Glenoid component with improved fixation stability

Abstract

A glenoid component is provided to reduce glenoid loosening when implanted in orthopedic joint replacement / reconstruction, such for a shoulder. The glenoid component can include pegs or a keel and articulating surface geometry that uses complex, non-spherical geometry to recreate a level of constraint that is adequate, but not excessive, to thereby mitigate loosening of the glenoid component after implantation. In addition, some embodiments provide that peak stresses both within cement and at an interface of the cement and a supportive component can be reduced. Further, geometry of the pegs can allow stresses to be evenly applied to a cement mantle formed in the supportive component. Finally, the pegs can be configured to desired lengths in order to avoid placement in areas of the supportive component, for example, that have insufficient bone stock.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is based on and claims priority under 35 U.S.C. §120 to U.S. Provisional Application No. 60 / 784,237, filed on Mar. 21, 2007, entitled “GLENOID COMPONENT WITH IMPROVED FIXATION STABILITY,” the entire contents of which is expressly incorporated by reference herein.BACKGROUND[0002]Field of the Inventions[0003]The present inventions relate generally to orthopedic joint replacements, and more specifically, to a glenoid component.[0004]Description of the Related Art[0005]Anatomically, a joint is a more or less movable junction in the body of a subject of two or more bones. As used herein, the term is meant to include the different kinds of ligaments, tendons, cartilages, bursae, synovial membranes and bones comprising the mobile skeletal system of a subject in various quantities and configurations.[0006]The shoulder joint is the body's most mobile joint, in that it can turn in many directions. The shoulder is a ball-and-...

AI Technical Summary

Benefits of technology

This patent is about an orthopedic device that has special bearing and supportive components. The device can be used in an orthopedic joint to improve its mobility, make it stick to the supportive component better, and reduce the stress and forces that may cause the bearing component to become loose.

Problems solved by technology

The shoulder is an unstable joint easily subject to injury because of its range of motion, and because the ball of the humerus is larger than the glenoid that holds it.

Some shoulder problems arise from the disruption of these soft tissues due to injury or overuse, or underuse of the shoulder.

Other problems can arise from degenerative processes.

Anterior instability may occur when the arm is placed in a throwing position Both partial and complete dislocation cause pain and unsteadiness in the shoulder joint.

Osteoarthritis and rheumatoid arthritis can cause destruction of the shoulder joint and surrounding tissue and degeneration and tearing of the capsule or rotator cuff.

However, available treatment options are less than adequate in restoring shoulder joint function.

While some constraint is necessary for a stable joint, too much will increase the forces that contribute to glenoid loosing, one of the most significant problems in shoulder replacement.

Because different activities require different levels of constraint in different areas of the glenoid, a simple spherical or dual radius surface may provide too much constraint in certain areas.

Optimum glenoid constraint may not be able to be achieved with a simple spherical surface.

As such, prior art glenoid components do not take into account the differing levels of constraint required for different activities or the varying curvature of the natural glenoid.

Since cement 40 and the cement bone interface 42 are weak in tension, this often results in the cement mantle 40 breaking free from the bone or breaking apart due to local high stresses.

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