Assessment of the intra and inter-rater reliability of the posterior talar glide test and it’s modified version performed by novice and experienced rater on a complete sample of subjects

Lateral ankle sprain (LAS) is one of the most common musculo-squeletal injury with a high incidence a recurrence rate. Additionally, after suffering from a LAS, there is a high risk of developing a chronic ankle instability (CAI). CAI is complex condition defined by a propensity for ankle sprain and a consistent feeling of the ankle giving way. Guidelines where suggested to clinicians by the international ankle consortium (IAC) in order to optimize the treatment and mitigate the risks of developing CAI for the patients recovering from LAS. Amongst the test suggested by these guidelines, one in particular is aimed at assessing the posterior glide of the talus in the talocrural joint, the posterior talar glide test (PTGT). The theory supporting this test is based on the hypothesis that the talus could remain malpositioned after a LAS causing a change in the arthrokinematics of the ankle and simultaneously a reduction of dorsiflexion range of motion (ROM). The reliability of the test has been previously investigated in the past two decades. The intra-rater reliability estimation ranged from poor to excellent based on intraclass correlation coefficient 95% confidence interval (ICC 95% CI) ranging from -0,64 to -0,99 with standard error of measurement (SEM) ranging from 0,34° to 2,71° and minimum detectable change (MDC) ranging from 3,78° to 4,67°. Inter-rater reliability estimation raged from poor to excellent based on ICC 95% CI ranging from -0,27 to 0,92 with SEM ranging from 1,08° to 1,31° and MDC ranging from 3,00° to 3,68°. A lack of agreement and differences in the experimental protocol between the studies that investigated the reliability of the PTGT highlights the need for more research on the topic. Therefore, the aims of this study were multiple. First, this study evaluated the intra- and inter- rater reliability of the PTGT performed by experienced and unexperienced clinicians. The second aim was to objectively assess the horizontal plane of the foot during the PTGT with a modified PTGT. Finally, the reproducibility of measurement was performed on several ankle sprains population, i.e., CAI, copers or healthy individuals. To do so, a sample of twenty-eight participants were recruited and PTGT measures were taken by two raters, one was novice and one was experienced. The PTGT was performed twice with box and twice without by each rater on each ankle. The results show an excellent intra-rater reliability for the novice rater with ICC of 0,96 a SEM of 2,3° and a MDC of 4,2°. The addition of the box has no significant impact on the intra-rater reliability of the novice rater but increases the intra-rater reliability of the experienced rater with an ICC going from 0,93 to 0,96, SEM going from 2,4° to 1,4° and MDC going from 4,3° to 3,3°. The inter-rater reliability found without the box is poor to good with ICC = 0,64, SEM = 2,8° and MDC = 4,7°. The inter-rater values increase when the box is added to moderate to good with ICC = 0,78, SEM = 2,3° and MDC = 4,2°. Overall the results encourage the use of a box when performing the PTGT making it a reliable enough test to use in a clinical setting. However, major inconsistencies still remain with the design of the PTGT and more research is needed to make it a gold standard test for the evaluation of posterior talar glide in the talocrural joint.