DEFINITION

Glenohumeral arthritis represents the loss of articular cartilage and joint space, often with associated osteophyte and cyst formation, bone erosion, and soft tissue contractures.

It can result from degeneration, inflammatory pathology, trauma, cuff deficiency, or can be multifactorial and is associated with loss of function and pain in varying degrees that can dramatically affect a patient's quality of life.

Rotator cuff tendon tears have increased prevalence with age and can occur independently or as a result of the disease process causing glenohumeral degeneration. The arthritic etiology though can help provide insight into the rotator cuff integrity.

Rotator cuff tear arthropathy (RCTA) describes the unique progression of glenohumeral arthritis that occurs in patients who have sustained massive rotator cuff tendon tears and involves cephalic migration of the humerus with characteristic degenerative changes.10

Although irreparable rotator cuff tears are classically associated with RCTA, they can also be seen with rheumatoid as well as osteoarthritis, although the degree and quality of tendon involvement may vary.

Surgical treatment originally included the use of total shoulder arthroplasty, but due to the high rate of glenoid loosening from abnormal contact loading, hemiarthroplasty later became the preferred surgical option.1,5,6,11

The development of reverse total shoulder arthroplasty (RTSA) has expanded prosthetic options for this condition and offered surgeons the ability to address patients who have continued glenoid degenerative progression as well as loss of rotator cuff function.2,4

The key aspects in managing this condition are recognizing this unique form of glenohumeral arthritis and understanding the pathophysiology that results in poor outcomes with the use of conventional total shoulder replacement.

It is also essential to determine patient's physiologic age and activity levels, as well as understanding the patient's goals for surgical intervention which can include improving function, pain, stability, or a combination of these.

 

 

ANATOMY

 

The glenohumeral joint relies on a combination of static stabilizers, including negative intra-articular pressure, articular surface geometry, labrum, capsular ligaments, and dynamic stabilizers, including the rotator cuff muscles, deltoid, pectoralis major, and latissimus dorsi.3,7,9,13

 

The rotator cuff is a convergence of tendons consisting of the subscapularis, supraspinatus, infraspinatus, and teres minor that attach just lateral to the articular surface on the humeral tuberosities.

 

Although many static as well as dynamic stabilizers affect shoulder stability, the rotator cuff muscles play an important role in centering and stabilizing the humeral head within the glenoid concavity throughout a range of motion by force couple balancing. The loss of these tendons diminishes the ability of the humerus to be compressed into the glenoid, leading to a loss of the ball-and-socket mechanism of the glenohumeral joint and is a key step in progression of rotator cuff arthropathy.

 

Even without cephalic migration of the humerus, the loss of these structures can compromise the longevity of conventional shoulder arthroplasty, and their contribution to both worsening function and pain must be determined.

 

The deltoid muscle originates from the lateral clavicle, acromion, and scapular spine and inserts on the deltoid tuberosity of the humerus and is innervated by the axillary nerve. It is the primary means for arm elevation, particularly following rotator cuff dysfunction.

 

The bony anatomy surrounding the glenohumeral joint is especially critical with the loss of soft tissue restraints, particularly the coracoacromial arch which comprises the coracoid, acromion, and coracoacromial ligaments.

 

The loss of concavity compression provided by the rotator cuff places greater emphasis on these structures. The active pull of the deltoid can progressively advance the humeral head upward toward the acromion and eventually without the static restraint of the coracoacromial ligament, results in progressive

displacement between the coracoid and acromion.14

 

PATHOGENESIS

 

The term rotator cuff tear arthropathy was first popularized by Dr. Neer in the early 1980s, describing a constellation of symptoms, including rotator cuff insufficiency, superior migration of the humeral head, advanced glenohumeral arthritis, and potential bony architectural changes including acetabularization

of the acromion and alterations in the proximal humerus.10

 

Rotator cuff tear etiology can result from progressive degeneration, trauma, or be multifactorial but regardless of the cause, a chronic retracted tear involving multiple tendons is the initial step to progression of this pathology.

 

Although the loss of multiple rotator cuff tendons is necessary for development of RCTA, not all patients with cuff tears progress to arthritis.

 

 

P.3841

 

A variety of theories have been proposed to explain why only some patients progress to arthritis after loss of rotator cuff function. Theories include a loss of nourishment from escaped synovial fluid, deterioration of cartilage cells from disuse, abnormal physical stresses, and accumulation of either calcium

phosphate crystals or cartilage debris. However, the exact etiology is still unknown and likely involves biologic as well as mechanical factors.3

 

The loss of stabilization results in superior migration of the humeral head from the active pull of the deltoid until mechanical abrasion occurs with the undersurface of the acromion and eccentric loading on the superior rim of the glenoid.

 

 

In the same instance, this migration reduces tension on the deltoid and alters its moment arm, diminishing its effectiveness for arm elevation. Therefore, the intact coracoacromial arch becomes the primary superior stabilizer to the uncovered humeral head.

 

The coracoacromial arch though can be compromised by progressive abrasion with the uncovered humeral head or during surgery by section of the coracoacromial ligament during acromioplasty.

 

Compromise of the coracoacromial arch coupled with a substantial rotator cuff defect permits anterosuperior instability of the humeral head with deltoid contraction.

 

This anterosuperior instability, or escape, eliminates the fulcrum needed for the deltoid to elevate the arm and leads to a loss of the ball-and-socket mechanism of the glenohumeral joint.

 

The loss of the ball-and-socket mechanism from loss of rotator cuff muscles and inability of a functioning deltoid to elevate the arm is known as

pseudoparalysis and is evident by lack of active glenohumeral elevation past 90 degrees with maintained passive elevation.

 

NATURAL HISTORY

 

Rotator cuff tendon tears can result from multiple etiologies but studies following conservative treatment have noted progressive increase in size of the tear, atrophy of muscles, and pain with associated decrease in function.14,16

 

Patients with glenohumeral degeneration from osteoarthritis, avascular necrosis, or inflammatory diseases such as rheumatoid arthritis will typically have an intact rotator cuff, although potentially thinned. These patients lose function primarily from the pain associated with degenerative changes, and the rotator cuff can actually be protected from the resulting decrease in activities of the affected arm.

 

For patients who have sustained irreparable rotator cuff tears and have developed glenohumeral arthritis (ie, RCTA), the integrity of the rotator cuff, the articular cartilage, and the coracoacromial arch all characteristically degenerate in a progressive manner.

 

Few studies have attempted to follow patients during conservative management of RCTA, but progression has been noted of increasing tear size, fatty infiltration, cephalic migration, and glenohumeral arthritis.

 

As the disease progresses, patients can experience superior glenoid bone erosion, as well as anteriorly, depending on the integrity of the coracoacromial arch. The cephalic migration may also result in erosion of the acromion that may become problematic when tension is increased in the deltoid after placement of a reverse shoulder replacement and result in acromion fracture.

 

This progression of migration and worsening degeneration can result in increased pain, stiffness, diminishing function, and potentially anterosuperior instability.

PATIENT'S HISTORY AND PHYSICAL FINDINGS

 

Patients can report either an acute event that resulted in deterioration or from a chronically progressive decline in function and pain (“tear” vs. “wear”).

 

These patients can experience loss of range of motion either from functional limitations seen with rotator cuff deficiency or from bone erosions that alter the kinematics and stability of the shoulder.

 

 

Physical examination typically demonstrates pain with range of motion, as well as crepitus, often between the humeral head and the acromion. Due to loss of rotator cuff integrity, these patients can have a large subacromial effusion from synovial fluid escape.

 

Examination should include a careful evaluation of the rotator cuff:

 

Supraspinatus function can be evaluated by the inability to abduct the arm from the side as well as a positive drop arm test.

 

Subscapularis function can be evaluated by loss of internal rotation strength with a positive lift-off test, belly press sign, or bear hug test, which may affect implant choice due to anterior stability concerns.

 

Infraspinatus and teres minor function can be evaluated by loss of external rotation in adduction (infraspinatus) as well as abduction (teres minor), with a positive external rotation lag sign (infraspinatus) and hornblower's test (teres minor). It is important to rule out dysfunction of these muscles, which may compromise results and necessitate soft tissue transfers during the procedure to maximize patient's ability to reach their hand to their head.

 

It is also important to evaluate deltoid function, specifically for patients with a history of dislocation, trauma, or previous surgeries who may have sustained an injury to the axillary nerve. This may necessitate further nerve function studies to document integrity. Deficient axillary nerve functioning will significantly affect a patient's outcome and requires determination prior to placing a reverse shoulder prosthesis.

 

Patients can also suffer from instability from loss of dynamic restraint, and the direction should be evaluated. By having the patient contract their deltoid with the arm in an adducted position, the proximal migration and impaction into the acromion can be noted (FIG 1A,B).

 

If the coracoacromial arch is incompetent, then during deltoid contraction the proximal humerus can be delivered subcutaneously between the acromion and coracoid. This is described as anterosuperior escape of the humeral head (FIG 1C,D).

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs in two planes should be the initial diagnostic test. These should include an anteroposterior (AP) view in the plane of the scapula and an

axillary view. Other views that may be helpful include an AP view of the shoulder, true AP of the glenohumeral joint with the humerus in internal and external rotation, and a scapular Y view.

 

P.3842

 

 

 

FIG 1 • A,B. Characteristic findings of CTA, including superior displacement of the humeral head, femoralization of the proximal humerus, and “acetabularization” of the coracoacromial arch. In such a case, a conventional hemiarthroplasty, possibly using a special CTA head, may be considered. C,D. Anterosuperior escape of the humeral head resulting from surgical compromise of the coracoacromial arch. In such a case, a conventional arthroplasty will not provide stability, and a Delta CTA or reverse prosthesis may be considered. (Copyright Steven B. Lippitt, MD.)

 

 

The plain films can denote the typical features that are involved in all arthritic processes such as loss of joint space, osteophyte formation, cysts as well as bone loss.

 

Additionally, radiographs can provide clues to the etiology such as osteoarthritis, rheumatoid arthritis, avascular necrosis, prior proximal humeral fracture, or RCTA.

 

 

RCTA can be identified by characteristic radiograph findings. AP plain radiographs

 

 

Decreased acromiohumeral distance, typically less than 6 mm Superior and possibly anterior glenoid wear

 

 

Erosion of the acromion resulting in an “ acetabularized” appearance (FIG 2A,B) “Femoralization” of the proximal humerus (ie, rounding off of the tuberosities)

 

 

 

FIG 2 • A. Normal glenoid and normal head-glenoid relationship are seen on this AP radiograph in the plane of the scapula. B. Superior glenoid erosion and upward displacement of the head are seen on this AP radiograph in the plane of the scapula. This demonstrates femoralization of the proximal humerus and acetabularization of the coracoacromial arch. (continued)

 

 

Axillary radiographs

 

Direction and degree of humeral instability

 

 

Medial glenoid erosion and available bone stock for glenoid implant fixation Glenoid version and anterior/posterior glenoid wear

 

Computed tomography (CT) scan can evaluate the following:

 

 

Bony architecture of humerus, glenoid, and acromion Glenoid bone stock

 

 

Alterations in glenoid version and glenohumeral congruency Hardware from prior rotator cuff repairs

 

Magnetic resonance imaging (MRI) can assess the following:

 

Integrity of soft tissue and rotator cuff tendons, especially in patients with inflammatory arthritis

 

Rotator cuff retraction and fatty infiltration of the muscle belly which may prognosticate an irreparable tendon

 

 

 

FIG 2 • (continued) C,D. A proper axillary view will reveal anterior, posterior, or medial glenoid erosion. (Copyright Steven B. Lippitt, MD.)

 

 

P.3843

 

DIFFERENTIAL DIAGNOSIS

Septic arthritis Osteoarthritis Inflammatory arthropathy

Neuropathic (Charcot) arthropathy Crystalline arthropathy Suprascapular nerve entrapment Cervical pathology

 

 

 

NONOPERATIVE MANAGEMENT

 

The combination of an irreparable rotator cuff and glenohumeral arthritis typically results from a chronic process and nonoperative modalities may be attempted to alleviate pain and improve function. This may be the treatment of choice depending on the patient's overall physiologic health.

 

These modalities consist of the use of anti-inflammatory medications, cortisone injections, and physical therapy.

 

Physical therapy should focus on painless range of motion and not cause more inflammation and pain, which may create further loss of function. Protocols should focus on strengthening of the deltoid, any remaining rotator cuff, as well as periscapular muscles to help compensate for impaired cuff function.

 

Cortisone injections should be limited though in cases where surgical intervention may be inevitable, as this can cause further insult to remaining cuff as well as increase the risk of infection.

SURGICAL MANAGEMENT

Preoperative Planning

 

The type of surgical intervention should include consideration of the patient's age, preexisting medical conditions, pain, functional level, activities of daily living as well as the patient's compliance and expectations.

 

Physical examination, paying special attention to rotator cuff integrity and stability as well as arthritic etiology is instrumental in determining the type of the prosthesis that can maximize a patient's outcome (Table 1).

 

Preoperative radiographs and CT scans should be reviewed to determine the quality of glenoid bone stock, glenoid version, and deformity and determine if bone grafting may be necessary.

 

Radiographs can also identify any potential deformities that may prevent passage of the humeral stem. The AP radiograph allows templating to estimate the size and fit of the humeral components (FIG 3).

 

MRI can be valuable to assess the rotator cuff if the physical examination cannot determine if loss of function is physiologic or the result of painful arthritic progression. This can be especially important in patients with osteoarthritis and rheumatoid arthritis.

 

With both hemiarthroplasty and reverse shoulder arthroplasty, the patient must have realistic expectations and provide informed consent to the risk of anesthetic complications, infection, neurovascular injury, persistent pain, stiffness, weakness, fracture, instability, loosening, and wear of components.

 

Hemiarthroplasty indications are as follows:

 

 

Deficient nonreparable cuff Intact deltoid

 

 

 

Humeral head migration stable beneath adequate acromial arch Patient's shoulder with active forward elevation greater than 90 degrees Pain is the main complaint.

 

 

 

Minimize surgery risks Sufficient subscapularis Younger, more active patient

 

RTSA indications are as follows:

 

 

Deficient nonreparable cuff Intact deltoid

 

 

Unstable humeral head with incompetent coracoacromial arch Significant glenoid wear

 

 

Patient active forward elevation less than 90 degrees with humeral head anterosuperior escape (pseudoparalysis) Older, less active patient

 

 

Understanding of increased surgical risks Deficient subscapularis

 

Antibiotics should be given prior to starting the procedure.

 

Consideration for intraoperative frozen section analysis should be made if the patient has had prior surgery and the surgical plan includes revision to a new prosthesis.

 

Positioning

 

The patient can be placed in either the beach-chair or semi-Fowler recumbent position with the use of either a Mayfield or McConnell (McConnell Orthopedic Mfg. Co., Greenville, TX) headrest.

 

P.3844

 

 

Table 1 Types of Arthritis and Irreparable Rotator Cuff Defects and Their Characteristic Features

 

 

Glenohumeral Joint Surface	Rotator Cuff	Register (Glenohumeral Joint Alignment)	Active Elevation	Coracoacromial Arch	Anterosuperior Escape	Deltoid	Surgical Significance
Arthritic	Irreparable	Glenohumeral	>90	Intact	Absent	Intact	Consider
	supraspinatus	joint aligned	degrees				conventional
			but weak				hemi- or total
							shoulder
							arthroplasty
Arthritic	Irreparable	Superior	>90	Intact	Absent	Intact	Consider
	supraspinatus	displacement	degrees				conventional or
		with	but weak				special (eg,
		acromiohumeral					CTA)
		stability					hemiarthroplasty
Arthritic	Irreparable	Superior	<45	Compromised	Present	Intact	Consider Delta
	supraspinatus	displacement	degrees				or reverse
	and	without					arthroplasty
	infraspinatus	acromiohumeral
		stability
Arthritic	Irreparable	Superior	<45	Compromised	Present	Severe	Consider
	supraspinatus	displacement	degrees			compromise	conservative
	and	without					treatment,
	infraspinatus	acromiohumeral					resectional
		stability					arthoplasty, or
							shoulder fusion
Failed	Irreparable	Superior	<45	Compromised	Present	Intact	Consider
prosthetic	supraspinatus	displacement	degrees				reverse
	and infra-	without					shoulder
	spinatus	acromiohumeral					arthroplasty
		stability
CTA, cuff tear arthropathy.

 

 

The patient is moved to the lateral edge of the table to allow for the adduction and extension of the arm necessary for safe humeral canal access. A rolled towel placed underneath the medial border of the scapula can aid with anteverting the scapula, facilitating glenoid exposure.

 

 

 

FIG 3 • Templating view of the humerus taken with the arm in 30 degrees of external rotation with respect to the x-ray beam and with a magnification marker. (Copyright Steven B. Lippitt, MD.)

 

 

The patient is draped to allow maximum exposure of the operative extremity while allowing anesthesia access to the airway.

 

An adjustable mechanical arm holder or alternatively a padded Mayo stand can be used to assist in maintaining the arm in desired position during surgery.

 

Approach

 

The most commonly encountered approach uses the deltopectoral interval for access to the glenohumeral joint, whereas others have described the use of a superolateral deltoid-splitting approach. We prefer the deltopectoral approach, as it allows a reproducible exposure that does not disrupt the deltoid origin and provides a conveniently extensile exposure down the anterolateral arm if distal access is required, as is often required in cases of revision surgery. The coracoacromial ligament should be preserved as coracoacromial arch deficiency in the setting of large cuff tears may lead to anterosuperior escape. This approach will be used for all surgical interventions described in this chapter.

 

The subscapularis can be released through a variety of techniques, including tenotomy, subscapularis peel, or lesser tuberosity osteotomy. We prefer to perform a subscapularis peel with later reattachment to the lesser tuberosity through drill holes and the use of no. 2 suture.

 

A 360-degree release of the subscapularis is performed making sure to isolate and ligate the anterior humeral circumflex artery and veins. The subscapularis length is maximized and freed from the subcoracoid interface, and tendon is tagged for future repair. The axillary nerve should be identified at the anteroinferior border of the subscapularis and protected.

 

The biceps tendon, if present, is tenodesed to the upper border of the pectoralis major with the use of no. 2 nonabsorbable sutures.

 

The rotator cuff tear is identified and inability to repair is verified, and if any remaining rotator cuff tendons exist, they can be tagged and potentially used for later reattachment.

 

P.3845

 

 

A thorough débridement of scar tissue and capsule to allow a complete glenoid exposure is performed when inserting a glenoid implant. Implant selection for patients with irreparable rotator cuff tears and glenohumeral arthritis consists of the following:

 

Anatomic arthroplasty

 

Hemiarthroplasty using a conventional prosthesis

 

 

Hemiarthroplasty with a special head (eg, Delta CTA, Depuy, Inc., Warsaw, IN) Reverse shoulder arthroplasty

 

The loss of rotator cuff tendons creates dead space when placing a prosthesis and potential for hematoma formation. At completion of the case, a suction drain is placed beneath the deltopectoral plane and extends out the lateral arm just anterior to the deltoid insertion.

 

 

Perform closure of deltopectoral interval if desired and subcutaneous and skin closure. Sterile dry dressings are applied as well as a sling.

 

TECHNIQUES

Conventional Hemiarthroplasty and Special Hemiarthroplasty

Incision and Approach

 

A deltopectoral approach is used as described earlier.

 

The rotator cuff should be evaluated to ensure that the tear is irreparable.

 

Special attention should be made of the glenoid cartilage and determine if degenerative changes may necessitate a different prosthesis than a hemiarthroplasty.

Humeral Preparation and Sizing

 

 

Preoperative evaluation of the humerus helps to determine the size of the prosthesis and level of head resection. Progressively larger reamers are placed into the canal and stopped once cortical resistance is achieved (TECH FIG 1A).

 

 

TECH FIG 1 • A. Reaming the humerus until the first endocortical bite is achieved. B. Marking the humeral osteotomy at 45 degrees with the reamed axis of the shaft and in 30 degrees of retroversion. Care must be taken to protect the rotator cuff in making the osteotomy. C. Measuring the resected head to determine the diameter of curvature and the height. (continued)

 

The humeral head should be resected with the arm placed in external rotation of 30 and 45 degrees with the long axis of the shaft (TECH FIG 1B).

 

An alternative technique is using an osteotomy template to determine the anatomic neck of the humerus and therefore the neck-shaft angle and humeral head retroversion, making sure to account for and remove surrounding osteophytes. The angle is marked with electrocautery. Retractors are used to protect soft tissue structures, and the humeral head is resected.

 

Measure height and diameter of the curvature of the resected head (TECH FIG 1C).

 

The humeral head can be morselized and used as autogenous graft for impaction grafting of the humeral canal to improve bone stock and achieve improved fixation of the implant (TECH FIG 1D).

 

 

TECH FIG 1 • (continued) D. Impaction grafting of the medullary canal to achieve a secure press-fit without jeopardizing the strength of the diaphyseal cortex. E. Partial repair of the rotator cuff to the edge of the resected humerus. (Copyright Steven B. Lippitt, MD.)

 

 

P.3846

Component Placement

 

Once the trial component is placed, resect any prominent greater tuberosity that may impinge on the coracoacromial arch during arm elevation (TECH FIG 2A,B).

 

Consideration can be made for use of a special humeral head (eg, cuff tear arthropathy [CTA] head) that allows improved coverage of the greater tuberosity and allows more congruent arc with undersurface of the acromion (TECH FIG 2C).

 

Once trial is placed, ensure that implant allows 40 degrees of external rotation with the subscapularis approximated, 50% posterior translation on the posterior drawer test, and 60 degrees of internal rotation with the arm in 90 degrees of abduction (TECH FIG 2D-G).

 

 

 

TECH FIG 2 • A,B. Smoothing of the greater tuberosity lateral to the articular surface of the prosthetic humeral head. C. CTA head prosthesis, providing a smooth lateral articulation for the shoulder with irreparable cuff deficiency. (continued)

 

Final prosthesis can be assembled and placed into humeral canal.

 

No. 2 nonabsorbable sutures previously placed through humeral drill holes can then be used for subscapularis reattachment (TECH FIG 2H). Final Contouring and Wound Closure

 

Ensure smooth passage of the proximal humerus beneath the coracoacromial arch. If abutment occurs, perform smoothing on the humeral side, preserving the integrity of the arch.

 

 

Repair subscapularis Insert drain

 

 

Perform closure as previously described Sterile dressing and sling

 

P.3847

 

 

TECH FIG 2 • (continued) D-G. Balancing the soft tissue tension: 40 degrees of external rotation (D), 50% posterior translation (E,F), and 60 degrees of internal rotation in 90 degrees of abduction (G). H. Preparing for subscapularis reattachment to the cut edge of the humerus. (Copyright Steven B. Lippitt, MD.)

 

 

P.3848

• Reverse Shoulder Arthroplasty

Incision and Approach

 

Assess preoperative radiographs and possibly CT scan to ensure adequate glenoid bone stock and determine that appropriate screw placement into native bone can be achieved.

 

Use the deltopectoral approach as previously described.

 

 

Lyse adhesions and remove bursa from the humeroscapular motion interface, protecting the deltoid, acromion, and residual cuff tissue. Verify irreparability of the rotator cuff tendon tear and resect useless tissue.

 

 

Perform releases of subscapularis and capsule, preserving maximal length of the tendon. Make sure to protect axillary nerve during key aspects of the procedure.

Humeral Preparation

 

Insert humeral resection guide stem on the superior portion of the humerus and typically posterior and lateral to the bicipital groove to ensure passage into the medullary canal (TECH FIG 3A).

 

Resect humeral head in 0 degree of retroversion with cutting guide starting at the level of the superior aspect of the greater tuberosity (TECH FIG 3B). Glenoid Preparation

 

While protecting the axillary nerve, the capsule surrounding the glenoid is released to ensure full visualization of the glenoid. The long head of the triceps can be released during this step.

 

 

The labrum, residual cartilage, and osteophytes should be removed from the glenoid. Bone defects should be noted, and if necessary, bone graft is applied.

 

Mark a point that is 13 mm anterior to the posterior rim of the glenoid and 19 mm superior to the inferior glenoid rim or roughly at a point that is posterior and inferior to the intersection of the glenoid axis. Pin position can also be determined through the use of a metaglene positioner (TECH FIG 4A).

 

Drill the guidewire into this point (TECH FIG 4B).

 

The metaglene should be positioned on the inferior edge of the glenoid and with an approximate 10 degree inferior tilt to the plane of the glenoid.12

 

 

TECH FIG 3 • A, B. Humeral resection guide inserted for cut at 0 degree of retroversion. C. Resected humerus after removal of osteophytes. (Copyright Michael A. Wirth, MD.)

 

Once position is confirmed with the extrapolated axillary border, remove the metaglene and drill a central hole with the step drill (TECH FIG 4C).

 

The glenoid resurfacing reamer should be used to make the surface congruent with the backside of the baseplate; however, removal of subchondral bone should be minimized. Continue to maintain relationship between reamer and glenoid and not alter version (TECH FIG 4D).

 

Manual reaming can then be performed to remove any remaining cartilage or ensure a flat surface in all directions (TECH FIG 4E). Metaglene Placement

 

The metaglene peg is then inserted into the central hole.

 

 

The anterior aspect of the scapula and scapular neck should be palpated to determine trajectory of the inferior screw (TECH FIG 5A). The inferior locking screw typically is oriented perpendicular to the face of the glenoid.

 

The drill should be slowly advanced and repeatedly checked to ensure that the drill is contained within bone.

 

 

The cortex can be perforated for additional fixation. A screw length of at least 36 mm should be obtained.

 

If not, the drill is redirected or metaglene adjusted to ensure adequate screw purchase.

Screw Fixation

 

Once the inferior screw is inserted, attention can be placed to additional fixation points.

 

The superior locking screw should be placed next, and orientation should be guided anteriorly and superiorly toward the base of the coracoid process. Drill and insert the superior locking screw using similar technique as the inferior screw (TECH FIG 5B).

 

Anterior and posterior locking or nonlocking screws can then be applied, maintaining a convergent or parallel pattern from the central peg into reliable bone stock, keeping in mind that the glenoid is funnel-shaped in the transverse plane and narrows quickly medially.

 

 

The anterior screw orientation can be guided by palpation of anterior glenoid neck. A posterior screw can be drilled and inserted with relationship to posterior scapula.

 

 

The fixation of the metaglene should be evaluated and ensure concentric placement against native glenoid (TECH FIG 6A). The glenosphere is inserted onto the metaglene (TECH FIG 6B).

 

P.3849

 

 

TECH FIG 4 • A. A trial guide is placed and is used to allow accurate placement of guidewire. B. The glenoid guidewire is inserted 19 mm up from the inferior edge of the glenoid and 13 mm anteriorly to the posterior glenoid border. C. A step drill is inserted over the guidewire. D. Glenoid reaming is performed conservatively to preserve bone stock. E. Manual reaming to provide flat surface for metaglene. F. The Delta prosthesis from left to right: humeral stem, polyethylene cup, glenosphere, and metaglene. (Copyright Michael A. Wirth, MD.)

 

 

 

TECH FIG 5 • A. Preferred location of the inferior screw in the axillary border of the scapula. B. Inserting superior screw toward base of coracoid. (Copyright Frederick A. Matsen, MD.)

 

 

 

TECH FIG 6 • A. Inserting the metaglene, noting its flush position with the inferior glenoid. The desired location of the inferior screw is in the axillary border of the scapula. B. Placement of glenosphere onto metaglene. (Copyright Michael A. Wirth, MD.)

 

 

P.3850

Final Humeral Reaming

 

 

Progressively larger reamers are applied until cortical contact is achieved and humeral bone stock is preserved (TECH FIG 7A). Insert a trial stem with a metaphyseal reamer guide in 0 degree of rotation (TECH FIG 7B).

 

Metaphysis is reamed until bone purchase is achieved (TECH FIG 7C). Trial Placement

 

Perform a trial reduction of the prepared humerus (without trial components) to see if the reamed metaphysis can be reduced to the glenosphere, indicating that the humeral resection is adequate.

 

Assemble and insert the trial humeral component with a humeral trial cup of appropriate size that matches the glenosphere. This should be reduced with shoulder flexion and longitudinal traction.

 

 

If reduction is not possible, then humeral bone should be sequentially resected or preferably, soft tissue released. The prosthesis should be evaluated for the following:

 

 

Range of motion Stability

 

Medial abutment of the polyethylene against inferior scapula with adduction, anterior abutment with internal rotation, and posterior abutment with external rotation. If abutment occurs, then bony or soft tissue obstructions should be removed.

 

 

 

TECH FIG 7 • A. Inserting the metaphyseal reaming guide in 0 degree of retroversion to the appropriate depth for selected implant. B. Reaming the metaphysis over the metaphyseal reaming guide. (Copyright Michael A. Wirth MD.)

 

Joint tension can be evaluated by the following:

 

Palpating the conjoint tendon

 

Longitudinal traction on an adducted arm to see if the humerus separates from the glenosphere. This should be less than 1 to 2 mm.

Final Component Placement

 

 

Insert the glenosphere into the metaglene if not done prior to completing humerus, making sure proper alignment is encountered. The definitive humeral components are assembled.

 

The medullary canal is thoroughly irrigated.

 

 

If the prosthesis uses cement, then a cement restrictor is placed within the medullary canal. Drill holes are placed through the lesser tuberosity as described previously.

 

Remaining posterior rotator cuff tendons are repaired if possible.

 

The definitive implant can either be press-fit or cemented in 0 degree of retroversion (TECH FIG 8A).

 

Trial polyethylene liners are used to determine appropriate stability and tension. Ensure no abutment of polyethylene against inferior, anterior, or posterior scapular neck.

 

 

Insert polyethylene component and ensure that it is seated fully (TECH FIG 8B). Irrigate the wound completely.

 

Reduce the joint.

 

 

TECH FIG 8 • A. Insertion of a trial humeral component. B. Placement of polyethylene. (Copyright Michael A. Wirth, MD.)

• Wound Closure

Repair the subscapularis through drill holes on lesser tuberosity. Place a suction drain beneath the deltopectoral plane.

Close layers of deltopectoral interval, subcutaneous layer, and skin. Apply sterile dressing and sling.

 

 

PEARLS AND PITFALLS

 

 

Indications

• For patients who have lost the stabilizing effect of the rotator cuff tendons, then implant choices should consist of

hemiarthroplasty versus reverse shoulder replacement. The age and functional level of the patient should be taken into consideration when planning implant choice.

Imaging

• Preoperative plain radiographs as well as advanced imaging is necessary to evaluate remaining glenoid bone stock and

version.

Patient

positioning

• The operative extremity must be free to allow full adduction and extension for entry into humeral canal.

Approach

• Maintaining integrity of the deltoid origin as well as axillary nerve is essential in patients with nonfunctioning rotator cuff

tendons. Thorough glenoid exposure is necessary to properly place metaglene.

Revision

surgery

• Be aware of indolent infections and obtain appropriate preoperative labs as well as intraoperative frozen section analysis.

Cultures should be held for 2 weeks to ensure no growth of Proprionibacterium acnes.

Postoperative ▪ Patients without a rotator cuff are prone to hematomas and a drain should be placed to avoid this.

 

 

POSTOPERATIVE CARE

 

Hemiarthroplasty with a conventional prosthesis or hemiarthroplasty with a special head (eg, CTA)

 

Institute a continuous passive motion (FIG 4) and early active-assisted motion protocol as soon as possible postoperatively (unless major partial cuff repair has been carried out).

 

 

Elevation of the arm to 140 degrees is achieved before the patient leaves the medical center. For 6 weeks, external rotation is limited to what was easily achievable on the operating table.

 

 

Gentle progressive strengthening exercises, including the supine press, usually are started at 6 weeks. RTSA

 

Institute hand-gripping and active elbow flexion postoperatively.

 

Motion is withheld for 36 hours to minimize the risk of hematoma formation.

 

 

 

 

 

FIG 4 • Continuous passive motion. (Copyright Steven B. Lippitt, MD.)

 

 

Gentle activities, such as eating, are started at 36 hours, followed by the slow, progressive addition of other activities, reminding the patient of the need for the shoulder bones and muscles to have time to remodel to their new loading patterns.

 

Formal physical therapy begins at 6 weeks.

 

Avoid lifting anything heavier than 1 pound for 3 months.

OUTCOMES

Recent studies have demonstrated improved outcomes for pain and function with the use of reverse shoulder arthroplasty as compared to hemiarthroplasty for rotator cuff arthropathy with similar complication rates.8,15

Both hemiarthroplasty and reverse shoulder arthroplasty have shown improvement in pain and function, although RTSA offers the advantage of lengthening the deltoid lever to compensate for the decreased function of the rotator cuff.

In RTSA, these results provide only short to midterm outcomes, and long-term results are still unknown. Functional results have been shown in several studies to decrease after approximately 12 years, so patient age and activity level are important considerations. Consideration must also be made for the relatively high complication that has been associated with reverse shoulder arthroplasty in the literature.

Preoperative decision making must take into account the age and goals of the patient as well as available glenoid bone stock.

As always, risks can be encountered with either surgical approach, and conservative treatment should be maximized prior to proceeding with surgical options.

 

 

COMPLICATIONS

Systemic perioperative Anesthetic complications Deep venous thrombosis

Atelectasis

Cardiac events Local perioperative

Intraoperative fracture of humerus, glenoid, or acromion Axillary nerve or plexus injury

Deltoid injury Postoperative

Hematoma Infection

 

Instability

Fracture of humerus, glenoid, or acromion Prosthetic loosening

Pain Weakness

Failure to regain function

 

 

REFERENCES

1. Barrett WP, Franklin JL, et al. Total shoulder arthroplasty. J Bone Joint Surg Am 1987;69:865-872.

    

    

2. Boileau P, Watkinson DJ, Hatzidakis AM, et al. Grammont reverse prosthesis: design, rationale, and biomechanics. J Shoulder Elbow Surg 2005;14(1 suppl S):147S-161S.

    

    

3. Eukland KJ, Lee TQ, Tibone J, et al. Rotator cuff tear arthroplasty. J Am Acad Orthop Surg 2007;15:340-349.

    

    

4. Frankle M, Siegal S, Pupello D, et al. The reverse shoulder prosthesis for glenohumeral arthritis associated with severe rotator cuff deficiency. A minimum two-year follow-up study of sixty patients. J Bone Joint Surg Am 2005;87(8):1697-1705.

    

    

5. Franklin JL, Barrett WP, Jackins SE, et al. Glenoid Loosening in total shoulder arthroplasty. Association with rotator cuff deficiency. J Arthroplasty 1988:3:39-46.

    

    

6. Jensen K, Williams G, Russell I, et al. Rotator cuff tear arthropathy. J Bone Joint Surg Am 1999;81:1312-1324.

    

    

7. Labriola JE, Lee TQ, Debski RE, et al. Stability and instability of the glenohumeral joint: the role of shoulder muscles. J Shoulder Elbow Surg 2005;14:32-38.

    

    

8. Leung B, Horodyski M, Struk AM, et al. Functional outcome of hemiarthroplasty compared with reverse total shoulder arthroplasty in the treatment of rotator cuff tear arthropathy. J Shoulder and Elbow Surg 2012;21:319-323.

    

    

9. Matsen FA III, Lippitt SB. Shoulder Surgery: Principles and Procedures. Philadelphia: WB Saunders, 2003.

    

    

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10. Neer CS II, Craig EV, Fukuda H, et al. Cuff-tear arthropathy. J Bone Joint Surg Am 1983;65(9):1232-1244.

     

     

11. Nwakama AC, Cofield RH, et al. Semiconstrained total shoulder arthroplasty for glenohumeral arthritis and massive rotator cuff tearing. J Shoulder Elbow Surg 2000; 9: 302-307.

     

     

12. Nyffeler RW, Werner CM, Gerber C, et al. Biomechanical relevance of glenoid component positioning in the reverse Delta III total shoulder prosthesis. J Shoulder Elbow Surg 2005;14:524-528.

     

     

13. Rockwood CA, Matsen FA III, Wirth MA, et al, eds. The Shoulder, ed 3. Philadelphia: WB Saunders, 2004.

     

     

14. Yamaguchi K, Tetro AM, Blam O, et al. Natural history of asymptomatic rotator cuff tears: a longitudinal analysis of asymptomatic tears detected sonographically. J Shoulder Elbow Surg 2001;10:199-203.

     

     

15. Young SW, Zhu M, Walker CG, et al. Comparison of functional outcomes of reverse shoulder arthroplasty with those of hemiarthroplasty in the treatment of cuff-tear arthropathy: a matched-pair analysis. J Bone Joint Surg Am 2013;95:910-915.

     

     

16. Zingg PO, Jost B, Sukthankar A, et al. Clinical and structural outcomes of nonoperative management of massive rotator cuff tear. J Bone Joint Surg Am 2007;89:1928-1934.