Shoulder Hemiarthroplasty

Updated: Dec 23, 2015
  • Author: Paul H Eichenseer; Chief Editor: Dinesh Patel, MD, FACS  more...
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Overview

Background

Shoulder hemiarthroplasty is a shoulder replacement in which the broken humeral head is replaced with an artificial joint and the fractured bone is reconstructed around the artificial joint.

Shoulder arthroplasty is a rapidly evolving area of orthopedics focused on treating specific, painful ailments of the glenohumeral articulation. Broadly, shoulder arthroplasty encompasses surgeries using hemiarthroplasty (humeral prosthesis without replacement of the glenoid), total shoulder arthroplasty (humeral prosthesis with glenoid resurfacing via prosthesis), and reverse total shoulder replacement (humeral cup prosthesis with glenosphere implantation). [1, 2]

Although much less common than lower-extremity arthroplasty, shoulder arthroplasties have grown at annual rates between 6% and 13%. [3] Representing 3.1% of all joint replacements procedures, approximately 30,000 shoulder arthroplasties, half of which were hemiarthroplasties, are performed annually in the United States. [4]

The first shoulder arthroplasty, performed in 1893, is credited to French surgeon Jules Emile Péan. He inserted a platinum and rubber implant into a patient with glenohumeral destruction, secondary to tuberculosis, who refused amputation. [5] It was Charles Neer, however, who is credited with pioneering modern shoulder arthroplasty. Neer originally designed the humeral head prosthesis for the treatment of fractures about the humeral head, and later went on to describe shoulder arthroplasty in the treatment of glenohumeral arthritis. [6, 7]

Numerous shoulder prostheses have evolved since Dr Neer's introduction in the early 1950s, with the most current prostheses being modular systems made of cobalt-chrome alloy. Options offered by modern humeral prosthesis include varying sizes of head length and diameter to match patient anatomy and facilitate soft tissue balancing, varying stem lengths, smooth or coated stems, and cemented or cementless humeral component stems.

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Indications

Broadly, indications for shoulder hemiarthroplasty can be divided into those for acute fractures and those for chronic shoulder disease. Here, general indications will be presented and disease-specific indications will be discussed. With each indication, special attention must be paid to the integrity of each functional unit of the patient's shoulder, along with expected patient goals and outcomes.

Goals of hemiarthroplasty include relief of pain, improvement in overhead motion, and improvement in strength with overhead activities. Unrealistic expectations require additional patient education about possible postoperative limitations and lifestyle modifications, which may represent a contraindication to any type of arthroplasty if they persist.

General indications for shoulder hemiarthroplasty include the following [8, 9, 10] :

  • Pain for glenohumeral osteoarthritis that has failed conservative therapy with sparring of the glenoid articular surface
  • Any form of glenohumeral arthritis with inadequate glenoid bone stock when a glenoid component would otherwise be indicated
  • Patients at risk for glenoid component loosening (younger patients, patients requiring heavy usage of their shoulder)

Acute fracture indications for hemiarthroplasty include the following:

  • Neer four-part fractures [11, 12]
  • Neer three-part fractures [11, 12] when open reduction and internal fixation (ORIF) is complicated by poor bone quality
  • Neer three- and four-part fractures with concomitant humeral head dislocation [13]

It has been suggested that reverse shoulder arthroplasty may be a better choice from proximal humeral fractures than hemiarthroplasty is. [14, 15]

The following chronic shoulder diseases may be indications for hemiarthroplasty. [13]

Primary osteoarthritis

Patients with primary glenohumeral osteoarthritis typically complain of joint stiffness, crepitus, and pain. Hallmark radiographic findings include a loss of joint space, subchondral cysts, sclerosis, and osteophyte formation. Rotator cuff and deltoid function may be normal or abnormal and must be assessed. Patients with adequate glenoid bone stock and an intact rotator cuff usually benefit from total shoulder arthroplasty when compared to hemiarthroplasty.

In a large study comparing hemiarthroplasty to total shoulder arthroplasty, Pfahler et al [16] found that for 102 shoulders treated with hemiarthroplasty and 418 with total shoulder arthroplasty, both functional and subjective outcomes were better with total shoulder arthroplasty than hemiarthroplasty.

In a prospective randomized trial involving 51 shoulders, Gartsman et al [17] determined that total shoulder arthroplasty resulted in significantly greater pain relief and internal rotation than hemiarthroplasty, but was associated with increased cost, operative time, and blood loss.

Similarly, in a meta-analysis of 112 shoulders treated for osteoarthritis, Bryant et al [18] found that total shoulder arthroplasty offered better functional outcomes and decreased pain when compared to hemiarthroplasty at 2-year follow up.

Inflammatory arthropathies

The most common inflammatory arthropathy affecting the shoulder is rheumatoid arthritis. Clinical findings at the glenohumeral joint are similar to osteoarthritis. However, patients may present at a younger age and with more advanced joint destruction. Hemiarthroplasty is considered when glenoid bone stock is inadequate for total or reverse total arthroplasty.

Pfahler et al [16] determined that total shoulder arthroplasty functional outcomes were superior to hemiarthroplasty for 49 rheumatoid shoulders treated with hemiarthroplasty and 107 treated with total shoulder arthroplasty.

Similarly, Sperling et al [19] determined that total shoulder arthroplasty provided significantly greater pain relief and abduction when compared to hemiarthroplasty in the setting of an intact rotator cuff for rheumatoid patients.

Instability arthritis

Patients with primary or recurrent dislocation are at an increased risk for the development of glenohumeral osteoarthritis. Patients treated surgically for instability also demonstrate increased rates of glenohumeral osteoarthritis. Although a less common entity than primary osteoarthritis and rheumatoid arthritis, instability arthritis patients frequently present before the age of 50. The choice of hemiarthroplasty versus total shoulder arthroplasty is controversial in these patients.

Pfahler et al [16] showed that total shoulder arthroplasty has superior functional outcomes compared to hemiarthroplasty, but these results did not reach statistical significance.

Avascular necrosis of humeral head

Avascular necrosis (AVN) remains one of the major indications for hemiarthroplasty. Typically associated with alcoholism, corticosteroid use, radiation therapy, and sickle cell anemia, AVN presentation can vary widely, but patients frequently complain of pain in the setting of a functioning rotator cuff on physical examination. Plain film findings vary from normal to subtle lucency to complete osseous collapse. When deciding between hemiarthroplasty and total shoulder arthroplasty for the treatment of AVN, it appears that resurfacing of the glenoid is typically not necessary, except possibly in the setting of advanced arthritis. [16, 20]

Rotator cuff tear arthropathy

Patients with an irreparable rotator cuff tear in the presence of glenohumeral osteoarthritis present with pain and markedly decreased elevation. Plain films may show a complete loss of the subacromial space with the humeral head articulating with the undersurface of the acromion. Because hemiarthroplasty is inferior to reverse total arthroplasty for this condition in terms of functional outcome, [21] hemiarthroplasty is typically reserved for the case where glenoid bone stock is insufficient for glenosphere implantation. Total shoulder arthroplasty is contraindicated for risk of glenoid component loosening secondary to eccentric loading.

Glenohumeral chondrolysis

Chondrolysis is rare condition sometimes seen following previous shoulder intervention and presents with pain and stiffness. Muscle strength testing is typically normal and, with the exception of loss of joint space, radiographic findings of osteoarthritis are absent. Because of the frequently younger age of presentation in many of these patients, some surgeons may opt for biologic resurfacing of the glenoid with hemiarthroplasty. [13, 22] Other indications for biologic resurfacing include primary osteoarthritis, posttraumatic osteoarthritis, or postreconstructive osteoarthritis in young, active patients. Previously used biologic surfaces include anterior capsule, fascia lata autograft, and Achilles tendon allograft. [23, 24]

Tumor

Although an exceptionally rare indication, tumors requiring resection of the humeral head may be amenable to hemiarthroplasty. When rotator cuff function is severely affected by the resection, however, reverse total arthroplasty may be preferred. [13]

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Contraindications

Contraindications to hemiarthroplasty can be divided into relative and absolute contraindications. Absolute contraindications include the following:

  • Active infection
  • Neuropathic shoulder
  • Ankylosed shoulder
  • Previous glenohumeral arthrodesis
  • Incongruent glenoid and humeral surfaces
  • Severe loss of glenoid articular cartilage
  • Fracture treatable with ORIF
  • Nondisplaced fractures treatable nonoperatively
  • Unmotivated patient

Relative contraindications include the following:

  • Poor surgical candidate due to general medical health
  • Deltoid paralysis
  • Unrealistic patient expectations
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Technical Considerations

Procedural planning

The glenohumeral joint is a ball-and-socket articulation between the glenoid fossa of the scapula and the humeral head. Lacking any inherent stability, it is the most mobile joint in the human body. As such, the glenohumeral joint relies on both static and dynamic stabilizers for proper function. Dynamic stabilization and proper function is largely dependent on a functional, intact rotator cuff and its interaction with the deltoid. Reconstruction of the humeral head using good anatomic approximation is critical for optimization of shoulder biomechanics, particularly with respect to rotator cuff function, deltoid function, and soft tissue balance.

Iannotti et al defined many of the crucial anatomic measurements used to construct modular prostheses to best reproduce normal anatomy. The average radius of curvature of the humeral head in the coronal plane is 24 ± 2.1 mm (range, 19-28 mm). Average humeral head thickness was 19 ± 2.1 mm (range, 15-24 mm). Lateral humeral offset, or the distance from the base of the coracoid process to the most lateral part of the greater tuberosity, averaged 56 ± 5.7 mm (range, 43-67 mm). [25]

Boileau and Walch used a three-dimensional digitizer to obtain detailed measurements on humeral head version, inclination, and offset. Their studies showed average retroversion to be 21.5º ± 15.1º (range, –10.3º to 56.5º). The average neck-shaft angle measured 129.6º (range, 123.2º to 135.8º). Medial and posterior offsets averaged 2.6 ± 1.8 mm (range, –0.8 to 6.1 mm) and 6.9 ± 2.0 mm (range, 2.9-10.8 mm), respectively. [26]

Complication prevention

Preoperative administration of antibiotics (cephalosporins, vancomycin, or clindamycin) can minimize the risk of bacterial infection.

Proper head positioning to avoid hyperextension of the neck can minimize risk of cervical root compression during surgery.

Accounting for up to 20% of intraoperative complications, fractures can frequently be prevented with refined surgical technique. Etiologies include excessive reaming of the humerus, overzealous impaction of the humeral canal, or placing excessive torque on the humerus to expose the glenoid. [27] Caution must be exercised, especially with osteoporotic patients and those with rheumatoid arthritis. [28]

Iatrogenic neurologic injury can be prevented by the surgeon's familiarity with the normal shoulder anatomy, meticulous surgical technique, and an acute awareness of potential anatomic variants. The majority of neurologic injuries represent neuropraxias that resolve spontaneously over time. [27]

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