“Hip resurfacing has been a point of debate in the orthopaedic world for many years. The design aims to preserve bone stock to allow for future procedures however the metal-on-metal bearings caused adverse reactions to metal debris in some patients. Stephanie had received bilateral Birmingham hip resurfacings 8-years prior to meeting me.
She presented to clinic with pain on both sides that was starting to have a huge impact on her activities of daily living. This was getting so bad that it was starting to wake her at night.”
On clinical examination Stephanie was in a lot of discomfort when examining both hip joints. Her mobility was poor with a very slow and antalgic gait.
Blood inflammatory markers were performed to aid in ruling out infection and the CRP was 5mg/L. Her blood cobalt and chromium ion levels were vastly raised, suggesting the pain was due to an adverse reaction to the metal debris.
Anteroposterior plain radiograph demonstrating bilateral metal on metal Birmingham hip resurfacings. There is osteolysis surrounding both of the implants, which was better quantified on the computer tomography (CT) scan.
Stephanie was diagnosed with painful bilateral metal-on-metal Birmingham hip replacements secondary to metal ion induced synovitis and osteolysis causing micromovement of the components and subsequent bone pain.
A plan was made to revise both of her hip resurfacings in order to treat the pain and prevent further implant loosening and rising metal ion levels. We planned to use bone graft for this procedure to improve the area of contact with the new acetabular cup and the native acetabulum.
We revised her right sided hip resurfacing first (as this was causing her more pain and discomfort). We used an allograft bone graft to fill the extensive bone defect. A porous metal cup was used and secure with two iliac screws.
Four months later Stephanie underwent a second revision to replace her left hip resurfacing. On the left hand side there was a good amount of acetabular bone stock so bone allografting was not required.
Anteroposterior plain radiograph of the pelvis demonstrating the bilateral revision with acetabular bone graft on the right hand side.
Stephanie was able to return to all of her normal daily activities within 6-months of the revision surgery to the left hip. By 12-months after the second revision procedure, Stephanie was attending her local aquafit class 3 times week and using a cross-trainer and an exercise bike in the gym.
Metal on metal hips were introduced to solve the problem of polyethylene-induced osteolysis, however in some patients the osteolysis from MOM hips is severe within 10 years of the primary operation. Follow up with an anteroposterior plain radiograph at regular 3 yearly intervals after 5 years post operative will avoid uncontrolled osteolysis and allow straightforward revision surgery with good clinical outcome.
Evidence for this treatment
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