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) degrees ) and healthy (anterior 2.94 (2.21) degrees , lateral 3.19 (2.64) degrees ) 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.