ABOGRAFT: Antibiotic impregnated bone graft to reduce infections after hip replacement

In Sweden close to one in 12 people will have one or both of their hips partly replaced with a prosthesis. Undergoing a prosthetic hip replacement is considered the most successful treatment modern healthcare can offer to regain quality of life. However, the major cause for concern associated with the procedure is prosthetic joint infection (PJI). The number of hip replacement is projected to increase dramatically. Unfortunately, this means that more and more people will be at risk for PJI. As the effects of a prosthetic joint infection are serious and can be life threatening, efforts to reduce this risk are urgent.

The introduction of local antibiotics blended into bone cement has led to a 50% reduction in postoperative infection in primary hip replacement. Unfortunately, antibiotic impregnated bone cement cannot always be used and is not a very effective carrier for antibiotics.
Morselized bone allograft has been used as a carrier for local antibiotic treatment in multiple pilot studies and appears to be an attractive and effective treatment alternative. To date, a randomized clinical trial to support its use is lacking.

The aim of this pragmatic randomized controlled double blinded drug trial is to investigate whether antibiotic impregnated bone graft can decrease the risk of infection after hip replacement surgery.

Patients over the age of 18 who are undergoing a hip arthroplasty requiring bone graft. Patient currently having a joint infection are excluded.

To account for both gram-positive and gram-negative organisms and to ensure no loose particles get airborne causing allergic reactions in the respiratory tract we dissolve 1 gram of vancomycin powder with 8 ml tobramycin. We add this liquid mixture to the morselized bone allograft. The placebo group will in turn receive 8 ml NaCl (0.9%) added to the bone graft.

Each participating patient receives care as usual, and no additional visits are required. Prior to surgery the patient is screened for inclusion, informed, and signs an informed consent (more information can be found here: ‘for the patient’). During surgery the patient will be randomized to either the treatment or the placebo group. Neither the patients nor the treatment team knows to which group the patient has been assigned. Adverse events are monitored at the day of the operation, at discharge and during the wound control visit.

Primary: Reoperation due to infection. The diagnosis of a prosthetic joint infection with bacteria that are sensitive to either vancomycin or tobramycin in the same hip joint and within two years after the hip arthroplasty procedure is required to fulfill the outcome.

Secondary:

• Time and cause for reoperation for any reason within 2 and 5 years
• Time and cause for implant revision due to any reason within 2 and 5 years
• Type of microbe and antibiotic resistance pattern for cases complicated with postoperative infection

 

Safety outcomes:

• Differences between the two experimental groups regarding the frequencies of adverse events
• Differences between the two experimental groups regarding the rates of revision due to aseptic loosening
  

Adverse events are monitored and registered at the day of the surgery, at discharge and during the wound control visit. Follow-up data at 2 and 5 years after surgery will be collected from the Swedish Joint Replacement Register or country equivalent. Data is validated using medical chart review performed at each individual participating treatment site.

Read more about the people involved in this study under ‘The ABOGRAFT consortium’.

 

 

The study is registered at

• EU Clinical Trial number: 2024-510921-25-00
• ClinicalTrials.gov: ClinicalTrials.gov

 

Approval for this study was obtained by

• Swedish medical ethical committee (Etikprovningsmyndigheten): 2021-02690
• Swedish Drug Agency (Läkemedelsverket): Dnr. 5.1-2021-40666.

You can find a flyer with the study information here.