Study design and patients
Between September 2018 and March 2020, who had persistent ankle pain and associated activity restrictions despite at least 6 months of nonoperative management, mechanical instability with manual anterior drawer test (ADT) stress maneuvers, with or without recognizable tenderness on palpation medial to the tibialis anterior tendon, and follow-up for at least 2 years, were assessed for study inclusion (25 males and 18 females; average age, 38.4 years; age range, 20-65 years). Preoperative plain radiography and magnetic resonance imaging (MRI) were also conducted. All patients agreed to arthroscopic ATFL repair and were separated into two groups: AMAI group (AMAI including intraoperative AMAO resection; 15 males and 14 females) and pure CLAI (with AMAO but without AMAI, no AMAO resection; 10 males and 4 females). The study excluded patients with ALAI, manifest tibiotalar osteoarthritis, severe peripheral angioneuropathy, soft tissue infection at the surgical site, or a history of mental illness. All participants provided written informed consent, and the study was approved by our institution's Ethics Committee.
Preoperative and 2-year follow-up measurements of ankle dorsiflexion, the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and the visual analog scale (VAS) were taken. In all cases, the same pre- and postoperative questionnaires were used.
Operative procedure and rehabilitation
A tourniquet was used to prevent intraoperative bleeding after general anesthesia was administered. Traditional anteromedial and anterolateral portals are used for diagnostic ankle arthroscopy. This arthroscopy should include the removal of pathologically hypertrophied synovium and fibrous tissue such as the lateral malleolus, lateral gutter, anterior and inferior of the anterior lower tibiofibular ligament, anterior distal of the tibia, tibiotalar space, talar neck, medial malleolus, and medial gutter, as well as the arthroscopic treatment of other pathologic conditions such as talus osteochondral lesions. Furthermore, the patients in the AMAO group had AMAO resection, and the resection range is appropriate for ankle dorsiflexion and inversion without impingement under arthroscopic visualization until the medial gutter of the ankle mortise is exposed. Then double suture anchors (Smith & Nephew, Andover, MA) with a diameter of 2.9 mm are placed to the adequate visualization of the anterior distal face of the fibula. The first bone anchor is placed 1 cm superior to the tip of the fibula, the second bone anchor is then placed 1 cm superior to the first anchor in the anterior face of the fibula. The ATFL is repaired with the arthroscopic modified Broström technique[24]. The ankle is held in neutral to slight eversion then the sutures are tightened and knotted. Following complete arthroscopy, the portals were closed using a single nylon suture and the ankle is tested for stability.
The affected extremity was wrapped with and elastic bandage and elevated, local ice compress for 24h. The suture was removed 2 weeks postoperatively. The toes, hips, and knees could be exercised on the first day postoperatively, as well as slight dorsiflexion and plantar flexion of the ankle. Patients used crutches and followed partial weight-bearing with walking boots for 4 weeks. After that, patients began to abandon the crutches and started weight-bearing activities with walking boots. Until 6 weeks postoperatively, patients began normal weight-bearing activities without walking boots. Noteworthy, passive varus and valgus of the ankle were forbidden within 6 weeks postoperatively. In the follow-up regularly, we performed physical examinations and clinical evaluations of the patients, and guide further functional exercise.
Ankle model reconstruction and intelligent analysis
CT scans (64 detector rows, 0.625-mm-thick slices, 120 kV, 125 mA) of each patient's affected side ankle were performed before and after arthroscopic surgery, and the resulting Digital Imaging and Communications in Medicine (DICOM) data were used. Arigin 3D Pro (Shanghai Xinjian Medical Technology Co.) was used to analyze DICOM images and create a 3-dimensional reconstruction of the ankle. To achieve the desired effect, the software operation interface adjusts the window width and window level. Filtering and noise reduction are used in two-dimensional image preprocessing. Different gray thresholds were set in the cross-section, coronal plane, and sagittal plane to distinguish bone from soft tissue.
Artificial intelligence in the Arigin3D-STS-Design software identified osteophytes, and the clipping algorithm was used to remove the part of the surface distance of less than 1mm. The parameters of the osteophytes were then measured using the Arigin3D-STS-Design measurement module. The postoperative model was then superimposed onto the preoperative model using the ICP (iterative closest point) algorithm. Finally, we used a proximity mapping technique to quantify the morphologic changes in the postoperative model compared to the preoperative model.
Statistical analysis
The statistical software SPSS Version 19.0 (IBM, Chicago, IL, USA) was used for the analysis. A two-sample t test or a two-sample Wilcoxon rank-sum test were used to compare continuous variables. P values less than 0.05 were considered statistically significant.