to the anterior translation movement during clinical examination, and that is what has long been recognised and described as ‘anterolateral rotatory instability’ (ALRI).…”

Static anteroposterior knee laxity tests are poorly correlated to quantitative pivot shift in the ACL-deficient knee: a prospective multicentre study

“…The position of the markers is tracked by using commercial tablet (iPad; Apple, Cupertino, California, USA) software for video recording of the pivot shift test. A software application on the tablets automatically calculates the tibial translation, which is also displayed as a graph 25. Previous research has concluded that the method is valid for evaluation of the pivot shift 16.…”

An Extensive Evaluation of Different Knee Stability Assessment Measures: A Systematic Review

“…Muller et al (2015) [52] reported an ICC for intra-tester reliability ranging from 0.913 to 0.999 (95% CI range: 0.319 to 1.000) and ICC for inter-tester reliability of 0.949 (95% CI: 0.542 to 1.000) for iPad software (The PIVOT software, iOS, programming language Objective-C) designed specifically for quantifying the pivot shift test. Nevertheless, Hoshino et al (2013) [56] did quantify the pivot shift test using an iPad tablet (Apple Inc., Cupertino, CA, USA).…”

“…As a result, conducting the test in a prone position has been proposed and yielded a positive alternative to the Lachman test [51]. Moreover, Muller et al [52] examined the proficiency in performing the prone Lachman test as opposed to the classic Lachman. They showed that prone Lachman yielded 78% of positive predictive value while the classic Lachman 28%.…”