Abstract
The distal tibiofibular syndesmosis is crucial for ankle stability resisting diastasis and stabilizing against internal rotation and posterior fibular dislocation. Treatments for syndesmotic injuries include trans-syndesmotic screw or dynamic suture button fixation. In this technique, the torn posteroinferior tibiofibular ligament is reconstructed with anchor sutures running diagonally, mimicking the anatomic direction of the posteroinferior tibiofibular ligament fibers, ensuring syndesmotic anatomy and stability.
Technique Video
Distal tibiofibular syndesmosis is crucial in maintaining ankle stability by preventing tibiofibular diastasis. The structure consists of the following ligaments: anteroinferior tibiofibular ligament (AITFL), posteroinferior tibiofibular ligament (PITFL), and interosseus membrane, with some authors marking the interosseus ligament as a part of the interosseus membrane.
PITFL is built from 2 layers: superficial and deep: the superficial component inserts in the Volkmann tubercle after being directed superiorly and medially from the posterior margin of the lateral malleolus. Conical in shape, the deep component inserts into the posterior edge of the tibia from the proximal region of the malleolar fossa. Its implantation is directly posterior to the inferior tibial articular surface’s cartilaginous layer. Some authors call this structure a transverse ligament.1 The role of distal tibiofibular syndesmosis is to maintain tibiotalar congruence and stability over multidirectional forces affecting this joint.2,3 In particular, the PITFL has the highest restricting potential to diastasis, and the course of its fibers makes it the strongest in limiting internal rotation in the talocrural joint and posterior dislocation of the fibula.2, 3, 4 Because of its function and the fact that syndesmotic injuries occur mostly in supination and external rotation of the foot, it is the least common structure to be affected in such mechanisms, and it mostly occurs in combination with other injury to the syndesmotic structures.5,6
The most common treatment of syndesmotic injury is trans-syndesmotic screw or dynamic suture button fixation with no consensus in the literature about which method is better. Over the years, arthroscopy has emerged as a treatment option providing a less traumatic approach to the surgery. We describe arthroscopic reconstruction of the superficial PITFL.
Surgical Technique
The instructional video of PITFL reconstruction is presented in Video 1. Pearls, pitfalls, and risks of the technique are presented in Table 1. Steps of the technique are listed in Table 2.
Table 1.
Pearls and Pitfalls of the Technique
| Pearls | Pitfalls |
|---|---|
| Possibility to treat additional intra-articular lesions | Steep learning curve |
| No need for grafting | Suboptimal tensioning of the suture may cause ankle flexion range-of-motion limitation |
| Minimally invasive procedure | Chances of iatrogenic osteochondral lesion |
| Suits high-demanding patients well | Risk of iatrogenic sural nerve injury |
| Better cosmetic outcome | |
| Anatomic reconstruction |
Table 2.
Step-by-Step Description of the Technique
| Step 1 | Patient positioning and preparation |
| Step 2 | Posteromedial and posterolateral portal preparation |
| Step 3 | Assessment of the lesions |
| Step 4 | Debridement of scar tissue |
| Step 6 | Incision in the midpoint of the fibular PITFL insertion |
| Step 7 | Canal creation for fibular PITFL insertion for suture anchor |
| Step 8 | Corkscrew® FT suture anchor (Arthrex) implementation into the fibula |
| Step 9 | Suture anchor examination |
| Step 10 | Canal for the tibial anchor drilling in the Volkmann tubercle |
| Step 11 | PushLock anchor (Arthrex) preparation and threading with a suture deriving from the fibular anchor |
| Step 12 | PushLock sutureless anchor implantation in the tibia |
| Step 13 | Examination of the reconstruction |
| Step 15 | Cut of loose ends of the suture, instrumentation removal, and subsequent wound closure |
PITFL, posteroinferior tibiofibular ligament.
Patient Positioning and Preparation
The procedure is performed in the operating room with arthroscopic instrumentation described below. Before the operation, the patient is given a standard antibiotic prophylaxis. The operation starts with the patient placed prone and with the foot overhanging the table to facilitate the approach to the PITFL and to allow full range of passive movement. A pneumatic tourniquet is placed above the knee and inflated to 250 to 300 mm Hg to create a bloodless surgery field. The procedure should take no longer than 1 hour.
Equipment
Our technique requires the following equipment: standard 4-mm 30° arthroscope, 3-mm shaver, Corkscrew FT suture anchor (Arthrex), PushLock anchor (Arthrex), arthroscopic probe, arthroscopic elevator, and arthroscopic suture cutter.
Arthroscopic Portals
The operation begins by creating posterior portals to the ankle joint, following the method of van Dijk et al.7,8 Standard posterolateral and posteromedial portals for the posterior ankle compartment are used during the procedure.
Stabilization of the PITFL
After the portals are done, the arthroscope is inserted through the posterolateral portal into the ankle joint. The PITFL is identified, and the damage to the deep and superficial parts is assessed (Fig 1). Subsequently, through the discontinuity in the ligament, the arthroscope is advanced into the talocrural joint to examine any intra-articular lesions (Fig 2). The tibiofibular stability is evaluated by pushing the fibula laterally. An excessive displacement of the fibula may indicate syndesmotic instability. Next, debridement of the scar tissue begins. In cases of chronic lesions, more extensive tissue excision may be necessary. In our case, as the lesion was acute, we aimed to minimize tissue removal.
Fig 1.
View from the posterolateral portal. Key anatomic structures are labeled. The patient lies in the prone position, and the operation is done on the right leg. (A) The superficial part of the posteroinferior tibiofibular ligament (PITFL) is visualized. The arthroscopic findings confirm complete rupture of the PITFL. (B) After pushing laterally the torn ligament, the deep part of the PITFL is uncovered. Through the discontinuity in the ligament, the arthroscope can be inserted into the talocrural joint. (D, distal; L, lateral; M, medial; P, proximal.)
Fig 2.
View from the posterolateral portal. Key anatomic structures are labeled. The patient lies in the prone position, and the operation is performed on the right leg. The talocrural joint is inspected for any concomitant intra-articular lesions. The tibiofibular stability can be assessed by pushing the fibula laterally. (D, distal; L, lateral; M, medial; P, proximal.)
The anchor insertion point is selected at the midpoint of the native fibular PITFL insertion. During this step, the posterolateral portal is used for visualization, while the posteromedial portal is used for instrumentation. An incision is made at the midpoint of the fibular ligament insertion using a suture anchor guide, allowing access to the fibula behind the ligamentous tissue (Fig 3). Through the ligament, a canal for the anchor is predrilled using a drill with a slightly smaller diameter than that of the anchor (Fig 4). A 3.5-mm titanium Corkscrew FT suture anchor is then inserted into the fibular canal, ensuring it is fully embedded, with the anchor’s sutures extending from the surgical wounds (Fig 5).
Fig 3.
View from the posterolateral portal. Key anatomic structures are labeled. The patient lies in the prone position, and the operation is performed on the right leg. (A) After the inspection is done, the visualization heads to the fibular insertion of the superficial posteroinferior tibiofibular ligament. In the middle of the insertion, an approach to the subligamentous bone is created with a suture anchor guide. (D, distal; L, lateral; M, medial; P, proximal.)
Fig 4.
View from the posterolateral portal. Key anatomic structures are labeled. The patient lies in the prone position, and the operation is performed on the right leg. Through the hole in the ligament, the canal for the anchor is predrilled with an appropriately smaller diameter compared with the size of the anchor. (D, distal; L, lateral; M, medial; P, proximal.)
Fig 5.
View from the posterolateral portal. Key anatomic structures are labeled. The patient lies in the prone position, and the operation is performed on the right leg. In the previously created canal, the 3.5-mm suture anchor is screwed. (B) The anchor should be fully immersed in the fibular canal, with the anchor’s sutures protruding from the surgical wounds. (D, distal; L, lateral; M, medial; P, proximal.)
The portals are switched again, using the posteromedial portal for visualization and the posterolateral portal for instrumentation. At this stage, the Volkmann tubercle is visualized, and a canal is drilled in its center, again using a drill of a slightly smaller diameter than the size of the PushLock anchor (Fig 6). This anchor is threaded with sutures from the previously implanted anchor. The correction and adjustment of syndesmotic diastasis occur at this point, ensuring the appropriate tension for fixation. This is achieved by proximalization of the ligament to the Volkmann tubercle. This step should be done in the foot position so that the syndesmotic diastasis is the narrowest, in most cases in a neutral position (Fig 7). Once adjusted, the anchor is secured in the Volkmann tubercle canal with a few careful mallet blows (Fig 8).
Fig 6.
View from the posteromedial portal. The patient lies in the prone position, and the operation is performed on the right leg. Key anatomic structures are labeled. Next, the arthroscope visualizes the Volkmann tubercle, and a drill in the cannula is aimed at the structure. Next, the tibial canal is predrilled with an appropriately smaller diameter compared with the size of the PushLock (Arthrex) anchor. (D, distal; L, lateral; M, medial; P, proximal.)
Fig 7.
View from the posteromedial portal. The patient lies in the prone position, and the operation is performed on the right leg. Key anatomic structures are labeled. (A) The PushLock (Arthrex) is threaded with the sutures from the suture anchor. (B) The superficial posteroinferior tibiofibular ligament is approximated to the Volkmann tubercle. This step should be done in the foot position so that the syndesmotic diastasis is the narrowest, in most cases, in the neutral position. (D, distal; L, lateral; M, medial; P, proximal.)
Fig 8.
View from the posteromedial portal. The patient lies in the prone position, and the operation is performed on the right leg. Key anatomic structures are labeled. Next the PushLock (Arthrex) anchor is inserted into the tibia with a few meticulous mallet blows. (D, distal; L, lateral; M, medial; P, proximal.)
The suture should run diagonally, mimicking the anatomic direction of superficial PITFL fibers. Care should be taken to avoid excessive oblique inclination, which could expose the reconstruction to greater shear forces. The fixation is then assessed by checking the tibiofibular stability, anchor position, and position of the sutures (Fig 9). Special attention should be given to ensure anchors are fully embedded, sutures are tensioned properly, and there is no residual tibiofibular instability, as these factors can negatively impact outcomes.
Fig 9.
View from the posteromedial portal. The patient lies in the prone position, and the operation is performed on the right leg. Key anatomic structures are labeled. (A) After the PushLock (Arthrex) is inserted into the tibial canal, the fixation is assessed by pushing it with a probe. Care should be undertaken to assess the tension of the suture. (B) Next, the arthroscope is inserted into the talocrural joint, with an inspection of how the fixation affects the joint. (D, distal; L, lateral; M, medial; P, proximal.)
When the fixation is satisfying, the loose ends of the sutures can be cut and the instrumentation pulled out, with subsequent wound closure (Fig 10). If there is an additional lesion of the AITFL, the patient can be changed intraoperatively to the supine position and operated on according to our AITFL reconstruction procedure.9
Fig 10.
View from the posteromedial portal. The patient lies in the prone position, and the operation is performed on the right leg. Key anatomic structures are labeled. When the fixation is satisfactory, the loose ends of the suture can be trimmed with subsequent evacuation of the surgical instruments and wound closure. (D, distal; L, lateral; M, medial; P, proximal.)
Discussion
High ankle sprains, or syndesmotic injuries, occur mostly as sports injuries and account for 1 per 10,000 athletes exposed to sports.10 Those lesions should be treated operatively in an acute setting, as neglect can lead to osteoarthritis in the talocrural joint due to the elevation of pressure in the ankle joint. Moreover, in neglected cases, the patients may have activity-related pain, poor functional outcomes, instability, and stiffness of the ankle joint.11
The most common treatment modalities, such as trans-syndesmotic screw or suture button fixation, affect the whole syndesmosis and are not anatomic fixations. Moreover, according to Arbeitsgemeinschaft für Osteosynthesefragen, also known as AO Foundation guidelines, the screws should be removed, meaning that there is a need for subsequent operation. Additionally, both methods pose a risk for malreduction as they do not re-create the native anatomy of all syndesmotic structures.12 We believe that re-creation of the anatomy plays a crucial role in restoring the function of the syndesmosis and minimizes the risk of malreduction. Furthermore, our technique does not require hardware removal, and the fixation is finite, meaning that further surgeries are redundant.
The literature about PITFL reconstruction is scarce, yet the study by Little et al.13 reviewed the outcomes of open PITFL reconstruction in ankle fractures. They extended the posterolateral approach to a lateral malleolus fracture to access the posterior compartment of the ankle and fixed the PITFL on a 3.5-mm cortical screw. The arthroscopic modality utilized in our technique can enhance the procedure and decrease the size of the incision, improving patient satisfaction from the surgery and functional outcomes compared to open reconstructions.
A cadaveric study performed by Takahashi et al.2 compared anatomic fixation of the PITFL and AITFL with transyndesmotic fixation. Their results showed that in a setting of ruptured syndesmotic ligaments, the reconstruction only of the AITFL and dynamic syndesmotic fixation is sufficient in terms of biomechanical factors. Yet, as they mentioned in the limitations section, the study could not compute the natural axial load of the limb and combine dorsiflexion with rotational force, which may be crucial in the testing as this mechanism is particularly involved in syndesmotic injuries. We believe that restoration of the native course of the fibers reinstates function to the greatest extent.
This report describes an arthroscopic reconstruction of the superficial part of the PITFL. This particular method is suitable in almost every setting of the injury and mechanism because it restores the native course of the ligament. Furthermore, in contrast to the standard syndesmotic treatment modalities, it is minimally invasive, as isolated syndesmotic ligament injuries may be overtreated in such cases.
Disclosures
All authors (A.M., W.B., A.R-K., J.Z., G.K.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Supplementary Data
After creating posterior portals to the ankle joint, following the method of van Dijk et al.,7,8 the posteroinferior tibiofibular ligament (PITFL) insertion is identified, and the damage to both its superficial and deep parts is assessed. Subsequently, through the discontinuity in the ligament, the arthroscope is advanced into the talocrural joint to examine for any intra-articular lesions. Next, debridement of the scar tissue is recommended. For chronic lesions, more extensive tissue excision may be necessary. In our case, as the lesion was acute, we aimed to minimize tissue removal. The anchor insertion point is selected at the midpoint of the native fibular PITFL insertion, and then an incision is made using a suture anchor guide, allowing access to the fibula behind the ligamentous tissue. Through the ligament, a canal for the anchor is predrilled with a diameter slightly smaller than that of the anchor. A 3.5-mm titanium suture anchor is then inserted into the fibular canal, ensuring it is fully embedded, with the anchor’s sutures extending from the surgical wounds. The anchor placement is checked. It should be fully immersed into the tibial canal. The portals are switched again. At this stage, the Volkmann tubercle is visualized, and a canal is drilled in its center. The drill in the cannula is inserted from the posterolateral portal. The sutureless anchor is threaded with sutures from the previously implanted anchor in the fibular insertion. The correction and adjustment of syndesmotic diastasis occur at this point, ensuring the appropriate tension for fixation. This is achieved by proximalization of the ligament to the Volkmann tubercle. This maneuver should be performed with the foot in a neutral position. Once adjusted, the anchor is secured in the Volkmann tubercle canal with a few careful mallet blows. The suture should run diagonally, replicating the anatomic direction of the superficial PITFL fibers. Care should be taken to avoid excessive oblique inclination, which could expose the reconstruction to greater shear forces. Fixation is then assessed by checking tibiofibular stability to ensure that there is no excessive fibular subluxation. At this stage, the tension of the reconstruction is assessed. We recommend performing this maneuver by poking the reconstruction with the probe. Next, the anchor placement is checked to see if they are fully immersed into the canals. Once the fixation is satisfactory, the loose ends of the sutures are cut and the surgery comes to an end.
References
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
After creating posterior portals to the ankle joint, following the method of van Dijk et al.,7,8 the posteroinferior tibiofibular ligament (PITFL) insertion is identified, and the damage to both its superficial and deep parts is assessed. Subsequently, through the discontinuity in the ligament, the arthroscope is advanced into the talocrural joint to examine for any intra-articular lesions. Next, debridement of the scar tissue is recommended. For chronic lesions, more extensive tissue excision may be necessary. In our case, as the lesion was acute, we aimed to minimize tissue removal. The anchor insertion point is selected at the midpoint of the native fibular PITFL insertion, and then an incision is made using a suture anchor guide, allowing access to the fibula behind the ligamentous tissue. Through the ligament, a canal for the anchor is predrilled with a diameter slightly smaller than that of the anchor. A 3.5-mm titanium suture anchor is then inserted into the fibular canal, ensuring it is fully embedded, with the anchor’s sutures extending from the surgical wounds. The anchor placement is checked. It should be fully immersed into the tibial canal. The portals are switched again. At this stage, the Volkmann tubercle is visualized, and a canal is drilled in its center. The drill in the cannula is inserted from the posterolateral portal. The sutureless anchor is threaded with sutures from the previously implanted anchor in the fibular insertion. The correction and adjustment of syndesmotic diastasis occur at this point, ensuring the appropriate tension for fixation. This is achieved by proximalization of the ligament to the Volkmann tubercle. This maneuver should be performed with the foot in a neutral position. Once adjusted, the anchor is secured in the Volkmann tubercle canal with a few careful mallet blows. The suture should run diagonally, replicating the anatomic direction of the superficial PITFL fibers. Care should be taken to avoid excessive oblique inclination, which could expose the reconstruction to greater shear forces. Fixation is then assessed by checking tibiofibular stability to ensure that there is no excessive fibular subluxation. At this stage, the tension of the reconstruction is assessed. We recommend performing this maneuver by poking the reconstruction with the probe. Next, the anchor placement is checked to see if they are fully immersed into the canals. Once the fixation is satisfactory, the loose ends of the sutures are cut and the surgery comes to an end.