Intramedullary rod apparatus and methods of repairing proximal humerus fractures

Abstract

A bone stabilizing apparatus includes a stem member and an extension member, the stem member having a distal end for insertion within the intramedullary canal of a human humerus and the proximal end connected to the extension member. The extension member has radially directed threaded holes either pre-formed or created after the bone stabilizing apparatus is installed into the humerus. The threaded holes allow fixation of stabilizing screws with suture posts, or a washer structure to grip the surface of the bone and / or surrounding ligaments or muscle. A prosthetic or the natural humeral head can be attached to the extension member. In a preferred embodiment a guide structure directs the drill and stabilizing screws radially through the central axis of the extension member.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates to an apparatus and method for the fixation of proximal humerus fractures in which one or more bone pieces must be aligned with the major portion of the bone. In proximal humerus fractures, displacing forces such as muscle connections acting on the fragments of the fracture frequently cause bone fragments to separate and pull away from the main part of the humerus. In alternative embodiments, this invention provides an apparatus and methods for internal fixation of fractured humerus bones, nonunions, and primary and metastatic tumors, in each case providing anatomic alignment to reduce impingement and promote healing.[0003]2.Description of the Related Art[0004]The conventional methods and apparatuses for treating proximal humerus fractures have respective shortcomings relating to effective treatment of many of the numerous categories of fractures. These categories correspond to proximal humerus fr...

AI Technical Summary

Benefits of technology

[0012]It is therefore an object of this invention to overcome the above-identified problems in the related art, and to provide an apparatus and methods for precise and stable fixation of proximal humerus fractures to promote correct anatomic bone position with reduced chance of bone fixation failure or later impingement.

[0013]It is a further object of this invention to provide a method and apparatus for fixation of a proximal humerus fracture that allows motion of the humerus early in a patient's recovery.

[0014]Another object of this invention is to provide a method of stabilizing a proximal humerus fracture using inventive screw means to stabilize the fracture.

Problems solved by technology

Various apparatus and methods appear in the related art for treating proximal fractures of the humerus, including plates, screws, sutures and rods, but none of these solve all of the problems relating to fixation of these fractures.

One major problem in treating humerus fractures is the difficulty of finding adequate bone stock to secure the related art internal fixation means.

The related art methods of fixation are therefore frequently difficult and unsuccessful, leading to possible loss of fixation, loss of fracture reduction, nonunion or malunion.

Further, in many cases these methods do not allow early motion.

Such a means of fixation does not provide the ease, anatomic alignment, and stability of the present invention, thereby also possibly leading to loss of fracture reduction or fixation.

This type of device is ineffective, however; at assisting in the fixation of bone fragments such as the lesser or greater tuberosity, or when the head of the humerus is to be saved.

For example, the modular humeral prosthesis is designed to replace the natural humerus head and is not designed for a situation wherein the proximal humerus is fractured but the head is still attached or can be salvaged.

This restriction limits the flexibility of this related art because, frequently, the pre-installed aperture cannot be optimally positioned.

The Fixel intramedullary nail, however, is not addressed to, nor effective for, proximal humerus fractures, particularly the segmented proximal humerus fractures.

The reason that Fixel, and similar, methods are not effective for such segmented fractures is that the intramedullary nail secures bone fragments using individual screws attached to bone and traversing through the nail to attach to bone as well.

With segmented proximal humerus fractures, however, there is frequently little bone stock suitable for the screws to anchor to, and the bone that is available is frequently weak.

Further, in one embodiment directed toward the fixation of distal femoral or tibial fractures, the Fixel method requires the individual screws to pass through the slotted tip of the nail, thereby limiting the possible directions of approach.

This may serve for femoral and tibial fractures, but is unlikely to work for proximal humerus fractures with its accompanying complex anatomy and fracture patterns.

The alternative means employed by the intramedullary nail to secure bone fragments involves a plate, and a plate is not appropriate for use in many proximal humerus fractures wherein the strength of surrounding soft tissue or musculature and not the bone itself is the best means available for stabilizing the fracture.

Additionally, a plate is very prominent, and may cause impingement.

This Etheredge and related methods therefore rely on the strength of the bone to hold the plate, and in many patients with proximal humerus fractures the bone quality is not adequate for such fixation, thereby incurring the risk of loss of fixation of the fracture.

Further, this method is generally ineffective in a proximal humerus fracture wherein multiple bone fragments are separated from the humerus.

This is because a straight plate is not appropriate on a rounded humerus fragment, such as a head.

Therefore, any fixation applied to the superficial surface of the bone risks damage to the blood supply of the bone fragments.

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