By: 1 October 2009

IOS is a single-use disposable external fixator designed specifically for treating unstable tibial shaft fractures. It is available in two sizes (70mm and 110mm) to accommodate most tibial shaft fractures suitable for mono-lateral external fixation.

The simple appearance of IOS is deceptive as its design is the result of over ten years of research in fracture healing and management. IOS has several unique features which offer benefits to both the patient and the surgeon:

Movement – IOS has been designed so that the elasticity of the fixator body allows cyclical movement on weight-bearing to promote the growth of healing callus (see graph).

Size – the small size of IOS allows the surgeon to place the IOS fixator epicentric to the fracture so that on weight-bearing the forces work to reduce the fracture and not to distract it.

Fracture healing indicator – IOS is designed to provide an indication of when fracture stiffness has reached 15Nm/deg (the accepted safe stiffness for fixator removal) simply by removing the collets from one side of the fixator.

Robust – IOS has been designed without any moving parts however, this does mean that a good reduction must be achieved, and held, before IOS is applied. Patients are able to fully weight-bear as soon as possible.

In the example shown IOS was applied following reduction using the STORM device on a patient weighing 107 kilos, fracture was healed and the fixator removed at 13 weeks.