Clinical History, Examination and Blood Test Results

  • Step 6 case 1 is a 75-year-old lady who presented in 2014 with inability to walk and night pain in her left hip. She had bilateral metal on plastic hip replacements in the 1990s and the left hip was revised in 2011 due to osteolysis

  • She was taking regular naproxen for the pain.

  • Examination revealed a painful and stiff left hip. She had difficulty straight leg raising on the left side and walked slowly for a maximum of 200 yards. She had been told by a revision hip surgeon that her hip was un-reconstructable and that she would never walk properly again.

  • Blood C-reactive Protein was <10 mg/L.


Imaging Results

PRE-OP RADIOGRAPH

Click on the image for a closer look

The above radiograph is an anteroposterior (AP) radiograph of both hips showing bilateral hip replacements with polyethylene liners (it is difficult to distinguish ceramic from metal heads). The right hip stem is radiographically loose with radiolucent lines in all 7 Gruen zones.

The above image is a lateral radiograph of the left hip. The left acetabular cage is loose and protruding into the pelvis, when compared to the immediate post-operative radiographs from 2011 after the left hip revision surgery. The stem on the left hand side is well fixed.

  • Computer Tomography (CT) showed an intact posterior column.

Diagnosis

  • This patient was diagnosed with failure of both hips and offered re-revision of both hips, left side first.

Treatment

Anti-protrusio Cage

Click on the image for a closer look

 
 

This image shows a left-sided anti-protrusio cage. The inferior, spiked flanged is designed to be impacted into the ischium or lie on its outer surface. The superior flanges are designed to fix into ilium. The cages come in a range of sizes. The flanges are difficult to shape to the bone and there is a no fixation into the pubis. A polyethylene cup or dual mobility metal liner is cemented into the cage.

 
  • In 2014 she had bone grafting, a left-sided anti-protrusio cage and a cemented polyethylene cup to reconstruct the left acetabulum. The stem was retained.

Imaging Outcomes

POST-OP RADIOGRAPH

Click on the image for a closer look

3-YEARS POST-OP RADIOGRAPH

Click on the image for a closer look

AP of both hips post-revision of the left hip showed bone grafting, a left-sided anti-protrusio cage and a cemented polyethylene cup to reconstruct the left acetabulum. The stem was retained.

This AP radiograph was taken three years after the left hip was reconstructed using the anti-protusio cage. Note that the right side has been revised. 


Clinical Outcomes

  • Post-operative cultures of 5 specimens were negative for infection.

  • She went on to have revision of the right stem in 2015.

  • In 2017, she was walking several miles and no longer taking analgesics.


Learning Points

  • Cages can be used to fill in large acetabular defects.