Morphologic and histologic comparison between the patella and hamstring tendons grafts: a descriptive and anatomic...

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Tissue engineering

Background:

• Autografts are commonly used for anterior cruciate ligament (ACL) reconstruction.
• Patellar and hamstring tendons are popular autograft choices.
• Microscopic differences between these graft types require further investigation.

Purpose of the Study:

• To perform a morphologic and histologic comparison of patellar and hamstring tendon grafts.
• To analyze key structural parameters relevant to graft healing and integration.

Main Methods:

• Hamstring (semitendinosus, gracilis) and patellar tendons were harvested from 20 cadaveric knees.
• Light and electron microscopy, immunohistochemistry, and morphometry were employed.
• Analysis included collagen fibril thickness, fibril/interstitum ratio, vascularity, fibroblast density, and fibril distribution.

Main Results:

• Hamstring tendons exhibited a significantly higher fibril/interstitum ratio (20-30%) compared to patellar tendons.
• Fibroblast density was also significantly greater in hamstring tendons (35-50%).
• No significant differences were observed in collagen fibril thickness, blood vessel density, or fibril distribution.

Conclusions:

• Hamstring tendons possess a superior fibril/interstitum ratio and fibroblast density over patellar tendons.
• These findings suggest a potential advantage for hamstring grafts in tissue remodeling and regeneration.
• This could translate to improved outcomes in anterior cruciate ligament reconstruction.