Retrieval analysis of the PRECICE OPTY-LINE magnetically controlled realignment nail: A report of two cases

Abstract

Purpose

The OPTY-LINE extendable nail is a magnetically-controlled, intra-medullary realignment device that is specifically designed for open-wedge high tibial osteotomy (HTO). The aim of this study was to perform a comprehensive retrieval analysis of OPTY-LINE nails and assess them for any signs of damage, corrosion and wear.

Patients and methods

Two routinely explanted OPTY-LINE nails were initially radiographed and force tested before mechanical section and disassembly. Macroscopic and microscopic inspection was performed and specific areas of the nails were identified for profilometry and scanning electron microscopy.

Results

Radiographs did not show any evidence of implant failure. Force testing resulted in no force output from one nail, while the second nail generated a maximum force of 706 N. Macroscopic inspection revealed wear patterns consistent with off-axis loading. Energy Dispersive X-Ray Spectrometry did not identify physiologic fluid ingress, however, O-Ring seal wear and moisture within the mechanism was concerning. Black debris was embedded within the O-Ring grooves of both nails.

Conclusion

This retrieval study is the first to evaluate the performance of the OPTY-LINE nail. Signs of off-axis wear and corrosion were identified and we support current recommendations for routine implant removal within one year. This study will inform and guide further retrieval analyses of the OPTY-LINE nail.