Clinical History, Examination and Blood Test Result

  • Case 3 is a 49-year-old man who presented with a lump in his left groin after being referred by general surgeons.

  • He had bilateral metal-on-metal hip resurfacings which were both functioning well. The patient experienced increasing fullness in his left groin.

  • Examination revealed a good range of lumbar spine and hip movements and a palpable left iliac fossa mass (6cm in diameter).

  • His Cobalt level was 12.9ppb and his Chromium level was 18.7ppb, both higher than the MHRA action level of 7ppb.


Imaging Results

PRE-OP CT

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PRE-OP MRI

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This single pre-operative CT image shows the bilateral Birmingham hip resurfacing prior to surgery.

This series of three images shows the left intrapelvic pseudotumour in all three planes, coronal, axial and saggital. MARS MRI revealed that the muscles are in good condition and symmetrical on both sides. In the coronal image, the psuedotumour is deviating the external iliac artery towards the midline. This is confirmed with the angiogram below.

 

PRE-OP 3D CT ANGIOGRAM

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The three arrows show the deviation of the external iliac artery. This is caused by the psuedotumour pressing against the vessel.

 

Diagnosis

  • Left solid pseudotumour, 6cm in diameter, deviating the iliac vein and artery, secondary to metal debris from a hip resurfacing.

  • Revision was recommended to preserve long term hip function.

  • Excision of intra-pelvic pseudotumour will avoid future neuro-vascular problems (leg swelling, femoral nerve compression, deep vein thrombosis, emboli, leg ischaemia). Revision of the hip to a non-MOM bearing will remove the cause of the pseudotumour and prevent recurrence.


Treatment

  • He underwent a one stage, two step procedure.

  • Step one was combined with a vascular surgeon, to remove the solid psuedotumour in the supine position using an inguinal, retroperitoneal approach.

  • Step two was revision of the hip resurfacing in the lateral position and posterior surgical approach, to a ceramic on polyethlene total hip replacement.

 

INTRAOPERATIVE IMAGES - FIRST STEP

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The first image demonstrates the inguinal surgical approach, used to access the external iliac artery and pseudotumour. Image two demonstrates the anatomy of the pseudotumour and it's position in relation to the external iliac artery. Image three and four demonstrate the contents being removed from the pseudotumour. Image five shows the cavity left behind after tumour removal. Image six demonstrates the contents of the pseudotumour.

 

Imaging Outcomes

POST-OP RADIOGRAPH 

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This is the post-operative anteroposterior radiograph, showing the revision femoral and acetabular component.

  

3D RECONSTURCTION 

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This is a 3D reconstruction of the patient’s pelvis from a CT scan taken at a later date post-operatively. You can see the well positioned left components in 3D.


Clinical Outcomes

  • The patient returned to sports and gym exercises.


Learning Points

  • CT angiography can be useful in identifying how a psuedotumour is interacting with the surrounding vasculature. This helps in the planning of a procedure to remove the mass and revise the implant.

  • Excision of large and solid intra-pelvic pseudotumours will avoid future neuro-vascular problems (leg swelling, femoral nerve compression, deep vein thrombosis, emboli, leg ischaemia). Revision of the hip to a non-MOM bearing will remove the cause of the pseudotumour and prevent recurrence.