SLR - April 2010 - Daniel Arrhenius
Reference:
Lee SJ, Sileo MJ, Kremenic IJ, Orishimo K, Ben-Avi S, Nicholas SJ, McHugh M. Cyclic loading of 3 Achilles tendon repairs simulating early postoperative forces. Am J Sports Med. 2009 Apr;37(4):786-90.
Scientific Literature Reviews
Reviewed by: Daniel Arrhenius, DPM
Residency Program: Detroit Medical Center
Podiatric Relevance:
Stresses applied to the repaired Achilles tendon may exceed the strength provided post operatively by certain repair methods. This may affect the rehabilitation time frame as well as aggressiveness of post operative rehabilitation. Epitendinous cross stitch augmentation of Krackow method may be the procedure of choice for early range of motion and weight-bearing modalities.
Methods:
Fifteen human cadaveric Achilles tendons were transected 4cm proximal to tendon insertion. Tendons were repaired by 1 of 3 repair techniques. The techniques were percutaneous repair, non-augmented 4-stranded Krackow technique, 4-stranded Krackow repair augmented with a cross-stitch epitendinous weave. Tendons were cyclically loaded to 1000 cycles each at 20-100N, 20-190N, and 20-369 N. The number of cycles to initial gapping, 5mm- gapping, and total failure were compared using Mann-Whitney U tests with adjustments for multiple comparisons. Total failure was defined as greater than 1cm gapping or a precipitous drop of measured force.
Results:
Percutaneous repairs all failed during cyclic loading at 100N. Non-augmented Krackow repairs all failed during cyclic loading at 190N. Four augmented repairs failed during cyclic loading at 369N and one survived the entire cyclic loading protocol and failed at 550N. Mann-Whitney test revealed that for all three measures, the augmented repairs were stronger than both the Krackow and percutaneous repairs (P<0.05). The Krackow repairs were stronger than the percutaneous repairs (P=0.24). The mode of failure for the percutaneous repair technique was suture pull through the tendon. The initial failure of the non-augmented Krackow method was suture pull through the tendon. Total failure of this technique appeared to be a combination of suture pull through and suture breakage. The mode of failure for the augmented Krackow technique was suture breakage with the epitendinous sutures breaking first.
Conclusions:
Epitendinous cross stitch weave augmentation of the Krackow method of Achilles tendon repairs significantly increased gap resistance as well as repair strength. Early range of motion therapy protocols and ambulation in a CAM walker post-operatively may expose the Achilles tendon to sufficient forces that would cause gapping and failure in repair while using the non-augmented Krackow and percutaneous repair methods. On the basis of this study it is not advisable to start early range of motion on those undergoing percutaneous repair. Non-augmented Krackow repairs appear to be able to withstand early range of motion but not immediate weight bearing with 1 inch heel lift. The augmented Krackow technique of repair appears to be the only method able to withstand early range of motion and immediate weight-bearing with a 1 inch heel lift.