BACKGROUND

Some fractures of long bones may be treated by placing the bone into corrective alignment and inserting an intramedullary nail into a medullary canal of the aligned bone. The intramedullary nail may be fixed relative to the bone via fixation screws that are inserted into fixation holes that extend laterally through the intramedullary nail. Fixation screws may include, for example, headless screws (e.g., screws having a threading along an entire length thereof) which may be inserted such that the screws are flush to the bone. In some cases, however, the headless screws may be inserted too far into the bone, which may interfere with the intramedullary nail, lose purchase in a near cortex of the bone and/or protrude too far from a far cortex of the bone.

SUMMARY

The present disclosure relates to a system for treating a bone. The system includes a headless screw and an insertion device. The headless screw extends from a proximal end to a distal end and including a threading extending along an outer surface thereof. The headless screw includes a driving recess extending into the proximal end thereof. The insertion device includes an outer sleeve extending from a proximal end to a distal end and including a channel extending therethrough and a driving member. The driving member extends longitudinally through the channel of the outer sleeve from a proximal end to a distal end. The proximal end of the driving member extends proximally of the proximal end of the outer sleeve to a distal end configured to engage the driving recess of the headless screw to rotationally drive the headless screw into a bone. The outer sleeve is movable relative to the driving member between a first position, in which the distal end of the outer sleeve extends over and covers a proximal portion of the headless screw when the headless screw is engaged with the driving member in the operative configuration, to a second position, in which a distal end of the outer sleeve is longitudinally aligned with a proximal end of the headless screw.

In an embodiment, the headless screw further includes a retaining recess extending distally from the driving recess.

In an embodiment, the insertion device further includes a retaining member extending longitudinally through a channel of the driving member from a proximal end to a distal end configured to engage the retaining recess so that the headless screw is retained on the insertion device during insertion of the headless screw into the bone.

In an embodiment, the retaining recess includes a threading therealong and the distal end of the retaining member is correspondingly threaded so that, rotation of the retaining member about a longitudinal axis thereof relative to the driving member, engages the threading of the retaining member with the threading of the retaining recess to retain the headless screw on the insertion device.

In an embodiment, the proximal end of the retaining member includes a knob extending proximal of the proximal end of the driving member to rotate the retaining member relative to the driving member.

In an embodiment, the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first and second positions, the locking mechanism including a locking tab biased toward a locking configuration via a biasing element and a push button compressing the biasing element to move the locking tab toward an unlocked configuration.

In an embodiment, the driving member includes a first groove extending into an outer surface of the driving member so that when the locking tab is received within the first groove the outer sleeve is in the first position relative to driving member, and a second groove extending into the outer surface of the driving member proximal of the first groove so that when the locking tab is received within the second groove the outer sleeve is in the second position relative to the driving member.

In an embodiment, a core diameter of the proximal portion of the headless screw is larger than a core diameter along a remaining portion of the headless screw.

In an embodiment, the outer sleeve includes gripping features extending distally from the distal end thereof, the gripping features configured to engage the bone.

In an embodiment, the outer sleeve includes a threading along the distal end thereof configured to engage a corresponding threading along the proximal portion of the headless screw.

In an embodiment, the outer sleeve includes a proximal portion and a distal portion connected to one another via a friction interface, the distal portion being rotatable about a longitudinal axis thereof.

In an embodiment, the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member.

In an embodiment, the proximal portion of the outer sleeve includes a depth indicator that indicates a depth to which the headless screw has been inserted into the bone. In addition, the present disclosure relates to a bone screw insertion device. The device includes an outer sleeve extending from a proximal end to a distal end and including a channel extending therethrough and a driving member. The driving member extends longitudinally through the channel of the outer sleeve from a proximal end to a distal end configured to engage a driving recess of a bone screw. The outer sleeve is movable relative to the driving member between a first position in which the distal end of the outer sleeve extends over and covers a proximal portion of a bone screw engaged with the driving member, to a second position in which the distal end of the outer sleeve is longitudinally aligned with a proximal end of a bone screw engaged with the driving member.

In an embodiment, the system further includes a retaining member extending longitudinally through the channel of the driving member from a proximal end to a distal end, the retaining member being configured to releasably engage a retaining recess of a bone screw.

In an embodiment, the distal end of the retaining member is threaded to engage a corresponding threading of the retaining recess.

In an embodiment, the proximal end of the retaining member includes a knob extending proximal of the proximal end of the driving member to rotate the retaining member relative to the driving member.

In an embodiment, the outer sleeve includes a locking mechanism for locking the outer sleeve relative to the driving member in one of the first and second positions, the locking mechanism including a locking tab biased toward a locking configuration via a biasing element and a push button compressing the biasing element to move the locking tab toward an unlocked configuration.

In an embodiment, the driving member includes a first groove extending into an outer surface of the driving member so that when the locking tab is received within the first groove the outer sleeve is in the first position relative to driving member, and a second groove extending into the outer surface of the driving member proximal of the first groove so that when the locking tab is received within the second groove the outer sleeve is in the second position relative to the driving member.

In an embodiment, the outer sleeve includes gripping features extending distally from the distal end thereof, the gripping features configured to engage the bone.

In an embodiment, the outer sleeve includes a threading along an inner surface of a distal portion thereof configured to engage a corresponding threading along the proximal portion of a headless screw received within the outer sleeve.

In an embodiment, the outer sleeve includes a proximal portion and a distal portion connected to one another via a friction interface, the distal portion of the outer sleeve being rotatable about a longitudinal axis thereof relative to the proximal portion of the outer sleeve.

In an embodiment, the proximal portion of the outer sleeve includes a mating feature configured to mate with a corresponding mating feature on the driving member to prevent the proximal portion from rotating relative to the driving member.

In an embodiment, the proximal portion of the outer sleeve includes a depth indicator that indicates a depth to which the headless screw engaged to the driving member has been inserted into the bone. Furthermore, the present disclosure relates to a method for implanting a bone screw which includes assembling a headless bone screw with an insertion device by inserting a distal end of a driving member of the insertion device into a correspondingly sized and shaped driving recess of the headless screw; inserting the headless bone screw to a position adjacent to a target area of the bone with the insertion device in a first position with an outer sleeve mounted over the driving member so that a distal end of the outer sleeve extends over and covers a proximal portion of the headless screw; driving the headless bone screw into the bone by rotating the driving member until the distal end of the outer sleeve abuts a near cortex of the bone; drawing the outer sleeve proximally relative to the driving member from the first position to a second position in which a distal face of the outer sleeve is longitudinally aligned with a proximal face of the headless bone screw; and driving the headless bone screw further distally into the bone until the distal end of the outer sleeve contacts the near cortex of the bone, providing tactile feedback to the user that the headless screw is flush with the bone.

In an embodiment, the method further includes retaining the headless bone screw on the insertion device by threadedly engaging a threaded distal portion of a retaining member with a correspondingly threaded retaining recess of the headless bone screw, the retaining member extending longitudinally through the driving member.

In an embodiment, drawing the outer sleeve proximally relative to the driving member from the first position to the second position includes moving a locking mechanism of the outer sleeve from a locked configuration to an unlocked configuration so that a locking tab of the locking mechanism is movable from a first groove along the driving member to a second groove along the driving member.

In an embodiment, the locking tab is biased toward the locked configuration via a biasing.

In an embodiment, moving the locking mechanism from the locked configuration to the unlocked configuration includes pressing a push button to compress the biasing element so that the locking tab is disengaged from the first groove and the outer sleeve is proximally movable along the driving member, the locking tab reverts to the biased configuration to engage the second groove in the second configuration.

In an embodiment, the method further includes removing the insertion device from the implanted headless bone screw by disengaging the threaded distal portion of the retaining member from retaining recess and drawing the insertion device proximally therefrom.

In an embodiment, the method further includes retaining the headless bone screw on the insert device by threadedly engaging the distal end of the outer sleeve with the proximal portion of the headless screw.

In an embodiment, the outer sleeve includes a proximal portion and a distal portion connected via a friction interface, the distal portion being rotatable about a longitudinal axis thereof, such that, the distal portion correspondingly rotates along with the driving member relative to the proximal portion of the outer sleeve.

In an embodiment, when the distal end abuts the near cortex of the bone, the friction interface provides a feedback indicating that the proximal portion of the headless screw is driving into the bone.

