Mechanical comparison of two extensor tendon repairs of ankle tendons

Complete disruption of the extensor tendons is commonly encountered with lacerations to the dorsal aspect of the ankle. The purpose of this study was to compare two tendon repairs (modified Krackow and Kessler-Tajima) to determine which repair was stronger in an anatomical cadaver model. Twenty tendons (10 extensor hallucis longus and 10 tibialis anterior tendons) from 10 fresh-frozen cadaver legs were lacerated and then repaired with either a modified Krackow or Kessler-Tajima repair. Each tendon repair was tested for gap formation and maximum load failure. Results showed that the mean force to produce gap formation in the modified Krackow repair was 64.7 N in the extensor hallucis longus and 82.3 N with the tibialis anterior. Mean gap formation for the Kessler-Tajima in the extensor group was 26.0 N and the tibialis anterior was 41.8 N. This represented a 40% and 50% greater resistance to gap formation for the modified Krackow in these groups. With maximum load failure, the mean for the modified Krackow was 99.5 N for the extensor hallucis longus and 126.8 N for the tibialis anterior, while the Kessler-Tajima was 45.6 N and 72.1 N for these groups. This represented a 45% and 58% greater difference in the maximum load failure for the modified Krackow. Statistical analysis using a Student's t-test (p < .05) showed that there was a significant statistical difference between the two repairs for gap formation and maximum load failure. The authors conclude that the modified Krackow is stronger than the Kessler-Tajima repair.