The Story

“Susan, like many post-menopausal women, had osteoporosis, leading to a hip fracture that required a primary total hip replacement.

By the time she was referred to my clinic she’d already had three operations. The stem from the first operation (a short stem) was loose and infected, while the second stem suffered a periprosthetic fracture that a follow-up operation failed to fix.

Susan was miserable and bedbound. She was in a lot of pain and understandably frustrated. I knew I could help Susan. What I didn’t yet know was that it would take another three operations to do so.”


The Investigation

Susan was 68 years old when she presented with a painful, revised right total hip replacement. She was unable to walk, the wound was healed and all movements of the right hip were painful.

The plain film radiographs suggested loosening of the femoral stem. Susan’s blood inflammatory markers were normal.

The hip aspiration was performed two weeks after stopping antibiotics, which is a standard recommendation by microbiologists. This is due to a high suspicion of infection as a result of Susan’s three previous operations. The aspiration was negative for infection after extended cultures.


The Evidence

 

Anteroposterior plain radiograph showing an uncemented total hip replacement with cerclage wiring. There is a non-union of a periprosthetic fracture. A zone of lucency can be seen surrounding the femoral stem suggesting a loosening.

 

The Diagnosis

Susan had a loose right femoral stem, without evidence of infection.


The Plan

Since the infection test results came back negative, we could go ahead with revision of the stem only, retaining the well-fixed, well-sized, and well-positioned cup. Most surgeons send five separate specimens for microbiological testing from all revision hip operations, to know for sure whether or not there is any infection present. We did the same for Susan.


The Operation

We used a posterior approach to the hip. We removed the stem, retained the cup and used a modular, taper fluted stem to obtain fixation of at least two cortical diameters in length in the diaphysis of the femur.


The Outcome

 

Anteroposterior and lateral plain radiographs taken after single-stage revision, showing the new femoral stem. All of the cerclage wiring has been removed. Susan was able to walk the day after the operation.

 

Further Evidence and making a new plan

Unfortunately, all five samples taken at the time of the single-stage revision came back as positive for Staphylococcus epidermidis (rifampicin resistant). Our microbiology team confirmed that this could not be treated with antibiotics alone and that we would need to carry out a further two-stage revision.

Obviously, this was difficult news to break to Susan. It was the first time she was able to walk in three months – and now she needed a further two operations.

Our new plan was the only way to ensure a good outcome. The inadequately treated infection of a revised right total hip arthroplasty required a further two-stage revision.


The Second Operation

We undertook the first stage two weeks after the initial revision procedure. We were able to use the old incision and samples were once again sent for microbiology. Both components were firmly fixed, but the stem was more easily removed at this stage than if we had delayed re-revision.

We used a spacer with antibiotic impregnated cement, containing vancomycin and gentamicin.

After the first stage, the samples taken between operations again grew rifampicin resistant Staphylococcus epidermidis. Susan was treated with a six-week course of daptomycin, causing her CRP to fall to 20mg/L.


The Second outcome

 

Anteroposterior and lateral plain radiographs taken after the first stage of the two-stage revision process for infection. It shows the long c-stem cemented spacer.

 

The Third Operation

We carried out the second-stage operation, about eight weeks after the first stage was done. Once again, we took five samples to send for microbiological testing. We implanted a modular-taper fluted stem with a titanium cup.

Post-operatively Susan received strong systemic antibiotics – vancomycin, tazocin and amikacin.


The Third Outcome

Anteroposterior and lateral plain radiographs taken at three months after the second-stage operation, showing a fracture of the right acetabulum.

Anteroposterior and lateral plain radiographs taken 15 months after the second-stage operation shows a good implant position and ossification of the periprosthetic acetabular fracture.

Samples taken during the second stage of her procedure didn’t grow anything and her CRP reduced down to 7mg/L at one month post-op.

Susan returned to the clinic 15 months later and had good function of her right hip.


The Verdict

“Susan’s case was unusual, requiring three operations in three months. Had everything been straightforward, we’d have only needed to perform one operation to replace the loose short stem with a longer, more stable one.

As it turned out, it wasn’t that simple. The initial microbiological testing gave a negative result – but it was a false negative. There was an infection and this particular type required two more procedures to get rid of it completely.

Although the unplanned nature of such operations can be tough for all involved, by preparing for the unexpected, you can ensure the best possible outcome in the end.”