Clinical History, Examination and Blood Test Result

  • Case 4 is a 62-year-old lady who presented as an emergency with a third-time dislocation of her multiply revised left hip replacement. She had been suffering with pain in her left hip replacement.

  • Previously she had undergone left dynamic hip screw fixation for femoral neck fracture, followed by metal-on-polyethylene total hip replacement after femoral head avascular necrosis and then revision of the bearings to a ceramic on polyethylene hip for ARMD as a result of taper corrosion.

  • She had a CRP of 6mg/L and an ESR of 8mm/H.


Imaging Results

PRE-OP RADIOGRAPH

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This is the pre-operative radiograph showing a dislocated left ceramic-on-polyethylene hip replacement.

 

PRE-OP MARS MRI

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The MRI shows wasting of her gluteus maximus, medius and minimus. A large pseudotumour is seen lateral to her left hip joint.


Diagnosis

  • Adverse response to metal debris from the taper of a metal-on-plastic hip replacement can cause devastating soft tissue destruction with detachment of her left hip abductors from the greater trochanter causing multiple dislocations.


Treatment

  • This patient underwent excision of her large pseudotumour and a revision procedure in a single stage.

  • Key operative steps

    • Excision of the large pseudotumour

    • Explant the well-fixed socket and reinsertion of socket with dual mobility bearing

    • Removal of well-fixed stem with extended trochanteric osteotomy and plate fixation

    • Modular stem to replace this allowing for leg length and offset adjustment

    • Repair of damaged muscle

 

INTRAOPERATIVE IMAGE - DISSECTION

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INTRAOPERATIVE IMAGE - DEAD TISSUE

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This image shows the dissection of the dead tissue. An adverse reaction to the metal debris, released at the trunnion interface between the stem and the head of her original meta-on-polyethylene total hip replacement has caused this.

This image shows the removed tissue.


Imaging Outcomes

POST-OP RADIOGRAPH 

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This is the post-operative anteroposterior radiograph showing a long revision femoral stem with the head articulating in a dual mobility liner. An extended femoral trochanteric osteotomy was utilised to explant the old femoral stem, which is held with a plate and wires.

 

Clinical Outcomes

  • Post-operatively this patient was walking with a stick and demonstrated good control of her left hip considering the amount of muscle wasting.


Learning Points

  • Adverse reactions to metal debris can be caused by both wear particles from metal-on-metal bearings as well as from corrosion, releasing ions, from the stem/head taper.