Various osteotomies for humeral stem removal in revision shoulder arthroplasty.

Extensile approach for distal exposure.

Describe techniques and instruments to assist with stem removal with bony ingrowth or cement.

Presently preferred method for humeral stem removal.

Allows controlled “fracture” of the humerus to aide with stem removal.

Reduce iatrogenic stem fracture.

Assist with complete cement removal in revision cases for infection.

Well-fixed humeral stem.

Cemented or bony in growth with distal spot welding preventing removal.

Humeral malalignment.

Imaging:

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  X-rays:

  
  
  
  
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    Anteroposterior (AP) and lateral in the plane of the scapula and axillary views.

    
    
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    AP and lateral X-rays of the humerus:

    
    
    
    
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      i. View distal extent of humeral stem.

      
      
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      ii. Rule out distal deformities or other bony abnormalities.

  
  
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  CT scan and MRI (noncontrast):

  
  
  
  
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    Assist with evaluating bone quality and areas of lucency.

    
    
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    Allows for evaluation of glenoid version, bone stock, and rotator cuff muscle–tendon unit integrity.

If there is any suspicion for infection, preoperative labs should be obtained:

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  CBC.

  
  
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  ESR.

  
  
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  CRP.

If there is high suspicion clinically with inconclusive laboratory findings, then proceed to perform an arthrocentesis or arthroscopic biopsy sent for the following:

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  Cell count.

  
  
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  Gram stain.

  
  
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  Culture (aerobe and anaerobe):

  
  
  
  
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    Cultures should be held for at least 14 days to allow adequate culture time for Propionibacterium acnes.

Instruments ( Fig. 58.1 ):

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  Positioning:

  
  
  
  
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    Anesthesia: general or laryngeal mask airway.

    
    
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    Preoperative regional anesthesia via an interscalene injection or catheter is used adjunctively for pain management.

    
    
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    The patient is placed in the semi-beach-chair position (~45 degrees of hip flexion and 30 degrees of knee flexion):

    
    
    
    
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      i. The head is secured in padded holder with the neck in a neutral position.

    
    
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    The operative arm is secured in a pneumatic arm holder ( Fig. 58.2 ):

    
    
    
    
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      i. The contralateral arm is secured to the body or with a well-padded arm holder.

      
      
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      ii. Venodynes (sequential compression devices) are placed on the calves to decrease the incidence of deep venous thrombosis.

    
    
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    Prep and drape:

    
    
    
    
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      i. The author’s preference is for a chlorhexidine scrub followed by chlorhexidine prep.

      
      
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      ii. Drape as medial to the scapula as possible.

      
      
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      iii. Expose distal humerus to allow for extension of prior incision for humeral exposure as needed.

  
  
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  Operative technique:

  
  
  
  
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    Incision:

    
    
    
    
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      i. Standard landmarks are outlined on the shoulder:

      
      
      
      
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        The anterior, lateral, and posterior border of the acromion, the acromioclavicular joint, the clavicle, and the coracoid process.

      
      
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      ii. Mark prior incision extending it distal and lateral if extensile approach is needed.

    
    
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    Instruments:

    
    
    
    
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      i. Implant-specific extraction system.

      
      
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      ii. Osteotome (flexible or Lambotte osteotomes).

      
      
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      iii. Burr (narrow tip).

      
      
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      iv. Sagittal saw.

      
      
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      v. Curettes.

      
      
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      vi. Cerclage wires.

      
      
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      vii. Wire cutters.

      
      
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      viii. Strut allograft (available).

      
      
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      ix. Nerve stimulator.

      
      
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      x. Ultrasound cement remover.

      
      
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      xi. Fluoroscopy.

  
  
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  Operative technique:

  
  
  
  
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    The patient is placed in the semi-beach-chair position with the operative arm in a pneumatic holder:

    
    
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    Incision:

    
    
    
    
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      i. Mark prior incisions and determine the utility of the incision or if a separate one is necessary.

      
      
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      ii. Preference: extensile deltopectoral incision (deltopectoral approach with distal extension to an anterolateral humeral incision as needed).

    
    
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    Exposure:

    
    
    
    
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      i. Deltopectoral approach:

      
      
      
      
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         In revision cases, deltopectoral interval can be obscured by scarring/adhesions:

         
         
         
         
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           Important:

           
           
           
           
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             Coracoid is an important marker to avoid excessive medial dissection.

             
             
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             Start proximally to identify the triangular space formed by the superior medial portion of the deltoid and the superior medial portion of the pectoralis major muscle.

             
             
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             Nerve stimulator is useful to guide dissection when muscle planes appear confluent.

         
         
      2. 
         

         Continue dissection to the distal extent of the stem:

         
         
         
         
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           Native tissue may be defined easier by exposing distally beyond prior surgical field.

           
           
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           Soft-tissue attachments should be maintained, but release may be required to improve visualization (i.e., pectoralis major and latissimus dorsi).

           
           
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           Deep cultures:

           
           
           
           
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             Taken along the stem–bone interface.

      
      
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      ii. Once the interval is defined:

      
      
      
      
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         It is important to develop submuscular spaces:

         
         
         
         
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           Subdeltoid:

           
           
           
           
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             Subperiosteally elevate the anterior deltoid with a Cobb elevator:

             
             
             
             
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               Important: Aberrant dissection of the anterior deltoid off the humerus can denervate the muscle.

               
               
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               Tip: Start distally in native tissue and continue proximally.

               
               
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               Important: As the anterior deltoid is released distally, watch for bridging vessels.

             
             
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             Subdeltoid adhesions can be extensive and a clear space should be developed to the posterior rotator cuff.

           
           
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           Subacromial:

           
           
           
           
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             Often subacromial space can be difficult to enter due to scar tissue:

             
             
             
             
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               Place axial traction on the arm maximizing subacromial space.

               
               
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               A Cobb elevator or a no. 15 blade placed parallel to acromion can be used to open space allowing further blunt finger dissection.

           
           
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           Subcoracoid:

           
           
           
           
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             Often scarred in as well:

             
             
             
             
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               Identifying the proximal musculature of the short head of the biceps can help define the lateral-most extent of the conjoined tendon.

               
               
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               Sharp and blunt dissection can help open a space deep to the conjoint tendon allowing retractor placement and continued dissection.

      
      
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      iii. Perform the tug test (evaluates continuity of axillary nerve):

      
      
      
      
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         Use the index finger to find the axillary nerve medial and deep to the conjoint tendon.

         
         
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         Next, find the circumflex branch along the deep lateral portion of the deltoid.

         
         
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         Apply gentle traction to the medial portion of the nerve. This will transmit across the nerve and should be felt with the contralateral index finger.

         
         
         
         
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           Important: In revision cases, scar tissue and adhesions can make identifying the axillary nerve difficult. A nerve stimulator can be especially helpful in isolating the nerve.

      
      
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      iv. Retractors are placed deep to the anterior deltoid and conjoint tendon exposing the proximal humerus:

      
      
      
      
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         The rotator cuff tendon can be evaluated at this point.

      
      
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      v. Excise any visible scar tissue.

      
      
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      vi. Rotator interval and biceps release:

      
      
      
      
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         The biceps tendon (if present) is identified and the sheath is opened proximally along the bicipital groove.

         
         
      2. 
         

         The biceps can be followed proximally; once the top of the humerus is reached:

         
         
         
         
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           Identify the coracoid process and the coracoid base.

           
           
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           Direct the remainder of the release toward the coracoid base effectively opening the rotator interval.

           
           
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           The biceps tendon can be transected as close to its origin on the superior glenoid.

           
           
           
           
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             Important: Avoid continuing release by following the biceps tendon posteriorly as this can cause transecting of the supraspinatus tendon.

      
      
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      vii. Subscapularis tendon release:

      
      
      
      
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         Release the subscapularis tendon as far lateral on the lesser tuberosity to preserve as much soft tissue for subsequent repair.

         
         
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         Tag tendon with nonabsorbable sutures (i.e., 0 Ethibond).

         
         
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         Advance soft-tissue release inferiorly along the humeral shaft and continue the capsular release posteromedial along humeral neck.

      

      

      
      

      Important: Check the location of the axillary nerve as it can often be scarred to the inferior capsule and can be at risk of injury during the medial release.

      
      
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      viii. Dislocate prosthesis:

      
      
      
      
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         Extension, adduction, and external rotation will help facilitate and maintain exposure of the humeral head.

         
         
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         Blunt retractors are placed medially and a brown deltoid is used laterally to help retract the deltoid posteriorly.

    
    
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    Stem removal:

    
    
    
    
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      i. Remove the prosthetic head or the polyethylene component with an extraction device or round tamp/osteotome and mallet.

      
      
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      ii. The surrounding soft tissue is removed with a rongeur to clearly visualize the bony margins.

      
      
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      iii. Evaluate the implant fixation.

      
      
      
      
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         If grossly unstable, the stem may be removed by hand; if not, an extraction device may be necessary.

      
      
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      iv. Attach an extraction device:

      
      
      
      
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         If trial with an extraction device is unsuccessful, then a narrow-tip burr or a thin osteotome can be used to circumferentially interrupt the proximal bone–cement interface with the prosthesis.

         
         
         
         
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           Important: Keep the instrument parallel with the prosthesis to avoid iatrogenic fracture or unwanted bone removal.

         
         
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         Alternative: A tamp can be placed along the medial edge of the prosthesis and may dislodge the implant with a mallet.

      
      
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      v. Prosthesis well fixed:

      
      
      
      
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         Humeral window:

         
         
         
         
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           Boundaries of the pectoralis major tendon are identified.

           
           
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           A rectangular anterior humeral osteotomy is performed along the proximal, lateral, and distal portion of the pectoralis major tendon.

           
           
           
           
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             The size of the osteotomy is determined based on the stem length and the ability to reach the proximal and distal portions of the stem.

             
             
             
             
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               The distal extent of the osteotomy should be carefully planned because if the osteotomy length is too short, it may be difficult to disrupt the bone–cement interface distally.

             
             

             Tip: Extending the osteotomy to the tip of the stem may assist in easier removal of the implant especially if the entire cement mantle and cement restrictor require removal.

             
             
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             After planning the osteotomy size and location, an osteotome can be used to open the top, lateral, and inferior portions.

             
             
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             With the osteotome in the lateral opening, flexing and bending the osteotome will help open the osteotomy along the medial border.

             
             

             Tip: A series of drill holes placed medially can help with reducing the risk of fracturing the cortical window (Fig. 58.3).

           
           
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           Once osteotomy is completed, the cortical window is wedged open.

           
           
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           An osteotome can be used to disrupt the interface with the humeral prosthesis.

         
         
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         Longitudinal humeral osteotomy (preferred method):

         
         
         
         
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           Insertion points of the deltoid and the pectoralis major are identified along with the bicipital groove.

           
           
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           A microsagittal saw is used to score the bone along the length of the bicipital groove continuing medial to deltoid insertion and lateral to pectoralis major insertion.

           
           
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           Use a narrow osteotome to create a linear osteotomy extending through the cement to prosthesis.

           
           
           
           
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             Osteotomy is continued distally in small increments while gently attempting to wedge open the osteotomy interrupting bone–implant or cement–implant interface.

           
           
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           As the osteotomy is continued distally, reassess if the humeral prosthesis has disengaged:

           
           
           
           
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             Antibiotics stem removal with an extraction device or tamp and mallet.

           
           
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           A narrow osteotome can be placed carefully within the osteotomy along the implant to help disrupt the interface.

           
           
           
           
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             Important: As the osteotomy is wedged open, monitor for distal progression of the osteotomy and inadvertent fracturing of the osteotomy site ( Fig. 58.4 ).

         
         
      3. 
         

         Stem removed:

         
         
         
         
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           Revision for aseptic loosening:

           
           
           
           
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             The cement mantle can be retained and a new prosthesis cemented into it.

           
           
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           Revision for septic loosening:

           
           
           
           
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             If cemented, curette out the cement and the membranous tissue with

             
             
             
             
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               Reverse cutting curettes.

               
               
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               Ultrasound cement remover.

         
         
      4. 
         

         Osteotomy closure (performed prior to reimplantation):

         
         
         
         
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           Cerclage wires are placed around the humerus:

           
           
           
           
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             Important: Stay along the cortical surface to avoid entrapping any neurovascular structures.

           
           
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           Drill holes are placed on both sides of the osteotomy and with heavy sutures passed through the holes and tied closing osteotomy:

           
           
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           Cortical strut graft:

           
           
           
           
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             If the cortex is relatively thin, with concerns for potential fracture, then the osteotomy can be augmented with a cortical strut graft (i.e., fibula).