Clinical History, Examination and Blood Test Results

  • Step 7 case 8 is a 62-year-old male with bilateral total hip replacements. These were thought to have been completed approximately 30-years ago

  • He presented with pain in both legs, worse on the right and localised to the knee

  • CRP of 5 ruling out infection


Imaging Results

RADIOGRAPH 

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RADIOGRAPH (KNEES)

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This radiograph shows loosening of both acetabular components. From the radiograph it is difficult to gauge the size of the acetabular defect

These pre-operative radiographs of the knees were to identify if degenerative joint disease in the knees was causing the reported knee pain. Some degenerative disease is present, however the source of the pain is the loosened acetabular component in the right hip


Diagnosis

  • Loose right acetabulum of a metal-on-plastic THR with some subluxation

  • Loose left acetabulum


Treatment (Stage 1)

  • Initial plan was reconstruction of the right hip with an augment or a restoration cup

  • Intraoperatively the decision was made to convert the procedure to a girdlestone

  • The defect was too large for reconstruction with a cage, restoration anatomic cup, augments or bone graft

  • CT was completed post-op to design a custom acetabular implant


Imaging Outcomes (Stage 1)

PRE-OP SCANNOGRAM 

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PRE-OP CT (AXIAL)

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These scannograms show the pre-operative situation before the second stage of this patients procedure

This axial CT was used to design the patients custom implant. Above is just a few slices. Note how thin each CT slice is; 1mm slices are used in the design protocol

 

HEMIPELVIC DEFECT

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This is a 3D model of the patients hemipelvis which has been reconstructed from the CT scan taken after the first stage procedure. This demonstrates the size of the defect which is very difficult to appreciate from the initial radiograph. The second image shows existing bone cement

 

Treatment (Stage 2)

IMPLANT DESIGN

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TRABECULAR TITANIUM

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This series of images shows the 3D design of the implant created specifically for this patient. The areas in blue will be manufactured out of trabecular titanium to encourage bony ingrowth and osseointegration of this implant

This image shows the structure of the 3D printed trabecular titanium metal used to produce these implants. This is designed to contact the bone to allow for bony ingrowth to occur

 
  • Operation steps

    • Old incision was used to gain access - Posterior approach 

    • Socket was prepared as per the custom plan

    • Custom implant was inserted with very good screw fixation 

    • Dual mobility bearing was used 

    • Cement in cement femoral stem 

    • Good length and stable 

    • Wash


Imaging Outcomes (Stage 2)

POST-OP RADIOGRAPHS

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This radiograph shows the custom implant in situ. Note the existing stem was retained

POST-OP EOS

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These post-operative EOS images demonstrate the functional position of the acetabular implant. Note the level of the knees and the flat pelvis, demonstrating that there is no leg length discrepancy post-op

 

POST-OP CT SCAN

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This CT scan was taken to assess the position of the implant within the bony pelvis

 

Clinical Outcomes

  • The patient returned to clinic 7-weeks after his operation

  • He was mobilising well using two crutches as advised with the plan to reduce down to a single crutch on the left side

  • The patient is happy with the outcome of his revision


Learning Points

  • Coming soon