Summary

This study evaluates the biomechanical strength of compressed peroneus longus allografts, finding that while compression reduces strength compared to original grafts, it maintains similar strength to smaller diameter grafts, suggesting potential for use in smaller patients.

Abstract

Introduction

There is broad agreement on the minimum diameter required for grafts in anterior cruciate ligament (ACL) reconstruction surgery, with a recommended minimum diameter of 8 millimeters for hamstring grafts. However, it is unclear what happens when a larger diameter graft is compressed to a smaller diameter and how this might affect the biomechanical properties of the graft. Our hypothesis is that a compressed graft may have similar strength to the original but with a smaller diameter.

Objectives: To determine if the biomechanical strength of compressed allografts is maintained despite altering their diameter, and if compression techniques could be used for smaller patients such as women and children.

Methods

A biomechanical cadaveric case-control study was conducted using 30 long fibular allografts (PL), with 20 having a diameter of 9 millimeters (mm) and 10 having a diameter of 8 mm. They were divided into three groups: Group A with tendons of 9 mm diameter, Group B with tendons compressed from 9 mm to 8 mm, and Group C with tendons of 8 mm diameter. Each group was tested using a Zwick/Roell Z005 (Ulm, Radeberg, Bickenbach, Germany) tensile testing machine, which performed cyclic loads followed by continuous tensile loading in the event of no failure in the previous load. The cyclic load varied between 50 and 250 N at 1 Hz for 1000 cycles. At the end of the cycles, the grafts were stressed to failure, and measurements were recorded for the different failure points of the allografts in each group.

Results

Grafts in Group A showed an average maximum force (F) at failure of 1902 Newtons (N) (SD 432.12, 95% CI). Grafts in Group B (compressed tendons) showed an average maximum force of 1608 N (SD 233.12, 95% CI), demonstrating a statistically significant difference from Group A. Group C showed a maximum force at failure of 1341 N (SD 936.67, 95% CI). No statistically significant difference was found between Group B and Group C.

Conclusions

The results indicate that the compressed group had less strength than the original (9 mm diameter, maximum strength of 1902 N vs. 1608 N for the compressed group). When compared to the smaller graft, there was no significant difference between the compressed group and the smaller diameter group; however, the compressed group shows a tendency to have more strength than the smaller graft.