Anatomic Shoulder Arthroplasty for Fracture: Indications and Technique

Fig. 9.1

Deltopectoral approach. Main landmarks: coracoid process, acromion, and distal deltoid insertion. Vision from this approach is optimal

The subcutaneous tissues are divided and the deltopectoral interval is entered; the cephalic vein may be retracted either medially or laterally. Sometimes it could be difficult to identify the deltopectoral groove because of hematoma or poor quality of the muscles. It is easier to find the groove between the deltoid and the pectoralis, proximally near the clavicle where there is a natural fat space.

Bursectomy is often an important step: hematoma and bursa must be removed to gain a good view of the fracture anatomy.

It is necessary to identify the superior margin of the pectoralis major, which is an important anatomic landmark in verifying the height of the future implant, to correctly access the surgical site (Fig. 9.2). The clavipectoral fascia is opened and a self-retaining retractor is placed between the conjoined tendon and deltoid. It is easy to identify the long head of the biceps that is an excellent landmark to find the interval between the tuberosities. Tenotomy is performed (Fig. 9.3). The arm is then placed into abduction and internal rotation, and the greater and lesser tuberosities are identified. It is essential to preserve them with all the bone. Two no. 2 nonabsorbable sutures are placed in Mason-Allen-type stitches at the bone-tendon junction through the subscapularis and infraspinatus in order to manage the tuberosities (Fig. 9.4). It is helpful to release both tendons (subscapularis, infraspinatus) to obtain free fragments that can be easily placed around the implant.

Fig. 9.2

It is very important to identify the top margin of the pectoralis major muscle (PM) that allows to define the height of the implant. To the left there is a ruler that measures the height of the rasp in relation to the tendon

Fig. 9.3

Identify the tendon of the long head of the biceps (LHB). Frequently you perform a tenotomy

Fig. 9.4

Two no. 2 nonabsorbable sutures are placed in Mason-Allen-type stitches at the bone-tendon junction through the subscapularis and infraspinatus in order to manage the tuberosities (GT greater tuberosities, LT lesser tuberosities, D diaphysis)

The rotator interval is opened till the glenoid to release the coracohumeral ligament to expose the humeral head and the glenoid.

With the tuberosities retracted, the head fragment is removed; in order to measure the head size, it should be better to remove it in one piece (Fig. 9.5).

Fig. 9.5

Removal of the head if possible in one piece to allow a correct measurement

At this point the inspection of the glenoid can be easily done in order to assess its integrity and the good condition of the cartilage.

9.3.2 Humeral Preparation

The arm is left along the trunk and externally rotated, and the humeral shaft is exposed.

Since the metaphysis is typically “absent” due to the fracture, the humeral shaft is prepared with hand reamers until there is a gentle cortical resistance. A humeral trial is then placed. During this step, the surgeon must check carefully the fit of the diaphysis and the version and the depth of the implant. The fit is obtained evaluating the relationship between the stem and the canal; the retroversion is identified with anatomic references according to the used system (the alignment rod into the appropriate retroversion hole, referring to the forearm and to the condyles) (Fig. 9.6); the appropriate depth of the implant is measured referring to anatomic landmarks: the calcar and the distance between the tip of the humeral head and the upper margin of the pectoralis major [5.5 cm; (Fig. 9.7)].

Fig. 9.6

Left: evaluation of the (yellow circle) refers to the filling of the rasp in the diaphysis. Right: evaluation of the orientation of the stem with the alignment rod: transepicondylar axis, yellow; forearm axis, red

Fig. 9.7

(a) The distance between the tip of the humeral head and the upper border of the pectoralis major (green arrows). (b) The appropriate depth of the implant is measured referring to anatomic landmarks: the calcar (blue circle) and the distance between the tip of the humeral head and the upper margin of the pectoralis major (5.5 cm) (yellow circle). (c) The same ruler intraoperatively

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