Percutaneous screw fixation for a femoral head fracture: a case report.

Femoral head fracture associated with hip dislocation is relatively rare but very severe injury. Due to its severity and the need of joint exposure for the reduction of femoral head fracture, the surgical treatment cannot but accompany many complications, including the osteonecrosis of the femoral head, heterotopic ossification, and post-traumatic osteoarthritis. We report a case of less invasive percutaneous screw fixation for the femoral head fracture with excellent clinical result.

Ising phases of Heisenberg ladders in a magnetic field.

We show that Dzyaloshinskii-Moriya (DM) interactions can substantially modify the phase diagram of spin-1/2 Heisenberg ladders in a magnetic field provided they compete with exchange. For nonfrustrated ladders, they induce a local magnetization along the DM vector that turns the gapless intermediate phase into an Ising phase with broken translational symmetry, while for frustrated ladders, they extend the Ising order of the half-integer plateau to the surrounding gapless phases of the purely Heisenberg case. Implications for experimental ladder and dimer systems are discussed.