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Total Shoulder Arthroplasty

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Topic updated on 07/11/16 4:28pm
Introduction
  • Replacement of humeral head and glenoid resurfacing
    • cemented all-polyethylene glenoid resurfacing is standard of care
  • Total shoulder arthroplasty unique from THA and TKA in that
    • greater range of motion in the shoulder
    • success depends on proper functioning of the soft tissues
    • glenoid is less constrained
      • leads to greater sheer stresses and is more susceptible to mechanical loosening
  • Factors required for success of TSA
    • rotator cuff intact and functional
      • if rotator cuff is deficient and proximal migration of humerus is seen on x-rays (rotator cuff arthropathy) then glenoid resurfacing is contraindicated 
      • if there is an irreparable rotator cuff deficiency then proceed with hemiarthroplasty or a reverse ball prosthesis
      • an isolated supraspinatus tear without retraction can proceed with TSA 
        • incidence of full thickness rotator cuff tears in patients getting a TSA is 5% to 10%
        • if positive impingement signs on exam, order a pre-operative MRI
    • glenoid bone stock and version
      • if glenoid is eroded down to coracoid process then glenoid resurfacing is contraindicated
      • see Walch classification below
  • Outcomes
    • pain relief most predictive benefit (more predictable than hemiarthroplasty) 
    • reliable range of motion
    • good survival at 10 years (93%)
    • good longevity with cemented and press-fit humeral components
    • worse results for post-capsulorrhaphy arthropathy q
Classification
 
Walch Classification of Glenoid Wear
Type A well-centered 
A1 minor erosion
A2 deeper central erosion
Type B head subluxated posteriorly 
B1 posterior wear
B2 severe biconcave wear
Type C glenoid retroversion of more than 25 degrees (dysplastic in origin)

Indications
  • Indications 
    • pain (anterior to posterior), especially at night, and inability to perform activities of daily living
    • glenoid chondral wear to bone   
      • preferred over hemiarthroplasty for osteoarthritis and inflammatory arthritis
    • posterior humeral head subluxation
  • Contraindications
    • insufficient glenoid bone stock
    • rotator cuff arthropathy
    • deltoid dysfunction
    • irreparable rotator cuff (hemiarthroplasty or reverse total shoulder are preferable) q 
      • risk of loosening of the glenoid prosthesis is high ("rocking horse" phenomenon)
    • active infection
    • brachial plexus palsy
Preoperative Imaging
  • Radiographs
    • true AP
      • determine extent of arthritis and look for superior migration of humerus
    • axillary view
      • look for posterior wear of glenoid
  • CT scan
    • obtain CT scan to determine glenoid version and glenoid bone stock
  • MRI
    • evaluate rotator cuff condition
Approach
  • Deltopectoral
    • detach the subscapularis and capsule from anterior humerus
    • dislocate shoulder anteriorly
    • tight shoulders may require release of the upper half of the pectoralis tendon to increase exposure and dislocation
      • pectoralis major tendon passes on top of the biceps tendon to attach to the humerus
  • Complications
    • axillary nerve damage is the most common complication
      • axillary nerve and posterior humeral circumflex artery pass beneath the glenohumeral joint in the quadrilateral space 
Technical considerations
  • Capsule
    • anterior capsule contracture (passive ER < 40°)
      • treatment
        • anterior release and Z-lengthening
    • posterior capsule stretching
      • treatment
        • volume-reducing procedure (plication of posterior capsule)
  • Glenoid deficiency and retroversion
    • glenoid deficiency q 
      • treatment
        • build up with iliac crest autograft or part of the resected humerus 
        • do not use cement to build up the deficiency
    • retroverted glenoid  
      • treatment
        • build up posterior glenoid with allograft
        • eccentrically ream anterior glenoid
  • Glenoid component
    • convex superior to flat
    • recreate neutral version
    • peg design is biomechanically superior to keel design
    • polyethylene-backed components superior to metal-backed components
      • glenoid not large enough to accommodate both metal and PE
    • uncemented glenoid has a lower rate of loosening
    • conforming vs. nonconforming
      • both have advantages and neither is superior
      • conforming is more stable but leads to rim stress and radiolucencies
      • nonconforming leads to increased polyethylene wear
  • Humeral stem fixation
    • cemented stem or uncemented porous-coated implants 
    • position of humeral stem should be 25-45° of retroversion   
      • if position of glenoid retroversion is required, then the humeral stem should be less retroverted to avoid posterior dislocation
    • avoid valgus positioning of humeral stem
    • avoid overstuffing the humeral head
      • increases joint reaction forces and tension on the rotator cuff
      • the top of the humeral head should be 5 to 8 mm superior to the top of the greater tuberosity
    • intraoperative humerus fracture
      • greater tuberosity fracture
        • treatment
          • if minimally displaced, insert a standard humeral prosthesis with suture fixation and autogenous cancellous bone grafting of the greater tuberosity fracture
      • humeral shaft fracture
        • treatment
          • remove prosthesis and add longer stem with cement and reinforce with cerclage wiring
Rehabilitation
  • Passive or active-assisted motion only during early rehab
    •  limiting factor in early postoperative rehabilitation is risk of injury to the subscapularis tendon repair q 
  • Progress to ER isometrics
  • Limit passive external rotation
    • risk of tear and pull-off of subscapularis tendon from anterior humerus
      • tear leads to anterior shoulder instability (most common form of instability after TSA)
      • treatment of subscapularis pull-off is early exploration and repair of tendon
      • test for pull-off of subscapularis
        • weak belly-press test
        • inability to put hand in back pants pockets or tuck shirt behind the back
      • avoid pushing out of chair during acute rehab
  • IR eccentric and isometric
Complications
  • Glenoid loosening
    • most common cause of TSA failure (30% of primary OA revisions)
    • risk factors
      • insufficient glenoid bone stock
      • rotator cuff deficiency
    • 2.9% reoperation rate for loosening (28% with revision)
    • radiographic lines
      • presence of radiographic lines does not correlate with symptoms
      • progression of a radiographic line does correlate with symptoms
        • progression present in 50% of patients as early as 3 to 4 years after TSA
      • radiolucency around the glenoid does not always correlate with clinical failure
        • at 3- and 7-year follow-up did not correlate with poor functional outcomes or pain
  • Humeral stem loosening
    • more common in RA and osteonecrosis
    • rule out infection
  • Subscapularis repair failure q  
  • Malposition of components
  • Improper soft tissue balancing
    • failure due to undiagnosed presence of rotator cuff tears
  • Iatrogenic rotator cuff injury
    • can occur if humeral neck osteotomy is inferior to level of rotator cuff insertion 
  • Stiffness
  • Infection
    • early infection (<6 weeks) can be treated with open irrigation and debridement
    • late infection (>6 weeks) should be treated by explant and staged reimplantation after IV antibiotic course
    • Propionibacterium acnes (P. acnes) 
      • high bacterial burden around the shoulder 
      • common cause of indolent infections and implant failures
  • Neurologic injury
    • axillary nerve is most commonly injured
    • musculocutaneous nerve can be injured by retractor placement under conjoint tendon

 

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Qbank (16 Questions)

TAG
(OBQ12.172) In which of the following clinical circumstances would it be appropriate to eccentrically ream the anterior glenoid? Topic Review Topic

1. 72-year-old male undergoing a shoulder arthroplasty due to rotator cuff arthropathy
2. 65-year-old female with a glenoid retroversion of 13-degrees undergoing shoulder arthroplasty
3. 70-year-old female with humeral anteversion of 13-degrees undergoing shoulder arthroplasty
4. 65-year-old female with glenoid retroversion of 25-degrees undergoing shoulder arthroplasty
5. 59-year-old male with significant glenoid bone stock deficiency and severe osteoarthritis

PREFERRED RESPONSE ▶
TAG
(OBQ12.241) Which of the following preoperative factors is a contraindication to total shoulder arthroplasty? Topic Review Topic

1. Passive external rotation less than 10 degrees
2. Eccentric posterior glenoid erosion
3. A 2-cm full-thickness supraspinatus tendon tear
4. Inflammatory arthritis
5. A preganglionic brachial plexus injury

PREFERRED RESPONSE ▶
TAG
(OBQ11.50) Which of the following statements regarding propionibacterium acnes infections after shoulder arthroplasty is incorrect? Topic Review Topic

1. It is usually associated with fevers
2. Cultures need to be held for 14 days
3. It colonizes the shoulder at increased rates compared to the knee and hip
4. Men have a higher bacterial burden than females
5. It is an important cause of clinical implant failure

PREFERRED RESPONSE ▶
TAG
(OBQ11.252) During a total shoulder arthoplasty (TSA), which of the following technical maneuvers would most likely place the rotator cuff tendons at risk of injury? Topic Review Topic

1. Excessive retraction on the deltoid muscle during a delto-pectoral approach
2. Palpation of the rotator cuff insertion prior to humeral head resection
3. A humeral cut with 30 degrees of retroversion
4. Excessive bone removal with the humeral neck osteotomy
5. A humeral cut with 45 degrees of inclination

PREFERRED RESPONSE ▶
TAG
(OBQ09.85) A 65 year-old man has progressive debilitating pain and crepitus in his shoulder. Active forward elevation is 120 degrees and external rotation strength is normal. Radiograph and CT scan are shown in Figures A and B. Which treatment will likely give him the best outcome in 3 years. Topic Review Topic
FIGURES: A   B        

1. Arthroscopic capsular release
2. Humeral head arthroplasty with glenoid bone grafting followed by staged glenoid component implantation
3. Hemiarthroplasty
4. Reverse total shoulder replacement
5. Total shoulder arthroplasty

PREFERRED RESPONSE ▶
TAG
(OBQ09.219) A 62-year-old man undergoes a total shoulder arthroplasty for osteoarthritis. He accidently uses his operative arm to rise from a chair 3 weeks after surgery and thereafter complains of anterior shoulder pain. Radiographs are significant for anterior dislocation of the prosthesis. What is the most likely mechanism for this complication? Topic Review Topic

1. long head biceps rupture
2. supraspinatus rupture
3. subscapularis rupture
4. infraspinatus rupture
5. labral tear

PREFERRED RESPONSE ▶
TAG
(OBQ08.12) The placement of a standard all-polyethylene glenoid component for shoulder arthroplasty is contraindicated in which of the following scenarios? Topic Review Topic

1. Irreparable rotator cuff tear
2. Previous glenoid resurfacing
3. Rheumatoid arthritis
4. Osteoarthritis
5. Osteoporosis

PREFERRED RESPONSE ▶
TAG
(OBQ08.24) During the initial rehabilitation phase following total shoulder arthroplasty through a delto-pectoral approach, motion and strengthening are typically restricted because of which factor? Topic Review Topic

1. Protection of the subscapularis tendon
2. Protect of the supraspinatus tendon
3. Risk of dislocation
4. Risk of loosening
5. Intra-articular effusion

PREFERRED RESPONSE ▶
TAG
(OBQ07.27) Which of the following factors has the greatest influence on early postoperative restrictions following total shoulder arthroplasty through a deltopectoral approach? Topic Review Topic

1. Release of the superior border of the pectoralis
2. Strength of the capsular repair
3. Strength of the subscapularis repair
4. Presence of glenoid retroversion
5. Quality of the patients' bone

PREFERRED RESPONSE ▶
TAG
(OBQ06.153) A 75-year-old right-hand dominant female has persistent right shoulder pain for the past 5 years. An axial CT scan is shown in the Figure A. If a total shoulder arthroplasty is planned, what other procedure must be performed based on this patient's imaging? Topic Review Topic
FIGURES: A          

1. rule out infection
2. bone grafting of the glenoid
3. rotator cuff repair
4. acromioplasty
5. humeral head biopsy

PREFERRED RESPONSE ▶
TAG
(OBQ04.66) A 72-year-old male who underwent right total shoulder arthroplasty 8 months ago is unable to lift his right hand off his back and has weakness with internal rotation. What is the most likely diagnosis? Topic Review Topic

1. Brachial neuritis
2. Long head of biceps rupture
3. Subscapularis insufficiency
4. Subscapularis nerve palsy
5. Standard postoperative recovery

PREFERRED RESPONSE ▶
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