A Medical Professional's Resource: Shoulder Replacement for Treatment of Glenohumeral Arthritis in Younger Patients

Introduction

Shoulder replacement has been a treatment option for patients with glenohumeral arthritis since the first anatomic design was developed in the 1950’s. Decades of development have made shoulder arthroplasty a successful treatment option today. Several studies reporting on patients of all ages with glenohumeral arthritis show clinical improvements and good survivorship. Total shoulder replacement is now considered the gold standard for the surgical management of advanced glenohumeral arthritis.

Despite the published clinical effectiveness of total shoulder arthroplasty, later failure and outcome deterioration are major concerns, especially for younger patients. Young, in terms of shoulder arthroplasty, has been arbitrarily defined as under age 55 in most studies. While chronological age is not always a predictor of remaining life expectancy, overall health status, and activity level for any single patient, studies have shown that it correlates with activity level and increased expectations after joint replacement surgery and is likely the best defining characteristic of the “young, active patient.”

The goals of shoulder arthroplasty in patients of all ages are pain relief and functional restoration. Younger patients, however, tend to have greater functional demands and expect to return to high levels of activity after surgery, with increased participation in physically demanding activities, including labor, recreation and sports. Understanding the expected physical demands of a patient is a very important consideration when choosing among shoulder replacement options. One can anticipate that younger patients will have greater expectations for activity and functional outcome from their shoulder replacement over the remaining years, which likely will increase stress and wear on the prosthetic components.

Longer-term studies have shown evidence of implant loosening, especially of the glenoid, and deterioration of function with use of anatomic total shoulder arthroplasty in younger patients. Since these patients are more likely to experience implant failure in their lifetime, the primary focus of alternative replacement options has been to avoid the use of prosthetic glenoid implants, preserve glenoid bone stock, and to use humeral implants that facilitate revision surgery.

Diagnostic Considerations

While older patients treated with shoulder arthroplasty tend to have a diagnosis of primary glenohumeral osteoarthritis or rotator cuff arthropathy, younger patients present with a greater variety of other pathologies, including primary osteoarthritis, post-traumatic arthritis, capsulorraphy arthropathy, inflammatory arthritis, avascular necrosis, chondrolysis, and glenoid dysplasia. Each of these different etiologies of glenohumeral arthritis is associated with specific pathologic findings that impact the surgical management.

Patient Evaluation

A thorough medical history and physical evaluation are necessary to provide information to guide the decision-making process. Previous operative reports, imaging studies and injury records should be obtained. Medical co-morbidities, patient expectations, functional goals, and psychosocial issues need to be considered. Examination of the shoulder can identify muscle atrophy, glenohumeral stability and subluxation, limitation of motion, and shoulder strength, including rotator cuff strength.

Plain radiographs are necessary for diagnostic purposes and surgical planning.

Advanced imaging is used to further define bony and soft tissue anatomy. CT scan is considered to be more accurate than plain radiographs and MRI for evaluating glenoid anatomy.

To help avoid or delay surgical intervention, all non-operative options must be exhausted in the younger patient with advanced glenohumeral arthritis, including managing expectations, modifying patient activities, and treating with physical therapy, anti-inflammatory medications, and glenohumeral injections.

Humeral Arthroplasty Without Glenoid Treatment (Partial Replacement)

Although relatively uncommon, there are occasional patients who present with arthritis that only involves the humeral head, and not the glenoid articular surface. These patients can be treated with humeral head replacement or resurfacing.  Humeral head replacement can be achieved with full resurfacing, partial humeral head resurfacing, stemless humeral head replacement and stemmed humeral head replacement—all of which require a concentric glenohumeral articulation. Appropriate soft tissue and capsular releases are required to restore glenohumeral motion.

• Humeral head resurfacing removes the arthritic humeral surface and covers it with a metallic cap, preserving bone stock, which can be beneficial in subsequent revision surgery.
• Partial humeral head resurfacing is an option to treat focal cartilage defects. In this procedure, the intact native cartilage is preserved and the implant replaces a focal defect in the humeral head.
• Stemless humeral head replacement is a newer technology that involves removal of the entire humeral articular segment and implantation of an epiphyseal implant to which the modular humeral head is attached. Stemless humeral heads have had good early results in Europe, but are not fully approved in the United States.
• Stemmed humeral head replacements are much more commonly used and more extensively studied than humeral head resurfacing and stemless humeral head replacements.

Humeral Arthroplasty with Glenoid Treatment

The combination of concern for glenoid failure in younger patients treated with total shoulder replacement and recognition that the outcome of humeral head replacement may be inferior to that of total shoulder replacement led to the development of non-prosthetic glenoid treatments. Avoidance of a glenoid prosthesis eliminates the problem of a loose glenoid component. The goal of these techniques is to restore a concentric glenohumeral articulation while preserving the bone stock of the glenoid. Eccentric glenoid wear with posterior bone loss and retroversion is corrected with glenoid reaming.

Biologic resurfacing with Achilles tendon allograft, meniscus allograft, fascia lata, and dermal grafts has been attempted with variable and somewhat limited success. Although early results showed promise, longer-term results often demonstrate deterioration.

Humeral head replacement with glenoid reaming arthroplasty, “Ream-and-Run” arthroplasty, was developed by Frederick Matsen, MD, at the University of Washington in Seattle as an alternative glenoid treatment that eliminates the risk of glenoid loosening. In this procedure, the glenoid is reamed in order to restore a concentric articulating surface and stimulate formation of a fibrocartilaginous surface to articulate with the humeral head. Matsen et al reported excellent results with this technique and showed significant improvement in function and pain with “Ream-and-Run” arthroplasty in patients younger than age 55.

Conclusion

Treatment of advanced glenohumeral arthritis in younger patients is challenging. Several treatment options exist and one solution does not fit all patients. Total shoulder arthroplasty has the most predictable results, but concerns over implant longevity limit its use in younger patients.

When considering options, patient expectations and future revision surgeries are major considerations. Humeral resurfacing and humeral head replacement are reasonable options in younger, high-demand patients without glenoid degeneration. Humeral head replacement with glenoid reaming arthroplasty (“Ream-and-Run”) is a good option for high-demand patients with glenoid arthritis. Younger patients with low demand are good candidates for total shoulder arthroplasty.