Background: Impairment in proprioception has been suggested to be one of the causes of FAI. This study aimed to establish intra-session reliability of the Biodex System 2 in assessing joint position sense (JPS) and kinesthesia (K)~in addition to determining if there was any side to side difference in JPS and kinesthesia in people with unilateral functional ankle instability.
Materials and methods: Both JPS and K were determined by means of the Biodex Systems 2. During evaluation of JPS, participants' ability to actively reproduce ankle joint position was tested three times in each of the two predetermined positions. During evaluation of K, data collection began with the foot placed in a starting position of 0 degrees (neutral position).
Results: A total of 25 participants (mean age 22.0 years, 95% confidence interval 19.9 to 24.1 years) were recruited into this study. No difference in JPS (p = 0.162 to 0.764) and K (p = 0.089 to 0.683) were found between the sprained and uninvolved ankle of subjects with unilateral functional ankle instability. There is moderate to good intra-session reliability in using the Biodex System 2 to assess JPS (ICC = 0.868 to 0.950, p < 0.01) and K (ICC = 0.825 to 0.893, p < 0.01).
Conclusion: This study suggests that there is perhaps no difference in JPS and K between both ankles in people with unilateral FAI. Proprioceptive deficits may not always be present in every case of FAI.
Clinical relevance: Proprioceptive training may not be beneficial in some patients with unilateral FAI.