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Shoulder Hemiarthroplasty

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Topic updated on 04/10/16 1:46pm
Introduction
  • Humeral articular surface replaced with stemmed humeral component coupled with either
    • standard humeral head
    • extended-coverage head
Indications
  • Indications
    • primary arthritis, if:
      • rotator cuff is deficient
      • glenoid bone stock is inadequate
      • risk of glenoid loosening is high
        • young patients
        • active laborers 
    • rotator cuff arthropathy
      • hemiarthroplasty > rTSA if able to achieve forward flexion > 90 degrees 
    • osteonecrosis without glenoid involvement
    • proximal humerus fractures 
      • three-part fractures with poor bone quality
      • four-part fractures
      • head-splitting fractures
      • fracture with significant destruction of the articular surface
  • Contraindications
    • infection
    • neuropathic joint
    • unmotivated patient
    • coracoacromial ligament deficiency
      • provides a barrier to humeral head proximal migration in the case of a rotator cuff tear
      • superior escape will occur if coracoacromial ligament and rotator cuff are deficient
Outcomes
  • Rotator cuff deficiency
    • status of the rotator cuff is the most influential factor affecting postoperative function in shoulder hemiarthroplasty 
  • Proximal humerus fractures
    • provides excellent pain relief in a majority of patients
    • outcome scores inversely proportional to 
      • patient age
      • time from injury to operation
Preoperative Imaging
  • Radiographs
    • true (Grashey) AP of shoulder
      • taken 30-40 degrees oblique to the coronal plane of the body 
      • findings
        • helps determine extent of DJD
        • delineation of fracture pattern
    • axillary view
      • findings
        • look for posterior wear of glenoid
        • helps quantify displacement in cases of fracture
  • CT scan
    • obtain CT scan to determine glenoid version and glenoid bone stock
    • useful if fracture pattern is poorly understood after radiographic evaluation
  • MRI
    • useful for evaluation of rotator cuff
Surgical Techniques
  • Approach
    • deltopectoral approach
  • Shaft preparation and prosthesis placement
    • humeral head resection
      • start osteotomy at medial insertion line of supraspinatus
    • determine retroversion, implant height and head size
      • retroversion
        • 30° of retroversion is ideal
        • lateral fin should be slightly posterior to biceps groove
        • excessive anteversion leads to risk of anterior dislocation
        • excessive retroversion leads to risk of posterior dislocation
      • implant height
        • greater tuberosity should be
          • 5 to 8 mm below the top of the prosthetic humeral head
            • functions to
              • maintain cuff and biceps tension
              • recreate normal contour of medial calcar
            • technique to achieve
              • cement prosthesis proud
              • distance from top of prosthesis head to upper border of pectoralis major should be 56mm.
      • head size
        • determine size by using
          • radiograph of contralateral shoulder or
          • measuring size of native head removed earlier in procedure
          • using too large of a head may "overstuff" joint
  • Fixation
    • cemented prosthesis
      • standard of care
      • provides better quality of life, range of motion, and strength compared to uncemented humeral component
  • Tuberosity reduction
    • introduction
      • tuberosity migration is one of the most common causes of failure for fractures treated with hemiarthroplasty
    • technique
      • strict attention to securing the tuberosities to each other and to the shaft
      • autogenous bone grafting from the excised humeral head will decrease the incidence of pull-off and improve healing rates
      • tuberosity reduction must be anatomic or it may lead to a deficit in rotation q
Rehab
  • Early passive motion until fracture has healed
    • duration usually 6-8 weeks
  • Strengthening exercises begin once tuberosity has fully healed
Complications
  • Progressive glenoid arthrosis
    • increased risk with
      • young patients
      • active patient
    • treatment
      • conversion to total shoulder arthroplasty
  • Tuberosity displacement/malunion
    • one of the most common complications of shoulder hemiarthroplasty when used to treat fracture
    • treatment
      • repositioning of the tuberosity with bone grafting
  • Joint overstuffing
    • may lead to
      • stiffness
      • accelerated arthritis of glenoid
  • Subcutaneous (anterosuperior) escape
    • occurs when both rotator cuff and coracoacromial arch are deficient

 

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Qbank (2 Questions)

TAG
(SBQ07.21) A 60-year-old man has chronic shoulder pain and weakness. Radiographs show moderate glenohumeral arthritis and narrowing of the acromio-humeral distance. He is scheduled to undergo either hemiarthroplasty or total shoulder arthroplasty. His postoperative function will be most affected by which of the following factors? Topic Review Topic

1. The integrity of the rotator cuff
2. The integrity of the coracoacromial ligament
3. The presence of glenoid wear
4. The presence of an inferior head osteophyte
5. The extent of AC joint arthritis

PREFERRED RESPONSE ▶
TAG
(OBQ05.137) A 78-year old female sustained a 4-part proximal humerus fracture on her dominant side 2 days ago and undergoes a shoulder hemiarthroplasty. Intraoperatively, the lesser tuberosity reduction was difficult and placed too close to the greater tuberosity, which was anatomic. What post-operative problem is likely to result due to the position of the lesser tuberosity? Topic Review Topic

1. external rotation deficit
2. internal rotation deficit
3. multi-directional instability
4. forward elevation weakness
5. elbow flexion weakness

PREFERRED RESPONSE ▶




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