Inclusion Criteria:  Age greater than or equal to 18 years First monomicrobial osteoarticular infection of knee or hip prosthesis with staphylococcus sensitive to dalbavancin (determined by a minimum inhibitory concentration by microdilution of the strain in question for vancomycin less than or equal to 2mg/L) and rifampicin, treated surgically by debridement, antibiotics and implant retention with change of moving parts (acute infections) or change in 1 stage (chronic infections) Social security affiliation Signature of informed consent  Exclusion Criteria:  Hypersensitivity to glycopeptides or rifampin or to any of the excipients Porphyrias Probabilistic antibiotic treatment not administered within 24 hours of surgery Probabilistic antibiotic treatment that did not take into account the bacterium causing the infection in its spectrum Acute hematogenous infection (acute secondary) Use of background treatment incompatible with the inducing effect of rifampicin (see Summary of Product Characteristics for rifampicin) Contraindications to rifampin therapy: Moderate to severe impairment of liver function, patients with a history of hypersensitivity to other rifamycins, porphyria.  Hepatic cirrhosis  Use of ototoxic therapy, such as an aminoglycoside Renal function with glomerular filtration rate less than 30 ml/min as measured by MDRD (Modification of Diet in Renal Disease) Pregnant and breastfeeding women: at inclusion a blood pregnancy test will be performed for women of childbearing age. The results will be communicated to the patient by a physician of her choice. Women of childbearing age not using an effective method of contraception (pill, intrauterine device, vaginal ring, contraceptive skin patch, hormonal subcutaneous implant, surgical sterilization) Protected persons defined in the following articles of the public health code:  L. 1121-6: persons deprived of liberty by a judicial or administrative decision, persons hospitalized without consent and persons admitted to a health or social establishment for purposes other than research; L. 1121-8: adults subject to a legal protection measure or unable to express their consent; L. 1122-1-2: persons in emergency situations who are unable to give prior consent.