Study follow-up

A subjective evaluation (questionnaires), physical examination and radiographic analysis are performed preoperatively and again 6 weeks, 6 and 12 months postoperatively. The further follow-up visits include yearly examination, as the long-term follow-up is essential regarding the outcome parameter of this trial (Schedule of events see Table 2). Patients enrolled in our study do not need any additional outpatient visits or radiographic investigations. The data that we obtain from the medical records include the patient’s age and sex, date of injury, date of surgery, classification of the ankle fracture, grade and locations of intra-articular lesions such as chondral lesions, loose bodies, ligamentous damage and presence or absence of concurrent synovitis, course of wound healing, pre- and posttraumatic activity level, time to return to work and sports and quality of life. Pseudonymization is performed for all patients’ details.

Schedule of events

In order to blind subjective evaluation, questionnaires are answered before physical examination is performed. Patients will answer questions about their general satisfaction, pain level (VAS), activity level and any complaints. The Short Form 12 (SF-12) [29] and the Tegner Activity Scale (TAS) [30] are filled in pre- and postoperatively.

For the physical examination blinding of the patients is not feasible as the arthroscopy portals are visible. The physical examination consists of the inspection of the hind foot including hind foot axis, ankle swelling and wound healing. The important anatomical landmarks are examined for any painful structure. Clinical tests involve medial and lateral ligament stability and non-weight bearing, assisted dorsal and plantar range of motion measured with a goniometer. The physical examination further includes functional outcome scores. The AOFAS Score (American Orthopaedic Foot and Ankle Society) [31], JSSF Score (Japanese Society of Surgery of the Foot) [32], OMAS (Olerud and Molander Score) [33], Karlsson Score are used to evaluate postoperative functional outcome.

The AOFAS score is the primary outcome parameter. It is one of the most widely used scoring systems to evaluate functional ability and physical examination incorporated in a numeric scale. It has been widely adopted and has become an accepted standard of assessing patients after foot and ankle surgery. A validated German language version is used.

The JSSF, OMAS, Karlsson Score, TAS and SF-12 are recorded postoperatively. Further secondary outcome parameter are radiographic analysis, arthroscopic findings of intra-articular lesions, time to return to work/sports and complications.

The radiographic assessments comprise the routine x-rays (non-weight bearing, a.p. and lateral) and a CT scan preoperatively and postoperatively. Postoperative radiographs and x-rays performed 6 weeks after the operation are non-weight bearing films. Beginning with 1-year of follow-up, weight-bearing films will be obtained. Position of implants, potential secondary dislocation and fracture consolidation/healing are evaluated and documented via radiographic analysis. The displacement of the fracture site is controlled fluoroscopically intra- and postoperatively; displacement is graded into three groups (no dislocation, dislocation ≤2 mm and dislocation >2 mm). In case sub-optimal reduction or malreduction ≥2 mm is recognized using intraoperative x-ray or arthroscopy, fixation will be removed and the reduction will be performed again. Thereafter the reduction is re-evaluated using x-ray and arthroscopy. If malreduction of ≥2 mm should be recognized in postoperative CT-scans revision surgery would be discussed with the patient. Radiographic assessment of posttraumatic osteoarthritis is performed according to the classification system by Kellgren et al. [34].

Detailed description and classification of the fracture are performed using the AO classification system.

The appearance, description and classification of intra-articular findings in the arthroscopic group are documented. Detailed description of the lesion, capsular, ligaments, ventral syndesmosis, grading and localization of chondral lesions (ICRS classification), loose bodies is recorded and analysed. These intraoperative findings are further analysed according to fracture classification. In order to determine the frequency and distribution of the chondral lesions in the series, fractures of the same type will be grouped together and statistical analysis will be performed to compare these groups. In Fig. 5 two examples of intra-articular pathologies are presented.

Exemplary arthroscopy images showing an osteochondral lesions grade 4 (ICRS) on the medial talus and loose bodies

According to the Data and Safety Monitoring Board Guidelines (National Institute of Health, NIH) we establish a group of experts (experienced trauma surgeons, who are not involved in our study) who independently review and evaluate the accumulated study data for participant safety, study conduct and progress and also efficiency of our study. In detail, arthroscopical findings and arthroscopy-associated complications will be evaluated thoroughly after 15 patients in the intervention group (AORIF). Based on these results, they will make recommendations concerning continuation, modification or termination of the trial.