CLINICAL HISTORY AND EXAMINATION

Although description of a detailed shoulder history and examination are beyond the scope of this textbook, certain aspects of the history and physical examination are important in preoperative planning for revision shoulder arthroplasty. The patient’s complaints are reviewed, such as the type of symptoms (pain, stiffness, weakness), duration of symptoms (weeks, months, years), indication for the primary arthroplasty, initial results of the primary arthroplasty (relief of all symptoms, relief of some symptoms, no improvement from surgery), and the presence of any symptoms of infection (previous history of infection, fevers, wound redness, wound drainage). These shoulder-specific complaints help the surgeon decide which patients are candidates for revision shoulder arthroplasty. A patient with complaints of only mild pain, mild weakness, or mild stiffness may initially best be treated with nonoperative modalities even if radiographs demonstrate positive findings such as glenoid erosion after hemiarthroplasty. Similarly, a patient with a sudden onset of symptoms of a short duration to date may be experiencing a transient acute rotator cuff tendinitis not directly related to the shoulder replacement. In this situation, a period of non-operative treatment would certainly be indicated. Special attention is given to factors that could make the operative procedure more difficult. The number and type of all previous shoulder surgeries, arthroplasty and nonarthroplasty, should be recorded in the patient’s history. Chronic use of nonsteroidal anti-inflammatory medications can result in excessive operative blood loss, so they should be discontinued the week before surgery.

Any medical history of systemic illness (diabetes mellitus, cardiac problems) should be considered in preoperative planning. Although these factors may not affect the actual surgical procedure, they may necessitate special considerations in the patient’s postoperative care. Appropriate medical consultations should be obtained well in advance of the surgery date. The availability of appropriate care of these systemic illnesses, including the availability of consultants, should be confirmed before surgery.

All of our patients undergo a thorough shoulder examination, much of which is detailed in Chapter 7. The visual appearance of the shoulder yields useful information in candidates for revision shoulder arthroplasty. The presence and location of surgical scars are noted. The preoperative plan should include whether all or part of a previous skin incision site is to be used or whether a completely new incision is to be created (Fig. 36-1). In thin patients, anterior superior escape of a prosthetic humeral head caused by anterior superior rotator cuff deficiency may be obvious (Fig. 36-2). Special attention should be paid to the condition of the deltoid, especially if it has previously been surgically violated (Fig. 36-3). Atrophy of the supraspinatus and infraspinatus should be noted as well (Fig. 36-4).

Figure 36-1 Previous skin incision used in primary shoulder arthroplasty.

Figure 36-2 Hemiarthroplasty located subcutaneously secondary to anterior superior escape.

Figure 36-3 Atrophy (asterisk) of the anterior deltoid.

Figure 36-4 Atrophy of the supraspinatus and infra-spinatus.

Both active and passive mobility is recorded, as detailed in Chapter 7. Special attention should be paid to evaluation of the deltoid muscle. If deltoid contractility appears to be compromised, further evaluation with electromyography and nerve conduction studies should be performed before revision shoulder arthroplasty.

The integrity of the rotator cuff is tested (see Chapter 7). Details of this examination are of paramount importance in preoperative planning for revision surgery. Although a minor rotator cuff deficiency such as an isolated supraspinatus tendon tear may have little influence on preoperative planning, larger rotator cuff tears (two-, three-, and four-tendon tears), especially when coupled with static or dynamic glenohumeral instability, may change the type of revision prosthesis to be inserted (reverse instead of unconstrained).

The results of the clinical history and examination are documented in the patient’s chart and reviewed well in advance of surgery as part of preoperative planning.

RADIOGRAPHY

Recent (within 3 months) magnification- and fluoroscopy-controlled radiographs are obtained in all patients who are candidates for revision shoulder arthroplasty. The same views obtained for primary arthroplasty, including an anteroposterior view of the glenohumeral joint with the arm in neutral rotation, an axillary view, and a scapular outlet view, are obtained in the revision scenario. Additionally, full-length orthogonal views of the humerus (anteroposterior and lateral) are obtained to evaluate diaphyseal cortical bone quality (Fig. 36-5). The previous arthroplasty is inspected on these radiographs for signs of loosening of the glenoid and humeral components, signs of mechanical failure of components (Fig. 36-6), appropriateness of component size and position, signs of static or dynamic instability (Fig. 36-7), and signs of infection (Fig. 36-8).

Figure 36-5 A and B, Full-length orthogonal radiographic views of the humerus taken before revision shoulder arthroplasty.

Figure 36-6 Mechanical failure of a keeled glenoid component detected on anteroposterior radiography.

Figure 36-7 Static superior migration after total shoulder arthroplasty.

Figure 36-8 Osteolysis around both the glenoid and humeral components is strongly suggestive of infection.

Preoperative radiographic templating can be useful in planning revision shoulder arthroplasty, especially in cases of proximal humeral deficiency. In most of these cases, the proximal humeral deficiency with resultant rotator cuff compromise constitutes an indication for revision with a reverse-design prosthesis. In patients demonstrating proximal humeral bone loss, bilateral full-length magnification-controlled anteroposterior humeral radiographs are obtained. These radiographs are used to help select the height at which to implant the humeral stem. Using the full-length humeral radiographs, the desired position of the reverse prosthesis is templated on the radiograph of the unaffected humerus, and the level of the metaphyseal-diaphyseal junction of the humeral component is marked (Fig. 36-9). The distance from the transepicondylar axis at the elbow to this point is measured (Fig. 36-10). A mark is made at the same distance from the transepicondylar axis on the affected radiograph. A second mark is made at the most proximal extent of the humeral shaft (Fig. 36-11). The distance between the desired prosthetic level at the metaphyseal-diaphyseal junction and the proximal extent of the humeral shaft is measured (Fig. 36-12). A ruler is used during surgery to measure the distance and mark the level on the humeral stem for the desired prosthetic position (Fig. 36-13). This technique of preoperative planning provides only a guideline and may be superseded by intraoperative observations.

Figure 36-9 The desired position of the reverse prosthesis is templated on the unaffected humeral radiograph (A), and the level of the metaphyseal-diaphyseal junction of the humeral component is marked (B).

Figure 36-10 The distance from the transepicondylar axis at the elbow to the desired level of the metaphyseal-diaphyseal junction of the humeral component is measured.

Figure 36-11 A mark is made at the same distance from the transepicondylar axis on the affected radiograph. A second mark is made at the most proximal extent of the humeral shaft.

Figure 36-12 The distance between the desired prosthetic level at the metaphyseal-diaphyseal junction and the proximal extent of the humeral shaft is measured.

Figure 36-13 A ruler is used during surgery to measure the distance and mark the level on the humeral stem for the desired prosthetic position.

Rarely, proximal humeral bone loss during revision surgery is sufficiently severe to necessitate use of a custom implant or proximal humeral composite bone graft. Templates are useful to determine whether existing prefabricated implants are sufficient or whether a custom-manufactured implant is required.

SECONDARY IMAGING

A computed tomographic arthrogram is obtained in all patients for evaluation of the rotator cuff tendons and musculature before revision shoulder arthroplasty (Fig. 36-14). This study further assists in evaluation of possible component loosening. Many patients exhibit radiolucent lines around the glenoid component after unconstrained total shoulder arthroplasty. Use of computed tomographic arthrography assists in determining whether these components are indeed loose by demonstrating radiographic contrast material around the base of the component (Fig. 36-15). Computed tomography also provides the greatest osseous detail of the glenoid and can show the presence and extent of bony glenoid deficiency. Bony deficiencies can occur after erosion from hemiarthroplasty (Fig. 36-16). In these cases the computed tomogram helps determine whether the existing glenoid bone is sufficient to allow implantation of a glenoid component. Bony deficiencies more commonly occur concomitantly with loosening of the glenoid component (Fig. 36-17). In these cases the computed tomogram allows the bony deficiency to be classified as contained or uncontained (Fig. 36-18).¹

Figure 36-14 Evaluation of the rotator cuff tendons and musculature with computed tomographic arthrography.

Figure 36-15 Glenoid component loosening identified on computed tomographic arthrography. Note the contrast material located around the keel of the glenoid component.

Figure 36-16 Central glenoid bony deficiency caused by glenoid erosion after hemiarthroplasty.

Figure 36-17 Bony glenoid deficiency caused by loosening of the glenoid component.

Figure 36-18 Classification of bony glenoid deficiency. A, Contained. B, Uncontained—anterior. C, Uncontained—posterior. D, Uncontained—combined.

The rotator cuff is evaluated, including assessment of tendinous integrity and muscle quality (fatty infiltration). The condition of the long head of the biceps tendon is noted, particularly its position (centered, subluxated, dislocated, ruptured), to assist in identifying it at the time of surgery.

SPECIAL TESTS

In all candidates for revision shoulder arthroplasty, regardless of whether signs of infection are present, a preoperative infection workup is indicated, including hematologic evaluation consisting of a complete blood cell count with differential, a sedimentation rate, and C-reactive protein. Additionally, fluoroscopically guided shoulder aspiration performed at the time of computed tomographic arthrography is obtained and the specimen submitted for aerobic, anaerobic, fungal, and mycobacterial culture. If the findings are suggestive of infection (increased sedimentation rate, increased C-reactive protein, leukocytosis, moderate to many leukocytes observed in aspirated joint fluid), intraoperative frozen histologic sections are planned at the time of shoulder arthroplasty. The patient is educated that the revision surgery may be staged if infection is further suspected by the results of intraoperative histologic tissue analysis. If the preoperative infection workup yields a positive culture from the aspirate, infection is considered present and the treatment plan proceeds accordingly. In all patients with an infected shoulder arthroplasty, consultation with an infectious disease specialist is obtained preoperatively.

Electromyography and nerve conduction studies are performed in any patient with a suggestion of neurologic deficiencies on physical examination. Specifically, all patients unable to reliably contract the deltoid should undergo neurologic testing before revision shoulder arthroplasty. If the deltoid is compromised, neurologic consultation is obtained. Revision shoulder arthroplasty is reserved until the time of deltoid/axillary nerve recovery. In patients with permanent deltoid insufficiency, revision arthroplasty is contraindicated and resection arthroplasty is considered.