Summary

We set out to compare the biomechanical performance of a high resistance transosseous flexible suture frame with FiberTape®; compared to standard Krakow suture technique in mid-substance acute patellar tendon ruptures, using 12 cadaveric knees. Both techniques surpassed the mechanical requirements. We found no difference in the tendon gap separation nor the strain to failure between them.

Abstract

Introduction

Mid-substance acute patellar tendon ruptures usually occurs in a tendon previously affected by chronic tendinopathy. Standard repair techniques require suturing the injured remnants to resist the high biomechanical demands, sometimes supported by wire frames placed through bone tunnels in the patella and tibial tuberosity. With percutaneous techniques not living up to expectations, we still require a technique that doesn’t require heavy sutures on the remnant of an already pathologic tendon, contributing sutures to an already poor biological environment. We set out to compare the biomechanical performance of a high resistance flexible suture frame compared to standard Krakow suture technique.

Methods

Cadaveric study including 12 fresh frozen knees. We performed a mid-line anterior approach and created a mid-substance traumatic patellar tendon rupture using a scalpel. We numbered each knee and randomized into two groups: the first group (6 knees; suture frame group) had tunnels drilled into the distal patella and anterior tibial tuberosity and a high resistance flexible suture frame was installed using FiberTape®; the second group (6 knees: standard technique group) was repaired using a FiberWire® Nº2 and Krakow suture technique. All knees were then mounted on a validated biomechanical system that forces knee extension through quadriceps tendon traction and a sensor was installed to monitor the distance between the proximal and distal remnant. All knees were submitted to 50 cycles of full knee range of motion at 240N. After completion, all knees were blocked at 45º at tension raised until construct failure. Data analysis included non-parametric mean comparisons using U Mann Whitney with significance set at 5%.

Results

Median separation of tendon gap along the 50 cycles was no statistically different (p 0.99) between the suture frame group (4.0mm) and the standard technique group (3.8mm). Construct failure occurred at 674N and 604N respectively, with no significant difference among groups (p < 0.01).

Conclusions

Both techniques surpassed the mechanical requirements. We found no difference in the tendon gap separation between the high resistance flexible suture frame and standard Krakow suture technique. We describe a de novo technique that allows minimal alteration of the biological environment of the ruptured tendon while maintaining biomechanical properties of standard technique.