An interventional study of Antibiotic dosage practice in Osteoarthritis, Hip, Total Hip Arthroplasty and Prosthetic-joint Infection, sponsored by Soren Overgaard. Completed at 36 sites in Denmark. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by Soren Overgaard · Not applicable, Interventional, and Prevention
Aim: To compare the effect of one single dose versus multiple doses of prophylactic antibiotics administered within 24 hours, on the development of PJI in patients with osteoarthritis undergoing primary THA.
The study is designed as a cross-over, cluster randomized, non-inferiority trial. All Danish orthopedic surgery departments performing primary THA with the majority being within inclusion criteria will be involved: Based on national quality databases, two-year cohorts of approximately 20,000 primary THAs conducted at all public and private orthopedic departments in Denmark, this includes 36 sites corresponding to a total of 39 departments.
The outcome measures will be extracted from the following national databases: The Civil Registration System (CRS), The Danish Hip Arthroplasty Register (DHR), The Danish National Patient Registry (DNRP), The Hospital Acquired Infections Database (HAIBA), The Danish National Prescription Database (NPR), Statistics Denmark and Danish Agency for Labour Market and Recruitment registry (STAR).
Details regarding the Arms and Interventions:
The preoperative dose of antibiotic must be administered prior to surgical incision and in cases of delay with regards to planned surgical incision:
Dicloxacillin/Cloxacillin: If the preoperative antibiotic dose is administered >60 minutes prior to surgical incision, the initial dose must be repeated.
Cefuroxime: If the preoperative antibiotic dose is administered >90 minutes prior to surgical incision, the initial dose must be repeated.
Treatment A, Single-dose practice:
For patients ≥ 120 kg:
One preoperative single dose of either Dicloxacillin/Cloxacillin 3g OR Cefuroxime 3g administered intravenously prior to surgical incision.
In cases of cephalosporin allergy or general beta lactam allergy one preoperative single dose of Clindamycin 900mg may be administered intravenously, prior to surgical incision, regardless of weight.
Treatment B, Multiple-dose practice:
For patients ≥ 120 kg:
One preoperative single dose of either Dicloxacillin/Cloxacillin 3g OR Cefuroxime 3g administered intravenously prior to surgical incision, followed by 3 postoperative doses of Dicloxacillin/Cloxacillin 2g x 3 OR Cefuroxime 1.5g x 3, administered within 24 hours after the preoperative dose.
After the first postoperative dose, the remaining doses may be administered perorally for pragmatic reasons. Administration of peroral doses as followed regardless of weight:
Dicloxacillin p.o. 1g, 12 and 18 hours postoperatively. OR Amoxicillin and clavulanic acid p.o. 875mg/125*mg, 12 and 18 hours postoperatively.
*If the center or region does not have access to amoxicillin and clavulanic acid 875/125mg a dose of 1g / 125mg (this means amoxicillin 500mg + amoxicillin and clavulanic acid 500mg/125 mg) may be administered.
In cases of cephalosporin allergy or general beta lactam allergy one preoperative single dose of Clindamycin 900mg may be administered intravenously, prior to surgical incision, regardless of weight, followed by 2 postoperative doses corresponding to:
For patients \<120kg: 300mg, 8 and 16 hours postoperatively. For patients ≥ 120kg: 600mg, 8 and 16 hours postoperatively. The same doses apply in cases of transmission to peroral antibiotics.
Implementation: The senior biostatistician is responsible for the randomization process of the centers. Each center will be allocated a code by the senior biostatistician responsible and reported to a central database. The randomization and allocation procedure will be known for the given year conditioning the given center.
Ethics and Dissemination: This trial has been approved by the Regional Ethical Committee (VEK) (21069108) and The Danish Medicines Agency (2021091723) without imposing an obligation to notify.
628 studies on the registry are indexed under Osteoarthritis, Hip; 121 are open to participants now.
This study's enrollment of 20,000 is above the median of 90 across 450 interventional studies indexed under Osteoarthritis, Hip.
Browse Osteoarthritis, Hip studies →Soren Overgaard is the lead sponsor of 3 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
1. All patients receiving a primary Total Hip Arthroplasty (THA) due to primary and secondary causes of osteoarthritis
Exclusion Criteria:
One preoperative single dose of either Dicloxacillin/Cloxacillin 2g OR Cefuroxime 1.5g administered intravenously prior to surgical incision. As the study is a non-inferiority trial, we have chosen the Experimental design category.
Other: Antibiotic dosage practice
One preoperative dose of either Dicloxacillin/Cloxacillin 2g OR Cefuroxime 1.5g administered intravenously prior to surgical incision followed by 3 postoperative doses of Dicloxacillin/Cloxacillin 1g x 3 OR Cefuroxime 750mg x 3 within 24 hours after the preoperative dose.
Other: Antibiotic dosage practice
Patient inclusion starts day one, cross-over of departments from treatment A (single-dose) to B (multiple-dose) or vice versa after one year and end of inclusion happens after 2 years. All centers in Denmark use either Cloxacillin/Dicloxacillin, Cefuroxime or both drugs as standard prophylactic antibiotic practice for THA. In cases of cephalosporin allergy or general beta lactam allergy, the antibiotic clindamycin may be administered. In this trial, patients will be administered the standard prophylactic antibiotic practice of either single-dose (A) or multiple-doses (B) of antibiotics administered at each respective cluster that respective year. Both practices of dose administration for antibiotic prophylaxis (i.e. single- or multiple-dose) follow current standards of treatment and are based on present clinical practice guidelines.
Incidence of Prosthetic joint infections (PJI)
The definition of PJI is based on revision surgery. Revision surgery is defined as a new surgical intervention the first time after the primary intervention including debridement alone or in combination with complete or partial removal or exchange of the implant. 1. Two or more intraoperative deep-tissue samples of phenotypically indistinguishable bacteria isolated from at least 3 deep-tissue samples 2. One or more positive intraoperative samples from a closed fluid aspirate AND a biopsy (fluid AND tissue) of phenotypically indistinguishable bacteria isolated 3. A PJI when an indication of deep infection is reported to The Danish Hip Arthroplasty Registry (DHR) by the surgeon upon revision surgery
Time frame: Within 90 days from index surgery
Number of patients with one or more Serious Adverse Events (SAEs)
SAEs are defined according to the ICH-GCP guidelines. SAE refers to an event involving a significant risk of death or disability of the patient (or their offspring), including, but not limited to, an event that: * results in death * is life-threatening - in the investigator's opinion the patient was in immediate risk of death from the adverse event when it appeared * requires hospitalization or prolongs existing hospitalization * results in permanent or significant disability * is a congenital anomaly SAEs are recorded from The Danish National Patient Registry (DNPR)
Time frame: Within 90 days from index surgery
Incidence of Potential PJI referred to as PJI-likely
PJI-likely is defined as at least one of the two criteria: 1. One single intraoperatively obtained positive culture (aspiration fluid OR tissue biopsy) regardless of microorganism 2. One single positive culture obtained from aspiration of synovial fluid regardless of microorganism AND any antibiotic prescriptions (ATC category J01) redeemed
Time frame: Within 90 days from index surgery
Length of hospital stay (LOS)
LOS defined as number of postoperative overnight stays, including transferals to other departments and hospitals. Data on LOS is acquired from DNPR.
Time frame: Within 90 days from index surgery
Incidence of Major Adverse Cardiovascular Events (MACE)
A MACE is defined a priori to include thromboembolic complications including venous thromboembolism, myocardial infarction, atrial fibrillation and stroke based on the diagnostic ICD10 codes listed in Appendix B. VTE is defined a priori as both deep venous thromboembolisms confirmed by compression ultrasound and pulmonary embolism confirmed by spiral computed tomography (CT), ventilation-perfusion scintigraphy or pathological removal of an embolus and based on the following diagnostic ICD10 codes: I26, I80.1-I80.9, I82.1-I82.9, or T81.7B-D. Data will be extracted from DNPR.
Time frame: Within 90 days from index surgery
Hospital-treated infections (excluding Surgical Site infections)
Any Hospital-treated infection is defined as any first-time hospital admission with a primary or secondary infection diagnosis after discharge from index THA surgery. Hospital-treated infections are identified from DNPR. The list of infections includes chronic and more rare infections, to detect possible flare-up in any possible ongoing infections. The list will exclude urinary tract infections (UTI) due to a high risk of different registration praxis registration for UTI among hospitals in Denmark.
Time frame: Within 90 days from index surgery
Proportion of patients with at least one dispensing for antibiotic
Community-based antibiotic use (any community-treated infection or antibiotic use after discharge) is defined as at least one dispensing after discharge from index THA surgery within 90 days for narrow- and broad-spectrum antibiotics based on the Anatomical Therapeutic Chemical classification (ATC) codes. All antibiotics in Denmark require prescriptions from a physician. The Danish National Health Service Prescription Database has registered all reimbursed prescriptions from all community pharmacies since 2004. Medications are coded according to the following ATC codes: J01CE, J01CF, J01DB, J01DC, J01DD, J01DE, J01DH, J01DI, J01CR, J01CA, J01F. J01E, J01MA ,J01AA
Time frame: Within 90 days from index surgery
Opioid use
Prescriptions will be identified using NPR. The following ATC codes (including all subcodes) are included: N01AH (opioid anesthetics), N02A (opioids), N07BC02 (methadone), and R05DA04 (codeine). We defined opioid users as patients who redeemed two opioid prescriptions within six months prior to THA surgery. Conversely, patients who did not redeem two or more opioid prescriptions within this timeframe were classified as opioid naïve. For opioid naïve patients, opioid use post-THA is defined as the redemption of two opioid prescriptions within 90 days following surgery. We assert that two separate redeemed prescriptions confirm actual medication use. We will calculate the treatment dosage based on the number of packages and volume redeemed within 90 days post-surgery. To investigate dosages, all doses will be converted to morphine milligram equivalents using a conversion factor specific to the type of opioid.
Time frame: Within 90 days from index surgery
Use of acetaminophen or non-steroidal anti-inflammatory drugs
Patients who received at least one prescription for acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) following THA surgery. Prescriptions of analgesics will be identified using NPR (41). All analgesics in Denmark except 10-tablet packages of acetaminophen / ibuprofen of dose 200mg ibuprofen require prescriptions from a physician. Following ATC codes (including all subcodes) are included M01A (NSAIDs) and N02BE01 (paracetamol). Duration of treatment will be calculated based on number of packages and volume. Since there is no clear definition of acetaminophen or non-steroidal anti-inflammatory users, we define these users as patients who redeemed two prescriptions within 6 months before THA.
Time frame: Within 90 days from index surgery
Any revision after THA
Revision surgery is defined as a new surgical intervention the first time after the primary intervention including debridement alone or in combination with complete or partial removal or exchange of any implants. Rate of revision is defined as revision due to any cause within 90 days from primary THA surgery. Any revision will be recorded from DHR and DNPR.
Time frame: Within 90 days from index surgery
Incremental cost-effectiveness
The incremental cost-effectiveness will be calculated based on the costs per patient in the two antibiotic practices. Costs related to antibiotic prophylaxis, hospital admissions and readmissions, hospital outpatient visits, visits to General practitioner and costs related to sick leave from work will be included. Data will be collected from: * The Danish National Patient Registry (DNPR) * The Civil Registration System (CRS) * The Danish Agency for Labor Market and Recruitment registry STAR
Time frame: Within 90 days from index surgery
Rate of revision after THA
Revision surgery is defined as a new surgical intervention the first time after the primary intervention including debridement alone or in combination with complete or partial removal or exchange of the implant. The rate of revision is recorded from The Danish Hip Arthroplasty Registry (DHR) and The Danish National Patient Registry (DNRP). Revision due to any cause including PJI and aseptic loosening will be included.
Time frame: Within 1 year from index surgery
Mortality rate after index surgery
1-year mortality rate is defined by date of death due to any cause after index surgery. Data is collected from The Civil Registration System (CRS).
Time frame: Within 1 year from index surgery
Incidence of Superficial incisional Surgical Site Infection
To be defined
Time frame: Within 90 days from index surgery
Documents are hosted by the registry — open the source record to download them.
Plan to share: Yes — Access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), will be provided to anyone who wishes to access the data.
Supporting information: Study protocol, Sap
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Soren Overgaard