infizierte Hüftprothesen

Prosthetic hip infections are one of the most severe complications of total hip arthroplasties.

Epidemiology

Prosthetic hip infections complicate around 0.57% of total hip arthroplasties .

Risk factors

Risk factors for prosthetic hip infections can be separated into pre-operative and post-operative risk factors.

Pre-operative risk factors may include:

  • existing underlying infection
  • previous local surgery

Post-operative risk factors may include:

Clinical presentation

  • pain at the site of the arthroplasty
  • stiffness of the prosthetic joint
  • swelling around the site
  • overlying skin redness
  • tenderness

Pathology

The main methods by which a prosthetic joint can become infected are:

  • directly during implantation
  • haematogenous spread
  • reactivation of a latent infection

The most common causative micro-organisms are Gram-positive bacteria, including Staphylococcus aureus, Staphylococcus epidermidis and coagulase-negative Staphylococcus. Infections may also be caused by fungi such as Candida .

Radiographic features

Plain radiograph

Plain radiographs are the main imaging method utilized in diagnosis of prosthetic joint infections. Signs that may be seen include:

  • periosteal reaction
  • wide band of radiolucency at the cement-bone or metal-bone interface
  • patchy osteolysis
  • implant loosening
  • bone resorption around the implant
  • transcortical sinus tracts
CT

CT is useful in helping to distinguish between septic and aseptic loosening of the joint .

Nuclear medicine
Bone scintigraphy (Tc-99m)

Bone scintigraphy is a highly sensitive method for diagnosing prosthetic joint infections, but it is not very specific, as increased periprosthetic bone activity can be due to a variety of causes .

PET

The use of PET in prosthetic joint infections is a relatively novel application. FDG-PET is thought to be highly sensitive and specific for diagnosis infection in hip prostheses, and may aid pre-operative planning .

Treatment and prognosis

Orthopedic surgery is indicated in most cases, unless the patient is not fit for surgery. Surgical options include:

  • polyethylene exchange with component retention and intravenous antibiotic therapy
  • one-stage replacement arthroplasty
  • two-stage replacement arthroplasty
  • resection arthroplasty 

In very severe cases, amputation may be necessary.

See also

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