The Mark II Prosthesis

A newer system, named the Mark II (Link America),14 was created and was used to treat acetabular tumors in the late 1980's. This design has been the most commonly placed saddle prosthesis for neoplastic lesions, although the total number is still probably not many more than 100 insertions (per the data reported).1, 3, 5, 8, 13, 16  
  

  • Saddle rests on polyethylene sleeve which rotates on peg attached to a base component
  • Base components available in differing lengths(60 to 160mm) to accommodate bone loss or patient variability (base is attached to femoral stem)
  • Set screw is used to prevent base/saddle dislocation
  • Locking pin within conical portion of base for rotational15 

Note the swivel points. This allows for greater functionality15

By attempting to restore the iliofemoral weight bearing axis, this new saddle prosthesis achieved three objectives13

1- Stable reconstruction without leg length discrepancy

2- Early weight-bearing without pain

3- Satisfactory results (to be discussed later)        

Axial CT, normal findings. Ilium rests between both saddle prongs15

Mark II Illustration15

Note how saddle cradles ilium15

Options12

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