Shoulder Hemiarthroplasty

Question 1

What are the indications of humeral hemiarthroplasty?

Answer 1

1. primary arthritis, if:

rotator cuff is deficient

glenoid bone stock is inadequate

risk of glenoid loosening is high

• young patients
• active laborers

2. rotator cuff arthropathy

hemiarthroplasty > rTSA if able to achieve forward flexion > 90 degrees

3. osteonecrosis without glenoid involvement
4. proximal humerus fractures

three-part fractures with poor bone quality

four-part fractures

head-splitting fractures

fracture with significant destruction of the articular surface

Question 2

What are the contra-indications of hemiarthroplasty?

Answer 2

• 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

Question 3

What is the most influential factor affecting postoperative function in shoulder hemiarthroplasty ?

Answer 3

status of the rotator cuff is the most influential factor affecting postoperative function in shoulder hemiarthroplasty

Question 4

Hemiarthroplasty implant height:

Answer 4

▪ Greater tuberosity should be7 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.

Question 5

What is the diagnosis and treatment?

No signs of infection.

Rotator cuff ok

Answer 5

left shoulder hemiarthroplasty with associated glenoid erosion. The next best step in this patients treatment is a revision of the humeral head and placement of a prosthetic glenoid component.

Question 6

What is the major cause for revision within the first 2 years after shoulder arthroplasty?

Answer 6

Peri-prosthetic shoulder infection

Question 7

What are the risk factors for shoulder prosthetic infection?

Answer 7

• postoperative hematoma
• intra-articular steroid injection within 3 months of surgery
• smoking
• young age
• male gender
• arthroplasty for trauma
• revision surgery

Question 8

What are the micro-organisms most commonly isolated?

Answer 8

1. Staphylococcus aureus
2. Staphylococcus epidermidis
3. Cutibacterium acnes (most common) characteristics

gram-positive, facultative, aerotolerant, anaerobic rod that ferments lactose to propionic acid

concentrated in the axilla within the dermal sebaceous glands

forms biofilm within 18-90h (found on implant surface and on synovial tissue) >> planktonic

explains why aspiration is only 17% sensitive

Mean duration of culture incubation between 7-21 days

Question 9

What is the Antibiotic of choice for the treatment of C.acnes?

Answer 9

Penicillin is the antibiotic of choice for treatment of C.acnes

Question 10

What is the mechanism of action of penicillin?

Answer 10

Blocks cross linking of the transpeptidase enzyme during cell wall synthesis

Question 11

Which of the following is the most likely complication that might occur when cable fixation is placed 4 cm inferior to the insertion of the latissimus dorsi?

Answer 11

Iatrogenic radial nerve injury

Question 12

Classification of shoulder periprosthetic fracture?

Answer 12

Wright and Cofield system:

Type A fractures: proximal to the stem tip and are treated with ORIF

Type B fractures: at the level of the stem tip and are treated with ORIF

Type C fractures: distal to the stem tip and can be initially treated nonoperatively.

Question 13

What are the indications of shoulder arthrodesis?

Answer 13

• Stabilization of paralytic disorders
• Brachial plexus palsy
• Irreparable deltoid and rotator cuff deficiency with arthropathy
• Salvage of a failed total shoulder arthroplasty
• Reconstruction after tumor resection
• Painful ankylosis after chronic infection
• Recurrent shoulder instability which has failed previous repair attempts
• Paralytic disorders in infancy

Question 14

What are the contraindications of shoulder arthrodesis?

Answer 14

• Ipsilateral elbow arthrodesis
• Contralateral shoulder arthrodesis
• Lack of functional scapulothoracic motion
• Trapezius, levator scapulae, or serratus anterior paralysis
• Charcot arthropathy during acute inflammatory stage (Eichenholtz 0-2)
• Elderly patients
• Progressive neurologic disease