Views: 0 Author: Site Editor Publish Time: 2026-11-06 Origin: Site
Distal tibiofibular syndesmotic injuries are common in complex ankle fractures and rotational ankle trauma. They can occur alongside high fibular fractures, including Maisonneuve injuries, as well as certain fractures at the level of the syndesmosis.
When the syndesmotic complex is disrupted and the ankle is unstable, the fibula must be restored to its anatomical position within the tibial incisura and stabilized to allow the injured ligaments to heal.
Syndesmotic screw fixation has traditionally been used to maintain this relationship. However, several technical questions remain debated among orthopedic surgeons:
Should one or two syndesmotic screws be used?
Should the screw engage three or four cortices?
When, if ever, should the screw be routinely removed?
Should the screw pass through the fibular plate or be inserted separately?
How can anatomical reduction of the fibula within the tibial incisura be confirmed?
Although clinical evidence has helped clarify some of these questions, there is still no single fixation construct that is appropriate for every syndesmotic injury. The most important principle is to achieve and maintain an anatomically reduced, stable distal tibiofibular joint.
The distal tibiofibular syndesmosis is a ligamentous complex that connects the distal tibia and fibula. It plays an essential role in maintaining the ankle mortise and controlling the relationship between the two bones during ankle movement.
The syndesmotic complex includes:
Anterior inferior tibiofibular ligament (AITFL): Connects the anterior distal tibia and fibula.
Posterior inferior tibiofibular ligament (PITFL): Connects the posterior distal tibia and fibula.
Interosseous ligament (IOL): A strong ligamentous structure that continues from the interosseous membrane between the tibia and fibula.
Injury to these structures may result in abnormal separation, translation, or rotation of the distal fibula relative to the tibia.
Syndesmotic disruption commonly occurs during rotational ankle injuries, particularly pronation-external rotation mechanisms.
In a high fibular fracture pattern, such as a Maisonneuve injury, the force may travel through the syndesmotic complex and interosseous membrane, producing proximal fibular fracture and distal tibiofibular instability.
Certain transsyndesmotic fibular fractures may also be associated with syndesmotic disruption.
However, not every fibular fracture at or above the syndesmosis produces the same degree of instability. The entire ankle injury pattern must be assessed, including medial-sided injury, posterior malleolar involvement, and syndesmotic integrity.
When the syndesmosis is unstable, the fibula may lose its normal position within the tibial incisura.
This can affect:
Ankle mortise alignment.
Talar position and joint congruity.
Load distribution across the ankle joint.
Stability during weight-bearing and ankle movement.
If the syndesmosis heals in a malreduced position, patients may experience persistent pain, restricted ankle motion, instability, and an increased risk of post-traumatic degenerative changes.
For unstable injuries, the treatment objective is to restore the normal relationship between the distal tibia and fibula and maintain it during ligament healing.
A proximal fibular fracture associated with syndesmotic disruption is a characteristic feature of a Maisonneuve injury.
In many cases, the proximal fibular fracture is treated indirectly rather than with direct fixation. The primary surgical objective is to restore the length, alignment, and rotation of the fibula and reconstruct the stability of the ankle mortise.
The general treatment sequence includes:
Identify and assess the proximal fibular fracture and associated ankle injuries.
Restore the anatomical position of the distal fibula within the tibial incisura.
Address associated medial and posterior malleolar fractures when indicated.
Assess syndesmotic stability after the relevant fractures have been reduced and fixed.
Stabilize the syndesmosis if residual instability is present.
The surgeon should not assume that fixation of the syndesmosis alone will correct every component of a Maisonneuve injury. Fibular length, rotation, and the position of the distal fibula must all be considered.
After appropriate fixation of the associated ankle fractures, the syndesmotic complex should be assessed for both stability and anatomical reduction.
Intraoperative evaluation is important because static preoperative radiographs may not fully demonstrate dynamic instability.
A lateral stress test can be performed using a small bone hook to apply controlled lateral traction to the fibula.
The surgeon observes whether abnormal widening or displacement occurs at the distal tibiofibular joint.
The test should be performed under fluoroscopic guidance when appropriate.
Any interposed bone fragments or soft tissue within the syndesmosis should be identified and addressed because they may prevent anatomical reduction.
The surgeon can assess abnormal anterior-posterior movement of the distal fibula using a finger or bone hook.
The fibula is gently translated in both directions to evaluate whether excessive movement is present relative to the tibia.
This assessment helps identify instability that may not be obvious on standard radiographs.
Depending on the injury pattern, additional methods may include:
External rotation stress testing.
Direct visualization of the syndesmosis.
Fluoroscopic comparison with the contralateral ankle.
Arthroscopic assessment in selected cases.
Stability should be evaluated in more than one plane. Lateral translation alone may not identify abnormal fibular rotation or anterior-posterior displacement.
Accurate reduction is one of the most important steps in syndesmotic fixation.
The surgeon must restore:
Fibular length.
Fibular alignment.
Fibular rotation.
Anterior-posterior position within the tibial incisura.
If the fibula remains malpositioned, even a technically secure syndesmotic screw may maintain an abnormal ankle mortise.
If the fibula is displaced, anatomical reduction should be achieved before definitive syndesmotic fixation.
A small bone hook may be used to apply controlled traction to the lateral malleolus and restore the distal fibula to its appropriate position.
The surgeon should assess the fibular position using intraoperative fluoroscopy and, when necessary, direct visualization.
Particular attention should be paid to:
Fibular rotation within the incisura.
Distal fibular length.
Anterior-posterior translation.
The relationship between the fibula and the lateral wall of the talus.
A Kirschner wire (K-wire) may be used for temporary fixation once satisfactory reduction has been obtained.
A 2.0 mm K-wire may be inserted from the lateral side to maintain the reduced position temporarily.
In the technique described here, the entry point is located approximately 1–2 cm proximal to the joint line and below the planned distal syndesmotic screw position.
The ankle should be maintained in a neutral position during reduction and temporary fixation.
Fluoroscopic images should be obtained in appropriate planes to assess the reduction. Comparison with the contralateral ankle may provide additional information when normal anatomical variation makes interpretation difficult.
The exact K-wire entry point and trajectory should be adapted to the patient's anatomy, fracture configuration, and planned definitive fixation.
One important technical problem is inadequate anterior-posterior reduction of the fibula.
A fibula that is positioned too far anteriorly or posteriorly may appear acceptable on an anteroposterior view while remaining malreduced.
A lateral fluoroscopic view can help identify this problem. Abnormal alignment between the tibial plafond and talar dome may suggest residual malposition, although it should not be used as the only criterion.
Whenever possible, reduction should be confirmed using multiple imaging planes or direct visualization.
Once anatomical reduction has been achieved and instability confirmed, syndesmotic fixation may be performed using a screw or another appropriate stabilization device.
Syndesmotic screws are designed to maintain the relationship between the distal tibia and fibula during ligament healing. They are not intended to function as conventional compression screws across a fracture.
In the traditional screw fixation technique:
Maintain the ankle in a neutral position.
Identify the planned screw entry point proximal to the tibial plafond.
Prepare the drill trajectory across the fibula and into the tibia.
Use fluoroscopy to confirm the planned direction and position.
A commonly described technique directs the drill from posterolateral to anteromedial, approximately 30 degrees from posterior to anterior, relative to the transverse plane.
A 2.5 mm drill bit may be used for the preparation of a 3.5 mm cortical screw, depending on the selected system and the manufacturer's recommendations.
If a fibular plate is already present at the planned fixation level, the syndesmotic screw may be inserted through an appropriate plate hole. Alternatively, it may be placed separately when the anatomy and fixation plan allow.
The exact screw level and trajectory should be selected according to the patient's anatomy and the required fixation construct rather than following one fixed measurement in every case.
The required screw length is measured using a depth gauge.
Because the syndesmotic screw is intended to maintain the relationship between the tibia and fibula rather than compress a fracture, the traditional technique may involve tapping both the fibula and tibia before screw insertion.
The surgeon may select a 3.5 mm or 4.5 mm cortical screw, depending on the patient's anatomy, bone quality, and fixation requirements.
The foot should remain in a neutral position during screw insertion.
Fluoroscopy should be used to confirm screw position and syndesmotic alignment.
The number of syndesmotic screws remains a debated topic.
Some surgeons prefer a single screw for routine syndesmotic stabilization, while others use two screws in selected high-risk or more unstable injuries.
Two screws may be considered in certain Maisonneuve injuries or when additional fixation strength is required.
When a second screw is used, it is generally positioned parallel to the first screw and approximately 1.5–2 cm proximal to it, according to the anatomy and fixation construct.
The temporary K-wire can be removed after satisfactory reduction and definitive fixation have been confirmed.
What does the evidence say?
Clinical studies and systematic reviews have not established a universal advantage of two screws over one screw for all syndesmotic injuries. Screw number should be determined by injury severity, stability, bone quality, and the surgeon's assessment.
Another long-standing question concerns the number of cortices engaged by the syndesmotic screw.
Tricortical fixation: The screw engages the fibular cortex and the near and far tibial cortices.
Quadricortical fixation: The screw engages both fibular cortices and both tibial cortices.
Both techniques are used clinically. Available comparative evidence has not demonstrated a consistent, universal clinical advantage of one configuration over the other.
The choice should consider the required construct stability, bone quality, fracture pattern, and the surgeon's preferred technique.
Commonly used syndesmotic screws include 3.5 mm and 4.5 mm cortical screws.
The selection depends on the fixation strategy and patient-specific factors. A larger screw is not automatically better, and adequate reduction is more important than simply increasing screw diameter.
After insertion, the surgeon should confirm:
Correct screw trajectory.
Appropriate screw length.
Satisfactory fibular position.
No unintended displacement during tightening.
Stable syndesmotic alignment.
If the syndesmotic screw does not follow the prepared drill trajectory, it may push the fibula away from its reduced position.
This can result in syndesmotic malreduction even when the screw appears securely inserted.
To reduce this risk:
Maintain the fibula in the correct position throughout insertion.
Avoid excessive tightening.
Confirm reduction before and after screw placement.
Use fluoroscopy in more than one plane.
Consider direct visualization when reduction is uncertain.
Whether syndesmotic screws should be routinely removed after healing has been one of the most frequently discussed questions in ankle fracture surgery.
Historically, many surgeons preferred to remove syndesmotic screws several weeks or months after surgery, particularly before unrestricted ankle movement or weight-bearing.
However, more recent clinical evidence does not support routine removal in every patient.
Removal may be considered when patients develop:
Persistent pain related to the implant.
Mechanical irritation.
Restricted ankle movement that is reasonably attributed to the screw.
A symptomatic broken or prominent screw.
Other implant-related problems requiring intervention.
The RODEO randomized clinical trial and subsequent systematic reviews have challenged the practice of routine syndesmotic screw removal.
On-demand removal, in which the screw is retained unless symptoms or other clinical indications develop, has shown outcomes that are not inferior to routine removal in the studied populations.
Routine removal also carries potential risks, including wound complications, infection, screw breakage during extraction, and additional healthcare costs.
Therefore, the decision to remove a syndesmotic screw should be individualized rather than based on a fixed postoperative schedule.
When a fibular plate is used to stabilize the lateral malleolus, the syndesmotic screw may be inserted through a suitable plate hole.
Alternatively, it may be placed independently alongside the plate.
Both configurations are used in clinical practice.
The choice depends on:
The position of the fibular plate.
Available screw-hole locations.
The planned screw trajectory.
Fibular fracture morphology.
The required fixation construct.
The most important considerations are achieving anatomical syndesmotic reduction and ensuring that the screw does not interfere with other fixation components.
There is no universally preferred plate-through versus plate-independent configuration for every patient.
Postoperative imaging is important for evaluating screw position, fracture alignment, and the relationship between the distal tibia and fibula.
Intraoperative imaging should be used to assess:
Fibular length and alignment.
Syndesmotic reduction.
Screw trajectory and length.
Ankle mortise congruity.
The position of associated fracture fixation.
Anteroposterior, mortise, and lateral views provide complementary information.
In complex syndesmotic injuries, postoperative CT can provide a more detailed assessment of fibular position within the tibial incisura.
Bilateral CT comparison may be particularly useful when malreduction is suspected or when the injury involves a high fibular fracture, substantial comminution, or complex syndesmotic disruption.
MRI is useful for evaluating ligament injuries and associated soft-tissue pathology, particularly before surgery or when persistent symptoms require further investigation.
However, it is not generally the primary imaging method for assessing postoperative screw position or precise bony syndesmotic reduction. CT is usually more appropriate for evaluating the rotational and translational position of the distal fibula.
The anterior inferior tibiofibular ligament (AITFL) attaches to the anterior distal tibia and fibula.
An avulsion fracture from the anterolateral tibia is known as a Tillaux-Chaput fracture. An avulsion from the fibular side is commonly referred to as a Wagstaffe fracture.
These injuries may compromise syndesmotic stability and should be carefully evaluated during ankle fracture surgery.
For a displaced Tillaux-Chaput fragment, the surgeon should first restore the fragment to its anatomical position.
A small dental hook or another suitable reduction instrument may be used to manipulate the fragment.
A 1.0 mm K-wire can be used for temporary fixation when the fragment size and bone quality permit.
The reduction should be checked under fluoroscopy or by direct visualization.
A protective drill sleeve is used to protect the surrounding soft tissues.
A 2.5 mm drill bit may be used to prepare the screw hole, with the drill directed as close to perpendicular to the fracture plane as practical.
In a lag-screw technique, the near fragment is prepared as a gliding hole, while the far fragment is prepared for thread purchase. The far cortex should not be unintentionally penetrated when the planned fixation does not require it.
The precise drill diameter and trajectory should be matched to the selected screw system and fragment morphology.
After drilling, the depth is measured.
For the traditional technique described here, the near fragment is overdrilled to create a gliding hole, and the far fragment is tapped to obtain thread purchase.
A 4.0 mm cancellous screw with a washer may be selected when the fragment is sufficiently large to accept the implant.
A washer can help distribute the screw head load and reduce the risk of fragment damage.
The screw is inserted to secure the Tillaux-Chaput fragment in its anatomical position.
The surgeon should confirm:
Adequate reduction of the fragment.
Stable fixation.
Restoration of the anterior syndesmotic attachment.
No intra-articular screw penetration.
Appropriate syndesmotic stability after fixation.
Anatomical fixation of an AITFL avulsion fragment may restore an important component of syndesmotic stability. In selected cases, this may reduce or eliminate the need for additional transsyndesmotic fixation, but stability must always be reassessed.
When the avulsion fragment is too small or comminuted to accept a conventional screw, alternative fixation methods may be considered.
Options include:
A smaller 2.0 mm cortical screw in suitable fragments.
Suture fixation.
Suture-anchor fixation.
Repair of the ligament to the appropriate bony attachment site or periosteal tissue.
The choice depends on whether the avulsion originates from the tibial or fibular side, the available bone stock, and the quality of the remaining ligament tissue.
Small fragments should not be forced to accept an oversized screw because this may cause fragmentation or fixation failure.
For sufficiently large fragments:
Screw fixation may provide direct compression and stable fixation when the fragment can safely accommodate the implant.
For small or fragile fragments:
Suture-based fixation or ligament repair may be more appropriate than screw fixation.
The goal is to restore the AITFL attachment and syndesmotic stability while avoiding additional damage to the avulsed fragment.
One screw is commonly used, while two screws may be considered in selected unstable or high-risk injuries. Current evidence does not establish that two screws are universally superior to one.
Both tricortical and quadricortical fixation are accepted techniques. Clinical studies have not demonstrated a consistent universal advantage of one over the other. The choice depends on the injury pattern, required stability, and surgeon preference.
No. Routine removal is generally not necessary in every patient. On-demand removal may be considered when symptoms or implant-related problems develop.
Yes. Syndesmotic screws may loosen or break during recovery. A broken screw does not automatically require removal. The decision depends on symptoms, function, healing, and the location of the broken implant.
Suture-button devices provide dynamic fixation, while screws provide more rigid stabilization. Some studies report advantages for flexible fixation in selected outcomes, but the overall evidence remains heterogeneous. Both methods have a role in treating unstable syndesmotic injuries.
Assessment may include intraoperative fluoroscopy, direct visualization, and postoperative CT. Bilateral CT comparison can be helpful when rotational or translational malreduction is suspected.
A Tillaux-Chaput fracture is an avulsion fracture of the anterolateral distal tibia at the attachment of the anterior inferior tibiofibular ligament. It may be associated with syndesmotic instability.
Syndesmotic screw fixation remains an established option for treating unstable distal tibiofibular syndesmotic injuries. However, important technical questions remain, including screw number, diameter, cortical purchase, implant position, and routine removal.
Current evidence supports a more individualized approach rather than one universal fixation protocol.
The most important surgical principles are to restore fibular length, alignment, and rotation; achieve anatomical reduction within the tibial incisura; assess syndesmotic stability carefully; and maintain reduction with an appropriate fixation construct.
For Tillaux-Chaput fractures and other syndesmotic avulsion injuries, anatomical restoration of the ligament attachment is also important. When the avulsion fragment is too small for screw fixation, suture-based techniques may provide an alternative.
Ultimately, successful syndesmotic treatment depends not simply on inserting a screw, but on achieving accurate reduction and maintaining ankle stability throughout healing.
