Hip resurfacing

Question 1

What are the indications for MOM hip resurfacing?

Answer 1

• Pt with advanced arthritis & good proximal femoral bone stock
  
  • pt wiht proximal femoral deformity making THR difficult
  • PT with high risk of sepsis due to prior infection or immmunsupresses
  • pt w with neuromuscular diagnosis

Question 2

What are the contraindications for MOM hip resurfacing?

Answer 2

• Absolute
  
  • bone stock deficiency of femoral head or neck ( cystic change)
  • abnormal acetabular anatomy ( small)
  • pregnant women/child bearing age
• Relative
  
  • coxa vara - > risk femoral neck fractures
  • significant LLD - resurfacing doesn’t allow or correct this
  • female gender

Question 3

What are the adv of hip resurfacing?

Answer 3

• Preservation of femoral bone stock
• improved restoration of hip biomechanics with lower LLD
• lower dislocation rates
• rapid recovery
• revision easier than an intremedullary THR
• better stability cf standard small heasds (22-32)
• ability to engage in higher demand activities

Question 4

What are the disadv of hip resurfacing?

Answer 4

• lack of modularity with inability to adjust length or correct offset
• requires larger exposure than conventional THR

Question 5

What are the outcomes of THR?

Answer 5

• Variable
• better results in young , larger males with excellent bone stock tx for OA than for dysplasia or osteonecrosis
• some recent studies show few diff between resurfacing and THR

Question 6

What are the complications of hip resurfacing?

Answer 6

1. Periprosthetic femoral neck fx
   
   • 0-4%
   • PC=groin pain
   • freq cause for revision in post op period <20 wks
   • thought to be due to Osteonecrosis
   • risk factors
     
     • notching of femoral neck- see pic
     • osteoportic bone
     • large areas of preexisting Osteonecrosis
     • Femoral neck impingement ( malaligned acetabular compoenent
     • Female sex
     • varus positioning of head
   • Revise to THR
2. Implant loosening aseptic
   
   • esp femoral cemented component
3. Heterotopic ossification
   
   • > than cf THR
4. Elevated metal ions in blood and urine- unknown significance
5. Pseudotumour
   
   • maybe asymptomatic
   • symptomatic ->> revision