Clinical and radiographic outcomes of a large series of toe fusions using the Smart Toe implant

R. Walker, N. Chang, J. Dartnell, W. Nash, A. Abbasian, S. Singh, I. Jones1

Introduction: In 2009 the Smart Toe implant was introduced as an option for lesser toe fusion in our department. The Smart Toe is an intramedullary device made from Nitinol, an alloy that can change shape with a change of temperature, expanding within the intramedullary canals of the proximal and middle phalanx to achieve fixation. The advantages of the Smart Toe are that patients are spared 6 weeks with K-wires protruding from their toes and there is no need for wire removal. We conducted a retrospective review of radiographic and clinical outcomes to assess the performance of this implant.

Methods: We present a consecutive series of 192 toe fusions using the Smart Toe implant in 86 patients, between January 2009 and November 2013. All radiographs and case notes were reviewed to assess for radiological fusion, satisfactory clinical outcome and complications.

Results: One patient was lost to all follow up. Radiographic follow up was available for 186 of 192 implants (95%). 137 toes (74%) were fused by 6 weeks, and 152 (81%) at final follow up. Clinical notes were available for 182 implants (94%) in 85 patients. At 6 weeks 50 patients reported satisfactory outcomes in 105 toe fusions (58%). At final follow up 70 patients reported satisfactory outcomes in 150 toe fusions (82%). 7 patients experienced complications in 19 toes (10%). 2 implants were broken and 2 implants had cut out. There were 3 phalanx fractures. In all 4 toes were revised, and there was 1 amputation. Clinically, out of the 34 non-united toes only 5 were symptomatic.

Conclusion: Overall 82% of toe fusions using the Smart Toe implant yielded entirely satisfactory clinical outcomes. Radiographic fusion occurred in 81% but most non-unions were asymptomatic. There were a small number of significant complications, and 4 patients out of 85 required revision surgery.