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Views: 0 Author: Site Editor Publish Time: 2026-05-11 Origin: Site
Orthopedic trauma surgery is a discipline deeply rooted in mentorship, technical training, and surgical tradition. From the earliest stages of residency, many operative principles are treated as unquestionable standards. Any deviation from these “rules” is often considered improper technique.
However, as surgeons gain experience and develop the ability to independently balance surgical risks and clinical outcomes, some long-standing principles naturally come under scrutiny. One such debate concerns whether a distal tibiofibular syndesmotic screw must always be inserted perfectly parallel to the ankle joint line in the coronal plane.
A retrospective study conducted by Turkish researchers explored the clinical and radiographic outcomes of syndesmotic screws inserted either parallel or non-parallel to the ankle joint line. Patients were divided into two groups based on postoperative screw angulation, and both imaging and functional outcomes were analyzed.
Patients with syndesmotic screw angulation between -3° and +3° relative to the ankle joint line.
This group included:
Cases where anatomical alignment was achieved on the first attempt
Cases requiring multiple intraoperative adjustments before obtaining the desired angle
Patients with screw angulation outside the ±3° range.
This group included:
Unintentional intraoperative deviations
Anatomical limitations preventing ideal alignment
Cases in which surgeons accepted mild malalignment to reduce fluoroscopy exposure and operative time
Figure 1.Postoperative radiographs demonstrating:
(a) Syndesmotic screw angulation exceeding ±3° relative to the ankle joint line
(b) Syndesmotic screw angulation maintained within the ±3° range
After standard preoperative preparation and patient positioning, fracture fixation was performed first. Syndesmotic stability was then evaluated under fluoroscopy using both the hook test and external rotation stress test.
In both groups, the ankle joint was maintained in a neutral position during syndesmotic screw insertion.
Under fluoroscopic guidance, reduction forceps were used to anatomically reduce the syndesmosis. Before screw insertion, proper fibular positioning within the tibial incisura was confirmed on both anteroposterior and lateral fluoroscopic views.
The syndesmotic screw was inserted approximately 30° anteriorly along the anatomical axis of the fibula.
Under fluoroscopic guidance, surgeons attempted to position the screw parallel to the tibiotalar joint line.
All patients received:
4.0 mm syndesmotic screws
Tricortical fixation
Screw placement positioned 1–3 cm proximal to the joint line
All patients followed a standardized rehabilitation program:
Non-weight-bearing walking for 6 weeks
Transition to full weight-bearing after 6 weeks
Routine implant removal at approximately 3 months postoperatively
Figure 2.Illustration of syndesmotic screw placement from Surgery Reference guidelines.
There was a statistically significant difference in screw angulation between the two groups (P < 0.001).
Compared with the non-parallel group, the parallel group demonstrated:
Significantly longer operative times
Significantly higher intraoperative fluoroscopy exposure(P < 0.05)
Early postoperative radiographs showed no statistically significant difference in medial clear space measurements between the two groups (P = 0.067).
During follow-up:
8 patients in the parallel group developed radiolucency or osteolysis around the screw
3 patients in the non-parallel group demonstrated similar findings
Screw breakage occurred in:
4 patients (8.3%) in the parallel group
1 patient (4.3%) in the non-parallel group
The difference was not statistically significant (P = 0.39).
At the 3-month follow-up:
The parallel group showed significantly higher:
AOFAS scores
Ankle range of motion
(P < 0.05)
However, by the 6-month follow-up, there were no statistically significant differences between the two groups (P > 0.05).
Figure 3.Baseline characteristics of enrolled patients.
Figure 4.Radiographic and clinical evaluation results of both groups.
Figure 5.Radiograph demonstrating radiolucency around a syndesmotic screw inserted parallel to the joint line prior to implant removal, suggesting peri-screw osteolysis.
In this study, the parallel group demonstrated a higher rate of screw breakage, along with radiographic evidence of peri-screw osteolysis, likely caused by micromotion.
Researchers proposed a biomechanical explanation for the lower breakage rate in the non-parallel group.
When the screw direction unintentionally aligned with the oblique fibers of the interosseous membrane, the screw may have experienced reduced perpendicular shear stress.
This alignment could theoretically decrease stress concentration and reduce the likelihood of screw fatigue failure.
Figure 6.After healing of the oblique interosseous membrane fibers, a transversely inserted screw may be subjected to vertical shear stress, increasing the risk of screw breakage.
Figure 7.When the screw orientation aligns with the direction of the oblique interosseous membrane fibers, vertical shear forces acting on the screw may decrease, potentially lowering the risk of hardware failure.
This study demonstrated that syndesmotic screws inserted either parallel or non-parallel to the ankle joint line in the coronal plane achieved comparable clinical outcomes.
Although these findings are not yet sufficient to establish a universal surgical guideline, non-parallel screw insertion was associated with several practical advantages, including:
Reduced fluoroscopy exposure
Fewer fluoroscopic shots during screw placement
Shorter operative time
These results suggest that if the first syndesmotic screw insertion is not perfectly parallel to the ankle joint line, immediate revision or repeated adjustment may not always be necessary, provided that syndesmotic reduction remains anatomically acceptable and fixation stability is maintained.
