Integral, One-Piece Humeral Head Device

Abstract

A humeral head augment device for use in a modular shoulder prosthesis. The humeral head augment device has an external bearing surface with at least one surface portion that includes a radius of curvature. The radius of curvature is configured to constrain translational movement of the implanted shoulder prosthesis when the humeral head augment device is positioned within the shoulder prosthesis. The humeral head augment device also includes a coupling mechanism designed to lock the humeral head augment device to either the stem or the humeral head, thereby ensuring proper operational positioning of the device within the shoulder prosthesis and allowing the implanted shoulder prosthesis to function in a patient suffering from rotator cuff arthropathy. A shoulder prosthesis using a humeral head augment device, a method for assembling a shoulder prosthesis and method for using a humeral head augment device in a shoulder prosthesis are also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional application of pending U.S. application Ser. No. 11 / 688,309 filed on Mar. 20, 2007, now U.S. Pat. No. ______, the disclosure of which is included by reference herein in its entirety.TECHNICAL FIELD[0002]The present invention relates generally to orthopaedic implants. More particularly, the present invention relates to a shoulder replacement prosthesis and the method of use for treating rotator cuff arthropathy.BACKGROUND OF THE INVENTION[0003]Deterioration of an individual's rotator cuff may lead to the need to undergo a shoulder arthroplasty procedure. In severe cases, a person's humeral head may translate in a more superior direction during abduction of their effected arm resulting in the superior surface of the humeral head articulating with both the inferior surface of the acromion and the acromioclavicular joint. Articulation between these two bones could lead to accelerated destruction of the humeral...

AI Technical Summary

Benefits of technology

The solution effectively constrains post-operative translational movement, enhances joint stability, and maintains a full range of motion by optimizing the geometric mismatch between the humeral head and acromion, reducing joint pain and improving functional outcomes for patients with rotator cuff arthropathy.

Problems solved by technology

Deterioration of an individual's rotator cuff may lead to the need to undergo a shoulder arthroplasty procedure.

Articulation between these two bones could lead to accelerated destruction of the humeral head and erosion of the acromion and the acromioclavicular joint.

Both of these treatment modalities led to the overstuffing of the joint space and a resultant reduced range of motion for the effected arm of the individual.

Several non-implant surgical techniques have been used with limited success in an attempt to address the rotator cuff tear arthropathy, including surgically smoothing the greater tubercle.

Unfortunately, the individual still experienced reduced range of motion and joint pain because of the bone on bone contact.

Problems that have been seen with these types of designs is excessive post-operative translation in the superior direction because of the previous bone loss and the use of a single radius of curvature for the two bearing portions.

Another problem encountered with the extended bearing modular humeral heads is the head being incorrectly rotated when the prosthesis is assembled in the operating room.

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