## 6 Discussion  
Chronic lateral ankle instability is a common condition in both recreationally active people and athletes [1; 3]. It is associated with disabling symptoms for the patients with decreased strength, diminished range of motion and functional impairment, which determine serious consequences in terms of time lost from work and sport [19]. CAI is initially treated conservatively with bracing and functional rehabilitation [20; 21]. Patients who experience residual instability after 3-6 months of conservative treatment \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Average** & **Range** & \(\mathbf{p}\) \\ \hline VAS PRE & 5.6 & 2–9 & \\ \hline VAS POST & 0.7 & 0–7 & \(p<0.05\) \\ \hline UCLA PRE & 7.7 & 4–8 & \\ \hline UCLA POST & 9.2 & 6–10 & \(p<0.05\) \\ \hline AOFAS PRE & 66.5 & 40–95 & \(p<0.05\) \\ \hline AOFAS POST & 94 & 88–100 & \\ \hline HALASI PRE & 4.3 & 2–8 & \\ \hline HALASI POST & 4.5 & 2–8 & \\ \hline KARLSSON–PETERSON PRE & 71 & 40–90 & \(p<0.05\) \\ \hline KARLSSON–PETERSON POST & 87.9 & 70–90 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Score results pre- and post-operatively. Figure 5: Kaplan–Meier survival distribution. are eligible for surgery in order to restore ankle stability and prevent the occurrence of early arthrosis of the ankle joint. Many surgical procedures have been described ranging from simple repairs to complex reconstructions [22]. The techniques are divided into anatomic repairs, non-anatomic tenodesis and anatomic reconstructions using autograft or allograft. The gold standard is anatomic repair with the Brostrom technique and its modifications; the main limit of this surgical procedure is in the case of severely attenuated or absent ligaments [23]. Non-anatomic tenodesis is nowadays less used as hindfoot biomechanics are not correctly restored [24]. A systematic review of the literature with a mean follow up of 15.3 years published by [PERSON] et al. evaluated eight hundred and one ankles and concluded that anatomical repair compared to non-anatomical tenodesis resulted in a diminished loss of range of motion and less development of secondary osteoarthritis [25]. Therefore, non-anatomic tenodesis procedures have been replaced by anatomic reconstructions with allograft, autograft or fibular periosteal flap. The surgical technique we perform in our department is minimally invasive reconstruction of the lateral ligament complex using semitendinosus tendon autograft. In the present study, we enrolled forty-seven patients with a mean follow up of 6.7 years. The aim was to assess the post-operative clinical outcome, return to sport and rate of sprain recurrence. Pain relief and functional outcome were evaluated using the VAS scale, the AOFAS score and the Karlsson-Peterson ankle instability score. The promising results we collected are in accordance with other similar studies. [PERSON] et al. performed minimally invasive reconstruction of lateral ligaments of the ankle using semitendinosus autograft on twenty-five patients and reported an increase in AOFAS score from a mean pre-operative value of 71.1 to a mean post-operative value of 95.1 [12]. Similarly, in another study on thirty-six patients who underwent anatomical reconstruction of the lateral ligaments of the ankle with semitendinosus allograft, the improvement in terms of AOFAS score was from 42.3 pre-operatively to 90.4 post-operatively [26]. Also, the Karlsson-Peterson ankle instability score in a systematic search of the literature published by [PERSON] et al. showed a post-operative increase to a mean value of 90.1 after anatomic reconstruction of the lateral ligament complex [24]. In order to evaluate the ability to return to everyday activities and participation in physical activity and sports after surgery, the UCLA score was collected both pre-operatively and after the surgical procedure.