How To Conquer Talar Neck Fracture Malunions

Given their high post-traumatic malunion rate, talar neck fractures present considerable challenges for foot and ankle surgeons. These authors present effective techniques for performing an opening wedge osteotomy to resolve talar neck malunions, offering a closer look at the literature and an illustrative case study.

Talar neck fractures remain problematic among foot and ankle surgeons. Fewer than 1 percent of all foot and ankle fractures occur in the talus but 50 percent of talar fractures tend to occur within the talar neck.^1,2 This is troublesome as researchers have reported a talus malunion rate of between 9 and 47 percent, which results in a varus deformity of the hindfoot.³

In 1970, Hawkins described a three-part classification system of vertical talar neck fractures as they correlate with the incidence of avascular necrosis.⁴ Type I injuries include vertical fractures of the talar neck that have a minimally displaced fracture line entering the subtalar joint between the middle and posterior facets. Type II fractures are vertical and displaced with the subtalar joint subluxated or dislocated, but with the talus reduced in the ankle mortise. Type III fractures have characteristics that are similar to Type II fractures in addition to a dislocation of the ankle (tibiotalar articulation).

In 1978, Canale and Kelly modified this talar neck fracture classification, adding an additional fracture pattern with dislocation of the subtalar, tibiotalar and talonavicular joints.⁵

Traditional plain film imaging of suspected talar neck fractures may prove to be inadequate to capture talar neck shortening and malrotation. When one suspects talar neck involvement, we advise obtaining a computed tomography (CT) scan. However, if there is concern for avascular necrosis (AVN), physicians should perform magnetic resonance imaging (MRI), particularly in fractures at a level of Hawkins type II or greater.

Talar neck fractures often lead to malposition of the subtalar and midtarsal joints. This is a result of medial neck impaction leading to comminution and shortening. The lateral neck is subject to tension, which leads to distraction. This result can also lead to rotational displacement of the talar head.⁵ It is important when reducing a talar neck fracture that the surgeon makes both medial and lateral incisions. Reduce the lateral neck (tension side) and rotate it to anatomic position. The medial neck will often have a gap on the compression side. In regard to internal fixation, one can reduce the lateral talar neck with a compression screw. Fixate the medial talar neck, utilizing either a plate or a screw as a strut to combat compression of the comminuted surfaces.

Key Insights On Talar Neck Shortening

Often, surgeons inadequately address the medial neck shortening, particularly when it comes to closed-reduced Hawkins Type II fractures.^2,6-10 Failure to address this deformity intraoperatively results in shortening of the medial column. This produces a cavovarus hindfoot deformity with internal rotation and forefoot adduction.¹¹ Although the previous literature has described acceptance of less than 5 mm displacement, Sangerozan and coworkers, in a study of seven cadavers, demonstrated talar neck displacement of only 2 mm was enough to cause significant load redistribution of the subtalar joint facets.¹²

Shortening of the talar neck component predisposes the individual to malunion and further painful sequelae, particularly lateral column overload. A malunion with shortening of the talar neck medially leads to a shortened medial column. This produces a forefoot varus and forefoot adduction at the longitudinal axis (talonavicular joint). This drives the heel position into varus, creating an adductovarus deformity. The patient will demonstrate significant limited range of motion with an increased incidence of post-traumatic arthritis, primarily created by the fracture involvement of the anterior and middle facets. This is most problematic throughout the stance phase of the gait cycle as the foot is unable to pronate and creates lateral column overload secondary to the varus hindfoot position, resulting in an antalgic gait.¹¹

By performing a subcapital opening wedge osteotomy of the talar neck along the medial column, one can achieve correction of the adductovarus deformity through lengthening of the medial column. If the subtalar joint is still supple, it will reduce during the distraction lengthening process. If the subtalar joint remains fixed, one may need to consider a Dwyer osteotomy or subtalar joint arthrodesis. Triple arthrodesis may also be a consideration in patients with longstanding advanced osteoarthritis.

Case Study: When There Is A Talar Neck Malunion Following A ‘Twisted’ Ankle

A 52-year-old female with no significant past medical history and an allergy to penicillin presented to our office with a more than one-month history of pain in her right ankle. The patient related that she “twisted” her ankle and has had constant throbbing and aching that have been progressing in severity. She says the pain increases with ambulation, standing and shoe gear. The patient relates that she presented to the emergency department after the injury and her X-rays did not show a fracture or bone abnormality. She then followed up with her primary care provider and began resting, icing the lower extremity and immobilizing the ankle via a controlled ankle motion (CAM) boot. The patient also began physical therapy secondary to a presumed diagnosis of an ankle sprain. Symptoms continued to worsen and she eventually got a referral for further evaluation.

During her examination, we noted that her neurovascular status was intact bilaterally. She had no open lesions or signs of infection. However, residual edema and ecchymosis were present at the right foot and ankle. There was pain on palpation of the medial and lateral ankle, along the deltoid ligaments and along the course of the tibialis posterior tendon. Pain with ankle joint range of motion was also present.

At this point, the patient initially received continued conservative treatment in the form of rest, ice, elevation and immobilization in a CAM boot until we could perform magnetic resonance imaging (MRI). The MRI revealed a comminuted talar neck and talar body fracture with a Mercedes-sign configuration fracture extending superiorly to the apex of the weightbearing talar dome. No diastasis of the fracture lines was visible. She had a small avulsion fracture of the lateral malleolar posterior colliculus at the calcaneofibular ligament and posterior tibiofibular ligament origins with mild tendinopathy of the peroneal tendons. We then scheduled the patient for open reduction internal fixation (ORIF) of the talus to the right foot the following week. For the internal fixation, we employed two compression screws, countersunk medially and laterally.

Over the next two years, the patient continued to have pain and noticed her foot was progressively turning in. She felt like she was walking on the outside of her foot. The pain laterally became intolerable. The physical exam detected a decreased range of motion to the subtalar joint. On resting calcaneal stance position, the patient demonstrated a calcaneal varus. Radiographs showed an abducted talus with a talocalcaneal angle reduced to less than 18 degrees with a talo-first metatarsal angle of –20 degrees. The lateral view showed minimal changes to the subtalar joint and no changes in the Chopart’s joint. The foot remained supple. The calcaneal axial view demonstrated a calcaneal varus position.

We diagnosed a talar neck malunion. We decided the patient would need an opening wedge osteotomy of the talar neck to restore medial column length and correct residual forefoot adduction. We would address the calcaneal varus depending on its reduction intraoperatively.

Step-By-Step Surgical Pearls

Make an incision on the medial aspect of the left foot, beginning proximally at the medial malleolar tip and curving distally to the navicular tuberosity. Take care to avoid the deltoid ligament and make a medial capsular incision across the talonavicular joint. Preserve the dorsal periosteum over the talar neck. Make an osteotomy within the mid-neck with a sagittal saw. Take care to irrigate with saline during this process. Then carefully complete the osteotomy at the lateral neck, leaving a periosteal sleeve. Then utilize a Hintermann retractor with 0.062-inch K-wire guide pins and distract the osteotomy open, achieving correction under fluoroscopy. With this maneuver, the heel became neutral.

Correct the adduction and visualize the position of the distal talar neck. Then insert a tricortical femoral head allograft in bone marrow aspirate into the approximately 8 mm deficit. Insert two headless screws within the talar head and use the screws as struts to avoid compression.

Postoperatively, the patient wore a posterior splint for two weeks. We removed the sutures and then placed her in a below-knee cast. The patient remained in a non-weightbearing cast for six weeks. After six weeks, range of motion exercises began following graft incorporation. The patient started weightbearing, but remained in a CAM boot for another six weeks.

A Closer Look At The Research

When performing a subcapital opening wedge osteotomy of the talus, the podiatric surgeon must be conscientious to provide adequate medial column length for restoration of the varus hindfoot alignment while preserving a potentially traumatized vascular supply secondary to the initial insult.

In an effort to understand the correlation between varus malalignment of the talar neck and hindfoot varus deformity, Daniels and coworkers performed an in vitro study involving 12 cadaveric specimens.¹³ The authors demonstrated that a 5 mm deficit through a wedge resection of the talar neck correlated to an average varus malaligment of the talar neck of 17.1 ± 2.4 degrees, an average of 4.8 ± 1.2 degrees hindfoot varus, an average of 8.7 ± 2.3 degrees of internal rotation and an average of 11.5 ± 2.4 degrees of adduction of the forefoot.

Barg and colleagues in 2016 described a dorsal medial approach for exposure and correcting the underlying deformity through a medial opening wedge osteotomy at the previous fracture plane, citing a 4 to 10 mm displacement as necessary to provide adequate reduction.¹⁴ The authors noted good postoperative outcomes and no avascular necrosis in their seven patient cohort.

Matsumura and colleagues in 2008 reported a case study that involved performing an opening wedge osteotomy with a tricortical iliac crest bone graft secondary to a talar head fracture.¹⁵ They noted the patient had a return to full activity at three months.

Likewise, Monroe and Manoli in 1999 described performing an osteotomy for malunion of a talar neck fracture in a 34-year-old patient.¹⁶ They also reported an increase in American Orthopedic Foot and Ankle Society (AOFAS) scores from 11 to 85 at the final 56-month follow-up. In a retrospective review of seven patients, Suter and coworkers in 2013 demonstrated an increase in patient AOFAS scores from 40.9 preoperatively to 83.9 with no incidence of avascular necrosis when performing a talar neck opening wedge osteotomy secondary to a post-traumatic talar neck fracture malunion.³

In Conclusion

Opening wedge osteotomy of the talar neck offers an alternative to subtalar joint arthrodesis in the treatment of post-traumatic talar neck fracture malunion. One should utilize a non-compressible screw or plate along the medial talar neck column in conjunction with bone grafting to maintain proper realignment. Using this technique, surgeons have demonstrated good clinical outcomes throughout the literature with bone grafting incorporation and restoration of a rectus foot type.

Dr. Visser is the Director of the Foot and Ankle Surgery Residency at SSM Health DePaul Hospital in St. Louis.

Dr. Wolfe is a first-year resident at SSM Health DePaul Hospital.

Dr. Gonzalez is a second-year resident at SSM Health DePaul Hospital.

Dr. Ermitano is a first-year resident at SSM Health DePaul Hospital.

Dr. Berns-Thompson is a third-year resident at SSM Health DePaul Hospital.

References

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3.     Suter T, Barg A, Knupp M, Henninger H, Hinterman B. Talar neck osteotomy to lengthen the medial column after a malunited talar neck fracture. Clin Orthop Relat Res. 2013; 471:1356-1364.
4.     Hawkins LG. Fractures of the neck of the talus. J Bone Joint Surg Am. 1970;52(5):991-1002.
5.     Canale ST, Kelly FB Jr. Fractures of the neck of the talus. Long-term evaluation of seventy-one cases. J Bone Joint Surg Am. 1978; 60(2):143-56.
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7.     Rammelt S, Winkler J, Grass R, et al. Reconstruction after talar fractures. Foot Ankle Clin. 2006; 11(1):612-84.
8.     Huang PJ, Cheng YM. Delayed surgical treatment of neglected or mal-reduced talar fractures. Int Orthop. 2005; 29(5):326-329.
9.     Fortin PT, Balazsy JE. Talus fractures: evaluation and treatment. J Am Acad Orthop Surg. 2001; 9(2):114-127.
10.     Monrole MT, Manoli A. Osteotomy for malunion of a talar neck fracture: a case report. Foot Ankle Int. 1999; 20(3):192-195.
11.     Sproule J, Glazebrook M, Younger A. Varus hindfoot deformity after talar fracture. Foot Ankle Clin N Am. 2012; 17(1):117-125.
12.     Sangeorzan BJ, Wagner UA, Harrington RM, et al. Contact characteristics of the subtalar joint: the effect of talar neck misalignment. J Orthop Res. 1992; 10(4):544-551.
13.     Daniels T, Smith J, Ross T. Varus malalignment of the talar neck. J Bone Joint Surg. 1996; 78A(10):1559-1567.
14.     Barg A, Suter T, Nickisch F, Wegner N, Hintermann B. Osteotomies of the talar neck for posttraumatic malalignment. Foot Ankle Clin N Am. 2016; 21(1):77-93.
15.     Matsumara T, Sekiya H, Hoshino Y. Correction osteotomy for malunion of the talar head: a case report. J Orthop Surg. 2008; 16(1):96-98.
16.     Monroe M, Manoli A. Osteotomy for malunion of a talar neck fracture: a case report. Foot Ankle Int. 1999; 20(3):192-195.

For further reading, see “How To Master Talonavicular Fusions” in the April 2005 issue of Podiatry Today, “Treatment Considerations For Avascular Necrosis Of The Second Metatarsal” in the November 2014 issue, or “Current Insights On Treating Freiberg’s Avascular Necrosis Of The Second Metatarsal Head” in the May 2015 issue.