Treatment strategies for partial chronic instability of the distal syndesmosis: an arthroscopic grading scale and operative staging concept

The aim of this study was to evaluate three different anatomical reconstruction techniques for the partial chronic isolated instability of the syndesmosis based on own arthroscopic classification criteria. A retrospective study was conducted to review 32 patients (15 female, 17 male; average age 41; range 18-71) with isolated partial chronic instability of the syndesmosis. During the arthroscopic examination of the patient, the instability of the syndesmosis was assessed by inserting a dissector of defined size into the distal tibiofibular joint. The lateralization of the fibula in the distal tibiofibular joint was then semi-quantitatively evaluated and classified. In all cases, open reconstructive surgery was carried out at the same time. Depending on the grading of the instability assessed arthroscopically (Grades I-III), one of three different anatomical reconstruction techniques was performed: suture of the anterior inferior tibiofibular ligament (AITFL), ligament repair using periosteal flaps, or autogenous plantaris tendon graft. Patients in all three groups were treated with a screw and an additional preassembled suture-button device. At 8 weeks after surgery, the screw was removed and full weight bearing was allowed. Clinical and radiological follow up were obtained at an average time of 17 months after surgery. Clinical evaluation of the reconstruction techniques was assessed using the American Orthopaedic Foot and Ankle Score (AOFAS) and the Weber Score. The median AOFAS score was significantly higher than before surgery for all three groups. In addition, the Weber score was significantly lower in all three groups than before surgery, indicating substantial improvement. There were no complications after the arthroscopies and the reconstructive surgeries. But in two cases, suture granuloma occurred within the 17-month window, which was treated with a revision operation and removal of the suture-button device. Depending on the arthroscopic classification of the partial chronic instability of the syndesmosis, the three different anatomical reconstruction techniques potentially provide appropriate treatment options based on the grade of injury.