62.3.1 Age, Bone Quality, and Comorbidities

A patient’s age and bone quality are two important factors for determining the choice of surgery. A patient younger than 60 years, male, with a good bone quality is the model patient for a hemiarthroplasty procedure.

However, for patients who are between their 60s and 70s, the decision is made based on comorbidities and the presence of functional disorders prior to the trauma. After the 70s, there are no more indications to use hemiarthroplasty and we recommend using a reverse shoulder prosthesis.

Female patients younger than 65 years should have a proper evaluation of bone quality. Although the bone quality is not considered a contraindication to a prosthetic implantation, a poor bone quality or a comminution of the greater tuberosity could preclude the use of hemiarthroplasty in these patients because poor functional results should be expected. ⁴

62.3.2 Fracture Patterns

Hemiarthroplasty has been indicated for severe fracture patterns, including fracture dislocations, four-part fractures, and three-part fractures in which the quality of the bone is low or there is a risk for avascular necrosis, head-split fractures of the proximal humerus, and fractures from previously failed surgeries.

A valgus-impacted four-part fracture is relatively unlikely to lead to osteonecrosis of the humeral head, and some surgeons may treat it less aggressively. A conserved medial soft-tissue hinge, a periosteal integrity, may explain the relatively low risk of osteonecrosis in a valgus-impacted four-part fracture. ⁵ A very unstable calcar is another indication to perform hemiarthroplasty in selected cases.

62.3.3 Rotator Cuff Integrity

The rotator cuff integrity has a key role in the decision-making. Although the rotator cuff integrity can be assessed only intraoperatively, we can get an idea of its condition prior to surgery by asking the patient about previous occurrences of shoulder pain or functional impairment of the shoulder. An intact cuff and absence of rotator muscle atrophy are necessary before opting for a hemiarthroplasty procedure.

62.3.4 The Absence of Glenoid Arthrosis

Glenoid arthrosis should be considered in the decision on whether or not to perform a hemiarthroplasty. Glenoid arthrosis is a factor when it comes to choosing between total shoulder arthroplasty and hemiarthroplasty depending on the patient’s expectations of return to physical activities.

In older patients who want predictable pain relief and short-term functional outcome, studies show that total shoulder arthroplasty may be a better option. However, in younger patients (<55 years), hemiarthroplasty is a less complicated and faster procedure without the worry of glenoid wear or loosening. ⁶ Therefore, hemiarthroplasty is generally preferred for younger patients because they tend to expect to return to high-level activities postsurgery, for example, sports, exercise, and other physically demanding activities. ⁷

62.5.1 Preoperative Preparation

Preparation for surgery is a very important step in arthroplasty of shoulder fractures. Patient discomfort often limits radiographic analysis. Typically, a true scapular anteroposterior (AP), scapular Y, and axillary lateral radiographs are obtained to evaluate the fracture and to check whether a dislocation is present. Since radiographic images are so important, it is imperative that preparation for surgery includes preoperative radiographic planning.

The principle of restoring the native anatomy is a constant. Two critical evaluations for obtaining optimal results are the correct height and the retroversion of the implant. ⁸ To evaluate the appropriate humeral height, scaled radiographs of the injured and uninjured arms are necessary. On these radiographs, we should evaluate if the calcar is still present or broken. We can also measure the height of the greater tuberosity and, of course, determine the correct height of the prosthetic implant based on the uninjured arm ( Fig. 62.1 ).

In certain instances, a CT scan can be obtained to better understand the fracture pattern and for reference during surgery. CT scans could be very useful for identifying the margins of fracture, as well as the tuberosity fragmentation and displacement.

During the procedure, unless there is a compromise in the vasculature, surgery should not be immediately performed through edematous skin. The best time for surgery is usually 6 to 10 days after injury. From our experience, after 20 days it gets more challenging to mobilize tuberosity fragments because of early fracture healing. If the fracture heals early, this will cause the surgery to be more challenging, requiring a more extensive dissection of both the soft tissue and bone. This extensive dissection may negatively affect the final healing of the tuberosity.

Another important factor to consider during the preoperative planning is the prosthesis design. The traditional humeral prosthesis has not been adapted sufficiently to suit the needs of proximal humerus fracture surgery. The stems can be too bulky and hence prevent anatomic reduction of the tuberosity. In addition, the stems allow only minimal contact between the tuberosity and the diaphysis. Therefore, the probability of bony union is low, and the risk of tuberosity migration and malunion is high.

Specific fracture-dedicated stems consisting of relatively little metal seem to allow unaltered tuberosities to be reduced anatomically, with more space available for bone grafting to further promote healing. Recent studies have shown better results for tuberosity healing using fracture-specific stems as opposed to conventional bulky stems. ^{4 , 9} However, other authors disagree with this theory showing only 14% of failure using a large metaphyseal volume hemiprosthesis for complicated fractures of the proximal humerus. ¹⁰ Nevertheless, a recent report showed that the use of large metaphyseal volume arthroplasty in complex proximal humerus fracture is correlated with poor results in a large amount of patients, and the tuberosity resorption was observed in 70% of cases. ¹¹ In the light of this controversial issue, we assume that correct indications, appropriate surgical technique, and the correct implant are the mainstays to achieving a satisfactory clinical outcome.

62.5.2 Positioning

During surgery, the patient should be put in the “beach-chair” position, with the scapula supported and all bony projections padded appropriately. The arm should be freely movable. Complete arm extension and adduction should be ensured prior to starting the procedure, to achieve a good access to the medullary canal.

62.6.1 Dissection and Identification

A 2.5- to 3-inch incision is placed into the deltopectoral interval. If the incision is placed well in a limited space, and specific retractors are used, this will allow the surgery procedure to go smoothly ( Fig. 62.2 ). The deltopectoral interval is dissected with the arm in the abducted position. This allows for an easy identification of the deltopectoral interval. The cephalic vein is identified. We prefer to take the vein medially with the small strip of deltoid. We use the Bovie electrocautery like an elevator to assist in identifying the clavipectoral fascia.

Next, the coracoid process is identified and a small Hohmann retractor is inserted on top of the coracoacromial ligament. After elevating, abducting, and internally rotating the arm, we dissect underneath the deltoid shell to identify the acromion. Once the acromion is identified, a curved retractor is inserted on top of the acromion.

With the arm in the neutral position, the conjoint tendon is located and identified. The clavipectoral fascia is cut in a lateral direction to the connected tendon. The arm is moved by slight flexion and a self-retaining retractor is used to hold the deltoid in the lateral position, as well as the conjoint tendon in the medial position.

The superior margin of the pectoral major is identified. According to some authors, this could be an anatomic landmark in verifying the height of the future implant. The arm is moved with slight internal rotation. Next, the long head of the biceps tendon (LHBT) is identified, which serves as a critical landmark for finding the interval between the tuberosities.

The bursa overlying the proximal part of the humerus should be removed. Once the LHBT is identified, it should be tagged with sutures. We perform tenodesis of the LHBT at the end of the procedure. We follow the LHBT through the rotator interval, just to the supraglenoid tubercle, and then a tenotomy is performed. The intra-articular portion of the tendon is removed.

Placing an osteotome or an elevator with a blunt end in between the tuberosities, the line of the fracture can be found. The line of fracture should be followed by going through the rotator cuff’s soft tissue. It is better to follow this line instead of making a separate (iatrogenic) fracture line. If bleeding originates from the anterior humeral circumflex artery and/or from any of its supporting vessels, it can be controlled using electrocautery.

To better expose the greater tuberosity, the arm is placed in abduction and internal rotation. The greater tuberosity is gently mobilized. Next, just at the bone–tendon junction, four horizontal heavy no. 5 high-resistance nonabsorbable sutures are positioned around the greater tuberosity; two sutures are planted in the infraspinatus, while the other two sutures are placed in the teres minor ( Fig. 62.3 ).

The lesser tuberosity is identified by bringing the arm in flexion and internal rotation. Two stay sutures are placed where the subscapularis meets the bone tendon. The tuberosities are retracted gently and the rotator interval is completely opened along the line of the fracture until the glenoid rim. Preservation of the coracoacromial ligament is advised to maintain the coracoacromial arch.

The humeral head fragment is located, mobilized, and taken out and measured using a caliper. It is important to measure the resected humeral head to decide the corrected size (diameter and height) of the implant. When the size falls between two measures, the smaller one should be selected. This is important to obtain an easy soft-tissue reconstruction and to avoid the chance of using an implant that is too large for the space (overstuffing), which may cause complications like glenoiditis and tendon impingement.

The glenoid surface is evaluated to see if there is some cartilage wear zone or rim fracture. If everything is good, we move on. The humeral shaft is exposed and the arm is placed in extension. Then cylindrical reamers are used to prepare the medullary canal and trial implants are inserted by increasing the diameter. During this preparation, the proximal end of the shaft should be evaluated properly and the calcar checked. If the calcar is broken or fractured, it should be fixed during preparation of the medullary canal. We prefer to fix the calcar using a cerclage technique using a Luque wire ( Fig. 62.4 ).

The trial stem is placed such that the stem sits just on the medial calcar so as to restore the so-called gothic arch. ¹² After determining the correct trial implant and measuring the head size, retroversion should be selected. The prosthetic head should be turned in the direction facing the glenoid. The forearm should be at the side and in neutral rotation (about 20 inches retroverted in comparison with the elbow’s transepicondylar axis). Using an electrocautery or marking pen, place a mark on the lateral cortical humeral shaft. We prefer to use implants that have eccentric head offset. This allows a rotation to the most lateral position. In this position, a minimal “medial overhang” of the humerus head will be observed when the “gothic arch” is being restored.