Load to Failure and Stiffness of Interference Screw vs Pulvertaft Weave for Distal Fixation in Peroneal Allograft Reconstruction

Abstract

Background:

Allograft reconstruction of the peroneal tendons is an option for treatment of major tears of 1 or both peroneal tendons. No consensus on a superior distal fixation method has been reported. The purpose of the study was to compare load to failure and stiffness of a Pulvertaft weave (PTW) through a residual tendon stump to direct-to-bone interference screw (IS) fixation.

Methods:

Fifteen pairs of long leg cadaver specimens were used. All grafts were secured proximally to the peroneus brevis myotendinous junction via a PTW technique. Distally, the tendons were either sutured to the peroneus brevis stump via PTW or secured to the base of the fifth metatarsal via IS. Stiffness (slope of force/displacement) was measured for the intact tendon and after reconstruction, and finally each specimen was loaded to failure.

Results:

Mean load to failure was significantly higher in the PTW group compared with the IS group (373.6 ± 265.5 N vs 150.1 ± 93.1 N; P = .01). The PTW and IS groups had significantly lower stiffness compared with the intact specimens (P < .001). There was no statistical significance in stiffness between the 2 techniques (P = .96).

Conclusion:

The PTW technique yielded higher load to failure in comparison to IS. There was no difference in overall construct stiffness between both techniques. Both constructs demonstrated 19% decrease in stiffness compared to the intact state.

Clinical Relevance:

The PTW and IS constructs were biomechanically similar, and these results suggest that both should be moderately overtensioned to compensate for an inherent decreased initial stiffness.