The objective of the study is to evaluate post-operatively the postural control through the Delos system with the Riva method of patients already treated surgically of external capsulo-ligament reconstruction due to ankle instability.

The patients will then be divided into two control groups: one group will undergo reconditioning through the Delos system and one group will undergo standard rehabilitation treatment.

Primary outcome: improvement of joint stability and postoperative proprioception after reconditioning with the Delos system.

Secondary outcomes: improvement of performance indicators and reduction of disability and satisfaction and assessment of long-term ankle stability after reconditioning with Delos system.

Inclusion Criteria:

• patients already undergoing surgery and with at least 4 months of follow-up;
• patients of both sexes aged between 18-40 years;
• patients who have given their informed written consent to participate in the study;
• patients who have given the willingness to reach the Hospital to carry out the checks.

Exclusion Criteria:

• patients with BMI> 30 kg / m2;
• patients with rheumatoid arthritis;
• patients with chronic inflammatory joint diseases;
• patients with pre-existing deambulation kinematics abnormalities (amputations, neuro- muscular diseases, polio, hip dysplasias);
• patients with Severe arthrosis of the ankle (Kellgren-Lawrence> 3);
• patients with Severe knee arthritis (Kellgren-Lawrence> 3);
• patients with severe postural instability;
• patients with cognitive impairments;
• patients with concomitant neurological diseases.