Patellar Fracture Risk Is Not Affected by Harvest Length During Bone-Patellar Tendon-Bone Harvest: A Biomechanical...

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Sports Medicine

Background:

• Bone-patellar tendon-bone (BPTB) autograft harvest carries a risk of patellar fracture.
• Understanding the relationship between patellar harvest size and fracture risk is crucial for patient safety.

Purpose of the Study:

• To biomechanically evaluate the effect of 20-mm versus 25-mm patellar defect sizes on the ultimate load to failure (ULTF).
• To assess the immediate fracture risk of the patella following BPTB harvest of varying defect lengths.

Main Methods:

• Twelve cadaveric knee specimens were used, with patellar defects randomized to 20 mm or 25 mm.
• The extensor mechanism was loaded to failure at 30° knee flexion to record ULTF and failure modes.
• Statistical analysis compared ULTF and defect percentages between the two groups (P < .05).

Main Results:

• No significant difference in ULTF was found between the 20-mm (2,313 ± 863 N) and 25-mm (2,443 ± 839 N) groups (P = .815).
• The 25-mm group had a significantly larger percentage of patellar defect (49.1% ± 4.1%) compared to the 20-mm group (39.5% ± 3.9%) (P = .005).
• Patellar bony failure occurred in 7 of 10 specimens.

Conclusions:

• Harvesting up to a 25-mm patellar bone block is biomechanically safe.
• The risk of patellar fracture is low even with larger harvest sizes within this range.