Clinical History, Examination and Blood Test Results

  • Case 3 is a 33-year old Kurdish lady with a raised BMI and a history of bilateral developmental dysplasia of the hip.

  • Her left hip was replaced at the age of 22. The femoral component was an S-ROM stem (11/13 taper) with a 22.5mm head. The acetabular component was an uncemented titanium cup.

    • During the primary procedure there was an intra-operative fracture which was cabled.

    • This hip replacement performed well for 10 years.

  • She presented to us in 2018 with pain in both hips and a leg length discrepancy.

  • Investigations:

    • WCC, CRP and ESR were all normal.


Imaging Results

RADIOGRAPH 6-WEEKS POST-PRIMARY

Click on the image for a closer look

RADIOGRAPH 4-YEARS POST-PRIMARY

Click on the image for a closer look

This was the 6-week post-operative anterior posterior radiograph from her primary procedure demonstrating an S-ROM component with cerclage wires due to an intra-operative fracture.

This anterior posterior radiograph shows the implant 4-years after the primary procedure. The implant is well positioned and there is no evidence of loosening.

 

RADIOGRAPH AT PRESENTATION

Click on the image for a closer look

PRE-OP CT SCAN (Coming soon)

Scroll through the images

This lady presented with bilateral hip pain and a leg length discrepancy. This radiograph demonstrates evidence of acetabular component loosening as it has rotated from its original position. There is evidence of greater trochanter osteolysis however the stem is well fixed and remains integrated distally.

Due to the complexity of this revision, a pre-operative CT scan was ordered to assess the bone stock of the innominate bone.

 

PRE-OP MRI (Coming soon)

Scroll through the images

PRE-OP EOS (Coming soon)

Scroll through the images

A pre-operative MRI scan was ordered in this complex case to assess the soft tissues surrounding the left hip joint.

An EOS scan was ordered in this complex case to aid in planning to plan for correction of her leg length discrepancy with the revision procedure.


Diagnosis

  • Loosening of the acetabular component on a background of a left total hip replacement secondary to DDH.


Treatment

  • This patient only required revision of their loose acetabular component.

  • Key Surgical Steps

    • She was placed in a standard lateral position and posterior approach was performed.

    • 5 microbiology samples were sent.

    • The cup was explanted and 22.5 metal femoral head was removed using the JRI head remover. 

    • The stem was well fixed and therefore retained.

    • The acetabulum was assessed. As expected she had a very small dysplastic acetabulum with superior bone loss.

    • The acetabulum was reamed and then a LIMA Delta TT cup was trialled. This gave good AP fit. A superior acetabular augment was trialled with the cup to restore the centre of rotation.

    • The LIMA cup was used as it has augment and dual mobility options at relatively small sizes compared to a lot of competitors.

    • The final cup augment construct was implanted.

    • A dual mobility liner was inserted to reduce risk of dislocation which would high in a revision DDH setting.

    • The head was replaced with a Bioball head. This is because Depuy do not manufacture a revision ceramic head for the S-ROM stem. This allowed us to change her to a ceramic on poly on metal bearing while increasing the head size to 28mm.

    • She was trialled and stable.


Imaging Outcomes

POST-OP RADIOGRAPH

Click on the image for a closer look

 

POST-OP CT SCANNOGRAM

Click on the image for a closer look

This is the post-operative radiograph demonstrating the new acetabular component with the trabecular structure of the augment seen superiorly.

Axial imaging was ordered to assess the final position of the implant.


Clinical Outcomes

  • She made an excellent recovery and was discharged home. Unfortunately 2 out of 5 samples were positive for Cutibacterium acnes (formerly Propionibacterium acnes).

  • On the advice of our microbiology MDT she was started on a 12 week course of amoxicillin.

  • The diagnosis of PJI secondary to Cutibacterium acnes is increasing due to improving diagnostic methods as it is a slow growing difficult to culture organism.

  • Following her antibiotic course completion she has made an excellent recovery and there is no evidence of any ongoing infection. She is currently awaiting her right hip to be replaced.


Learning Points

  • Complex revision surgery is made simpler with good planning.

  • S-ROM revision ceramic heads must be sourced from Bioball.

  • Augmentation is a good solution for acetabular bone loss on the ladder of reconstruction.

  • Cutibacterium acnes infection is difficult to diagnose and the threshold for preoperative aspiration needs to be considered and perhaps lowered.