Talus Fractures: Evaluation and Treatment

Christopher Lee, MD; Dane Brodke, MD; Paul W. Perdue, Jr, MD; Tejas Patel, MD

Disclosures

J Am Acad Orthop Surg. 2020;28(20):e878-e887. 

In This Article

Treatment

The indication for surgical fixation of the talar neck and body fractures is any notable displacement. Cadaver models have shown that as little as 2 mm of talar neck displacement leads to a more concentrated high-pressure contact area in the middle and anterior facets of the subtalar joint[18] and that varus malalignment of the talar neck decreases subtalar motion by 24% to 32% in each plane.[19] In historical series, many displaced fractures were treated nonsurgically and varus malunion was a frequent result.[6] In a 2004 review of the functional outcomes of 70 patients at an average 5-year follow-up, hindfoot malalignment due to malunion was the single most salient predictor of pain, dysfunction, and the need for secondary surgeries.[13] These findings led to a current recommendation that nonsurgical treatment be reserved for truly nondisplaced injuries.[20] Reflecting the increasing rarity of nonsurgical treatment of talar neck fractures, Dodd and Lefaivre[15] reported that 96% of cases reported from 2000 onward were treated surgically.

Neck

The widely preferred approach for surgical treatment of talar neck fractures is a dual anterior incision technique.[9,13,17,20,21] The anteromedial approach provides access between the tibialis anterior and tibialis posterior tendons. An incision is made from the medial ankle joint to the navicular-cuneiform joint. The long saphenous vein is protected, and dissection is carried down to the superomedial talar neck. Dissection along the neck itself should be minimized as much as possible.[22] This incision can also be adjusted if preoperative planning identifies the possible need for a medial malleolar osteotomy. The anterolateral approach is between the peroneus brevis and tertius. An incision is made from the distal syndesmosis (anterolateral corner of the ankle) toward the fourth metatarsal. The superficial peroneal nerve is protected, and the sinus tarsi fat pad and extensor digitorum brevis origin are elevated to expose the superolateral talar neck and lateral process. Alternatively, a sinus tarsi approach can be used as the lateral window, with a slightly more plantar incision from the distal fibula toward the fourth metatarsal which may afford easier visualization of the lateral process.

The combination of anteromedial and anterolateral incisions facilitates anatomic reduction because talar neck fractures are frequently comminuted on the medial side (failing in compression) and noncomminuted on the lateral side (failing in tension). A dual incision approach allows reduction maneuvers to be performed while simultaneously visualizing both aspects of the fractured neck, thus helping to prevent rotational and angular malreductions. Reduction of medial and lateral cortices should be confirmed under direct visualization and fluoroscopy (AP or Canale view) before proceeding with fixation.

Fixation can be performed with dual minifragment plates, a combination of plating and positional screws or screws alone.[17,20] Longitudinal lag screws, particularly on the medial side, are often contraindicated because overcompression through medial comminution may cause varus collapse.[17] With dual plating, the lateral plate spans from just anterior to the lateral process to the lateral head-neck junction and the medial plate spans from plantar to the medial talar body cartilage to the medial head-neck junction. Another fixation option is a posterolateral to anteromedial percutaneously placed lag screw, with or without a medial anterior-to-posterior positional screw.[22] Although screw fixation may reduce dissection of the talar neck's tenous vascular supply, the biomechanical strength and ability to maintain an anatomic reduction may be superior with plate fixation. Thus far there is no clinical evidence of the superiority of either technique,[17,22,23] and biomechanical data are similarly inconclusive.[24,25] One biomechanical study compared screws alone with screw and blade plate fixation and found no notable differences in yield point, stiffness, or load to create a 3 mm deformation.[24] Notably, the screws failed with bending or pullout and plate fixation failed with a fracture at the margin of the plate. Smaller, more flexible plates may not produce the same failure mechanism. Another caveat was that the screws used were conventional 3.5 cortical or 4.0 cancellous screws. Headless variable-pitch screws may improve fixation strength relative to conventional cannulated screws.

Body

The principles of talar body fracture treatment overlap with those of talar neck fracture treatment, with the additional challenge of visualizing the talar dome. Dual anterior approaches are typically used, with the occasional addition of a medial or lateral malleolar osteotomy to facilitate exposure (Figure 4). One cadaver investigation demonstrated that dual anterior incisions expose approximately the anterior half of the talar dome, suggesting that osteotomy is useful for posterior fracture planes.[26] In the series by Vallier et al[12] in 2003, of 57 talar body fractures, 65% were treated with dual anterior approaches, 28% necessitated a medial malleolar osteotomy, and 5% necessitated a lateral malleolar osteotomy.

Figure 4.

The patient is a 46-year-old man presenting with a left comminuted talar body fracture. A, AP radiograph showing the talar body fracture with partial extrusion of the lateral body. B, Lateral radiograph showing the comminuted talar body fracture. C, Coronal CT cut showing a midsagittal split with medial comminution of the talar body. D, Sagittal CT cut again demonstrating notable comminution of the talar body. E, AP radiograph showing the final fixation. F, Lateral radiograph showing the final fixation. G, Intraoperative photograph of the chevron medial malleolar osteotomy. H, Intraoperative photograph of the medial malleolar osteotomy after the final fixation. The yellow arrows indicate the posterior tibial tendon.

One of the earliest descriptions of medial malleolar osteotomy for talar body fractures is credited to Ziran et al.[27] The technique involves an initial extension of the anteromedial incision along the medial malleolus. Anteriorly, capsule is released up to the axilla of the medial plafond and posteriorly, the posterior tibial tendon is partially released from its sheath and retracted. The osteotomy is performed obliquely with an oscillating saw directed toward the medial shoulder. The cut is completed with an osteotome to minimize damage to the articular surface and facilitate cartilage interdigitation on repair. It is thought to be important that the cut passes perpendicularly through the articular cartilage at the medial axilla of the joint to permit a congruent articular surface to be restored. van Bergen et al[28] analyzed the optimal osteotomy angle, finding the optimal cut to be angled 60° up from the horizontal (line drawn across tibial plafond), corresponding to 30° down from the longitudinal tibial axis. van Bergen et al[28] further described the use of two arthroscopic right-angled aiming probes, placed in the anterior and posterior axillas of the medial plafond, to find the ideal cut plane.

Other described techniques include step cut and biplanar chevron techniques. The step cut technique was found to be highly reliable in one series of 14 patients, with prompt healing by 6 weeks and no loss of reduction.[29] The biplanar chevron technique was found in another series to produce an unacceptably high malunion rate of 30% unless fixed with a buttress plate rather than two lag screws.[30] Fixation placement should be mindful of future procedures, including tibiotalar arthrodesis or total ankle arthroplasty. In the relatively common case of a medial malleolus fracture accompanying a talar body fracture, the talus can be exposed through this fracture plane.

Process

Approximately 20% of fractures of the talus involve a fracture to the lateral process.[11] This has been termed the "snowboarder" fracture because of its association with the dorsiflexion and eversion fall mechanism commonly seen in snowboarding injuries.[31] CT is considered essential for proper diagnosis because the size of a lateral process fracture may be underestimated on plain radiographs. Although many lateral process fractures were treated nonsurgically or with excision in historical series, the outcomes were poor, likely because of underappreciation of the important contribution of the lateral process to the subtalar joint.[32] The trend more recently has been toward surgical treatment with open reduction and internal fixation.[32] Isolated lateral process fractures can be approached with an anterolateral approach similar to that described above, with the proximal extent of the incision beginning slightly more lateral, at the tip of the fibula.[20] A small diameter lag screw or small diameter buttress plate along the inferolateral talar neck can be used for fixation. It is additionally important to address ligament injuries associated with this fracture because ankle instability can remain with bony fixation alone. The authors of a recent series recommended that nonsurgical treatment be reserved for nondisplaced, small-fragment and extra-articular fractures.[32]

Posterior process fractures are associated with approximately 18% of talus fractures.[11] It is important not to confuse small posterior process fractures with a symptomatic os trigonum. Similar to lateral process fractures, the extent to which larger posterior process fractures involve the subtalar joint may be underappreciated on plain radiographs and CT imaging is therefore essential to planning treatment. Small, nonreconstructable posterior process fragments can be excised, but large fragments should be fixed to restore the subtalar joint surface. If fixation is indicated, a posteromedial approach can be used between the medial malleolus and the medial border of the Achilles tendon, with dissection adjacent to the flexor hallucis longus tendon and neurovascular bundle.[20]

Head

Talar head fractures represent 5% to 10% of talus fractures.[11] Similar to lateral and posterior process fractures, most reconstructable fragments should be fixed to restore proper joint mechanics. The talar head is an essential component of the medial column of the foot that helps maintain the longitudinal arch. In a recent surgical technique study, a dual incision technique was used, and medial-to-lateral screws recessed into subchondral bone, or a medial column spanning plate, were used for fixation.[33]

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