Management Options For Talar AVN

Recently, I had a patient sent to me for evaluation of early avascular necrosis (AVN) of the talus. The patient had a subtle talar body fracture missed on initial radiographs. Previous treatment was for a presumed ankle sprain with rest, ice, compression and elevation (RICE), along with physical therapy. After continued and worsening pain, a consulting podiatrist obtained an MRI, which showed the subtle talar fracture and also AVN of the talus. The patient was subsequently sent to us for further evaluation and treatment about three months from the initial injury with continued pain. We discussed a number of different options ranging from more conservative to more invasive, and ultimately decided on primary subtalar joint arthrodesis. We arrived at this decision based on the extent of the AVN as visualized on the MRI, the patients desire to return to work as soon as possible and wanting an option with the least likelihood of requiring further intervention.

This discussion led me to think about the difficulty we face when treating these injuries. Currently, there are no level 1 studies looking at the surgical management of talar AVN and most of the published literature is in the form of small case series or cohorts of patients. Furthermore, the literature seems inconclusive regarding the ideal treatment modality and the factors that should guide those modalities.¹ In this blog post I will discuss several available options for the management of talar AVN.

First, many of the available studies recommend a trial of conservative care prior to another intervention for the management of talar AVN.^2,3 This involves a period of complete or protected non-weight-bearing to allow for revascularization of the bone while helping to prevent talar dome collapse. Canale and Kelly reported 23 patients undergoing conservative therapy with non-weight-bearing for greater than nine months or patellar tendon-bearing brace. In the non-weight-bearing group, 89 percent of the patients reported excellent or good outcomes, while only 33.3 percent of patients reported good outcomes following PTB, with 66.7 percent having fair or poor results.²

Additionally, extracorporeal shock wave therapy (ESWT) has shown good results for management of talar AVN. Zhai and colleagues conducted what is currently the only Level 1 study for any form of treatment looking at talar AVN. This study was a prospective randomized controlled trial to evaluate the role of ESWT as compared to physical therapy among 34 patients with post traumatic AVN of the talus. They reported significant improvement in American Orthopaedic Foot and Ankle Society (AOFAS) hind-foot score from 65.7 to 92.3 at final follow-up in those undergoing ESWT. The visual analog scale (VAS) score and ankle function were also significantly better than those in the control group. MRI at 18 months showed greater than 50 percent improvement in the necrotic area in the ESWT group. These results are very promising for the management of talar AVN.³

Core decompression is one minimally invasive surgical option for the treatment of talar AVN. Reports on outcomes of core decompression for early-stage AVN of the talus have been satisfactory, particularly in non-traumatic cases. Several studies looked at this and reported on the efficacy of core decompression.⁴ One should note, however, that most studies looking at this have been in non-traumatic cases of AVN.

Vascularized bone grafting is another option, with several studies presenting satisfactory and reproducible results in the treatment of AVN. The mechanism is thought to be via inducing revascularization by creeping substitution from the surrounding vascularized bone into the avascular region of talus.^5,6

Primary subtalar joint arthrodesis, ankle fusion, and tibio-talo-calcaneal arthrodesis are all examples of joint destructive management options that would allow for preservation of the integrity of the talus but at the expense of joint mobility. Urquhart and colleagues in their series of 11 patients with various hindfoot arthrodeses for symptomatic AVN of the talus noted good-to-excellent results in nine out of eleven patients, concluding that hindfoot arthrodesis for AVN had excellent clinical results.⁷

Finally, reports of total ankle replacement (TAR) for talar AVN cite mixed results, although one study from Devalia and colleagues reported a two staged technique in a cohort of seven patients. The first stage involved a primary subtalar fusion that would revascularize the talus through creeping substitution and once complete fusion was achieved, a TAR was carried out. They observed significant improvement in pain with no evidence of talar component subsidence with mean follow up of three years.⁸

Ultimately, there are many options, and every clinical scenario deserves consideration of the patient's unique situation, their goals and the specifics of that patient's pathology. These are rare cases and talar AVN can have severe implications for the patient, mobility and limb function overall if not managed appropriately. Hopefully, this discussion offers some points to consider when treating these patients in your practice setting.

Dr. Ali Rahnama is a fellowship-trained foot and ankle surgeon and an Assistant Professor at the Georgetown University School of Medicine in Washington, D.C. You can follow him on Instagram @DrAliRahnama for interesting cases and educational material. 

References

1. Dhillon MS, Rana B, Panda I, Patel S, Kumar P. Management options in avascular necrosis of talus. Indian J Orthop. 2018;52(3):284-296.

2. 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;60:143–56.

3. Zhai L, Sun N, Zhang BQ, Wang JG, Xing GY. Effect of liquid-electric extracorporeal shock wave on treating traumatic avascular necrosis of talus. J Clin Rehabil Tissue Eng Res. 2010;14:3135–3138.

4. Mont MA, Schon LC, Hungerford MW, Hungerford DS. Avascular necrosis of the talus treated by core decompression. J Bone Joint Surg Br. 1996;78:827–830.

5. Nunley JA, Hamid KS. Vascularized pedicle bone-grafting from the cuboid for talar osteonecrosis: Results of a novel salvage procedure. J Bone Joint Surg Am. 2017;99:848–854.

6. Kodama N, Takemura Y, Ueba H, Imai S, Matsusue Y. A new form of surgical treatment for patients with avascular necrosis of the talus and secondary osteoarthritis of the ankle. Bone Joint J. 2015;97-B:802–808.

7. Urquhart MW, Mont MA, Michelson JD, Krackow KA, Hungerford DS. Osteonecrosis of the talus: Treatment by hindfoot fusion. Foot Ankle Int. 1996;17:275–282.

8. Devalia KL, Ramaskandhan J, Muthumayandi K, Siddique M. Early results of a novel technique: Hindfoot fusion in talus osteonecrosis prior to ankle arthroplasty: A case series. Foot (Edinb) 2015;25:200–205.