Patient characteristics and inclusion/exclusion criteria:
Between April 2021 to July 2021, 253 cases of lateral ankle injury who were planned to be treated surgically at our hospital were collected prospectively according to the including and excluding criteria. And all patients were treated surgically by three surgeons specializing in foot and ankle sports medicine. Among those cases, 60 patients were required to perform traditional open insertional repairing procedure because of the patient’s personal willingness or the reasons unsuitable of arthroscopic repair (Fig. 1).
The clinical inclusion criteria were included: lateral ankle ligaments injury (LAI) with repetitively sprain or persistent symptoms of pain and swelling and failed with conservative treatment; acute lateral ankle ligaments injury; Positively anterior drawer and talar tilt tests; Preoperative MRI was showing both ATFL and CFL injury; the conditions requiring open procedures: large avulsive fracture of distal fibular unable dissection arthroscopically, CFL injury near the calcaneus insertion, combined with peroneal tendon injury, peroneal tendon dislocation. Exclusion criteria were included: Previous ankle surgeries; MRI were showing absence of ATFL or CFL which was suitable for ligament reconstruction; Infection involving ipsilateral ankles, Congenital ankle deformity or disease, ankle fracture or dislocation requiring surgical intervention (including medial/lateral/posterior malleolar and talar/calcaneus fractures, not including lateral and medial malleolar avulsion fracture). Sixty patients were divided into two groups: arhroscopic locating group (29 cases) and open locating group (31 cases).
Surgical procedures and intraoperative measurements:
Arthroscopic locating group:
After spinal anesthesia, patients were placed in the semilateral decubitus position, and a pneumatic thigh tourniquet was used to control the pressure at 300 mmHg. Arthroscopic procedure was performed according to the previously study[17], Standard anteromedial (AM) and anterolateral (AL) portals were established, and the intra-articular lesions were investigated and addressed using a 4.0-mm 30O angled arthroscope and a shaver. After the synovial tissue and the fibular insertion of ATFL were debrided, and the lowest point of fibula (LPF) were identified under arthroscopic view via AM portal, and a marker was made at this point by a 4.0-mm radiofrequency ablation. Following that, a 3.0-mm bone tunnel was made at this point by a power drill via AL portal (Fig. 2). The bundle just running inferiorly and posteriorly below the LPF, was identified as iATFL and the arciform fiber (Fig. 3). We labelled this fiber by a blue-color PDS II suture(VICRYL™ Polyglactin 910 Sterile Synthetic Absorbable Surgical Suture PDS™ II (Polydioxanone) Sterile Synthetic Absorbable Surgical Suture ), which was percutaneously introduced by a 16# spinal needle just at the level of the fibula tip, and penetrated through the deep layer of the iATFL, and into the ankle joint under the arthroscopic visualization (Fig. 3B). After that, a traditional open Brostrom procedure was performed[18]. The inferior extensor retinaculum (IER) was dissected and retracted distally, The lateral ankle ligament was exposed and the penetrating point of PDS II suture on iATFL and the arciform fiber was verified (Fig. 4A) intraoperatively, and the distances of penetration point to the horizontal line cross the fibular tip and the vertical line cross the FOT were measured. Following that, the distances of bone tunnel to the fibular tip, the fibular insertion of anterior-inferior tibiofibular ligament (AITFL), and the Fibular obscure tubercle (FOT) were measured using a calliper (Shanghai Measuring and Cutting Tools Company Ltd., Shanghai, China) (Fig. 5);when the measurement completed, the ATFL and CFL were sutured to the fibular insertions using three 2.3-mm suture anchors ( Osteoraptor, Smith and Nephew, Andover, MA, USA) (Fig. 4B). The inferior extensor retinaculum (IER) and capsule were advanced proximal and sutured to the anterior border of the lateral malleolus.
Open locating group:
The traditional open Brostrom procedure was performed directely, and a 3.0-mm bone tunnel was made at the ATFL insertion referenced to FOT by a power drill after capular dissection. And the measurements and ligaments repair procedure were performed as mentioned above.
The distances of bone tunnel to the fibular tip, the fibular insertion of anterior-inferior tibiofibular ligament (AITFL), and the Fibular obscure tubercle (FOT) were measured and compared between two groups.
Postoperative computed Tomography (CT) evaluation:
A 32-multi-detector-row CT (GE Medical System, Milwaukee, WI, USA) was used in this study with a 0.4 mm slice thickness. Then a 3-dimensional images were reconstructed.
The diameter of bone tunnel which was prepared for suture anchor implantation was calculated as a diameter of 3.0 mm. The distances of bone tunnel to the fibular inferior tip and the FOT were measured on 3D CT oblique sagittal view. The FOT on sagittal view was defined as a corner of the anterior inferior slope of distal fibula from the anterior tubercle of fibula (ATF) to the fibular inferior tip (Fig. 6A)[19]. The 3d-CT measurements were compared between two groups. The angle of suture anchor in axial plane was defined as a angle between the line tangent to articular surface of fibula and the axial line of the drilled bone tunnel (Fig. 6B-C). If the implanted suture anchor was neither penetrated into the fibular articular surface and fibular groove nor broken the lateral wall of bone tunnel, we considered it’s a safe angle in axial plane for suture anchor implantation (Fig. 7).
Statistical analysis:
Statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) version 22.0 (SPSS Inc., Chicago, IL, USA). Means and standard deviations were reported for numerical variables. T test was used to compare between two samples, and p < 0.05 was indicating statistically significant.