Locking pin plate assembly adapted for fracture fixation

Abstract

A lockable pin plate assembly which has a pin plate adapted to be secured to stable bone and provided with pin holes for pins for pinning an unstable bone fragment. One or more pin holes are engageable by pins of an integral U-pin. The pins have stop surfaces thereon which are resiliently displaced when the pins are seated to automatically and self-lock the pin and the pin plate to oppose withdrawal and backing out of the pins from the pin plate. In a preferred embodiment, each pin of the U pin has a leading portion and a trailing portion, the leading portion being of smaller diameter to pass freely through an elliptical hole in the pin plate whereas the trailing portion is of larger size to become locked in the pin hole as it is advanced therein.

Description

CROSS REFERENCE APPLICATION [0001]This application is a continuation-in-part of U.S. application Ser. No. 12 / 533,675 filed Jul. 31, 2009, the content of which is incorporated herein by reference.FIELD OF THE INVENTION [0002]The invention relates to a lockable pin plate assembly for fracture fixation which includes a pin plate adapted to be secured to stable bone and a pin member for engaging an unstable bone fragment of the fracture and securing the fragment to the plate.[0003]In particular, the invention relates to the pin member which serves to pin the unstable bone fragment and concurrently secures the pin member in locked engagement with the pin plate.[0004]The invention further relates to a method for pinning the unstable bone fragment by a pin member while the pin member becomes lockably secured to the pin plate. In the case of fractures of the end of a bone, a small fragment can be produced which can be secured by the invention.BACKGROUND [0005]One common method of fixing fra...

AI Technical Summary

Benefits of technology

The invention provides a locking pin plate that restricts movement of the pin in relation to the plate. The pin can be easily inserted without cutting and leaving no end protruding in soft tissue. The cross member of the U pin provides flexibility to develop the force to displace the legs of the pin. The U pin can also be formed to have different diameters over its length to provide greater strength to cantilever bending and avoid soft tissue irritation.

Problems solved by technology

Although this technique is effective when the fragments are relatively large in relation to the diameter of the screw, when the fragment size is small in relation to the diameter of the screw, the size of the screw hole required in the bone fragment can weaken the fragment and cause it to fragment further, resulting in failure of fixation.

If the fragments are small or consist of poor quality bone, thread purchase can be inadequate, resulting in failure of fixation.

If the pin is not rigidly secured into an opposite stable bone fragment, this may result in failure of fixation.

In addition, they are cumbersome to manufacture and complicate the surgery by requiring the surgeon to bend and / or thread the end of the pin through the tabs in the plate.

In addition, most of these require the surgeon to crimp a portion of the plate with a bending instrument, which adds to the complexity of the procedure and may be difficult to do because of difficult access to the plate from a limited exposure.

In addition, many of these embodiments require the pin to be bent or cut after the pin is in place which adds further to the complexity of the surgery.

Finally, since many of these designs leave the end of the pin extending out of the plate, the cut end can cause irritation of the soft tissues and even tendon rupture.

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