Equinoxe® Shoulder

How Does It Work?

The shoulder is the most mobile joint in the body. The shoulder joint is similar to a ball-and-socket joint but more closely resembles a golf ball on a tee. The rotator cuff provides the stability – keeping the golf ball on the tee.

The shoulder joint is comprised of three main bones: the collarbone (clavicle), the shoulder blade (scapula) and the upper arm bone (humerus). The glenoid (part of the scapula) and humeral head (part of the humerus) are normally the parts of the shoulder that have to be replaced because they rub together when you move your arm. In a healthy shoulder, these portions of bone are covered with cartilage, which allows for painless motion—lifting, pushing and pulling. But arthritis can damage this protective cartilage, which makes these motions painful.

Arthritis is one of the most common conditions that causes wear and tear to your joint cartilage and develops after years of constant motion and pressure on the joints. If non-surgical treatment options such as medication, physical therapy or lifestyle changes fail to provide relief, your surgeon may recommend shoulder replacement surgery.

Primary Shoulder Replacement

Shoulder replacement surgery replaces the damaged part of your shoulder to recreate the natural contours of the bones in a healthy shoulder. Sometimes, only the ball is replaced (hemiarthroplasty), while other times, both the ball and socket are replaced (total shoulder arthroplasty). The ball is usually metal and the socket is usually plastic.

During surgery, an incision is made in the front of the shoulder. Once your surgeon exposes your shoulder joint, the surgeon will remove the damaged bone and cartilage. The head of the humerus is then removed and a metal stem is placed into the humeral canal. This provides a stabilizing anchor for the head.

Reverse Shoulder Replacement

If you have a massive, irreparable rotator cuff tear and arthritis, your surgeon may opt to perform a reverse shoulder replacement. The rotator cuff is a group of muscles and tendons that surround the shoulder in order to keep the humerus centered while performing shoulder-related tasks such as lifting the arm. When a rotator cuff tears, the muscles lose their ability to keep the humerus centered on the glenoid, causing your humerus to move upward and out of the socket. This instability, combined with arthritis or a previous shoulder injury, can cause severe pain and loss of function.

In this procedure, the anatomy of the shoulder is reversed by attaching a metal ball (glenosphere) to the glenoid and the plastic socket (humeral liner) to the upper humerus.

How Will It Feel?

The primary goal of the Equinoxe Shoulder System is to help you enjoy your daily activities with reduced pain and increased mobility. One of the main ways this is achieved is by ensuring a correct fit.

The Equinoxe allows your surgeon to choose from multiple humeral head heights, and an anatomically pear shaped glenoid design ensures a precise fit. A unique advantage of the Equinoxe is that any size humeral head can be paired with any size glenoid to best match your unique anatomy (Figure A).

If you are having a reverse shoulder replacement, the system will help restore pain-free shoulder function by empowering your deltoid to become the main functioning muscle in the absence of a healthy rotator cuff. The Equinoxe’s glenosphere is larger than most competing brands and helps maximize range of motion. The glenosphere also overhangs on the bottom of the glenoid, which minimizes impingement on the scapula and allows you to fully lower your arm to your side (Figure B).

How Long Will It Last?

The Equinoxe is designed to withstand long-term wear and tear from normal everyday activity. Only the highest quality materials are used to provide you the longest potential use of the implant.

The Equinoxe system is unique in that it features a platform stem that allows the surgeon to do either a primary shoulder replacement or a reverse with the same humeral stem. This design also conserves more of your bone because it does not require the surgeon to remove the original stem in the rare case a revision surgery becomes necessary.

The Equinoxe reverse is the only system that offers your surgeon an anatomic-shaped baseplate with six screw holes. This gives the surgeon multiple options to achieve solid bone fixation. Additionally, the bone cage can be filled with some of your own bone to promote bone growth, giving you and the surgeon the confidence of a secure long-term fit.

The Right Choice for You

Your surgeon will consider a wide variety of variables when selecting the shoulder implant that’s right for you. Your age, height, weight, lifestyle and your general health are among the most important factors. The Equinoxe Shoulder System is designed to accommodate these and other variations in anatomy to provide you with the best possible outcome.