Total Shoulder Arthroplasty or Hemiarthroplasty for Arthritis: Current Trends and Technical Considerations

CHAPTER PREVIEW

CHAPTER SYNOPSIS

This chapter contains a review of the debate between total shoulder arthroplasty and hemiarthroplasty for the surgical treatment of glenohumeral arthritic conditions. The indications and contraindications of glenoid resurfacing are discussed. The treatment protocol we follow in our arthroplasty practice for common glenohumeral arthritic conditions and the supporting literature is described. Special considerations of shoulder arthroplasty, including common surgical pitfalls, complications, and rehabilitation, are included.

IMPORTANT POINTS:

Consideration must be given to the indications and contraindications of glenoid resurfacing prior to proceeding with a total shoulder arthroplasty. Following is a list of these guidelines.

1

Contraindications to glenoid resurfacing:
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  Insufficient glenoid bone stock precluding the preparation and insertion of a glenoid component
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  Supraspinatus tears, including an insufficient anterior or posterior rotator cuff (i.e., massive rotator cuff tear)
2

Relative contraindications to glenoid resurfacing with a polyethylene component:
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  Patients younger than 40 years of age
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  Axillary or suprascapular nerve palsy
3

Indications for glenoid resurfacing:
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  Glenohumeral arthritic conditions involving both the humeral and glenoid articular surfaces with adequate glenoid bone to support an implant and a functionally intact rotator cuff (isolated supraspinatus tears are not contraindications to glenoid resurfacing so long as the anterior and posterior rotator cuff is intact)

CLINICAL/SURGICAL PEARLS:

1

Treatment protocol for primary glenohumeral osteoarthritis:
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  Total shoulder arthroplasty is the treatment of choice.
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  Hemiarthroplasty is used only if glenoid bone is inadequate to support a glenoid implant.
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  Reverse prosthesis is used in cases of rotator cuff insufficiency.
2

Treatment protocol for rheumatoid arthritis:
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  Total shoulder arthroplasty is the treatment of choice.
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  Hemiarthroplasty is used only if glenoid bone is inadequate to support a glenoid implant.
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  Reverse prosthesis is used in cases of rotator cuff insufficiency.
3

Treatment protocol for osteonecrosis:
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  If there is no glenoid involvement, a humeral resurfacing prosthesis is used.
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  If there is glenoid involvement and the patient is younger than 40, a humeral resurfacing prosthesis and biologic glenoid resurfacing are used. If the patient is older than 40, a total shoulder arthroplasty is performed.
4

Treatment protocol for dislocation arthropathy:
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  Total shoulder arthroplasty is the treatment of choice.
5

Treatment protocol for posttraumatic arthritis:
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  Total shoulder arthroplasty is the treatment of choice.
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  Hemiarthroplasty is performed only if glenoid bone is inadequate to support a glenoid implant.
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  Reverse prosthesis is used in cases of rotator cuff insufficiency or cases requiring tuberosity osteotomy due to major malunion.
6

Treatment protocol for chondrolysis:
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  Humeral resurfacing prosthesis and biologic glenoid resurfacing are used in young patients.
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  In patients older than 40, total shoulder arthroplasty is performed.
7

Treatment protocol for rotator cuff arthropathy:
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  Reverse shoulder arthroplasty is the treatment of choice.
- •
  
  Hemiarthroplasty is performed only if glenoid bone is inadequate to support a glenoid implant.

CLINICAL/SURGICAL PITFALLS:

1

Axillary nerve injury is possible.
2

Postoperative posterior glenohumeral instability is a potential complication.
3

Intraoperative proximal humerus fracture can occur.

VIDEO AVAILABLE:

Not applicable.

Glenohumeral joint replacing and resurfacing techniques have been a mainstay of shoulder arthritis treatment since Neer’s introduction of shoulder arthroplasty. Glenohumeral joint arthritis has numerous etiologies, including primary osteoarthritis, inflammatory arthritis, osteonecrosis, dislocation arthropathy, posttraumatic arthritis, chondrolysis, and rotator cuff arthropathy. Primary glenohumeral osteoarthritis is the most common indication for implantation of an unconstrained total shoulder arthroplasty. Shoulder replacement has proven to be an effective and durable treatment for shoulder arthritis, with sustained and significant postoperative improvements in patients’ pain and functional scores. A successful outcome following shoulder replacement depends on multiple patient variables and physician choices. The underlying etiology, patient anatomy (i.e., bone and soft tissue quality), and patient expectations must be appropriately assessed preoperatively. Selection of the proper implant and treatment protocol by the surgeon will determine the ultimate outcome.

For the shoulder surgeon planning treatment of a patient with glenohumeral arthritis, there are two main options: total shoulder arthroplasty (TSA) and hemiarthroplasty. Until recently, whether to resurface or not to resurface the glenoid had been a persistent point of debate. Historically the amount of experience and numbers of patients treated with hemiarthroplasty were greater than those treated with TSA. Therefore, statistical comparison and determination of significance between treatment groups was impossible. In addition, glenoid component failures early in the TSA experience fortified the position of hemiarthroplasty proponents. Hemiarthroplasty implantation is not technically difficult, takes little operative time, and requires minimal surgical dissection. TSA, on the other hand, is a more technical procedure, requires adequate exposure of the glenoid to address deformity and allow for component insertion, and demands a thorough knowledge of shoulder anatomy to avoid iatrogenic injury. As surgeon experience and implant quality has increased, the outcomes following TSA have also improved. With larger patient cohorts, data have proven statistically that TSA is superior to hemiarthroplasty in treating glenohumeral arthritis.

The purpose of this chapter is multifaceted. First we discuss the historical debate and current literature covering the treatment of glenohumeral arthritis with TSA or hemiarthroplasty. Second, this chapter will report our indications and considerations for performing TSA or hemiarthroplasty for common glenohumeral arthritic conditions. A discussion of technical considerations of shoulder arthroplasty, including preoperative planning, intraoperative considerations, and complications, is included. Finally we cover our rehabilitation protocol following shoulder replacement procedures.

TOTAL SHOULDER ARTHROPLASTY VERSUS HEMIARTHROPLASTY: LITERATURE REVIEW

The lack of clear evidence in the literature to determine implant superiority fueled the debate between TSA and hemiarthroplasty. Evidence citing the advantages and indications of glenoid resurfacing has been historically poor, yet the disadvantages, namely component loosening and failure, were often reported. Glenoid component loosening is a major complication following TSA, and contraindications to glenoid resurfacing include irreparable rotator cuff tears and inadequate glenoid bone stock ( Fig. 14-1 ). Radiolucent lines seen on postoperative radiographs around the glenoid component have been studied as to their impact on glenoid failure. The rate of postoperative glenoid component radiolucencies ranges from 40% to 90%. Despite the high incidence of radiolucency, the failure rate of cemented all-polyethylene glenoid components is rare, cited at 2%, owing to modern component design and implantation and cementing techniques ( Fig. 14-2 ). Although hemiarthroplasty outcomes are not affected by glenoid components, the incidence of humeral component radiolucency and humeral component migration has reached statistical significance. These humeral radiographic findings are more common in hemiarthroplasty patients; their effect on outcomes is unknown.

Direct comparison of TSA versus hemiarthroplasty has been most thoroughly evaluated in the treatment of primary osteoarthritis. The first prospective randomized study of total shoulder arthroplasty versus hemiarthroplasty was reported by Gartsman et al. Fifty-one patients with primary osteoarthritis were randomized to one of the two treatment groups. Total shoulder arthroplasty patients reported higher scores for pain relief, overall function, strength, and satisfaction than those treated with hemiarthroplasty. However, only pain relief demonstrated statistically significant superiority of total shoulder arthroplasty. The most statistically powerful comparison of TSA and hemiarthroplasty was a multicentric study from Europe in which 690 patients with primary glenohumeral osteoarthritis were evaluated after surgery at a minimum of 2 years. Although both groups demonstrated improvement in objective and subjective criteria, patients with total shoulder replacements improved more. Statistical significance was reached for all measured parameters. TSA was superior to hemiarthroplasty in pain relief, mobility, and overall function.

Two meta-analyses have been reported evaluating TSA and hemiarthroplasty. Both the study by Bryant et al and Radnay et al show clear superiority of total shoulder arthroplasty. Specific criteria included pain relief, forward elevation, external rotation, and patient satisfaction. Revision surgery was required for 6.5% of total shoulder replacements and 10.2% of hemiarthroplasties over a 30- to 116-month study period, also statistically significant.

Outcomes of TSA and hemiarthroplasty have also been reported for other diagnoses. In the treatment of rheumatoid patients, Sperling et al. reported improved outcomes with TSA over hemiarthroplasty with an intact rotator cuff. Superiority of TSA was also demonstrated in rheumatoid patients in a European study. Posttraumatic arthritis patients with an intact rotator cuff are best treated with TSA as well. TSA has not proven superior to hemiarthroplasty in cases of osteonecrosis and humeral head collapse without involvement of the glenoid.

TOTAL SHOULDER ARTHROPLASTY VERSUS HEMIARTHROPLASTY: INDICATIONS, CONTRAINDICATIONS, AND DISEASE-SPECIFIC CONSIDERATIONS

Indications and Contraindications

Successful glenoid resurfacing requires adequate glenoid bone stock to support the implant and a functional rotator cuff. The quantity and quality of glenoid bone stock is evaluated by preoperative imaging. The status of the rotator cuff is assessed both clinically and radiographically. Isolated small supraspinatus tears are not a contraindication to unconstrained TSA. Large supraspinatus tears decrease postoperative functional scores, but a functional anterior and posterior rotator cuff provides an adequate force couple to afford shoulder stability and motion postoperatively. The absence of one of these two requirements precludes glenoid resurfacing. Preoperative nerve lesions are relative contraindications to unconstrained TSA and include axillary nerve and suprascapular nerve lesions. Glenohumeral arthritis combined with axillary nerve palsy is best treated using resection arthroplasty or glenohumeral arthrodesis. Suprascapular nerve palsy is suitable for a hemiarthroplasty or reverse prosthesis. In our practice, preoperative imaging for shoulder arthroplasty consists of plain radiographs (anteroposterior, scapular outlet, and axillary views) and computed tomography (CT) arthrography. Plain radiographs coupled with CT bony windows completely demonstrate the bony structure of the glenoid. The CT arthrogram assesses the tendinous rotator cuff for tears and the muscular rotator cuff for fatty infiltration ( Fig. 14-3 ). In our practice, patient age also plays a role in the decision to resurface the glenoid; there is no defined guideline in the literature to follow. Patients younger than age 40 are treated with biologic glenoid resurfacing as opposed to a polyethylene component.

Disease-Specific Considerations: Primary Osteoarthritis

Primary osteoarthritis is the single most common diagnosis requiring shoulder replacement. Preoperative imaging studies demonstrate the variable relationship of the humeral head to the glenoid. A centered glenohumeral joint is found half the time, posterior erosion and biconcavity in 20% of cases, and posterior subluxation not associated with bone loss in 25% ( Fig. 14-4 ). Isolated supraspinatus tears are found in 14% of patients, half of these being full-thickness tears.

TSA with glenoid resurfacing is our treatment of choice for these patients. Hemiarthroplasty is rarely performed and only in patients with inadequate glenoid bone stock to implant a polyethylene component. If the rotator cuff is found to be inadequate (i.e., a compromised supraspinatus coupled with an anterior or posterior rotator cuff defect), then a reverse total shoulder prosthesis is selected.

Special attention should be given to the patient with severe posterior glenoid erosion. Preoperative CT scans should be used to plan the amount of glenoid correction that will be performed. A large glenoid deformity correction may lead to posterior instability of the implant, necessitating a posterior capsulorrhaphy and an altered postoperative rehabilitation protocol. The capsulorrhaphy must be completed before inserting the final humeral component ( Fig. 14-5 ). The treatment algorithm we follow in our practice for managing primary osteoarthritis and the following glenohumeral arthritic conditions is found in Figure 14-6 .

Rheumatoid Arthritis

Rheumatoid arthritis is a disabling secondary erosive arthritis caused by synovial inflammation and hyperplasia. Approximately 75% (60% to 90%) of rheumatoid patients will complain of shoulder pain, and 12% of all primary TSAs are performed for rheumatoid disease. Loss of the glenohumeral joint space without osteophytes is found on imaging studies. Medial migration of the humeral head with loss of glenoid bone stock should be evaluated closely. Rotator cuff lesions should be noted in these patients to direct treatment. Isolated full-thickness supraspinatus tears and partial-thickness supraspinatus tears occur in 8% and 9% of patients, respectively. Massive rotator cuff tears are found in 12% of patients.

A TSA with insertion of a polyethylene glenoid component is our treatment of choice in patients with rheumatoid arthritis (RA). Improved outcomes with glenoid resurfacing in these patients have been reported. The status of the rotator cuff must be considered before surgery. An incompetent rotator cuff is an indication to perform a reverse arthroplasty, depending on the glenoid bone stock. In our practice a hemiarthroplasty is implanted in the case of glenoid bone stock inadequate for component insertion. Attention should also be paid to the humeral bone stock preoperative radiographs. Cystic invasion of the metaphysis may require using a cemented humeral stem for adequate stability; these implants must be available at the time of surgery.

Osteonecrosis

The death of subchondral humeral bone and its resultant collapse secondary to vascular compromise defines osteonecrosis. The loss of the humeral articular surface and normal glenohumeral interface results in pain interfering with activities of daily living. Cruess outlined a staging system for osteonecrosis of the shoulder based on radiographic findings in osteonecrosis of the hip. The “crescent sign” radiographically defines subchondral bone collapse, and advancement of the disease will involve the glenoid interface. Magnetic resonance imaging (MRI) assists in evaluating early disease, before bony collapse is visible on radiograph. The rotator cuff is rarely involved in glenohumeral joint osteonecrosis.

The challenge for the shoulder surgeon in treating these patients is their young age. Without glenoid lesions and humeral defects involving less than 25% of the head, complete humeral resurfacing implants are used without addressing the glenoid ( Fig. 14-7 ). Large humeral lesions with epiphyseal bone loss and an uninvolved glenoid are treated using a stemmed hemiarthroplasty. Glenoid involvement must be assessed and addressed at the time of surgery. In patients younger than 40 with glenoid disease, we resurface the glenoid with an autologous fascia lata graft. In those older than 40, we opt for stemmed humeral components and all-polyethylene glenoid implants (TSA).

Dislocation Arthropathy

Articular cartilage injury occurs secondary to sheer and impaction in traumatic shoulder dislocation. Arthroscopic evaluation studies report the incidence of chondral lesions at 46%. Dislocation arthropathy was described and classified by Samilson and Prieto. The development of arthritis in these patients is associated with their age at the initial dislocation, the direction of the dislocation (posterior dislocations inducing more degeneration than anterior), and the presence of associated glenoid fractures. The number of dislocation events and previous stabilization surgery does not seem to affect the development of arthritis.

Imaging studies follow the pattern of primary osteoarthritis with joint space narrowing and osteophytes. In older patients, radiographs after a traumatic dislocation may demonstrate a narrow joint space without osteophytes, a condition we refer to as rapidly appearing instability arthropathy ( Fig. 14-8 ). Advanced imaging will evaluate the rotator cuff and position of the humerus relative to the glenoid. Posterior glenoid erosion and subluxation are often present, and full-thickness rotator cuff tears are found 20% of the time.