Morphometric and Histological Insights to Aid Graft Selection for Anterior Cruciate Ligament Reconstruction

TL;DR

This study compares knee tendons for ACL reconstruction, finding patellar, quadriceps, and gracilis tendons most suitable based on size and collagen density.

Contribution

Provides new morphometric and histological data to guide graft selection in ACL reconstruction.

Findings

Patellar and quadriceps tendons had the largest dimensions.

Gracilis tendon showed collagen density similar to ACL.

Plantaris tendon was often absent and less robust.

Abstract

Background: Anterior cruciate ligament (ACL) injuries are among the most common and debilitating knee injuries, especially in athletes. While autografts are widely used for ACL reconstruction (ACLR), the optimal choice of tendon remains controversial. This study aimed to analyze and compare the morphometric and histological characteristics of ACL and periarticular knee tendons (patellar, quadriceps, semitendinosus, gracilis, plantaris), in order to assess their suitability as grafts for ACLR.

Methodology: Thirty knee joints from 15 formalin-embalmed adult cadavers of 12 (80%) males and 3 (20%) females were dissected. Morphometric parameters (length, width, and thickness) of ACL and periarticular tendons were recorded using digital calipers. Femoral and tibial footprints of the ACL were analyzed for size and shape. Histological sections were stained with hematoxylin and eosin (H&E) and Masson’s Trichrome (MT) stains, and the integrated collagen density was quantified using ImageJ software (National Institutes of Health, Bethesda, MD).

Results: Patellar and quadriceps tendons had the largest dimensions, while gracilis showed the highest integrated collagen density, closely resembling that of the ACL. The plantaris tendon, though long, was often absent and structurally less robust. The femoral and tibial footprints displayed variable shapes, with half-moon and droplet patterns being most common, suggesting the need for personalized tunnel placement.

Conclusion: The patellar, quadriceps and gracilis tendons emerge as promising grafts due to favorable morphometry, histology and integrated collagen density. Quadriceps is a viable option for ACLR, while the gracilis with plantaris is an alternative option, depending on the availability of plantaris. This study provides baseline anatomical data to guide graft selection in ACLR and highlights the need for further biomechanical and clinical validation.

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