- note that the main displacement of the fibula is posterior (not lateral);
- reduction is achieved w/ IR of ankle & manual translation of fibula in an anterior direction until it reaches anterior tubercle of tibia;
- fibular fracture is reduced & provisionally transfixed to the tibia w/ horizontal 1.6 mm K wire or held with reduction clamp;
- in the study by Phisitkul P, et al (2012), the authors found that applying clamps on the lateral malleolar ridge of the fibula (which is the insertion
of the peroneal retinaculum laterally) and the center of the anteroposterior width of the tibia 10 mm above the joint line.
- this clamp position produced the most consistently accurate reduction through most of the degrees of instability in the sagittal plane;
- angling the forceps in the obique plan has the effect of translating the fibula anteriorly, keeping it in a malreduced position;
- ref: Forceps Reduction of the Syndesmosis in Rotational Ankle Fractures: A Cadaveric Study
- reduction clamp:
- consider straddling the medial and lateral malleolus with a reduction clamp, and then carefully apply compression with
different and varying degrees of torque (which translates the fibula anteriorly and posteriorly);
- look for the best reduction under flouro which requires the least amount of force;
- working hypothesis is that if excessive clamp force is required to maintain a reduction, then the fibula is too anteiror or posterior;
- Medial Clamp Tine Positioning Affects Ankle Syndesmosis Malreduction.
- dorsiflexion of the foot:
- conventional teaching mandates that during screw insertion foot is placed in dorsiflexion to bring the widest portion of talus into mortise;
- generally 5 deg of dorsiflexion is sufficient (more dorsiflexion might cause excessive widening of mortise which would then permanently
remain in widened position, leading to instability;
- other authors recommend full dorsiflexion;
- if screw is too tight it will restrict dorsiflexion (this is avoided by placing ankle in dorsiflexion during insertion);
- in contrast, the report by Tornetta P, et al. examined whether overtightening of the syndesmosis limits maximal ankle dorsiflexion;
- using a cadaveric model, the authors found no difference before and after syndesmotic fixation (w/ maximal tightening);
- angle between the reference wires with the ankle maximally dorsiflexed was measured before and after syndesmotic compression;
- syndesmotic compression was achieved with a 4.5-mm lag screw with the ankle in plantar flexion;
- there was no difference between the values for maximal dorsiflexion before and after syndesmotic compression;
- authors concluded that the position of the ankle was not important during syndesmotic fixation;
- authors caution that dorsiflexion of the ankle causes heel valgus and external rotation, which may cause an unstable syndesmosis
to be subluxated during dorsiflexion (leading to malreduction);
- ref: Overtightening of the Ankle Syndesmosis: Is It Really Possible?
- Operative Setup to Improve Sagittal Syndesmotic Reduction: Technical Tip.
- Malreduction of syndesmosis-Are we considering the anatomical variation?
- Direct visualization for syndesmotic stabilization of ankle fractures
- Malreduction of the tibiofibular syndesmosis in ankle fractures
- Iatrogenic Syndesmosis Malreduction Via Clamp and Screw Placement.
- The Measurement and Clinical Importance of Syndesmotic Reduction After Operative Fixation of Rotational Ankle Fractures
- APTF: Anteroposterior Tibiofibular Ratio, a New Reliable Measure to Assess Syndesmotic Reduction..