Acute ankle fractures are one of the leading pathologies disturbing ankle congruence. These fractures are extremely common with an incidence of 0.1–0.2 % per year [
1,
2]. Operative treatment performing open reduction and internal fixation (ORIF) is the standard of care for unstable or dislocated ankle fractures with the main goal of anatomical realignment of the joint and restoration of ankle stability [
3,
4]. Nevertheless, even successful anatomical reduction does not automatically lead to favourable clinical outcome. According to several studies, the mid- and long-term outcome following operative treatment of acute ankle fractures is often poor [
5,
6]. Residual symptoms following ankle fracture include chronic pain, stiffness, recurrent swelling and ankle instability [
5,
7]. There is growing evidence that this poor outcome might mostly be related to occult articular injuries involving cartilage and soft tissues [
2,
8,
9]. These intra-articular disorders have been shown to negatively affect the clinical results, but it is difficult to diagnose them by physical examination, standard radiography or CT-scans. Magnetic resonance imaging is the most reliable non-invasive diagnostic technique to identify osteochondral lesions (OCL). Nevertheless, in literature its sensitivity varies from 62 to 95 % [
10‐
13]. In case of acute fractures to the ankle, the sensitivity is further reduced due to the traumatic oedema leading to a misjudgement of the appearance and size of OCLs [
14]. In this context, many authors have emphasized the value of ankle arthroscopy [
6,
7,
15]. In the last decades, it has become a safe and effective diagnostic and therapeutic procedure and has also been proposed in fracture treatment [
16]. In ankle fractures, arthroscopically assisted open reduction and internal fixation (AORIF) allows a confirmation of the anatomic reduction, careful examination of the cartilage, capsular and intra-articular ligaments. If necessary, the intra-articular pathologies can immediately be addressed by removing ruptured ligaments and loose bodies, performing chondroplasty or micro fracturing if necessary [
15]. There is no evidence that a supplementary ankle arthroscopy leads to a higher complication rates in ankle fracture treatment [
8]. On the other hand, small or superficial chondral lesions might heal spontaneously without arthroscopic treatment. Further, the benefit of supplementary ankle arthroscopy in ankle fracture management has not yet been clearly demonstrated. There are only two randomised controlled trials evaluating the effect of additional ankle arthroscopy in isolated fractures of the distal fibula at the level of the syndesmosis (AO type 44 B1). Both documented a high incidence of intra-articular damage. In one study, patients treated arthroscopically showed significant better outcome results. Nevertheless, the vast majority of ankle fractures are managed by open procedures only [
17]. Given the absolute lack of RCTs comparing AORIF to ORIF in complex ankle fractures, it is not possible to give recommendations regarding the use of additional arthroscopy up to now. However, several studies could demonstrate that the incidence of OCLs is higher the more complex the fracture is [
2,
9]. Based on these findings, it is comprehensive that the effect of arthroscopy might be even more distinctive in complex ankle fractures. Therefore, we perform the first randomised controlled trial intended to report the short-, midterm- and long-term follow-up of patients who underwent operative treatment of complex ankle fractures – with and without ankle arthroscopy.