Talar Dome Access Through Posteromedial Surgical Intervals for Fracture Care

Evaluation of the horizontal approach to the medial malleolar facet in sagittal talar fractures through dorsiflexion and plantarflexion positions

BACKGROUND

Talar fractures often require osteotomy during surgery to achieve reduction and screw fixation of the fractured fragments due to limited visualization and operating space of the talar articular surface. The objective of this study was to evaluate the horizontal approach to the medial malleolus facet by maximizing exposure through dorsiflexion and plantarflexion positions.

METHODS

In dorsiflexion, plantarflexion, and functional foot positions, we respectively obtained the anterior and posterior edge lines of the projection of the medial malleolus on the medial malleolar facet. The talar model from Mimics was imported into Geomagic software for image refinement. Then Solidworks software was used to segment the medial surface of the talus and extend the edge lines from the three positions to project them onto the "semicircular" base for 2D projection. The exposed area in different positions, the percentage of total area it represents, and the anatomic location of the insertion point at the groove between the anteroposternal protrusions of the medial malleolus were calculated.

RESULTS

The mean total area of the "semicircular" region on the medial malleolus surface of the talus was 542.10 ± 80.05 mm2. In the functional position, the exposed mean area of the medial malleolar facet around the medial malleolus both anteriorly and posteriorly was 141.22 ± 24.34 mm2, 167.58 ± 22.36mm2, respectively. In dorsiflexion, the mean area of the posterior aspect of the medial malleolar facet was 366.28 ± 48.12 mm2. In plantarflexion, the mean of the anterior aspect of the medial malleolar facet was 222.70 ± 35.32 mm2. The mean overlap area of unexposed area in both dorsiflexion and plantarflexion was 23.32 ± 5.94 mm2. The mean percentage of the increased exposure area in dorsiflexion and plantarflexion were 36.71 ± 3.25% and 15.13 ± 2.83%. The mean distance from the insertion point to the top of the talar dome was 10.69 ± 1.24 mm, to the medial malleolus facet border of the talar trochlea was 5.61 ± 0.96 mm, and to the tuberosity of the posterior tibiotalar portion of the deltoid ligament complex was 4.53 ± 0.64 mm.

CONCLUSIONS

Within the 3D model, we measured the exposed area of the medial malleolus facet in different positions and the anatomic location of the insertion point at the medial malleolus groove. When the foot is in plantarflexion or dorsiflexion, a sufficiently large area and operating space can be exposed during surgery. The data regarding the exposed visualization area and virtual screws need to be combined with clinical experience for safer reduction and fixation of fracture fragments. Further validation of its intraoperative feasibility will require additional clinical research.

Dual Approach to Talar Dome Increases Access for Fracture Care Without Osteotomy

BACKGROUND

There is no consensus surgical treatment algorithm for talar body fractures, with authors recommending both soft tissue-only and osteotomy-based approaches. This study evaluates talar dome access via dual approaches to the talar dome through anterolateral transligamentous (ATL) and modified posteromedial (mPM) approaches.

METHODS

Ten cadaveric legs (5 matched pairs) were included. An mPM approach, between flexor hallucis longus and Achilles tendon, and an ATL approach, utilizing the anterolateral interval with transection of anterior talofibular ligament and calcaneofibular ligament, were performed on each specimen. Order of approach was alternated within each pair. Accessible dome surface area (DSA) was outlined by drilling with a 1.6-mm Kirschner wire at the visualized talar dome margin both with and without 4 mm of tibiotalar distraction using an external fixator. Specimens were analyzed by computed tomography (CT). Primary outcome was accessible DSA. Student t tests compared DSA accessed by different exposure methods.

RESULTS

An initial mPM approach exposed 25.6% and 33.6% of DSA without and with distraction (P = .002). An initial ATL approach accessed 47.0% and 58.1% of DSA without and with distraction, respectively (P = .003). Accessibility via dual approaches was 71.7% and 93% of DSA without and with distraction with an initial ATL approach and 71.3% and 87.5% of DSA without and with distraction with an initial mPM approach (P = .96 and .37, respectively). The central talar dome was inaccessible in an almond-shaped area, tapered at the medial and lateral ends. Anterior, lateral, and posterior articular margins were able to be fully exposed, often with overlapping exposure between posterior and anterior approaches, with distraction reliably improving lateral visualization.

CONCLUSION

Dual approaches provided access to greater than 70% and 85% of talar DSA without and with distraction, respectively. Order of approach did not significantly affect exposure and thus should be determined by surgeon discretion. These results may promote soft tissue-only treatment strategies in talar body fracture care with an extensile exposure of the talar dome surface. Careful preoperative planning optimizes the advantages of this approach.

LEVEL OF EVIDENCE

Level IV, case series.