The use of one compared with two distal screws in the treatment of femoral shaft fractures with interlocking intramedullary nailing. A clinical and biomechanical analysis.

The torsional and compressive biomechanical characteristics of a system for intramedullary fixation with a slotted locking nail and either one or two distal locking screws were evaluated in sixteen femora obtained from eight cadavera. No significant difference was found in the torsional rigidity or axial load to failure when one as opposed to two distal screws had been used. We also managed twenty-seven patients who had a fracture of the femoral shaft with interlocking fixation, using only a single distal screw for distal fixation. The average duration of follow-up was nine months (range, three to twenty-five months). The average time to radiographic healing was three months (range, two to six and one-half months). There were no non-unions or failures of the implant. Clinically unimportant migration of the distal screw occurred in five patients. We concluded that one distal screw provides adequate distal fixation of fractures of the femoral shaft treated with interlocking intramedullary nailing.

Biomechanical study of C1-C2 posterior arthrodesis techniques.

Fifteen cervical spines from cadavers were used to compare the rotational and translational stability of the Brooks fusion, a fusion construct using Halifax interlaminar clamps, and the Gallie fusion. The Brooks and Halifax clamp constructs exhibited significantly greater rotational and translational stiffness than the Gallie construct (P < 0.001). The Halifax clamp construct exhibited greater rotational stiffness and equal translational stiffness when compared with the Brooks construct (P < 0.05). The Brooks and Halifax fixation constructs provided superior fixation but presented technical challenges. The Gallie construct is less technically demanding but provides less stable fixation.