Achilles tendon rupture. A case report of percutaneous tendon repair

Biomechanical comparison of the primary stability of suturing Achilles tendon rupture: a cadaver study of Bunnell and Kessler techniques under cyclic loading conditions

INTRODUCTION

Biomechanical studies investigating suture techniques for Achilles tendon repair used single load to failure tests in order to evaluate the maximal load capacity of the repaired construct. During early rehabilitation the repair is repetitively loaded such as exercise or daily living activities like walking. Cyclic loading seems to duplicate the physiological loading conditions more closely than single cycle failure tests. Aim of this study was to test the most commonly used Achilles tendon repair techniques (Bunnell and Kessler repair) under cyclic loading conditions.

MATERIALS AND METHODS

Following tenotomy fresh human cadaveric tendons were sutured either with the Bunnell or Kessler technique. After repair, cyclic loading tests were performed with a uniaxial biomechanical testing machine Lloyd LR-5K Plus. Both groups were sutured with 0.7 mm PDS.

RESULTS

Except at maximum load we could not find significant differences between tendons sutured by Bunnell and Kessler techniques. During the cyclic testing there were no differences between both groups with respect to displacement. This applies also to the stiffness of the constructs, which we defined from the load to failure measurements. The failure modes in both groups differed; the tendons repaired by Kessler technique were cut by the tendons and in the Bunnell group the suture material tore in each specimen tested.

CONCLUSION

In our study Bunnell and Kessler techniques showed similar biomechanical properties using the same suture material. The typical failure mode of the Bunnell technique shows potential to optimise biomechanical behavior by using stronger suture material.

The Krackow stitch: a biomechanical evaluation of changing the number of loops versus the number of sutures

PURPOSE

The purpose of this study was to biomechanically evaluate several configurations of the Krackow stitch and determine which configuration provided the best fixation with regard to load to failure and elongation.

TYPE OF STUDY

Biomechanical study.

METHODS

Thirty fresh-frozen porcine Achilles tendons were randomly assigned into 6 groups. For 3 of the groups, 1 suture was used (No. 5 Ethibond; Ethicon, Somerville, NJ) with 2, 4, or 6 Krackow locking loops. For the other 3 groups, 2 sutures (interlocking and at 90 degrees) with 2, 4, or 6 Krackow locking loops were used. Data were evaluated using analysis of variance.

RESULTS

There were no statistical differences in peak load to failure and elongation among any of the 1-suture techniques regardless of the number of locking loops (2, 290 N; 4, 302 N; and 6, 298 N; standard deviation, 25.2, 9.0, and 28.6, respectively). Similarly, there were no statistical differences among any of the 2-suture techniques regardless of the number of locking loops (2, 534 N; 4, 492 N; and 6, 505 N; standard deviation, 42.0, 65.4, and 76.3, respectively). There was, however, a significant difference (P < .05) in peak load to failure between the 1-suture and the 2-suture groups. The mechanism of failure was suture rupture in all cases.

CONCLUSIONS

Load to failure did increase with the addition of a second interlocking suture placed at 90 degrees to the first.

CLINICAL RELEVANCE

Tendon fixation with gap formation or suture rupture is at risk of failure. This study identifies that increasing the number of sutures is more important than increasing the number of locking loops.

Spiked metallic washer and screw for reattachment of the Achilles tendon after repair of a distal rupture

The authors review Achilles tendon ruptures and treatment options for the acute and chronic rupture. A case is described involving reattachment of a chronic distal Achilles tendon rupture repair with a spiked metal washer and fully threaded cannulated cancellous screw. Spiked metal washers and their effects on soft-tissue pullout strength, and possible complications are discussed. In review of the literature, the authors have not found this type of fixation used to anchor the Achilles tendon, and feel it may be a viable option when faced with distal Achilles reattachment for the acute and chronic rupture.

The strength of Achilles tendon repair: an in vitro study of the biomechanical behavior in human cadaver tendons

Eighteen fresh frozen human Achilles tendons were used to test the ultimate strength of repaired tendon "ruptures." Three methods, the Kessler, the Bunnell, and the locking loop, were used to test the initial strength of Achilles tendon repair. The Kessler and Bunnell methods are current standard clinical configurations described for Achilles tendon repair. Under uniform and standardized laboratory conditions, the specimens were loaded to failure. The locking loop suture method was substantially stronger than either of the other two standard configurations. The latter two did not differ significantly from each other. The results of this study may be clinically relevant in terms of the choice of the repair method for surgically treated Achilles tendon ruptures.