Tendon transfer fixation in the foot and ankle: a biomechanical study.

BACKGROUND: Tendon transfers are often used in foot and ankle surgery. Different fixation devices and techniques have been described. The most recently developed ones are bone anchors and interference screws. MATERIALS AND METHODS: A biomechanical study was designed to compare tendon transfer fixation, using Corkscrew bone anchors 5 x 15.5 mm and Bio-interference screws (8 x 23 mm). Fifteen fresh cadaver specimens underwent both fixation techniques for split anterior tibial tendon transfer at the cuboid bone. All the specimens underwent standardized X-rays in order to evaluate mineral bone density using a standardized measurement system. All were tested until maximal load to failure. RESULTS: The ultimate load to failure of the tendon secured to the cuboid using anchors was 103 N (SD, 52), compared with 150 N (SD, 68) for tendons secured to the bone with interference screws (p = 0.003). No difference was found between the techniques that could be related to bone density. CONCLUSION: Interference screws provided greater strength than bone anchors. CLINICAL RELEVANCE: This study demonstrated increased strength in securing bone to tendon in vitro for SPLATT tendon transfer with interference screws as compared to suture anchors.

Dislocation of rotating-hinge knee prostheses with antidislocation mechanism.

At our institution, we have used Endo-Model prostheses (Waldermar Link GmbH & Co, Hamburg, Germany) for difficult knee reconstructions. These rotating-hinge prostheses have an antidislocation feature that prevents dislocation due to distraction disengagement. In a series of 192 consecutive prostheses, we have identified 2 cases of femorotibial dislocations. An increased flexion laxity allows excessive distraction and hence implant dislocation after antidislocation feature loosening. To our knowledge, there are no other reports in the literature regarding dislocation of a rotating-hinge knee prosthesis with antidislocation design.