The use of the Smart Toe implant for proximal interphalangeal arthrodesis in the lesser toe: a case series

D. Trigkilidas, R. Drabu, A. Keightley, P. Halliwell

Introduction: Lesser toe proximal interphalangeal joint arthrodesis is a common forefoot procedure for correction of claw toe deformities. The most common method of fixation is with k-wires. Although this is a very cost-effective method of fixation, well-known disadvantages include pin site infection, non union, wire migration and the inconvenience to the patients of percutaneous wires for up to six weeks. For these reasons, intramedullary devices for joint fixation without crossing the distal IP joint have been developed. Many different designs are currently available. The Smart Toe prosthesis which has appeared as a type I and II, is one such implant. In two recent studies using type I, the use of this implant is advocated. We wish to present our experience with the use of the Smart Toe II.

Methods: In this retrospective study we present a radiological review of 46 consecutive cases in 25 patients who underwent lesser toe interphalangeal arthrodeses using the Smart Toe II implant between July 2010 and November 2014 by the senior author. There were 7 (28%) male and 18 (72%) female patients. Post operative radiographs, taken at a mean follow up of 6 months, were reviewed for non-union, migration and implant failure.

Results: There were 9 (20%) implant fractures, 10 (22%) radiological non- unions and 5 (11%) implant migrations. 4 toes (9%) were sufficiently symptomatic to require revision.

Conclusion: In contrast to two previous studies, our series showed a high rate of implant fracture and non-union, sometimes leading to the need for revision surgery. We recommend caution in use of the Smart Toe II and welcome further reports of results. If our experience is replicated, we suggest the device's use is withheld pending appropriate studies to identify and address the reasons for implant failure, especially if more of the radiological failures come to require revision.