Is rotation the mode of failure in pertrochanteric fractures fixed with nails? Theoretical approach and illustrative cases.

PURPOSE: The present article reviews data from biomechanical and clinical studies which indicate that rotational instability can cause failure of fixation due to the particular characteristics of the fracture, the mechanical properties of the chosen implant or flaws in surgical technique. METHODS: Although radiographs give a similar impression in failure of fractures fixed with cephalomedullary nails, different mechanisms involving rotation of the femoral head may play a key role. RESULTS: The incidence of failure in pertrochanteric fracture fixation is decreasing as implants continue to evolve. It is possible that currently reported low failure rates do not apply equally to all subtypes of this diverse group of fractures. Since the introduction of sliding hip screws, "cut-out" due to varus collapse of the proximal fracture fragment has been the only reported mode of failure. CONCLUSION: Excessive rotation leading to eventual "cut-out" has not been adequately studied, and thus, available evidence is not sufficient to definitely prove this theoretical approach. As nailing is gradually overtaking extramedullary fixation as the treatment of choice, especially for comminuted pertrochanteric fractures which can be rotationally unstable, further research is warranted to improve our understanding of the pathogenetic mechanisms of failure.

Traumatic extrusion of the talus (missing talus).

Complete dislocation of the talus is an extremely rare injury. We report on a case that was treated according to a surgical technique described by Günal et al. According to this technique, a pseudarthrosis is created between the tibia and the calcaneus by transposing and fixing the medial malleolus laterally and displacing the entire foot anteriorly. The result was considered to be initially unsatisfactory. At the 2-year follow-up examination, the outcome was considered to be satisfactory. This was attributed to preservation of motion and stability in the new mortise.

Late results of surgical repair in recent ruptures of the lateral ligament of the ankle.

Between 1979 and 1994, 75 patients underwent primary repair of a Grade III rupture of the lateral ligament of the ankle. The operation was indicated after the demonstration of ankle instability on stress X-rays by anterior displacement of the talus by more than 8 mm or/and a talar tilt of more than 10 degrees. The patients were either young or engaged in sports activities or physically demanding jobs. An end-to-end suture of the torn ligament was undertaken under general anaesthesia. A non-weight-bearing cast was used for the first 2 weeks, followed by a walking cast until 6 weeks postoperatively. Sixty-one patients were followed up for 1-15 years (mean 10.3 years). At follow-up all but one patient had returned to their pre-injury level of activity without complaint or restriction.