Management of nonunion following subtalar arthrodesis. An analysis of the methods of revision surgery, and the risk factors in achieving arthrodesis

M. Myerson, S. Li, C. Taghavi, T. Tracey

Background: Subtalar nonunion has a detrimental effect on patients' function, and pose a significant challenge for surgeons particularly in the setting of higher risk factors.

Methods: We retrospectively analyzed a consecutive series of 49 subtalar nonunions between October 2001 and July 2013. Patient records and radiographs were reviewed for specific patient demographics and comorbidities, subsequent treatments, revision fusion rate, use of bone graft, complications, and clinical outcome.

Results: Forty-nine patients with a mean age of 49 years (range 23-80) were included. Sixteen (32%) were heavy smokers (>1 pack per day) and five (10%) had diabetes. Forty one (84%) of the nonunions were symptomatic and underwent a revision procedure at a mean of 16 months (range 2.8 to 57) from the time of the primary arthrodesis. Four of these patients required a triple arthrodesis at the time of revision. Bone graft was used in all cases, and in 25 cases (61%) additional adjuvant orthobiologics. Thirty-two (78%) of the patients achieved a solid arthrodesis at a mean of 3.4 months (range 1.4 to 7.6). Patients who were diabetic and smokers as a group had a 68% rate of union. Of the nine nonunions following a revision arthrodesis, five were in the setting of a prior ankle arthrodesis, three were complicated by a deep infection, and one had no obvious risk factors. Four of the repeat nonunions elected to not undergo an additional procedure, two had a successful third attempt at arthrodesis, one had an additional nonunion followed by a successful fourth attempt at arthrodesis, one had a successful tibiotalocalcaneal arthrodesis, and one ultimately required a below-knee amputation.

Discussion: Management of subtalar nonunions pose a significant challenge with a low rate of arthrodesis at 78% fusion rate, but which can be achieved with rigid fixation and utilization of bone graft and orthobiologics.