Unicortical self-drilling external fixator pins reduce thermal effects during pin insertion

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Surgical instrumentation

Background:

• External fixation devices are essential in orthopedic surgery.
• Pin loosening and infection are risks associated with external fixation.
• Thermal bone necrosis can occur during pin insertion.

Purpose of the Study:

• To compare heat production during insertion of unicortical versus bicortical external fixator pins.
• To evaluate the impact of rotational speed on pin insertion temperatures.
• To assess the risk of thermal damage associated with different pin types.

Main Methods:

• Utilized porcine bone specimens for temperature analysis.
• Employed thermographic cameras for simultaneous surface and cross-section temperature measurement.
• Inserted self-drilling unicortical and bicortical pins at varying rotational speeds (30-600 rpm).

Main Results:

• Maximum temperatures reached up to 77°C in bone debris and 42°C on the bone surface.
• Higher rotational speeds correlated with increased debris temperatures.
• Bicortical pin insertion generated significantly higher temperatures at lower speeds (30 rpm).

Conclusions:

• External fixator pin insertion generates substantial heat, particularly from bone debris at higher speeds.
• Unicortical, self-drilling fixator pins demonstrate a reduced risk of thermal damage to bone and surrounding tissues.
• Findings suggest unicortical pins may enhance patient safety in external fixation procedures.