Methods for less invasive glenoid replacement

Abstract

The invention features a glenoid (shoulder socket) implant prosthesis, a humeral implant prosthesis, devices for implanting glenoid and humeral implant prostheses, and less invasive methods of their use for the treatment of an injured or damaged shoulder.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation application of U.S. patent application Ser. No. 11 / 066,978 filed on Feb. 25, 2005, the entirety of which is hereby incorporated by reference herein and made a part of the present specification.FIELD OF THE INVENTION[0002]The present invention relates to the field of glenoid surface replacement.BACKGROUND OF THE INVENTION[0003]The invention provides a glenoid shoulder implant, a humeral implant, and devices for preparing the glenoid and humeral head for joint replacement.[0004]Shoulder replacement surgery is currently used to treat patients suffering from disabling pain due to worn or damaged shoulder joints, which can be caused by, e.g., arthritis or injury. The humeral implants currently in use are typically made from metal, and the implants are affixed to the bone using bone cement (e.g., polymethylmethacrylate) or by press fitting the implant into the bone using a roughened outer surface coating on the metal for ...

AI Technical Summary

Problems solved by technology

Keeled and pegged glenoid implants suffer from several disadvantages, which limit their lifespan once implanted and reduce the number of indications for which they can be used when the age of the patient is a factor.

For example, the glenoid implants can loosen due to poor fixation within the bone, and they are prone to wear and fatigue failure of the polyethylene due to adhesion, abrasion, and shear stress.

As arthritis progresses, the humeral head can wear medially and destroy the foundation of glenoid bone.

Thus, a typical keel or peg design can broach the glenoid vault and injure the suprascapular nerve along the suprascapular notch or spinoglenoid notch with resultant denervation injury to the rotator cuff muscles.

Broaching through the glenoid vault can also fracture the body of the scapula and cause early implant loosening.

There are also several disadvantages associated with current glenoid replacement surgical techniques.

Since the axillary nerve is located within 1 cm of the inferior capsule, there is potential risk of axillary nerve injury with resultant denervation injury to the deltoid muscle when these releases are performed.

However, use of the current keeled or pegged glenoid implants requires this extensive glenoid exposure for proper fitting and placement.

Current glenoid replacement surgery also requires a long skin incision and extensive soft tissue stripping in order to fully expose the glenoid circumferentially, which produces a cosmetically unappealing scar.

Therefore, many surgeons have difficulty preparing the glenoid site for a total shoulder replacement using the current techniques.

Because there are more than 20,000 shoulder arthoplasty surgeries performed per year, many U.S. patients incur a risk of continued pain and disability, neuromuscular injuries, or failed shoulder prostheses requiring revision surgery.

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