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

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.