Physeal response to absorbable polydioxanone bone pins in growing rabbits

Area of Science:

• Orthopedic surgery
• Pediatric orthopedics
• Biomaterials science

Background:

• Absorbable fixation materials offer potential for pediatric fractures.
• Concerns exist regarding degradation products impacting physeal growth.
• Transphyseal fractures require careful management in growing children.

Purpose of the Study:

• To evaluate the histologic response to transphyseal polydioxanone (PDS) bioabsorbable pins in a pediatric bone model.
• To assess potential adverse effects of PDS pins on physeal growth and function.
• To determine the safety of bioabsorbable pins for treating transphyseal fractures in immature bone.

Main Methods:

• Skeletally immature New Zealand White rabbits underwent surgical insertion of 1.3-mm PDS pins across the femoral physis.
• A control group received an empty drill hole in the contralateral femur.
• Histologic analysis, radiography, and bone length measurements were performed at 3, 6, 9, and 12 weeks post-surgery.

Main Results:

• No evidence of inflammation or foreign body reaction was observed around the PDS pins.
• The growth plate (physis) showed no distortion or adverse histologic changes.
• Bone length measurements indicated no significant difference between PDS pin and control groups.

Conclusions:

• Transphyseal placement of polydioxanone (PDS) bioabsorbable pins does not elicit an inflammatory response.
• PDS bioabsorbable pins appear safe for use in pediatric transphyseal fractures, without compromising physeal function.
• These findings support the potential utility of bioabsorbable pins in pediatric orthopedic surgery.