Dynamic axial nail for intramedullary treatment of long bone fractures

摘要

An intramedullary nail for fixation and stabilization of a fractured bone that also allows for a controlled amount of longitudinal motion at the fracture site to encourage bone remodeling and healing is described. The intramedullary nail has a proximal portion and a distal portion that are coupled together in a manner by a biasing assembly that provides for a controlled movement of the proximal and distal portions relative to each other so that when a patient puts pressure on the bone, such as when walking, the fracture site compresses and the bone ends move together, and when the pressure is released from the bone, the bone ends are biased apart by a controlled amount.

主权项

1. An intramedullary nail for placement in a bone, comprising:
a distal portion having a distal end having a first diameter and a proximal end having a second diameter, the second diameter of the proximal end of the distal portion being less than the first diameter of the distal end of the distal portion, the distal end of the distal portion and the proximal end of the distal portion being coaxially disposed about a longitudinal axis of the distal portion, the distal portion also having a first land created at a point where the first diameter of the distal end of the distal portion meets the second diameter of the proximal end of the distal portion; a proximal portion having a proximal end and a distal end, the distal end of the proximal portion telescopically arranged around the proximal end of the distal portion, the first land, and a portion of the distal end of the distal portion, the proximal portion being moveably engaged with the proximal end of the distal portion, the distal end
of the proximal portion having a first section having a first diameter sized to slide over the first diameter of the distal end of the distal portion, the first section having a second land formed by a second diameter of the first section, the second diameter of the first section being less than the first diameter of the first section; a space defined by the first land of the distal portion and the second land of the proximal portion disposed between the first diameter of the first section of the distal end of the proximal portion and the second diameter of the proximal end of the distal portion; a reversibly compressible bias member disposed in the space between first land and the second land for biasing the distal and proximal portions apart along the longitudinal axis; and an adjusting assembly configured to engage the distal and proximal portions such that actuation of the adjusting assembly results in providing for a selected overall maximum length of the arrangement of the distal and proximal portions along the longitudinal axis, the overall maximum length being selected before the distal and proximal portions are fixated to the bone, and a selected amount of reversible movement along the longitudinal axis between the proximal and distal portions, such that the arrangement of the proximal and distal portions has an uncompressed length equal to the selected overall maximum length and a compressed length that is less than the selected overall maximum length when a compressive force is applied along the longitudinal axis when the nail is fixed within with the bone.