A biomechanical study of the ankle syndesmosis after fibular graft harvest

Harvesting the fibula as corticocancellous bone graft is not without complications. Multiple clinical studies chronicled the morbidity at the donor site, both immediately after surgery and at long-term follow-up. To our knowledge, no cadaveric or biomechanical studies addressed the effect that fibular osteotomy has on the ankle syndesmosis. We carried out two experiments by using cadaveric tibias/fibulas to determine the ability of the ankle syndesmosis to resist both lateral and vertical displacement of the intact fibula, as well as lateral and vertical displacement of the distal fibular stump after serial fibular osteotomies had been made at distances of 14, 10, 6, and 4 cm from the tip of the lateral malleolus. The results of this study show that, once the fibula is cut, the syndesmosis provides significantly less resistance to lateral and vertical displacement. Further, although this resistance continues to decrease with each decrease in fibular stump length, the length of the fibular stump does not significantly affect the stability of the syndesmosis.