Each year, around 1500 infected Total Hip Arthroplasties (THA) need non-conservative surgery, remaining an issue for patients and healthcare units. The recommended treatment, relying on cohort reviews and international consensus follows a two-stage protocol. This protocol implies a first surgery to remove all infected implants and at least 6 weeks of antibiotic treatment without implant, then usually an antibiotic-free period and only then a second surgery to put back new implants and start the rehabilitation protocol, with usually more than a week of a second hospital stay. Between both surgeries, full-weight bearing is prohibited and joint stiffness and/or pain are rather usual complications. Failure rate is estimated at 10% in this two-stage strategy. The single-stage procedure (i.e. implanting back a new prosthesis during the same surgery after implant removal, synovectomy and lavage) is thought to be less susceptible to late functional complications (i.e. pain, stiffness and muscle deficiency) with a shorter, single hospital stay.

Although, with single-stage surgery, infection control could be less efficient because most pathogens produce during the first hours of infection an antibiotic-resistant layer called biofilm, allowing them to colonize and adhere to foreign objects like implants. This single-surgery protocol thus highly relies on antibiotics and has a list of contra-indications (based on experts' consensus): the presence of damaged soft tissues or a sinus tract, unknown pathogens, difficult to treat micro-organisms, severe immunosuppression and for many surgeons, each time a bone graft is necessary. Most of these contra-indications are directly related to the biofilm.

As no randomized control trial has ever compared single-stage versus two-stage surgery, the level of evidence for recommending one procedure over the other is low.

We conducted a survey that showed that most of the French reference centers have already switched to single stage surgery for single-stage non contra-indicated cases.

An antibiotic-loaded hydrogel coating (Defensive Antiadhesive Coating®, Novagenit SRL), has been proven to mechanically prevent the biofilm formation, while allowing a prolonged intraarticular antibiotic release, in a randomized controlled trial in primary prevention of infection in THA.

The addition of this biofilm inhibitor to a single-stage surgery might stand as a promising strategy for secondary prevention of peri-prosthetic hip joint infection. Moreover, using this device to prevent biofilm formation could expand one stage surgery to patients that are "normally" contra-indicated to one stage surgery.

Inclusion Criteria:

• Social security affiliation

• Signed informed consent

• Chronic periprosthetic hip joint infection defined according to the Musculoskeletal Infection Society criteria :

• Two positive periprosthetic cultures with phenotypically identical organisms

• or a sinus tract communicating with the joint,

• or having 3 of 5 minor criteria:

  • Elevated serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR);
  • Elevated synovial fluid White Blood Cell (WBC) count or change of ++ on leukocyte esterase test strip;
  • Elevated synovial fluid Polymorphonuclear Neutrophil Percentage (PMN%);
  • Positive histological analysis of periprosthetic tissue;
  • A single positive culture.

Exclusion Criteria:

• Patients with hypersensitivity to hydrogel components (hyaluronic acid and/or poly-lactic acid) known of Defensive Antibacterial Coating (DAC)®
• Pregnancy or positive pregnancy test (performed in women of childbearing age before inclusion)
• Life expectancy < 3 months
• Expected use of a cemented implant by the surgical team (for the treatment surgical protocol)
• Unable to give informed consent
• Patients under guardianship or curators
• Refusal to participate