Metaphyseal aspects of stapling. An experimental study in pigs

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Skeletal Biology

Background:

• Blount disease, a condition affecting the medial proximal tibial growth plate, can lead to progressive deformity.
• Surgical intervention, such as growth plate stapling, is used to correct such deformities.
• Understanding the metaphyseal bone response to stapling is crucial for optimizing treatment outcomes.

Purpose of the Study:

• To investigate the metaphyseal bone architecture changes following Blount stapling of the growth plate.
• To evaluate the temporal progression of these changes during the postoperative period.
• To identify the stereological parameters most sensitive to growth plate stapling.

Main Methods:

• Stereological analysis of metaphyseal bone architecture in 37 skeletally immature pigs (10 weeks old).
• Medial tibial growth plates were stapled, and animals were followed for up to 17 weeks postoperatively.
• Bone regions distal to the staple, representing bone modeling and bone remodeling zones, were analyzed separately.

Main Results:

• Growth plate stapling induced subtle, progressive changes in metaphyseal architecture.
• Bone remodeling zone (Zone 2) showed similar but less extensive changes compared to the bone modeling zone (Zone 1).
• Surface density was the most sensitive parameter, followed by trabecular distance; specific surface, trabecular diameter, and volume density changed with a delay.

Conclusions:

• Blount stapling initiates a metaphyseal bone response that evolves over time.
• Stereological investigation provides quantitative insights into bone's reaction to growth plate manipulation.
• Surface density is a key indicator for assessing early metaphyseal bone changes after growth plate stapling.