INTRODUCTION
Fractures of the lateral process of the talus account for approximately 0.86% of all ankle injuries and 24% of all talar body fractures (Fig. 1 ).1,2 2,3 4 5 6 7
FIGURE 1.: Preoperative AP (A) and lateral (B) radiographs of a lateral process fracture of the talus.
Operative management for isolated fracture has been shown to lead to superior AOFAS scores, although not a validated outcome measure, and allow for greater return to play in athletes.8
SURGICAL TECHNIQUE
The patient is placed in the supine position with all bony prominences well padded. A nonsterile tourniquet is placed about the thigh and insufflated before skin incision to aid visualization. The surgeon typically uses a headlamp to further improve visualization. For patients with an isolated lateral process, an approximately three-centimeter skin incision is created, starting approximately 1 cm plantar to the tip of the fibula and extending distally, in line with the plantar foot. The skin is incised and sharp dissection is performed to the capsule. The capsule is then opened to reveal the underlying pathology. For patients with a talar neck fracture with associated lateral process fracture, an anterolateral approach to the talar neck is preferred with the proximal aspect of the incision created approximately 1 cm plantar to its typical location. Dissection is then performed in its typical fashion. A key component to restoration of the lateral process is visualization of the inferior articular surface of the talus by exposure of the subtalar joint. This is aided by placement of a distractor or small external fixator, with one pin being placed in the distal fibula and the other in the lateral portion of the calcaneus (Fig. 2 ). A Freer elevator is next placed in the joint to confirm adequate distraction and location within the joint (Fig. 3 ). Next, the inferior articular surface of the talus is evaluated for any articular impaction (Fig. 4 ). If this impaction exists, a small osteotome or other instrument is used to disimpact and restore the articular surface. Kirschner wires are then placed through the subchondral surface and into the intact talus. This will allow for maintenance of articular reduction while bone graft is placed in the area of the defect from the disimpacted zone. The displaced lateral process cortical fragments are then reduced to the intact talus using a combination of dental picks and small pointed reduction clamps. Both the inferior articular surface articulation with the posterior facet of the calcaneus and the anterior aspect of the lateral process joining with the remaining lateral process or the talar neck provide the most consistent reads for this reduction. Once anatomic reduction is achieved, 0.45 Kirschner wires are placed to hold the fragment(s) in place. A 2.0 or 1.5 “T” plate is then contoured to fit the fragment(s) (Fig. 5 ). The vertical portion of the plate can be cut at its end to create 2 tines, which are impacted superiorly onto the intact talus, avoiding both the tibotalar joint and the anterior talofibular ligament. Screws are then sequentially placed in the plate to provide compression of the fragment(s) to the intact talus. A previously described technique of cutting, bending, and impacting the k-wires is used just caudal to the plate (Fig. 6 ).9
FIGURE 2.: A laterally based small distractor is placed to provide distraction of the subtalar joint, with one pin in the fibula and one in the calcaneus. Displayed on lateral (A) and mortise (B) radiographs.
FIGURE 3.: A Freer elevator is placed in the subtalar joint to confirm satisfactory distraction of the joint and proper location within the joint.
FIGURE 4.: Coronal CT scan of a patient with a lateral process of the talus fracture with impaction of inferior articular surface of the talus just medial to the fractured lateral process fragment.
FIGURE 5.: After disimpaction of the inferior articular surface and subsequent placement of rafting wires to hold the reduction, a T-plate is wired in place over the lateral process fragment. (Orientation: Distal to left, proximal to right, dorsal superior, plantar inferior).
FIGURE 6.: Final (A) mortise and (B) lateral Fluoroscopic radiographs display final fixation of the isolated lateral process fracture with select rafting wires left in place to maintain anatomic reduction of the inferior articular surface.
In patients with a talar neck fracture being treated with a plate along the lateral neck, the neck plate is placed with the posterior most screw hole overlying the previously applied lateral process T-plate to provide additional support (Figs. 7–10 ). AP, Canale, lateral, and Broden's hindfoot oblique views are used throughout the procedure, in conjunction with direct visualization, to confirm anatomic reduction and implant placement. One alteration of the technique, in patients with a talar neck or distal body fracture and involvement of the lateral process, is extension of the lateral talar neck plate onto the lateral process with either the use of a straight plate or a T-plate with the short portion of the plate placed on the lateral process fragment. The reduction technique remains the same, and the plate is contoured onto the lateral process to provide fixation. The capsule is closed with 3-0 monocryl and the skin using 4-0 nylon suture in an Allgower–Donati fashion to preserve cutaneous blood supply.10
FIGURE 7.: Lateral radiograph of a patient who sustained a talar neck fracture with involvement of the lateral process and body. The lateral process has relatively maintained its native position because of its ligamentous attachments.
FIGURE 8.: Intra-operative radiograph displaying reduction of the talar neck and the lateral process fragments with the anterior most portion of the lateral process being used as a read for reduction.
FIGURE 9.: A contoured T-plate is wired in place after reduction is achieved. The vertical portion of the plate was cut at its end to create 2 tines which are impacted superiorly onto the intact talus. Cortical allograft was applied in this patient due to significant lateral bone loss. (Orientation: Distal to left, proximal to right, dorsal superior, plantar inferior). Editor's Note : A color image accompanies the online version of this article.
FIGURE 10.: Final fluoroscopic canale (A), mortise (B) and lateral (C) radiographs and an intra-operative photograph (D) displaying lateral process plate fixation with an overlying 2.0 straight plate use for fixation of the lateral neck and serving as an additional buttress for the lateral process fragment and plate. Editor's Note : A color image accompanies the online version of this article.
CLINICAL SERIES
After institutional review board approval, a retrospective review was conducted to identify all patients treated surgically for a displaced lateral process fracture. Over a 5-year period, this technique was performed on 21 patients (22 fractures) with greater than one-year follow-up. The average follow-up was 24 months (range, 12–64 months). The average age was 43.2 years (range, 19–70 years). There were 15 male and 6 female patients. Eight patients sustained an isolated lateral process fracture, 11 sustained a lateral process fracture in combination with a talar neck fracture and 3 had a fracture of the lateral process with extension into the remainder of the talar body. All patients went on to unite their fracture without loss of reduction. Three patients with isolated lateral process and 9 patients who sustained a combined neck or body with lateral process fracture fractures developed radiographic evidence of subtalar arthritis. Four patients in the combined talar neck/body and lateral process group and 7 patients in the isolated lateral process fracture had an ipsilateral foot or ankle injury (Table 1 ). Despite 11 patients developing radiographic arthritis, only 3 patients, all in the combined fracture group, underwent a secondary procedure during the follow-up period; 2 underwent hardware removal and cheilectomy, whereas only one patient underwent subtalar arthrodesis.
TABLE 1.: Additional Injuries
DISCUSSION
Fractures of the lateral process in isolation account for approximately 0.86% of all ankle injuries and 24% of all talar body fractures.1,2 5 11
The lateral process possesses large articulations for both the distal fibula and the posterior facet of the calcaneus. Fixation of these fractures is critical to restore the native architecture of these joint surfaces. In addition, the lateral process plays a role in maintaining both subtalar and ankle kinematics, providing attachment for the lateral talocalcaneal, anterior talofibular, and posterior talofibular ligaments.7,12
Operative reduction and fixation of isolated fracture has been shown to lead to superior AOFS scores and allows for greater return to play in athletes.7
In relation to impaction, an important aspect of this technique is exposure of the subtalar joint and inferior articular surface of the talus. This inferior articular surface is often impacted and must be corrected to prevent alteration of loading normal force distribution across the subtalar joint. Placement of “rafting” screws through a plate, similar to fixation of a depression type tibial plateau fracture may be best able to maintain the reduction of the depressed fragment better than single screw fixation.
In reference to lateral process fractures associated with talar neck fracture, Sangeorzan et al13 Fig. 11 ).
FIGURE 11.: Sagittal CT images displaying a lateral process fracture in conjunction with a talar neck and body fracture. The anterior fragment, as seen in the superior image, plays a pivotal role as an intra-operative read in determining the correct orientation of the talar neck in relation to the body.
CONCLUSIONS
Plate fixation of the lateral process can provide a reliable means of fixation of both isolated lateral process fractures and those that occur in the face of talar neck fracture.
REFERENCES
1. Mukherjee SK, Pringle RM, Baxter AD. Fracture of the lateral process of the talus. A report of thirteen cases. J Bone Joint Surg Br. 1974;56:263–273.
2. Dale JD, Ha AS, Chew FS. Update on talar fracture patterns: a large level I trauma center study. AJR Am J Roentgenol. 2013;201:1087–1092.
3. McCrory P, Bladin C. Fractures of the lateral process of the talus: a clinical review. “Snowboarder's ankle.” Clin J Sport Med. 1996;6:124–128.
4. Vallier HA, Nork SE, Barei DP, et al. Talar neck fractures: results and outcomes. J Bone Joint Surg. 2004;86A:1616–1624.
5. Mayo KA. Fractures of the talus: principles of management and techniques of treatment. Tech Orthop. 1987;2:42–53.
6. Romeo NM, Hirschfeld AG, Githens M, et al. Significance of lateral process fractures associated with talar neck and body fractures. J Orthop Trauma. 2018;32:601–606.
7. Langer P, Nickisch F, Spenciner D, et al. In vitro evaluation of the effect lateral process talar excision on ankle and subtalar joint stability. Foot Ankle Int. 2007;28:78–83.
8. Valderrabano V, Perren T, Ryf C, et al. Snowboarder's talus fracture: treatment outcome of 20 cases after 3.5 years. Am J Sports Med. 2005;33:871–880.
9. Firoozabadi R, Kramer PA, Benirschke SK. Kirschner wire bending. J Orthop Trauma. 2013;27:e260–3.
10. Sagi HC, Papp S, DiPasquale T. The effect of suture patten and tension on cutaneous blood flow as assessed by laser flowmetry in a pig model. J Orthop Trauma. 2008;22:171–175.
11. Kirkpatrick DP, Hunter RE, Janes PC, et al. The snowboarder's foot and ankle. Am J Sports Med. 1998;26:271–277.
12. DiGiovanni CW, Langer PR, Nickisch F, et al. Proximity of the lateral talar process to the lateral stabilizing ligaments of the ankle and subtalar joint. Foot Ankle Int. 2007;28:175–180.
13. Sangeorzan BJ, Wagner UA, Hrrington RM, et al. Contact characteristics of the subtalar joint: the effect of talar neck misalignment. J Orthop Res. 1992;10:544–551.
