SmartToe, ToeGrip and buried k-wire versus percutaneous k-wire fixation for 2nd PIPJ arthrodesis: A comprehensive review of outcomes

Abstract

Background: Proximal interphalangeal joint arthrodesis is a reliable and repeatable method of surgical correction for the semi-rigid and rigid hammer toe deformity. In recent years the authors have noted a significant increase in the use of novel intramedullary devices in place of the traditional percutaneous Kirschner wires (k-wire). This paper set out to critically review three methods of internal fixation; ToeGrip implant, SmartToe implant and buried k-wire technique in comparison to the traditional method of percutaneous k-wire fixation during arthrodesis of the proximal interphalangeal joints (PIPJ) of the toes. The objectives were to review osseous fusion rates, infection, hardware complications, patient satisfaction, and the comparative cost of each modality.

Results: In total 3878 outcomes were reviewed consisting of 3255 percutaneous k-wires, 347 SmartToe implants, 218 ToeGrip implants, and 58 buried k-wires. Overall Infection rates where low; SmartToe infection rates ranged between 1.2% and 5%, percutaneous k-wire fixation 0.3%-7% buried k-wire 3.3%. The SmartToe Implant had the highest hardware failure rate up to 20.7%, the lowest hardware failure occurred in percutaneous k-wire studies at 0.1%-4.3%, no evidence of hardware failure was associated in both ToeGrip and buried k-wire techniques. Percutaneous k-wire migration ranged between 4.4%-5.5% and 3.8%-10% for the SmartToe implant, all significantly lower than buried k-wire migration of 33%. The SmartToe implant demonstrated the highest mean osseous union rate 87.2%, 83% in ToeGrip studies, similar results between the buried k-wire and percutaneous k-wire studies 72% and 73% respectively. Individual unit costs for k-wires £0.37, ToeGrip implant £236.94 and SmartToe implants £331, demonstrating a 640 and 894 fold increase in cost when using implants in comparison to k-wires. Patient satisfaction was poorly reported.

Conclusions: Percutaneous k-wire fixation remains a reliable and cost effective method of stabilisation during hammertoe correction in comparison to newer more costly implantable devices.

Level of evidence: IV - critical literature review.

Keywords: Arthrodesis; Kirschner wire; PIPJ; Proximal interphalangeal joint; SmartToe; ToeGrip.