Ream & Run Humeral Hemiarthroplasty

Frederick A. Matsen, III, MD

Despite advances in implant technology and surgical technique, the long-term results of total glenohumeral arthroplasty can be compromised by delayed loosening of the glenoid component, fragmentation, wear, and instability. The risk of prosthetic failure continues for the duration of the life of the patient after total shoulder arthroplasty.  Surgical revision after glenoid component failure is often challenging and may be unsuccessful because of scarring and irreversible glenoid bone loss.  On the other hand, humeral hemiarthroplasty alone has been shown to yield inferior functional results when the glenoid surface is compromised.  Earlier studies on hip and knee arthroplasty have provided encouraging evidence that reamed bone articulating with a convex metal prosthesis can remodel to a functional and durable arthroplasty concavity, sometimes lasting over four decades. Notably, the majority of so-called mold arthroplasty failures of the hip were on the femoral side and not on the acetabular side of the articulation. An analysis of pelvic specimens retrieved post mortem revealed that the concave acetabular joint surface was often covered with a smooth regenerated surface and had reestablished homogeneous and stable subsurface bone. Moreover, the tissue covering the acetabular concavity was found to resemble dermis and meniscus in terms of glycosaminoglycan content.

Frederick A. Matsen, III, MD of the Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington previously explored the ability of a reamed mammalian glenoid to undergo molded healing while in contact with a metal humeral prosthesis. In a canine model with use of a metal humeral hemiarthroplasty, he demonstrated that reamed glenoid bone became completely covered with conforming, living, and securely attached fibrocartilaginous tissue at twenty-six weeks after surgery.  The bone beneath this re-generated biological joint surface was uniform in structure and density, suggesting an even distribution of the load applied by the prosthetic humeral head. Dr. Matsen subsequently defined a reproducible technique applicable to human shoulders that involves spherically reaming the glenoid subchondral bone to a concavity concentric with the humeral head prosthesis. He initiated a prospective clinical study of this technique—humeral hemiarthroplasty combined with concentric glenoid reaming—to test the hypothesis that this approach to shoulder arthroplasty can significantly improve the comfort and function of arthritic shoulders.  The results of the study were encouraging.  In this JBJS/VJO video supplement, Dr. Matsen demonstrates his surgical technique.

Material Covered

• Humeral Cut
• Glenoid Exposure & Initial Preparation
• Glenoid Reaming
• Humeral Head Sizing
• Rotator Interval Plication
• Subscapularis Reattachment

Specifications

• Total Run Time: 28:19 minutes
• Catalog Number: 7068
• VJO Publication Date: September, 2009