The Rotator Cuff Deficient Arthritic Shoulder

CHAPTER PREVIEW

Chapter Synopsis

The diagnosis, natural history, and management of the rotator cuff deficient shoulder with osteoarthritis continue to present difficulties for all orthopedic surgeons. It represents a spectrum of shoulder diseases resulting from the insufficiency of the rotator cuff. This complex pathology requires an understanding of the etiology and biomechanics of the shoulder as well as confidence and experience with the surgical treatment options, specifically the hemiarthroplasty and reverse total shoulder replacement. This chapter reviews the shoulder arthroplasty options and the treatment algorithm that the authors follow. Surgical decision making and techniques that can give optimal results are also be discussed.

Important Points:

1

The indications for treatment of cuff-tear arthropathy are dependent upon the type of pathologic changes, severity, and symptomatology.
2

First-line treatment of cuff-tear arthropathy consists of nonsurgical management.
3

The surgical options for cuff-tear arthropathy include humeral surface replacement with or without an extended coverage humeral head, hemiarthroplasty with or without an extended coverage head, humeral head arthroplasty with biologic resurfacing of the glenoid, bipolar arthroplasty, and reverse shoulder arthroplasty.
3

The use of the standard glenohumeral total shoulder replacement is contraindicated in patients with cuff-tear arthropathy.
4

The reverse shoulder should only be used in a patient with an intact deltoid muscle.

Clinical/Surgical Pearls:

1

One of the most important goals of the hemiarthroplasty surgery is the recreation of the center of rotation of the humeral head.
2

For those tears that we deem irreparable, it is imperative that the coracoacromial arch remains intact in the event that cuff-tear arthropathy ensues.
3

Avoid any damage or detachment of the rotator cuff during surgery by making the humeral neck to approximate the natural version of the humeral head.
4

Release of the inferior capsule will allow for improvement in abduction of the humerus.
5

The reverse prosthesis is a technically difficult operation with high complication and reoperation rates, and the surgeon should feel completely comfortable prior to undertaking the procedure.

Clinical/Surgical Pitfalls:

1

Avoid damage to the rotator cuff through meticulous dissection and attention to protecting the cuff during exposure, humeral head resection, and retraction for glenoid exposure.
2

Avoid overstuffing of the joint by using too large a humeral head but attempt to recreate the center of rotation of the shoulder.
3

Make certain the acromial arch is intact if performing a hemiarthroplasty for cuff-tear arthropathy and that the patient has not undergone an acromioplasty with signs of humeral escape.
4

Improper version of the humeral head resection can lead to instability. Removal of all osteophytes can allow better visualization of the humeral head version and can prevent this mistake.

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Charles Neer first introduced the concept of “rotator cuff tear arthropathy” (CTA) to describe cases of glenohumeral arthritis associated with usually irreparable chronic rotator cuff tears in 1983. Although his initial cohort group included only 26 patients, he was able to contrast this subset of patients from those with standard shoulder osteoarthritis. He believed that they required a novel approach to their diagnosis and treatment. The identification of this subset has expanded into a much larger population of patients with rotator cuff deficient shoulders with arthritis.

The pathologic processes described by Neer’s original work included rotator cuff deficiency, a subcutaneous effusion, erosion of the articular surfaces, restricted motion, osteopenia, acetabularization of the acromion, and collapse of the humeral head. Neer believed that due to the deficient rotator cuff, the humeral head is able to sublux superiorly, leading to abrasion of the humeral head upon the undersurface of the acromion and superior glenoid. This instability increased in the anterior and posterior directions as the progressive cuff tear involves the subscapularis and infraspinatus tendons. In addition, he described a nutritional basis for the development of arthropathy, as it occurs secondary to a loss of the complete enclosure of the joint space. The defect in the rotator cuff no longer allows for efficient diffusion of nutrients from synovial fluid to the articular surfaces. This lack of nutrition may also play a role in the subsequent articular degeneration. The ultimate result can be a devastating clinical syndrome that leaves the patient with severe pain and disability. The current description of cuff-tear arthropathy is based on the spectrum of pathology consisting of rotator cuff deficiency, superior migration and instability of the humeral head, and glenohumeral joint degeneration.

The patient with cuff-tear arthropathy most often presents with complaints of debilitating pain and a limited range of motion. They often are concerned about the significant effusion that typically builds and produces significant swelling about the shoulder. They may report a history of shoulder problems, and many will report prior surgical procedures being done. Radiographically, they will display evidence of superior migration of the humeral head, a decrease in the acromiohumeral distance, osteophytes, joint space narrowing and erosion, acetabularization of the acromion, osteopenia, and glenohumeral subluxation. These radiographic findings differ with those of osteoarthritis, which typically demonstrates osteophytes on the inferior and medial border of the humeral head with posterior glenoid wear. Although the use of magnetic resonance imaging (MRI) and computed tomography (CT) may help confirm the diagnosis of cuff-tear arthropathy or demonstrate specific anatomic differences, findings typically seen on plain radiographs are often diagnostic alone.

The severity of cuff-tear arthropathy can vary widely. The nonoperative and surgical treatments depend upon the degree of symptomotology in conjunction with the degree of pathology. The indications for the use of shoulder arthroplasty in these cases will depend upon the degree of superior migration and instability of the glenohumeral joint. Seebauer et al. have developed a classification system based upon both the degree of superior migration and the degree of instability in the center of rotation. This classification describes two major categories of CTA: type I, in which the center of rotation remains stable; and type II, in which the kinematics are unstable. A third category regarding degree of glenoid bone loss is also now discussed.

Shoulder arthroplasty for rotator cuff tear arthropathy is a challenging pursuit that demands complex decision making, skill, and experience. It is important that the surgeon be comfortable with the pathology, indications, surgical techniques, and equipment prior to performing any type of shoulder arthroplasty in this difficult patient population. The following underscores the decision-making model that we consider in the treatment of cuff-tear arthropathy and our surgical approach.

Indications

The indications for treatment of cuff-tear arthropathy are dependent upon the type of pathologic changes, severity, and symptomatology. Often patients with cuff-tear arthropathy will have little or no symptoms until some minor incidental traumatic event, and thereafter they will rapidly develop severe symptoms including recurrent hemarthrosis, loss of function, and persistent pain. Symptomatic cuff-tear arthropathy can be extremely disabling and painful. The extent of their disability is consistently based on the degree of superior migration and loss of centralization of the humeral head. In some cases anterior superior instability becomes so great that the head “escapes,” leading to the clinical picture of pseudoparalysis of the shoulder in which the deltoid muscle is functional but the patient has a significantly limited ability to forward flex and abduct the arm. This is a devastating clinical syndrome that often can only be treated by shoulder arthroplasty.

First-line treatment of cuff-tear arthropathy consists of nonsurgical management. The use of nonsteroidal anti-inflammatory medications, cortisone injections, and physical therapy are the mainstays of nonoperative treatment. Many surgeons are hesitant to give repeated cortisone injections into the shoulder with CTA because of the risk of infection in a joint with a persistently large and often hemorrhagic effusion; however, it remains an excellent tool at the surgeon’s discretion. Unfortunately, many patients will not improve with nonoperative methods and require surgical treatment of their shoulder.

The surgical options for cuff-tear arthropathy include humeral surface replacement with or without an extended coverage humeral head, hemiarthroplasty with or without an extended coverage head, humeral head arthroplasty with biologic resurfacing of the glenoid, bipolar arthroplasty, and reverse shoulder arthroplasty. The use of the bipolar implant and biologic resurfacing has fallen out of favor in recent years due to reported results that are inferior to those of the other prosthesis ; the use of the humeral surface replacement is in its early stages but with promising results. The most consistent methods of treatment are with hemiarthroplasty and reverse total shoulder replacement. The decision of which surgical option to perform is based in large part on the Seebauer classification described earlier. This is a biomechanical classification system that considers the degree of superior migration and the amount of instability of the humeral head from the center of rotation. Glenoid bone stock is also descriptive in the classification and is considered when determining the ability to resurface the glenoid.

There are essentially two types of arthropathy described according to this classification: those in which the center of rotation remains stable, and those in which the kinematics become unstable secondary to the superior migration of the humeral head. Type IA is described as cuff-tear arthropathy (acetabularization of the acromion and demoralization of the humeral head) with an intact acromioclavicular joint, minimal superior migration, and dynamic joint stability, whereas a type IB is described as the same only with medial glenoid erosion. A type IIA involves significant superior migration of the humeral head and superior glenoid erosion. A type IIB refers to superior migration with an incompetent coracoacromial arch and anterior-superior escape.

Utilizing this system, surgical treatment of patients with types IA and B cuff-tear arthropathy are best treated with a surface replacement or hemiarthroplasty with or without an extended coverage head. Patients with type IIB will undergo a reverse shoulder prosthesis, whereas those with a type IIA require a review of their clinical exam. Those patients who have the ability to forward flex the shoulder to 80 degrees demonstrate stable kinematics and therefore are likely to benefit from a hemiarthroplasty, whereas those who cannot forward flex to 80 degrees demonstrate limited kinematics. If their “paralysis” is secondary to pain and the deltoid remains functional, they fare better with a reverse prosthesis. The use of the standard glenohumeral total shoulder replacement is contraindicated in patients with cuff-tear arthropathy. Matsen et al. demonstrated a high rate of failure associated with patients undergoing a total shoulder replacement with a deficient rotator cuff. Repeated proximal subluxation and eccentric superior edge loading of the glenoid, which has been referred to as the “rocking horse” effect, lead to a high rate of glenoid loosening that requires revision surgery.

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