A thorough history and physical examination should be conducted. This should include the intensity of pain, duration of symptoms, and secondary loss of function. Typical conservative treatments for glenohumeral degeneration include physical therapy, activity modification, and intra-articular injections.

Physical examination should rule out cervical radiculopathy. Focused examination on active and passive ROM should be noted, with global ROM loss characteristic. Rotator cuff strength should be noted.

Radiographs: anteroposterior (AP), scapular outlet, and axillary views should be obtained. AP views should be assessed for superior humeral head migration, which can be seen in the setting of rotator cuff tears. The AP view may also be used to template the humeral stem. The axillary view allows for evaluation of posterior glenoid wear. The position and severity of osteophytes and loose bodies are also noted.

CT: Evaluate for glenoid eccentric wear, retroversion, and other bony abnormalities. 3D reconstructions may provide further understanding.

MRI: MRI may be helpful to evaluate patients in whom a rotator cuff injury is suspected, that is, evidence of superior escape on radiographs, or history of prior surgery.

If not contraindicated, the authors prefer regional anesthesia for muscle paralysis and immediate postoperative pain control.

Beach chair: Instead of the upright position typically used in arthroscopy, the patient is placed in 45 degrees of reverse Trendelenburg and 15-degree airplane away from the affected side for a more ergonomic position for the surgeon and assistants ( Fig. 42.1 ).

Beanbag: We prefer to use a beanbag to position the patient. A large beanbag spans from the head to the hip. The beans are molded around the head to hold the neck in neutral flexion–extension, tilt, and rotation. The beans are molded around the affected shoulder; contouring the beans to be 2 cm lateral to the medial scapular border allows the arm to be free, and stabilizes the scapula to reduce scapular motion while the glenoid is addressed intraoperatively. The beans are then driven back along the lumbar region so the arm can be adducted, extended, and externally rotated freely. This step is confirmed prior to the case initiation as it is critical to dislocate the humerus.

Hydraulic arm positioner: This maintains arm position throughout the procedure.

Draping: The arm and shoulder girdle are draped extending to the medial clavicle. The acromion, clavicle, and coracoid should be visible. We use a mesentery-style draping, sealing the axilla and all drapes ( Fig. 42.2 ).

All bony prominences are well padded as needed.

Anatomic landmarks: The acromion, distal clavicle, acromioclavicular joint, and coracoid process are marked on the shoulder with a surgical pen.

Incision: We make a more oblique incision for the deltopectoral approach than standard, extending from the tip of the coracoid to the deltoid insertion centered on the humerus ( Fig. 42.2 ).

Skin and subcutaneous dissection:

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  Position the arm in 20 degrees of forward flexion and neutral rotation to relax the interval. Avoid arm extension.

  
  
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  Skin incision is made with a no. 10 blade, through the epidermis to the level of subcutaneous fat. We then switch to electrocautery given the vascularity of the area. Dissection is carried down to the level of the deltoid fascia.

  
  
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  Gelpi retractors are placed superiorly and inferiorly in the incision to aid in dissection. Lifting superficially will allow an easy plane of dissection.

  
  
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  Developing the deltopectoral interval:

  
  
  
  
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    Identification of the interval almost always requires medial dissection. Dissect medial across the deltoid fascia until the fat stripe is revealed. Continue the dissection 2 cm medial to the fat stripe.

    
    
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    Unroof the fat stripe; curved Mayo scissors are used to carefully open the deltopectoral fascia superficial in the fat stripe. If not immediately visible, the cephalic vein will be deep in the fat stripe.

    
    
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    Use the curved Mayo scissors to develop a plane medial to the cephalic vein, taking the vein lateral with the deltoid. Be aware there may be many tributaries to the cephalic that can be ligated with electrocautery. These are typically seen at the tip of the coracoid. Replace the Gelpi retractors deep to the cephalic vein in the aperture being developed. This will facilitate the identification of crossing vessels and separation of the interval.

  
  
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  Subdeltoid preparation:

  
  
  
  
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    Reposition the arm in 60 degrees of abduction to relax the deltoid.

    
    
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    Place a large Richardson retractor under the deltoid.

    
    
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    Release the subdeltoid adhesions. This can be done bluntly with a finger, a Darrach retractor, or carefully with electrocautery. First, clear anteriorly under the deltoid, and continue lateral and posteriorly. Continue with the lysis until a Brown retractor can be easily placed behind the head, subluxing it anteriorly.

    
    
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    Pitfalls:

    
    
    
    
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      i. Avoid damage to the axillary nerve as it wraps under the deltoid posteriorly. A tug test can be used to confirm the location of the axillary nerve. ¹⁶

      
      
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      ii. Preserve the coracoacromial ligament for anatomic TSA.

  
  
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  Biceps and rotator interval identification:

  
  
  
  
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    Position the arm back in adduction at the patient’s side. Palpate the lesser tuberosity, greater tuberosity, and biceps groove. The rotation of the arm should be adjusted so the biceps groove lies directly in front of the surgeon.

    
    
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    Identify the biceps tendon as it enters the groove inferiorly. Unroof the biceps tendon with electrocautery.

    
    
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    Once the biceps tendon is exposed, remove the tendon out of the groove with Mixter right angle forceps. The long head of the biceps is then tenodesed to the pectoralis major tendon with nonabsorbable sutures in a figure-of-8 configuration.

    
    
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    Transect the biceps tendon just cephalad to the tenodesis sutures.

    
    
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    Follow the biceps groove into the rotator interval from distal to proximal. We use curved Mayo scissors to incise the rotator interval. Stay on the medial aspect of the biceps groove to avoid errant supraspinatus injury. The Mayo scissors should easily transect the rotator interval; if the tissue is difficult to cut, this may indicate errant dissection into the rotator cuff.

  
  
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  Anterior humeral circumflex vessels (the three sisters):

  
  
  
  
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    Identify the vessels at the inferior aspect of the subscapularis insertion and ligate these with electrocautery. External rotation of the shoulder can facilitate exposure of the vessels.

  
  
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  Lesser tuberosity osteotomy (LTO):

  
  
  
  
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    Using electrocautery, clear the floor of the biceps groove near the subscapularis insertion.

    
    
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    Using an osteotome, cut a 5-mm wafer of bone starting in the floor and medial wall of the biceps groove, aimed directly medial.

    
    
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    Continue dissection medially on the superior and inferior border of the lesser tuberosity, mobilizing the subscapularis tendon and capsule.

    
    
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    Tag the upper and lower borders of the subscapularis tendon with nonreabsorbable suture.

  
  
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  Capsular release:

  
  
  
  
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    Externally rotate the arm.

    
    
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    Perform a generous capsular release off the humeral neck. Start anteriorly and extend inferiorly. Take care to avoid the insertion of the latissimus dorsi as it inserts on the anterior humerus just inferior to the capsule.

    
    
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    Release the capsule to the 6 o’clock position on the humerus.

Humeral preparation:

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  Dislocation: In concert, bring the arm into adduction and external rotation.

  
  
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  Retractor placement:

  
  
  
  
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    Place a Brown retractor laterally behind the head, a Bennett retractor medially around the head, and a Darrach retractor posterior to the head. Take care not to lever on the acromion excessively, as this may cause an iatrogenic fracture ( Fig. 42.3 ).

  
  
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  Neck cut:

  
  
  
  
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    Use the cutting guide to template the cut confirming version. Score the neck with electrocautery. Using the insertion of the supraspinatus and infraspinatus will approximate the angle of the cut.

    
    
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    Complete the cut with a saw.

    
    
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    Remove osteophytes with a rongeur, especially of the inferior neck.

  
  
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  Humeral preparation:

  
  
  
  
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    The initial entry reamer may be sunk on power and continued until two sizes under the preoperative template size.

    
    
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    Hand ream the final sizes until a good cortical fit is felt, and harder cortical bone can be seen in the reaming flutes.

    
    
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    Complete broaching: We start three sizes down from the reaming size (8-9-10, for a reamed 10). Mallet the broach to the appropriate height, matching version of the neck cut.

    
    
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    Avoid overstuffing the humeral canal. In most press-fit humeral systems, the final implant has a larger diameter than the corresponding broach. If between broaches, it is advisable to go with the smaller broach to avoid iatrogenic humeral fracture.

    
    
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    When complete, place a humeral cap to protect the soft bony surface.

Glenoid Preparation:

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  Internally rotate the arm, and translate the humerus posteriorly to expose the glenoid.

  
  
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  Retractors:

  
  
  
  
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    An anterior hip retractor is placed behind the posterior glenoid. Alternatively, a Bankart or a Fukuda retractor can be placed posteriorly.

    
    
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    A pointed Hohmann retractor is placed on top of the glenoid, just behind the origin of the long head of the biceps; take care not to injure the suprascapular nerve by avoiding placing the retractor too deep. The pointed Hohmann retractor will serve as the 12 o’clock position reference. Once placed, resect the biceps.

    
    
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    A two-pronged capsule retractor such as a large Bankart retractor is placed anteriorly ( Fig. 42.4 ).

    
    
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    Follow the upper border of the subscapularis back to the glenoid. Pull tension on the subscapularis tagging sutures to dissect between the middle glenohumeral ligament (MGHL) and the subscapularis with electrocautery. This will facilitate placement of the two-pronged capsule retractor.

    
    
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    Resect the anterior capsule and MGHL.

    
    
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    Beware of the axillary nerve as it dives inferior to the muscle belly of the subscapularis.

    
    
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    Free the subscapularis from the capsule posteriorly, and from the coracoid superiorly.

    
    
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    Remove loose bodies from the subcoracoid recess if present. Forward flexing the arm can relax the conjoined tendon to facilitate removal of these loose bodies.

  
  
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  Labral resection:

  
  
  
  
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    Using electrocautery, score the outer rim of the glenoid circumferentially.

    
    
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    Take care when dissecting the inferior labrum so as to not injure the axillary nerve. Place your finger or forceps on the inferior capsule to tension the capsule, pulling this away from the glenoid, and release the labrum.

    
    
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    Starting the labral resection at the 12 o’clock position where the dissection is easier and placing an Alice clamp to provide tension on the labrum may facilitate this step.

    
    
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    In patients with posterior glenoid erosion or posterior humeral subluxation, take care not to release the posterior capsule when removing the posterior labrum as this may lead to postoperative instability.

  
  
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  Remove osteophytes: Use a rongeur or osteotome to resect osteophytes.

  
  
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  Orient: Mark a 12 o’clock to 6 o’clock position line in the glenoid with electrocautery. Mark the 9 o’clock to 3 o’clock position line. The intersection of the lines approximates the central glenoid where the peg or keel will seat.

  
  
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  Place the alignment guide for the respective system.

  
  
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  Ream away the remaining glenoid cartilage to bleeding bone. Eccentric reaming of the anterior glenoid bone stock may be necessary to avoid placing the component in retroversion.

  
  
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  Trial the component: The trial should sit flush on the reamed glenoid surface; resurface as needed.

  
  
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  Anterior capsulectomy and subscapularis release:

  
  
  
  
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    Pearls:

    
    
    
    
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      i. Perform minimal reaming so that implant is seated on hard subchondral bone, and not on soft cancellous bone.

      
      
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      ii. For cementing, copiously irrigate with a pulse lavage to remove all debris. Apply cement, impact the glenoid component, and clear excess cement with curettes and forceps. Maintain pressure on the component through a finger or an instrument as the cement hardens.

Humeral component:

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  Insert the humeral trial component, taking care to dial in the correct version.

  
  
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  Reduce the humeral component and check soft-tissue tensioning and component stability.

  
  
  
  
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    Tips:

    
    
    
    
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      i. There should be approximately 50% translation when shucking the components in the AP plane. There should be a solid endpoint to posterior translation.

      
      
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      ii. Forward flex the arm to 90 degrees and confirm the component does not dislocate posteriorly or inferiorly; advanced primary OA may predispose to posterior instability.

      
      
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      iii. If too much laxity, upsize the head component.

      
      
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      iv. If cementing, place a cement restrictor, pulse irrigate, dry with vaginal packing, or endosteal suction, with care to reproduce the correct version and height.

  
  
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  Drill three bone tunnels in the biceps groove (proximal, middle, and distal) for suture passage and approximation of the LTO.

  
  
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  Impact the final stem prosthesis with care to dial in correct version, which is somewhere between 20 and 40 degrees of retroversion depending on the patient’s anatomy and native version.

  
  
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  Complete the suture repair of the LTO.

  
  
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  Check the ROM of the prosthesis with care to observe your lesser tuberosity repair; the repair and prosthesis should move as a single unit.

Closure:

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  Copious pulse irrigation.

  
  
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  Close the deltopectoral with a running nonreabsorbable suture—tagging the interval for later revision surgery if necessary.

  
  
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  Layered closure: running 0 Vicryl suture for fascia of Scarpa, 2–0 Vicryl for the subdermal layer, and 2–0 Prolene with escape stitch.

  
  
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  Sterile dressing.

  
  
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  Sling with abduction wedge applied in the OR.