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. The treatment of acute ankle fractures is determined by the classification of the injury based on radiographic findings. Operative treatment performing open reduction and internal fixation (ORIF) is the standard of care for unstable or dislocated ankle fractures. Anatomical realignment of the joint and restoration of ankle stability are the main goals of the operative treatment. Over the last decades the improved functional outcome has emphasized the importance of anatomic reconstruction. Nevertheless, successful anatomical reduction does not automatically lead to favorable clinical outcome. According to several studies, the mid- and long-term outcome following operative treatment of acute ankle fractures is often poor even though anatomical reconstruction of the joint has been achieved. Residual problems after acute ankle fractures include chronic pain, stiffness, recurrent swelling and instability. These problems occur despite the operative restoration of ankle congruence. There is growing evidence that the poor outcome might be mostly related to occult articular injuries involving cartilage and soft tissue damage. These intraarticular disorders have been shown to negatively affect the clinical results, but it is difficult to diagnose these intraarticular pathologies by physical examination, standard radiography or even CT-scans. In this context, many authors have well documented the value of ankle arthroscopy. Ankle arthroscopy is a standard minimally invasive technique that allows direct visualization of intraarticular structures without arthrotomy or malleolar osteotomy. In the last decades, it has become a safe and effective diagnostic and therapeutic procedure. In acute ankle fractures, arthroscopically assisted open reduction and internal fixation (AORIF) allows careful examination of the chondral aspects as well as the capsular and intraarticular ligaments. If necessary, the traumatic intraarticular pathologies can directly be addressed by removing loose bodies and ruptured ligaments extending into the joint, performing chondroplasty or micro fracturing if necessary. Furthermore, it allows a confirmation of the anatomic reduction without having any evidence that a supplementary ankle arthroscopy in acute ankle fracture treatment leads to a higher complication rate.

Until today, there are only two randomized controlled trials evaluating the effect of additional ankle arthroscopy. Both studies available comparing ORIF to AORIF included only patients with isolated fractures of the distal fibula at the level of the syndesmosis only. These are the most simple fractures that are regularly treated operatively. Thodarson et al. compared ORIF treatment of distal fibula fractures supplemented with or without ankle arthroscopy and found that 8 of 9 patients had articular damage to the talar dome in the arthroscopy group. Only minimal arthroscopic treatment was required and no outcome differences were noted after a mean follow-up of 21 months. Takao et al. documented an osteochondral lesion (OCL) in 74% in the arthroscopic group. In their study, the mean AOFAS score was significantly better when patients were treated arthroscopically. Moreover, several studies could consistently document, that the intraarticular damage is more pronounced the more complex the fracture is. Consequently, one must assume a more distinctive effect of arthroscopy in more complex fractures involving two malleoli or more - when compared to simple fractures.

Nevertheless, until now, the vast majority of ankle fractures are managed by open procedures only. Still, indications for AORIF are not clearly stated, and the effectiveness of AORIF compared with ORIF has not yet been determined for complex ankle fractures where the investigators would expect even better results as intraarticular lesions are more common in these fracture types. Moreover, the prognostic importance of traumatic articular lesions still remains unclear, although several studies suggest such injuries may be the source of functional deficits. Nevertheless, this concept seems to be intuitively comprehensible. In this context, only a prospective randomized study can sufficiently answer these open questions. Therefore, the investigators plan a randomized controlled trial intended to report the short-, midterm- and long-term follow-up of patients who underwent operative treatment of acute ankle fractures (AO A2, A3, B2, B3, C1-C3) - with and without ankle arthroscopy.