Copyright © 2006 by The Journal of Bone and Joint Surgery, Inc.
Commentary & Perspective
Commentary & Perspective by
Joseph P. Iannotti, MD, PhD
Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio
The debate about whether or not to resurface the glenoid when performing shoulder arthroplasty for osteoarthritis has continued for the last three decades. A basic assumption is that the pain associated with osteoarthritis is in part due to degenerative changes in both joint surfaces. If it is further assumed that joint replacement is successful because of the resurfacing of the joint surfaces, then it would seem reasonable to assume that resurfacing both surfaces would yield better results than resurfacing only one. This assumption has served as the basis for resurfacing both sides of the hip and knee in lower extremity prosthetic arthroplasty. Why would we consider these same principles to be invalid for shoulder arthroplasty? The answers may lie in the surgical techniques and the patient-selection criteria that are used in selecting one of these two options. There is a wide spectrum of disease that affects the cartilage, bone, and soft tissues of the shoulder that we label under the single disease heading, "osteoarthritis of the shoulder." The question raised in the study by Wirth et al. is: Is there a subpopulation of patients who have osteoarthritis but who would nevertheless do well with hemiarthroplasty?
Wirth and his colleagues present excellent clinical mid to long-term clinical results of glenohumeral arthritis treated with a hemiarthroplasty. The patients presented were very carefully selected from the population of patients at their institution who were being managed for osteoarthritis of the shoulder. The authors present clinical, imaging, and intraoperative criteria that clearly define a subpopulation of patients. Their ability to successfully achieve glenoid bone contouring and soft-tissue balancing that resulted in a centered humeral head within a structurally sound glenoid vault was, in their view, critical to the success of the hemiarthroplasty and was an additional reason for proceeding with surgery without use of a glenoid component.
The presence and severity of glenoid bone loss, eccentric wear, or humeral head subluxation are factors that affect clinical outcome1. Hemiarthroplasty and total shoulder arthroplasty have varying degrees of clinical success, depending on the severity of these anatomic factors1. In the study by Wirth et al., there was clear recognition of the issues of glenoid wear and humeral head subluxation as disease factors that affect the outcome of hemiarthroplasty. The authors clearly selected patients who did not have these adverse factors, or, when these factors were present, in choosing patients whose conditions could be corrected at the time of surgery. What becomes clear from the Wirth paper is that hemiarthroplasty can be successful when performed with use of specific surgical techniques in selected patients with certain disease characteristics. To gain insight into how frequently such patients are seen, it would be interesting to know how many osteoarthritic shoulders were treated with total shoulder arthroplasty by these surgeons in the same time period and using the same preoperative or intraoperative criteria.
What should not be concluded from the study by Wirth et al. is that all patients with shoulder osteoarthritis will do well with a hemiarthroplasty or that hemiarthroplasty will perform better than total shoulder arthroplasty for a random group of patients with osteoarthritis. The Wirth study is a well-defined retrospective case series but lacks the advantages of prospective design or the benefit of a comparative group of patients who underwent total shoulder arthroplasty. There have been other studies to evaluate the effectiveness of hemiarthroplasty compared with total shoulder arthroplasty in a broader spectrum of patients with osteoarthritis. Gartsman et al., in a prospective randomized clinical trial, compared the clinical results of hemiarthroplasty and total shoulder arthroplasty for a randomly selected group of patients with osteoarthritis and indications for shoulder replacement2. The Gartsman study showed a trend toward a more favorable outcome with use of total shoulder arthroplasty.
The study by Wirth et al. had a small sample size. The authors suggested that a study with approximately twice the number of patients would have shown statistical significance in favor of total shoulder arthroplasty. In another very recent prospective randomized study, Lo et al. did not show a significant difference in quality of life indicators after hemiarthroplasty or total shoulder arthroplasty3. Again, the sample size was not large enough to demonstrate statistical significance, but there was a clear trend toward a more favorable outcome with total shoulder arthroplasty in all outcome parameters. In considering the wide spectrum of pathology that we call osteoarthritis, it is likely that the inclusion of more patients in both of these studies would have demonstrated a statistical difference between groups in favor of total shoulder arthroplasty.
When the patients are not as carefully selected as those presented in the Wirth study, the literature suggests that there is an increasing prevalence of pain due to progressive glenoid arthrosis after hemiarthroplasty within the first five to ten years after arthroplasty4,5. However, there is also an increasing prevalence of glenoid component loosening in patients who have undergone total shoulder arthroplasty in this same time frame6. The fact that both problems increase with time suggests a need to know the difference in outcome between total shoulder arthroplasty and hemiarthroplasty with longer-term follow-up. This would require a carefully stratified retrospective study of a large patient population with at least five years of follow-up or a prospective randomized clinical trial with a minimum of five years of follow-up and the performance of multivariate statistical analysis to evaluate the patient and disease variables that are known to affect the outcome of patients after hemiarthroplasty and total shoulder arthroplasty.
*The author did not receive grants or outside funding in support of the research or preparation of this manuscript. The author received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity (DePuy and Johnson and Johnson). No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.
References
1. Iannotti JP, Norris TR. Influence of preoperative factors on outcome of shoulder arthroplasty for glenohumeral osteoarthritis. J Bone Joint Surg Am. 2003;85;251-8.
2. Gartsman GM, Roddey TS, Hammerman SM. Shoulder arthroplasty with or without resurfacing of the glenoid in patients who have osteoarthritis. J Bone Joint Surg Am. 2000;82:26-34.
3. Lo IK, Litchfield RB, Griffin S, Faber K, Patterson SD, Kirkley A. Quality-of-life outcome following hemiarthroplasty or total shoulder arthroplasty in patients with osteoarthritis. A prospective randomized trial. J Bone Joint Surg Am. 2005;87:2178-85.
4. Cofield RH, Frankle MA, Zuckerman JD. Humeral head replacement for glenohumeral arthritis. Semin Arthroplasty. 1995;6:214-21.
5. Levine WN, Djurasovic M, Glasson JM, Pollock RG, Flatow EL, Bigliani LU. Hemiarthroplasty for glenohumeral arthritis: results correlated to degree of glenoid wear. J Shoulder Elbow Surg. 1997;6:449-54.
6. Torchia ME, Cofield RH, Settergren CR. Total shoulder arthroplasty with the Neer prosthesis: long-term results. J Shoulder Elbow Surg. 1997;6:495-505.
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