OBJECTIVE To investigate the effects of different sterilization methods on 3D-printed polylactic acid (PLA) guide plates for orthopedic surgery, and to analyze their physical properties, microbial contamination, structural performance and biocompatibility after sterilization.

METHODS PLA guide plates for orthopedic surgery were prepared with 3D printing technology and divided into a blank group, a hydrogen peroxide plasma sterilization group, an ethylene oxide sterilization group and a pressure steam sterilization group. Before and after sterilization, the changes in volume and weight of the surgical guide plates were measured, microbial detection was conducted, structural changes were observed with a laser scanning confocal microscope, and cell co-culture was conducted to evaluate biocompatibility, thereby the effects of different sterilization methods were assessed.

RESULTS The three sterilization methods had no significant effect on the volume and weight of PLA surgical guide plates. Microbial detection showed that all three sterilization methods were effective in killing bacteria, and bacterial cultures were negative. Laser confocal scanning microscopy revealed that sterilization treatment caused certain changes to the microstructure of the surgical guide plates, but high-temperature sterilization had a more pronounced effect on the deformation of the guide plate edges. Cell co-culture results indicated that the surgical guide plates treated with the three sterilization methods exhibited acceptable cytotoxicity and had little effect on cell proliferation.

CONCLUSIONS All three sterilization methods cause microstructural changes to the surgical guide plate. Among them, pressure steam sterilization significantly deforms the structure of the guide plate, directly affecting its precise positioning of mutual spatial distances, angular relationships and orientation during surgery. Although hydrogen peroxide plasma sterilization does not cause significant deformation, ethylene oxide sterilization has the least impact on material properties and structural stability while ensuring the sterilization effect of PLA surgical guide plates.