We report a case of periprosthetic joint infection (PJI) caused by Propionibacterium granulosum less than one year after primary total hip arthroplasty performed through the modified Hueter direct anterior approach. A related species, Propionibacterium acnes , has notoriety as a cause of periprosthetic shoulder infection but is seldom a source of lower-extremity PJI1,2. Because of the similarities in bacterial skin flora between the groin and the axilla, there may be an association between the direct anterior approach and Propionibacterium - species infection. The patient was informed that data concerning her case would be submitted for publication, and she provided consent. A seventy-year-old woman with a body mass index of 36.1 kg/m2 and type-2 diabetes mellitus presented to our clinic with a painful right hip in August 2010. She had undergone a primary cementless total hip arthroplasty through a direct anterior approach at an outside institution in July 2009. After the index procedure, she had progressed well until about three months postoperatively, at which time she noted the insidious onset of pain in the proximal part of the right thigh with weight-bearing and hip movement. A cortisone injection for presumed greater trochanteric bursitis provided no relief. The symptoms continued for several months. A subsequent workup revealed an elevated C-reactive protein (CRP) level, and a loose femoral stem suggestive of failure of bone ingrowth was seen on radiographs. An attempted hip aspiration resulted in an insufficient quantity of aspirate for a cell count, although cultures were negative. She subsequently underwent revision arthroplasty due to a loose femoral component in May 2010. The diagnosis of a loose implant was confirmed intraoperatively, and the femoral stem was revised to a cemented implant by the original surgeon through the same surgical approach. All intraoperative cultures were negative. There were no …