Walch Glenoid Classification is a system of describing the current state of an arthritic shoulder. The Walch Glenoid Classification is determined by use of an X-Ray, CT scan, or MRI. The image is then analyzed based on how centered the humeral head (arm bone) is on the glenoid (socket), the shape of the glenoid, bone loss and erosion patterns, and glenoid retroversion. The Walch Glenoid Classification assists the surgeon in properly pairing treatment for each patient’s unique shoulder.
In cases of shoulder arthritis where the humeral head has rotated too far back in the shoulder, it can begin to wear a new socket in the glenoid. Traditionally, the glenoid is shaped similarly to a C, with the humeral head resting inside it. However, some arthritic shoulders have biconcavity (two sockets), resulting from poor humeral head subluxation, where the humerus wears down the bone in the glenoid causing it to look kind of like a rotated W.
The term Paleoglenoid refers to the natural glenoid surface, usually the anterior portion. The paleoglenoid is surrounded by intact cartilage and bone and serves as a reference point for surgical correction. The Neoglenoid is the eroded glenoid surface where the humerus now rests after years of arthritis. It is surrounded by worn cartilage and bone, and it is the area needing reconstruction.
Humeral head subluxation is the partial displacement of the humeral head from the center of the glenoid cavity. Unlike dislocation, the joint surfaces still maintain some contact, but the alignment is abnormal. This can cause joint wear, lead to biconcave glenoid formation, and require glenoid correction.
