Changes in joint position sense after surgically treated chronic lateral ankle instability

Background: A search of the literature shows that the effect of surgery on ankle proprioception has been hardly investigated. Objective: To examine the effect of anatomical reconstruction of the anterolateral capsuloligamentous complex on ankle joint position sense. Methods: A prospective study using the "slope box'' test. Ten consecutive patients were included in the study, and 10 healthy athletes represented the control group. Results: Similar test-retest reliability rates ( overall reliability 0.92; p = 0.0013) were obtained to those of the original designers of the method. There were no significant differences with respect to side dominance ( p = 0.9216). Investigation of the characteristics of mean absolute estimate errors showed that the controls tested became error prone in the range of slope altitudes 7.5 - 25 degrees in every direction, compared with the range 0 - 5 degrees ( range of p values 0.00003 - 0.00072). The results of the intervention group showed that, for the two main directions of interest ( anterior and lateral), preoperative differences in mean absolute estimate errors between injured ( anterior 3.91 (2.81)degrees; lateral 4.06 (2.85)) and healthy ( anterior 2.94 (2.21)degrees, lateral 3.19 ( 2.64)) sides ( anterior, p = 0.0124; lateral, p = 0.0250) had disappeared ( postoperative differences: anterior, p = 0.6906; lateral, p = 0.4491). The afflicted ankle had improved significantly after surgery in both important directions ( anterior, p< 0.0001; lateral, p = 0.0023). Conclusions: The study shows that differences in joint position sense between healthy and injured ankles disappeared as the result of surgery. Preoperative data show that proprioceptive malfunction is a cause of functional instability. If treatment is by means of surgery, the retensioning of the original anterolateral structures is inevitable, even if other grafting or surgical techniques are used.